Bug Summary

File:clang/lib/CodeGen/CGException.cpp
Warning:line 1298, column 36
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name CGException.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/CodeGen -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/CodeGen -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/CodeGen -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include -D NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/CodeGen -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-09-04-040900-46481-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/CodeGen/CGException.cpp

/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/CodeGen/CGException.cpp

1//===--- CGException.cpp - Emit LLVM Code for C++ exceptions ----*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This contains code dealing with C++ exception related code generation.
10//
11//===----------------------------------------------------------------------===//
12
13#include "CGCXXABI.h"
14#include "CGCleanup.h"
15#include "CGObjCRuntime.h"
16#include "CodeGenFunction.h"
17#include "ConstantEmitter.h"
18#include "TargetInfo.h"
19#include "clang/AST/Mangle.h"
20#include "clang/AST/StmtCXX.h"
21#include "clang/AST/StmtObjC.h"
22#include "clang/AST/StmtVisitor.h"
23#include "clang/Basic/DiagnosticSema.h"
24#include "clang/Basic/TargetBuiltins.h"
25#include "llvm/IR/IntrinsicInst.h"
26#include "llvm/IR/Intrinsics.h"
27#include "llvm/IR/IntrinsicsWebAssembly.h"
28#include "llvm/Support/SaveAndRestore.h"
29
30using namespace clang;
31using namespace CodeGen;
32
33static llvm::FunctionCallee getFreeExceptionFn(CodeGenModule &CGM) {
34 // void __cxa_free_exception(void *thrown_exception);
35
36 llvm::FunctionType *FTy =
37 llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
38
39 return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
40}
41
42static llvm::FunctionCallee getSehTryBeginFn(CodeGenModule &CGM) {
43 llvm::FunctionType *FTy =
44 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
45 return CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.begin");
46}
47
48static llvm::FunctionCallee getSehTryEndFn(CodeGenModule &CGM) {
49 llvm::FunctionType *FTy =
50 llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
51 return CGM.CreateRuntimeFunction(FTy, "llvm.seh.try.end");
52}
53
54static llvm::FunctionCallee getUnexpectedFn(CodeGenModule &CGM) {
55 // void __cxa_call_unexpected(void *thrown_exception);
56
57 llvm::FunctionType *FTy =
58 llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
59
60 return CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
61}
62
63llvm::FunctionCallee CodeGenModule::getTerminateFn() {
64 // void __terminate();
65
66 llvm::FunctionType *FTy =
67 llvm::FunctionType::get(VoidTy, /*isVarArg=*/false);
68
69 StringRef name;
70
71 // In C++, use std::terminate().
72 if (getLangOpts().CPlusPlus &&
73 getTarget().getCXXABI().isItaniumFamily()) {
74 name = "_ZSt9terminatev";
75 } else if (getLangOpts().CPlusPlus &&
76 getTarget().getCXXABI().isMicrosoft()) {
77 if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015))
78 name = "__std_terminate";
79 else
80 name = "?terminate@@YAXXZ";
81 } else if (getLangOpts().ObjC &&
82 getLangOpts().ObjCRuntime.hasTerminate())
83 name = "objc_terminate";
84 else
85 name = "abort";
86 return CreateRuntimeFunction(FTy, name);
87}
88
89static llvm::FunctionCallee getCatchallRethrowFn(CodeGenModule &CGM,
90 StringRef Name) {
91 llvm::FunctionType *FTy =
92 llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
93
94 return CGM.CreateRuntimeFunction(FTy, Name);
95}
96
97const EHPersonality EHPersonality::GNU_C = { "__gcc_personality_v0", nullptr };
98const EHPersonality
99EHPersonality::GNU_C_SJLJ = { "__gcc_personality_sj0", nullptr };
100const EHPersonality
101EHPersonality::GNU_C_SEH = { "__gcc_personality_seh0", nullptr };
102const EHPersonality
103EHPersonality::NeXT_ObjC = { "__objc_personality_v0", nullptr };
104const EHPersonality
105EHPersonality::GNU_CPlusPlus = { "__gxx_personality_v0", nullptr };
106const EHPersonality
107EHPersonality::GNU_CPlusPlus_SJLJ = { "__gxx_personality_sj0", nullptr };
108const EHPersonality
109EHPersonality::GNU_CPlusPlus_SEH = { "__gxx_personality_seh0", nullptr };
110const EHPersonality
111EHPersonality::GNU_ObjC = {"__gnu_objc_personality_v0", "objc_exception_throw"};
112const EHPersonality
113EHPersonality::GNU_ObjC_SJLJ = {"__gnu_objc_personality_sj0", "objc_exception_throw"};
114const EHPersonality
115EHPersonality::GNU_ObjC_SEH = {"__gnu_objc_personality_seh0", "objc_exception_throw"};
116const EHPersonality
117EHPersonality::GNU_ObjCXX = { "__gnustep_objcxx_personality_v0", nullptr };
118const EHPersonality
119EHPersonality::GNUstep_ObjC = { "__gnustep_objc_personality_v0", nullptr };
120const EHPersonality
121EHPersonality::MSVC_except_handler = { "_except_handler3", nullptr };
122const EHPersonality
123EHPersonality::MSVC_C_specific_handler = { "__C_specific_handler", nullptr };
124const EHPersonality
125EHPersonality::MSVC_CxxFrameHandler3 = { "__CxxFrameHandler3", nullptr };
126const EHPersonality
127EHPersonality::GNU_Wasm_CPlusPlus = { "__gxx_wasm_personality_v0", nullptr };
128const EHPersonality EHPersonality::XL_CPlusPlus = {"__xlcxx_personality_v1",
129 nullptr};
130
131static const EHPersonality &getCPersonality(const TargetInfo &Target,
132 const LangOptions &L) {
133 const llvm::Triple &T = Target.getTriple();
134 if (T.isWindowsMSVCEnvironment())
135 return EHPersonality::MSVC_CxxFrameHandler3;
136 if (L.hasSjLjExceptions())
137 return EHPersonality::GNU_C_SJLJ;
138 if (L.hasDWARFExceptions())
139 return EHPersonality::GNU_C;
140 if (L.hasSEHExceptions())
141 return EHPersonality::GNU_C_SEH;
142 return EHPersonality::GNU_C;
143}
144
145static const EHPersonality &getObjCPersonality(const TargetInfo &Target,
146 const LangOptions &L) {
147 const llvm::Triple &T = Target.getTriple();
148 if (T.isWindowsMSVCEnvironment())
149 return EHPersonality::MSVC_CxxFrameHandler3;
150
151 switch (L.ObjCRuntime.getKind()) {
152 case ObjCRuntime::FragileMacOSX:
153 return getCPersonality(Target, L);
154 case ObjCRuntime::MacOSX:
155 case ObjCRuntime::iOS:
156 case ObjCRuntime::WatchOS:
157 return EHPersonality::NeXT_ObjC;
158 case ObjCRuntime::GNUstep:
159 if (L.ObjCRuntime.getVersion() >= VersionTuple(1, 7))
160 return EHPersonality::GNUstep_ObjC;
161 LLVM_FALLTHROUGH[[gnu::fallthrough]];
162 case ObjCRuntime::GCC:
163 case ObjCRuntime::ObjFW:
164 if (L.hasSjLjExceptions())
165 return EHPersonality::GNU_ObjC_SJLJ;
166 if (L.hasSEHExceptions())
167 return EHPersonality::GNU_ObjC_SEH;
168 return EHPersonality::GNU_ObjC;
169 }
170 llvm_unreachable("bad runtime kind")__builtin_unreachable();
171}
172
173static const EHPersonality &getCXXPersonality(const TargetInfo &Target,
174 const LangOptions &L) {
175 const llvm::Triple &T = Target.getTriple();
176 if (T.isWindowsMSVCEnvironment())
177 return EHPersonality::MSVC_CxxFrameHandler3;
178 if (T.isOSAIX())
179 return EHPersonality::XL_CPlusPlus;
180 if (L.hasSjLjExceptions())
181 return EHPersonality::GNU_CPlusPlus_SJLJ;
182 if (L.hasDWARFExceptions())
183 return EHPersonality::GNU_CPlusPlus;
184 if (L.hasSEHExceptions())
185 return EHPersonality::GNU_CPlusPlus_SEH;
186 if (L.hasWasmExceptions())
187 return EHPersonality::GNU_Wasm_CPlusPlus;
188 return EHPersonality::GNU_CPlusPlus;
189}
190
191/// Determines the personality function to use when both C++
192/// and Objective-C exceptions are being caught.
193static const EHPersonality &getObjCXXPersonality(const TargetInfo &Target,
194 const LangOptions &L) {
195 if (Target.getTriple().isWindowsMSVCEnvironment())
196 return EHPersonality::MSVC_CxxFrameHandler3;
197
198 switch (L.ObjCRuntime.getKind()) {
199 // In the fragile ABI, just use C++ exception handling and hope
200 // they're not doing crazy exception mixing.
201 case ObjCRuntime::FragileMacOSX:
202 return getCXXPersonality(Target, L);
203
204 // The ObjC personality defers to the C++ personality for non-ObjC
205 // handlers. Unlike the C++ case, we use the same personality
206 // function on targets using (backend-driven) SJLJ EH.
207 case ObjCRuntime::MacOSX:
208 case ObjCRuntime::iOS:
209 case ObjCRuntime::WatchOS:
210 return getObjCPersonality(Target, L);
211
212 case ObjCRuntime::GNUstep:
213 return EHPersonality::GNU_ObjCXX;
214
215 // The GCC runtime's personality function inherently doesn't support
216 // mixed EH. Use the ObjC personality just to avoid returning null.
217 case ObjCRuntime::GCC:
218 case ObjCRuntime::ObjFW:
219 return getObjCPersonality(Target, L);
220 }
221 llvm_unreachable("bad runtime kind")__builtin_unreachable();
222}
223
224static const EHPersonality &getSEHPersonalityMSVC(const llvm::Triple &T) {
225 if (T.getArch() == llvm::Triple::x86)
226 return EHPersonality::MSVC_except_handler;
227 return EHPersonality::MSVC_C_specific_handler;
228}
229
230const EHPersonality &EHPersonality::get(CodeGenModule &CGM,
231 const FunctionDecl *FD) {
232 const llvm::Triple &T = CGM.getTarget().getTriple();
233 const LangOptions &L = CGM.getLangOpts();
234 const TargetInfo &Target = CGM.getTarget();
235
236 // Functions using SEH get an SEH personality.
237 if (FD && FD->usesSEHTry())
238 return getSEHPersonalityMSVC(T);
239
240 if (L.ObjC)
241 return L.CPlusPlus ? getObjCXXPersonality(Target, L)
242 : getObjCPersonality(Target, L);
243 return L.CPlusPlus ? getCXXPersonality(Target, L)
244 : getCPersonality(Target, L);
245}
246
247const EHPersonality &EHPersonality::get(CodeGenFunction &CGF) {
248 const auto *FD = CGF.CurCodeDecl;
249 // For outlined finallys and filters, use the SEH personality in case they
250 // contain more SEH. This mostly only affects finallys. Filters could
251 // hypothetically use gnu statement expressions to sneak in nested SEH.
252 FD = FD ? FD : CGF.CurSEHParent;
253 return get(CGF.CGM, dyn_cast_or_null<FunctionDecl>(FD));
254}
255
256static llvm::FunctionCallee getPersonalityFn(CodeGenModule &CGM,
257 const EHPersonality &Personality) {
258 return CGM.CreateRuntimeFunction(llvm::FunctionType::get(CGM.Int32Ty, true),
259 Personality.PersonalityFn,
260 llvm::AttributeList(), /*Local=*/true);
261}
262
263static llvm::Constant *getOpaquePersonalityFn(CodeGenModule &CGM,
264 const EHPersonality &Personality) {
265 llvm::FunctionCallee Fn = getPersonalityFn(CGM, Personality);
266 llvm::PointerType* Int8PtrTy = llvm::PointerType::get(
267 llvm::Type::getInt8Ty(CGM.getLLVMContext()),
268 CGM.getDataLayout().getProgramAddressSpace());
269
270 return llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(Fn.getCallee()),
271 Int8PtrTy);
272}
273
274/// Check whether a landingpad instruction only uses C++ features.
275static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI) {
276 for (unsigned I = 0, E = LPI->getNumClauses(); I != E; ++I) {
277 // Look for something that would've been returned by the ObjC
278 // runtime's GetEHType() method.
279 llvm::Value *Val = LPI->getClause(I)->stripPointerCasts();
280 if (LPI->isCatch(I)) {
281 // Check if the catch value has the ObjC prefix.
282 if (llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Val))
283 // ObjC EH selector entries are always global variables with
284 // names starting like this.
285 if (GV->getName().startswith("OBJC_EHTYPE"))
286 return false;
287 } else {
288 // Check if any of the filter values have the ObjC prefix.
289 llvm::Constant *CVal = cast<llvm::Constant>(Val);
290 for (llvm::User::op_iterator
291 II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) {
292 if (llvm::GlobalVariable *GV =
293 cast<llvm::GlobalVariable>((*II)->stripPointerCasts()))
294 // ObjC EH selector entries are always global variables with
295 // names starting like this.
296 if (GV->getName().startswith("OBJC_EHTYPE"))
297 return false;
298 }
299 }
300 }
301 return true;
302}
303
304/// Check whether a personality function could reasonably be swapped
305/// for a C++ personality function.
306static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn) {
307 for (llvm::User *U : Fn->users()) {
308 // Conditionally white-list bitcasts.
309 if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(U)) {
310 if (CE->getOpcode() != llvm::Instruction::BitCast) return false;
311 if (!PersonalityHasOnlyCXXUses(CE))
312 return false;
313 continue;
314 }
315
316 // Otherwise it must be a function.
317 llvm::Function *F = dyn_cast<llvm::Function>(U);
318 if (!F) return false;
319
320 for (auto BB = F->begin(), E = F->end(); BB != E; ++BB) {
321 if (BB->isLandingPad())
322 if (!LandingPadHasOnlyCXXUses(BB->getLandingPadInst()))
323 return false;
324 }
325 }
326
327 return true;
328}
329
330/// Try to use the C++ personality function in ObjC++. Not doing this
331/// can cause some incompatibilities with gcc, which is more
332/// aggressive about only using the ObjC++ personality in a function
333/// when it really needs it.
334void CodeGenModule::SimplifyPersonality() {
335 // If we're not in ObjC++ -fexceptions, there's nothing to do.
336 if (!LangOpts.CPlusPlus || !LangOpts.ObjC || !LangOpts.Exceptions)
337 return;
338
339 // Both the problem this endeavors to fix and the way the logic
340 // above works is specific to the NeXT runtime.
341 if (!LangOpts.ObjCRuntime.isNeXTFamily())
342 return;
343
344 const EHPersonality &ObjCXX = EHPersonality::get(*this, /*FD=*/nullptr);
345 const EHPersonality &CXX = getCXXPersonality(getTarget(), LangOpts);
346 if (&ObjCXX == &CXX)
347 return;
348
349 assert(std::strcmp(ObjCXX.PersonalityFn, CXX.PersonalityFn) != 0 &&(static_cast<void> (0))
350 "Different EHPersonalities using the same personality function.")(static_cast<void> (0));
351
352 llvm::Function *Fn = getModule().getFunction(ObjCXX.PersonalityFn);
353
354 // Nothing to do if it's unused.
355 if (!Fn || Fn->use_empty()) return;
356
357 // Can't do the optimization if it has non-C++ uses.
358 if (!PersonalityHasOnlyCXXUses(Fn)) return;
359
360 // Create the C++ personality function and kill off the old
361 // function.
362 llvm::FunctionCallee CXXFn = getPersonalityFn(*this, CXX);
363
364 // This can happen if the user is screwing with us.
365 if (Fn->getType() != CXXFn.getCallee()->getType())
366 return;
367
368 Fn->replaceAllUsesWith(CXXFn.getCallee());
369 Fn->eraseFromParent();
370}
371
372/// Returns the value to inject into a selector to indicate the
373/// presence of a catch-all.
374static llvm::Constant *getCatchAllValue(CodeGenFunction &CGF) {
375 // Possibly we should use @llvm.eh.catch.all.value here.
376 return llvm::ConstantPointerNull::get(CGF.Int8PtrTy);
377}
378
379namespace {
380 /// A cleanup to free the exception object if its initialization
381 /// throws.
382 struct FreeException final : EHScopeStack::Cleanup {
383 llvm::Value *exn;
384 FreeException(llvm::Value *exn) : exn(exn) {}
385 void Emit(CodeGenFunction &CGF, Flags flags) override {
386 CGF.EmitNounwindRuntimeCall(getFreeExceptionFn(CGF.CGM), exn);
387 }
388 };
389} // end anonymous namespace
390
391// Emits an exception expression into the given location. This
392// differs from EmitAnyExprToMem only in that, if a final copy-ctor
393// call is required, an exception within that copy ctor causes
394// std::terminate to be invoked.
395void CodeGenFunction::EmitAnyExprToExn(const Expr *e, Address addr) {
396 // Make sure the exception object is cleaned up if there's an
397 // exception during initialization.
398 pushFullExprCleanup<FreeException>(EHCleanup, addr.getPointer());
399 EHScopeStack::stable_iterator cleanup = EHStack.stable_begin();
400
401 // __cxa_allocate_exception returns a void*; we need to cast this
402 // to the appropriate type for the object.
403 llvm::Type *ty = ConvertTypeForMem(e->getType())->getPointerTo();
404 Address typedAddr = Builder.CreateBitCast(addr, ty);
405
406 // FIXME: this isn't quite right! If there's a final unelided call
407 // to a copy constructor, then according to [except.terminate]p1 we
408 // must call std::terminate() if that constructor throws, because
409 // technically that copy occurs after the exception expression is
410 // evaluated but before the exception is caught. But the best way
411 // to handle that is to teach EmitAggExpr to do the final copy
412 // differently if it can't be elided.
413 EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(),
414 /*IsInit*/ true);
415
416 // Deactivate the cleanup block.
417 DeactivateCleanupBlock(cleanup,
418 cast<llvm::Instruction>(typedAddr.getPointer()));
419}
420
421Address CodeGenFunction::getExceptionSlot() {
422 if (!ExceptionSlot)
423 ExceptionSlot = CreateTempAlloca(Int8PtrTy, "exn.slot");
424 return Address(ExceptionSlot, getPointerAlign());
425}
426
427Address CodeGenFunction::getEHSelectorSlot() {
428 if (!EHSelectorSlot)
429 EHSelectorSlot = CreateTempAlloca(Int32Ty, "ehselector.slot");
430 return Address(EHSelectorSlot, CharUnits::fromQuantity(4));
431}
432
433llvm::Value *CodeGenFunction::getExceptionFromSlot() {
434 return Builder.CreateLoad(getExceptionSlot(), "exn");
435}
436
437llvm::Value *CodeGenFunction::getSelectorFromSlot() {
438 return Builder.CreateLoad(getEHSelectorSlot(), "sel");
439}
440
441void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E,
442 bool KeepInsertionPoint) {
443 if (const Expr *SubExpr = E->getSubExpr()) {
444 QualType ThrowType = SubExpr->getType();
445 if (ThrowType->isObjCObjectPointerType()) {
446 const Stmt *ThrowStmt = E->getSubExpr();
447 const ObjCAtThrowStmt S(E->getExprLoc(), const_cast<Stmt *>(ThrowStmt));
448 CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
449 } else {
450 CGM.getCXXABI().emitThrow(*this, E);
451 }
452 } else {
453 CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
454 }
455
456 // throw is an expression, and the expression emitters expect us
457 // to leave ourselves at a valid insertion point.
458 if (KeepInsertionPoint)
459 EmitBlock(createBasicBlock("throw.cont"));
460}
461
462void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
463 if (!CGM.getLangOpts().CXXExceptions)
464 return;
465
466 const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
467 if (!FD) {
468 // Check if CapturedDecl is nothrow and create terminate scope for it.
469 if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
470 if (CD->isNothrow())
471 EHStack.pushTerminate();
472 }
473 return;
474 }
475 const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
476 if (!Proto)
477 return;
478
479 ExceptionSpecificationType EST = Proto->getExceptionSpecType();
480 if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
481 // noexcept functions are simple terminate scopes.
482 if (!getLangOpts().EHAsynch) // -EHa: HW exception still can occur
483 EHStack.pushTerminate();
484 } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
485 // TODO: Revisit exception specifications for the MS ABI. There is a way to
486 // encode these in an object file but MSVC doesn't do anything with it.
487 if (getTarget().getCXXABI().isMicrosoft())
488 return;
489 // In Wasm EH we currently treat 'throw()' in the same way as 'noexcept'. In
490 // case of throw with types, we ignore it and print a warning for now.
491 // TODO Correctly handle exception specification in Wasm EH
492 if (CGM.getLangOpts().hasWasmExceptions()) {
493 if (EST == EST_DynamicNone)
494 EHStack.pushTerminate();
495 else
496 CGM.getDiags().Report(D->getLocation(),
497 diag::warn_wasm_dynamic_exception_spec_ignored)
498 << FD->getExceptionSpecSourceRange();
499 return;
500 }
501 // Currently Emscripten EH only handles 'throw()' but not 'throw' with
502 // types. 'throw()' handling will be done in JS glue code so we don't need
503 // to do anything in that case. Just print a warning message in case of
504 // throw with types.
505 // TODO Correctly handle exception specification in Emscripten EH
506 if (getTarget().getCXXABI() == TargetCXXABI::WebAssembly &&
507 CGM.getLangOpts().getExceptionHandling() ==
508 LangOptions::ExceptionHandlingKind::None &&
509 EST == EST_Dynamic)
510 CGM.getDiags().Report(D->getLocation(),
511 diag::warn_wasm_dynamic_exception_spec_ignored)
512 << FD->getExceptionSpecSourceRange();
513
514 unsigned NumExceptions = Proto->getNumExceptions();
515 EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
516
517 for (unsigned I = 0; I != NumExceptions; ++I) {
518 QualType Ty = Proto->getExceptionType(I);
519 QualType ExceptType = Ty.getNonReferenceType().getUnqualifiedType();
520 llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType,
521 /*ForEH=*/true);
522 Filter->setFilter(I, EHType);
523 }
524 }
525}
526
527/// Emit the dispatch block for a filter scope if necessary.
528static void emitFilterDispatchBlock(CodeGenFunction &CGF,
529 EHFilterScope &filterScope) {
530 llvm::BasicBlock *dispatchBlock = filterScope.getCachedEHDispatchBlock();
531 if (!dispatchBlock) return;
532 if (dispatchBlock->use_empty()) {
533 delete dispatchBlock;
534 return;
535 }
536
537 CGF.EmitBlockAfterUses(dispatchBlock);
538
539 // If this isn't a catch-all filter, we need to check whether we got
540 // here because the filter triggered.
541 if (filterScope.getNumFilters()) {
542 // Load the selector value.
543 llvm::Value *selector = CGF.getSelectorFromSlot();
544 llvm::BasicBlock *unexpectedBB = CGF.createBasicBlock("ehspec.unexpected");
545
546 llvm::Value *zero = CGF.Builder.getInt32(0);
547 llvm::Value *failsFilter =
548 CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
549 CGF.Builder.CreateCondBr(failsFilter, unexpectedBB,
550 CGF.getEHResumeBlock(false));
551
552 CGF.EmitBlock(unexpectedBB);
553 }
554
555 // Call __cxa_call_unexpected. This doesn't need to be an invoke
556 // because __cxa_call_unexpected magically filters exceptions
557 // according to the last landing pad the exception was thrown
558 // into. Seriously.
559 llvm::Value *exn = CGF.getExceptionFromSlot();
560 CGF.EmitRuntimeCall(getUnexpectedFn(CGF.CGM), exn)
561 ->setDoesNotReturn();
562 CGF.Builder.CreateUnreachable();
563}
564
565void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
566 if (!CGM.getLangOpts().CXXExceptions)
567 return;
568
569 const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
570 if (!FD) {
571 // Check if CapturedDecl is nothrow and pop terminate scope for it.
572 if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
573 if (CD->isNothrow() && !EHStack.empty())
574 EHStack.popTerminate();
575 }
576 return;
577 }
578 const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
579 if (!Proto)
580 return;
581
582 ExceptionSpecificationType EST = Proto->getExceptionSpecType();
583 if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot &&
584 !EHStack.empty() /* possible empty when under async exceptions */) {
585 EHStack.popTerminate();
586 } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
587 // TODO: Revisit exception specifications for the MS ABI. There is a way to
588 // encode these in an object file but MSVC doesn't do anything with it.
589 if (getTarget().getCXXABI().isMicrosoft())
590 return;
591 // In wasm we currently treat 'throw()' in the same way as 'noexcept'. In
592 // case of throw with types, we ignore it and print a warning for now.
593 // TODO Correctly handle exception specification in wasm
594 if (CGM.getLangOpts().hasWasmExceptions()) {
595 if (EST == EST_DynamicNone)
596 EHStack.popTerminate();
597 return;
598 }
599 EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
600 emitFilterDispatchBlock(*this, filterScope);
601 EHStack.popFilter();
602 }
603}
604
605void CodeGenFunction::EmitCXXTryStmt(const CXXTryStmt &S) {
606 EnterCXXTryStmt(S);
607 EmitStmt(S.getTryBlock());
608 ExitCXXTryStmt(S);
1
Calling 'CodeGenFunction::ExitCXXTryStmt'
609}
610
611void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
612 unsigned NumHandlers = S.getNumHandlers();
613 EHCatchScope *CatchScope = EHStack.pushCatch(NumHandlers);
614
615 for (unsigned I = 0; I != NumHandlers; ++I) {
616 const CXXCatchStmt *C = S.getHandler(I);
617
618 llvm::BasicBlock *Handler = createBasicBlock("catch");
619 if (C->getExceptionDecl()) {
620 // FIXME: Dropping the reference type on the type into makes it
621 // impossible to correctly implement catch-by-reference
622 // semantics for pointers. Unfortunately, this is what all
623 // existing compilers do, and it's not clear that the standard
624 // personality routine is capable of doing this right. See C++ DR 388:
625 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#388
626 Qualifiers CaughtTypeQuals;
627 QualType CaughtType = CGM.getContext().getUnqualifiedArrayType(
628 C->getCaughtType().getNonReferenceType(), CaughtTypeQuals);
629
630 CatchTypeInfo TypeInfo{nullptr, 0};
631 if (CaughtType->isObjCObjectPointerType())
632 TypeInfo.RTTI = CGM.getObjCRuntime().GetEHType(CaughtType);
633 else
634 TypeInfo = CGM.getCXXABI().getAddrOfCXXCatchHandlerType(
635 CaughtType, C->getCaughtType());
636 CatchScope->setHandler(I, TypeInfo, Handler);
637 } else {
638 // No exception decl indicates '...', a catch-all.
639 CatchScope->setHandler(I, CGM.getCXXABI().getCatchAllTypeInfo(), Handler);
640 // Under async exceptions, catch(...) need to catch HW exception too
641 // Mark scope with SehTryBegin as a SEH __try scope
642 if (getLangOpts().EHAsynch)
643 EmitRuntimeCallOrInvoke(getSehTryBeginFn(CGM));
644 }
645 }
646}
647
648llvm::BasicBlock *
649CodeGenFunction::getEHDispatchBlock(EHScopeStack::stable_iterator si) {
650 if (EHPersonality::get(*this).usesFuncletPads())
651 return getFuncletEHDispatchBlock(si);
652
653 // The dispatch block for the end of the scope chain is a block that
654 // just resumes unwinding.
655 if (si == EHStack.stable_end())
656 return getEHResumeBlock(true);
657
658 // Otherwise, we should look at the actual scope.
659 EHScope &scope = *EHStack.find(si);
660
661 llvm::BasicBlock *dispatchBlock = scope.getCachedEHDispatchBlock();
662 if (!dispatchBlock) {
663 switch (scope.getKind()) {
664 case EHScope::Catch: {
665 // Apply a special case to a single catch-all.
666 EHCatchScope &catchScope = cast<EHCatchScope>(scope);
667 if (catchScope.getNumHandlers() == 1 &&
668 catchScope.getHandler(0).isCatchAll()) {
669 dispatchBlock = catchScope.getHandler(0).Block;
670
671 // Otherwise, make a dispatch block.
672 } else {
673 dispatchBlock = createBasicBlock("catch.dispatch");
674 }
675 break;
676 }
677
678 case EHScope::Cleanup:
679 dispatchBlock = createBasicBlock("ehcleanup");
680 break;
681
682 case EHScope::Filter:
683 dispatchBlock = createBasicBlock("filter.dispatch");
684 break;
685
686 case EHScope::Terminate:
687 dispatchBlock = getTerminateHandler();
688 break;
689 }
690 scope.setCachedEHDispatchBlock(dispatchBlock);
691 }
692 return dispatchBlock;
693}
694
695llvm::BasicBlock *
696CodeGenFunction::getFuncletEHDispatchBlock(EHScopeStack::stable_iterator SI) {
697 // Returning nullptr indicates that the previous dispatch block should unwind
698 // to caller.
699 if (SI == EHStack.stable_end())
700 return nullptr;
701
702 // Otherwise, we should look at the actual scope.
703 EHScope &EHS = *EHStack.find(SI);
704
705 llvm::BasicBlock *DispatchBlock = EHS.getCachedEHDispatchBlock();
706 if (DispatchBlock)
707 return DispatchBlock;
708
709 if (EHS.getKind() == EHScope::Terminate)
710 DispatchBlock = getTerminateFunclet();
711 else
712 DispatchBlock = createBasicBlock();
713 CGBuilderTy Builder(*this, DispatchBlock);
714
715 switch (EHS.getKind()) {
716 case EHScope::Catch:
717 DispatchBlock->setName("catch.dispatch");
718 break;
719
720 case EHScope::Cleanup:
721 DispatchBlock->setName("ehcleanup");
722 break;
723
724 case EHScope::Filter:
725 llvm_unreachable("exception specifications not handled yet!")__builtin_unreachable();
726
727 case EHScope::Terminate:
728 DispatchBlock->setName("terminate");
729 break;
730 }
731 EHS.setCachedEHDispatchBlock(DispatchBlock);
732 return DispatchBlock;
733}
734
735/// Check whether this is a non-EH scope, i.e. a scope which doesn't
736/// affect exception handling. Currently, the only non-EH scopes are
737/// normal-only cleanup scopes.
738static bool isNonEHScope(const EHScope &S) {
739 switch (S.getKind()) {
740 case EHScope::Cleanup:
741 return !cast<EHCleanupScope>(S).isEHCleanup();
742 case EHScope::Filter:
743 case EHScope::Catch:
744 case EHScope::Terminate:
745 return false;
746 }
747
748 llvm_unreachable("Invalid EHScope Kind!")__builtin_unreachable();
749}
750
751llvm::BasicBlock *CodeGenFunction::getInvokeDestImpl() {
752 assert(EHStack.requiresLandingPad())(static_cast<void> (0));
753 assert(!EHStack.empty())(static_cast<void> (0));
754
755 // If exceptions are disabled/ignored and SEH is not in use, then there is no
756 // invoke destination. SEH "works" even if exceptions are off. In practice,
757 // this means that C++ destructors and other EH cleanups don't run, which is
758 // consistent with MSVC's behavior, except in the presence of -EHa
759 const LangOptions &LO = CGM.getLangOpts();
760 if (!LO.Exceptions || LO.IgnoreExceptions) {
761 if (!LO.Borland && !LO.MicrosoftExt)
762 return nullptr;
763 if (!currentFunctionUsesSEHTry())
764 return nullptr;
765 }
766
767 // CUDA device code doesn't have exceptions.
768 if (LO.CUDA && LO.CUDAIsDevice)
769 return nullptr;
770
771 // Check the innermost scope for a cached landing pad. If this is
772 // a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
773 llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();
774 if (LP) return LP;
775
776 const EHPersonality &Personality = EHPersonality::get(*this);
777
778 if (!CurFn->hasPersonalityFn())
779 CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
780
781 if (Personality.usesFuncletPads()) {
782 // We don't need separate landing pads in the funclet model.
783 LP = getEHDispatchBlock(EHStack.getInnermostEHScope());
784 } else {
785 // Build the landing pad for this scope.
786 LP = EmitLandingPad();
787 }
788
789 assert(LP)(static_cast<void> (0));
790
791 // Cache the landing pad on the innermost scope. If this is a
792 // non-EH scope, cache the landing pad on the enclosing scope, too.
793 for (EHScopeStack::iterator ir = EHStack.begin(); true; ++ir) {
794 ir->setCachedLandingPad(LP);
795 if (!isNonEHScope(*ir)) break;
796 }
797
798 return LP;
799}
800
801llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
802 assert(EHStack.requiresLandingPad())(static_cast<void> (0));
803 assert(!CGM.getLangOpts().IgnoreExceptions &&(static_cast<void> (0))
804 "LandingPad should not be emitted when -fignore-exceptions are in "(static_cast<void> (0))
805 "effect.")(static_cast<void> (0));
806 EHScope &innermostEHScope = *EHStack.find(EHStack.getInnermostEHScope());
807 switch (innermostEHScope.getKind()) {
808 case EHScope::Terminate:
809 return getTerminateLandingPad();
810
811 case EHScope::Catch:
812 case EHScope::Cleanup:
813 case EHScope::Filter:
814 if (llvm::BasicBlock *lpad = innermostEHScope.getCachedLandingPad())
815 return lpad;
816 }
817
818 // Save the current IR generation state.
819 CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
820 auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, CurEHLocation);
821
822 // Create and configure the landing pad.
823 llvm::BasicBlock *lpad = createBasicBlock("lpad");
824 EmitBlock(lpad);
825
826 llvm::LandingPadInst *LPadInst =
827 Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
828
829 llvm::Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
830 Builder.CreateStore(LPadExn, getExceptionSlot());
831 llvm::Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
832 Builder.CreateStore(LPadSel, getEHSelectorSlot());
833
834 // Save the exception pointer. It's safe to use a single exception
835 // pointer per function because EH cleanups can never have nested
836 // try/catches.
837 // Build the landingpad instruction.
838
839 // Accumulate all the handlers in scope.
840 bool hasCatchAll = false;
841 bool hasCleanup = false;
842 bool hasFilter = false;
843 SmallVector<llvm::Value*, 4> filterTypes;
844 llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
845 for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end(); I != E;
846 ++I) {
847
848 switch (I->getKind()) {
849 case EHScope::Cleanup:
850 // If we have a cleanup, remember that.
851 hasCleanup = (hasCleanup || cast<EHCleanupScope>(*I).isEHCleanup());
852 continue;
853
854 case EHScope::Filter: {
855 assert(I.next() == EHStack.end() && "EH filter is not end of EH stack")(static_cast<void> (0));
856 assert(!hasCatchAll && "EH filter reached after catch-all")(static_cast<void> (0));
857
858 // Filter scopes get added to the landingpad in weird ways.
859 EHFilterScope &filter = cast<EHFilterScope>(*I);
860 hasFilter = true;
861
862 // Add all the filter values.
863 for (unsigned i = 0, e = filter.getNumFilters(); i != e; ++i)
864 filterTypes.push_back(filter.getFilter(i));
865 goto done;
866 }
867
868 case EHScope::Terminate:
869 // Terminate scopes are basically catch-alls.
870 assert(!hasCatchAll)(static_cast<void> (0));
871 hasCatchAll = true;
872 goto done;
873
874 case EHScope::Catch:
875 break;
876 }
877
878 EHCatchScope &catchScope = cast<EHCatchScope>(*I);
879 for (unsigned hi = 0, he = catchScope.getNumHandlers(); hi != he; ++hi) {
880 EHCatchScope::Handler handler = catchScope.getHandler(hi);
881 assert(handler.Type.Flags == 0 &&(static_cast<void> (0))
882 "landingpads do not support catch handler flags")(static_cast<void> (0));
883
884 // If this is a catch-all, register that and abort.
885 if (!handler.Type.RTTI) {
886 assert(!hasCatchAll)(static_cast<void> (0));
887 hasCatchAll = true;
888 goto done;
889 }
890
891 // Check whether we already have a handler for this type.
892 if (catchTypes.insert(handler.Type.RTTI).second)
893 // If not, add it directly to the landingpad.
894 LPadInst->addClause(handler.Type.RTTI);
895 }
896 }
897
898 done:
899 // If we have a catch-all, add null to the landingpad.
900 assert(!(hasCatchAll && hasFilter))(static_cast<void> (0));
901 if (hasCatchAll) {
902 LPadInst->addClause(getCatchAllValue(*this));
903
904 // If we have an EH filter, we need to add those handlers in the
905 // right place in the landingpad, which is to say, at the end.
906 } else if (hasFilter) {
907 // Create a filter expression: a constant array indicating which filter
908 // types there are. The personality routine only lands here if the filter
909 // doesn't match.
910 SmallVector<llvm::Constant*, 8> Filters;
911 llvm::ArrayType *AType =
912 llvm::ArrayType::get(!filterTypes.empty() ?
913 filterTypes[0]->getType() : Int8PtrTy,
914 filterTypes.size());
915
916 for (unsigned i = 0, e = filterTypes.size(); i != e; ++i)
917 Filters.push_back(cast<llvm::Constant>(filterTypes[i]));
918 llvm::Constant *FilterArray = llvm::ConstantArray::get(AType, Filters);
919 LPadInst->addClause(FilterArray);
920
921 // Also check whether we need a cleanup.
922 if (hasCleanup)
923 LPadInst->setCleanup(true);
924
925 // Otherwise, signal that we at least have cleanups.
926 } else if (hasCleanup) {
927 LPadInst->setCleanup(true);
928 }
929
930 assert((LPadInst->getNumClauses() > 0 || LPadInst->isCleanup()) &&(static_cast<void> (0))
931 "landingpad instruction has no clauses!")(static_cast<void> (0));
932
933 // Tell the backend how to generate the landing pad.
934 Builder.CreateBr(getEHDispatchBlock(EHStack.getInnermostEHScope()));
935
936 // Restore the old IR generation state.
937 Builder.restoreIP(savedIP);
938
939 return lpad;
940}
941
942static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope) {
943 llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
944 assert(DispatchBlock)(static_cast<void> (0));
945
946 CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
947 CGF.EmitBlockAfterUses(DispatchBlock);
948
949 llvm::Value *ParentPad = CGF.CurrentFuncletPad;
950 if (!ParentPad)
951 ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
952 llvm::BasicBlock *UnwindBB =
953 CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
954
955 unsigned NumHandlers = CatchScope.getNumHandlers();
956 llvm::CatchSwitchInst *CatchSwitch =
957 CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
958
959 // Test against each of the exception types we claim to catch.
960 for (unsigned I = 0; I < NumHandlers; ++I) {
961 const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
962
963 CatchTypeInfo TypeInfo = Handler.Type;
964 if (!TypeInfo.RTTI)
965 TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
966
967 CGF.Builder.SetInsertPoint(Handler.Block);
968
969 if (EHPersonality::get(CGF).isMSVCXXPersonality()) {
970 CGF.Builder.CreateCatchPad(
971 CatchSwitch, {TypeInfo.RTTI, CGF.Builder.getInt32(TypeInfo.Flags),
972 llvm::Constant::getNullValue(CGF.VoidPtrTy)});
973 } else {
974 CGF.Builder.CreateCatchPad(CatchSwitch, {TypeInfo.RTTI});
975 }
976
977 CatchSwitch->addHandler(Handler.Block);
978 }
979 CGF.Builder.restoreIP(SavedIP);
980}
981
982// Wasm uses Windows-style EH instructions, but it merges all catch clauses into
983// one big catchpad, within which we use Itanium's landingpad-style selector
984// comparison instructions.
985static void emitWasmCatchPadBlock(CodeGenFunction &CGF,
986 EHCatchScope &CatchScope) {
987 llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
988 assert(DispatchBlock)(static_cast<void> (0));
989
990 CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
991 CGF.EmitBlockAfterUses(DispatchBlock);
992
993 llvm::Value *ParentPad = CGF.CurrentFuncletPad;
994 if (!ParentPad)
995 ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
996 llvm::BasicBlock *UnwindBB =
997 CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
998
999 unsigned NumHandlers = CatchScope.getNumHandlers();
1000 llvm::CatchSwitchInst *CatchSwitch =
1001 CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
1002
1003 // We don't use a landingpad instruction, so generate intrinsic calls to
1004 // provide exception and selector values.
1005 llvm::BasicBlock *WasmCatchStartBlock = CGF.createBasicBlock("catch.start");
1006 CatchSwitch->addHandler(WasmCatchStartBlock);
1007 CGF.EmitBlockAfterUses(WasmCatchStartBlock);
1008
1009 // Create a catchpad instruction.
1010 SmallVector<llvm::Value *, 4> CatchTypes;
1011 for (unsigned I = 0, E = NumHandlers; I < E; ++I) {
1012 const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
1013 CatchTypeInfo TypeInfo = Handler.Type;
1014 if (!TypeInfo.RTTI)
1015 TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
1016 CatchTypes.push_back(TypeInfo.RTTI);
1017 }
1018 auto *CPI = CGF.Builder.CreateCatchPad(CatchSwitch, CatchTypes);
1019
1020 // Create calls to wasm.get.exception and wasm.get.ehselector intrinsics.
1021 // Before they are lowered appropriately later, they provide values for the
1022 // exception and selector.
1023 llvm::Function *GetExnFn =
1024 CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
1025 llvm::Function *GetSelectorFn =
1026 CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_ehselector);
1027 llvm::CallInst *Exn = CGF.Builder.CreateCall(GetExnFn, CPI);
1028 CGF.Builder.CreateStore(Exn, CGF.getExceptionSlot());
1029 llvm::CallInst *Selector = CGF.Builder.CreateCall(GetSelectorFn, CPI);
1030
1031 llvm::Function *TypeIDFn = CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
1032
1033 // If there's only a single catch-all, branch directly to its handler.
1034 if (CatchScope.getNumHandlers() == 1 &&
1035 CatchScope.getHandler(0).isCatchAll()) {
1036 CGF.Builder.CreateBr(CatchScope.getHandler(0).Block);
1037 CGF.Builder.restoreIP(SavedIP);
1038 return;
1039 }
1040
1041 // Test against each of the exception types we claim to catch.
1042 for (unsigned I = 0, E = NumHandlers;; ++I) {
1043 assert(I < E && "ran off end of handlers!")(static_cast<void> (0));
1044 const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
1045 CatchTypeInfo TypeInfo = Handler.Type;
1046 if (!TypeInfo.RTTI)
1047 TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
1048
1049 // Figure out the next block.
1050 llvm::BasicBlock *NextBlock;
1051
1052 bool EmitNextBlock = false, NextIsEnd = false;
1053
1054 // If this is the last handler, we're at the end, and the next block is a
1055 // block that contains a call to the rethrow function, so we can unwind to
1056 // the enclosing EH scope. The call itself will be generated later.
1057 if (I + 1 == E) {
1058 NextBlock = CGF.createBasicBlock("rethrow");
1059 EmitNextBlock = true;
1060 NextIsEnd = true;
1061
1062 // If the next handler is a catch-all, we're at the end, and the
1063 // next block is that handler.
1064 } else if (CatchScope.getHandler(I + 1).isCatchAll()) {
1065 NextBlock = CatchScope.getHandler(I + 1).Block;
1066 NextIsEnd = true;
1067
1068 // Otherwise, we're not at the end and we need a new block.
1069 } else {
1070 NextBlock = CGF.createBasicBlock("catch.fallthrough");
1071 EmitNextBlock = true;
1072 }
1073
1074 // Figure out the catch type's index in the LSDA's type table.
1075 llvm::CallInst *TypeIndex = CGF.Builder.CreateCall(TypeIDFn, TypeInfo.RTTI);
1076 TypeIndex->setDoesNotThrow();
1077
1078 llvm::Value *MatchesTypeIndex =
1079 CGF.Builder.CreateICmpEQ(Selector, TypeIndex, "matches");
1080 CGF.Builder.CreateCondBr(MatchesTypeIndex, Handler.Block, NextBlock);
1081
1082 if (EmitNextBlock)
1083 CGF.EmitBlock(NextBlock);
1084 if (NextIsEnd)
1085 break;
1086 }
1087
1088 CGF.Builder.restoreIP(SavedIP);
1089}
1090
1091/// Emit the structure of the dispatch block for the given catch scope.
1092/// It is an invariant that the dispatch block already exists.
1093static void emitCatchDispatchBlock(CodeGenFunction &CGF,
1094 EHCatchScope &catchScope) {
1095 if (EHPersonality::get(CGF).isWasmPersonality())
1096 return emitWasmCatchPadBlock(CGF, catchScope);
1097 if (EHPersonality::get(CGF).usesFuncletPads())
1098 return emitCatchPadBlock(CGF, catchScope);
1099
1100 llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
1101 assert(dispatchBlock)(static_cast<void> (0));
1102
1103 // If there's only a single catch-all, getEHDispatchBlock returned
1104 // that catch-all as the dispatch block.
1105 if (catchScope.getNumHandlers() == 1 &&
1106 catchScope.getHandler(0).isCatchAll()) {
1107 assert(dispatchBlock == catchScope.getHandler(0).Block)(static_cast<void> (0));
1108 return;
1109 }
1110
1111 CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveIP();
1112 CGF.EmitBlockAfterUses(dispatchBlock);
1113
1114 // Select the right handler.
1115 llvm::Function *llvm_eh_typeid_for =
1116 CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
1117
1118 // Load the selector value.
1119 llvm::Value *selector = CGF.getSelectorFromSlot();
1120
1121 // Test against each of the exception types we claim to catch.
1122 for (unsigned i = 0, e = catchScope.getNumHandlers(); ; ++i) {
1123 assert(i < e && "ran off end of handlers!")(static_cast<void> (0));
1124 const EHCatchScope::Handler &handler = catchScope.getHandler(i);
1125
1126 llvm::Value *typeValue = handler.Type.RTTI;
1127 assert(handler.Type.Flags == 0 &&(static_cast<void> (0))
1128 "landingpads do not support catch handler flags")(static_cast<void> (0));
1129 assert(typeValue && "fell into catch-all case!")(static_cast<void> (0));
1130 typeValue = CGF.Builder.CreateBitCast(typeValue, CGF.Int8PtrTy);
1131
1132 // Figure out the next block.
1133 bool nextIsEnd;
1134 llvm::BasicBlock *nextBlock;
1135
1136 // If this is the last handler, we're at the end, and the next
1137 // block is the block for the enclosing EH scope.
1138 if (i + 1 == e) {
1139 nextBlock = CGF.getEHDispatchBlock(catchScope.getEnclosingEHScope());
1140 nextIsEnd = true;
1141
1142 // If the next handler is a catch-all, we're at the end, and the
1143 // next block is that handler.
1144 } else if (catchScope.getHandler(i+1).isCatchAll()) {
1145 nextBlock = catchScope.getHandler(i+1).Block;
1146 nextIsEnd = true;
1147
1148 // Otherwise, we're not at the end and we need a new block.
1149 } else {
1150 nextBlock = CGF.createBasicBlock("catch.fallthrough");
1151 nextIsEnd = false;
1152 }
1153
1154 // Figure out the catch type's index in the LSDA's type table.
1155 llvm::CallInst *typeIndex =
1156 CGF.Builder.CreateCall(llvm_eh_typeid_for, typeValue);
1157 typeIndex->setDoesNotThrow();
1158
1159 llvm::Value *matchesTypeIndex =
1160 CGF.Builder.CreateICmpEQ(selector, typeIndex, "matches");
1161 CGF.Builder.CreateCondBr(matchesTypeIndex, handler.Block, nextBlock);
1162
1163 // If the next handler is a catch-all, we're completely done.
1164 if (nextIsEnd) {
1165 CGF.Builder.restoreIP(savedIP);
1166 return;
1167 }
1168 // Otherwise we need to emit and continue at that block.
1169 CGF.EmitBlock(nextBlock);
1170 }
1171}
1172
1173void CodeGenFunction::popCatchScope() {
1174 EHCatchScope &catchScope = cast<EHCatchScope>(*EHStack.begin());
1175 if (catchScope.hasEHBranches())
1176 emitCatchDispatchBlock(*this, catchScope);
1177 EHStack.popCatch();
1178}
1179
1180void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
1181 unsigned NumHandlers = S.getNumHandlers();
1182 EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
2
The object is a 'EHCatchScope'
1183 assert(CatchScope.getNumHandlers() == NumHandlers)(static_cast<void> (0));
1184 llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
1185
1186 // If the catch was not required, bail out now.
1187 if (!CatchScope.hasEHBranches()) {
3
Calling 'EHScope::hasEHBranches'
11
Returning from 'EHScope::hasEHBranches'
12
Taking false branch
1188 CatchScope.clearHandlerBlocks();
1189 EHStack.popCatch();
1190 return;
1191 }
1192
1193 // Emit the structure of the EH dispatch for this catch.
1194 emitCatchDispatchBlock(*this, CatchScope);
1195
1196 // Copy the handler blocks off before we pop the EH stack. Emitting
1197 // the handlers might scribble on this memory.
1198 SmallVector<EHCatchScope::Handler, 8> Handlers(
1199 CatchScope.begin(), CatchScope.begin() + NumHandlers);
1200
1201 EHStack.popCatch();
1202
1203 // The fall-through block.
1204 llvm::BasicBlock *ContBB = createBasicBlock("try.cont");
1205
1206 // We just emitted the body of the try; jump to the continue block.
1207 if (HaveInsertPoint())
13
Taking false branch
1208 Builder.CreateBr(ContBB);
1209
1210 // Determine if we need an implicit rethrow for all these catch handlers;
1211 // see the comment below.
1212 bool doImplicitRethrow = false;
1213 if (IsFnTryBlock
13.1
'IsFnTryBlock' is false
13.1
'IsFnTryBlock' is false
13.1
'IsFnTryBlock' is false
)
14
Taking false branch
1214 doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
1215 isa<CXXConstructorDecl>(CurCodeDecl);
1216
1217 // Wasm uses Windows-style EH instructions, but merges all catch clauses into
1218 // one big catchpad. So we save the old funclet pad here before we traverse
1219 // each catch handler.
1220 SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1221 CurrentFuncletPad);
1222 llvm::BasicBlock *WasmCatchStartBlock = nullptr;
15
'WasmCatchStartBlock' initialized to a null pointer value
1223 if (EHPersonality::get(*this).isWasmPersonality()) {
16
Assuming the condition is false
17
Taking false branch
1224 auto *CatchSwitch =
1225 cast<llvm::CatchSwitchInst>(DispatchBlock->getFirstNonPHI());
1226 WasmCatchStartBlock = CatchSwitch->hasUnwindDest()
1227 ? CatchSwitch->getSuccessor(1)
1228 : CatchSwitch->getSuccessor(0);
1229 auto *CPI = cast<llvm::CatchPadInst>(WasmCatchStartBlock->getFirstNonPHI());
1230 CurrentFuncletPad = CPI;
1231 }
1232
1233 // Perversely, we emit the handlers backwards precisely because we
1234 // want them to appear in source order. In all of these cases, the
1235 // catch block will have exactly one predecessor, which will be a
1236 // particular block in the catch dispatch. However, in the case of
1237 // a catch-all, one of the dispatch blocks will branch to two
1238 // different handlers, and EmitBlockAfterUses will cause the second
1239 // handler to be moved before the first.
1240 bool HasCatchAll = false;
1241 for (unsigned I = NumHandlers; I != 0; --I) {
1242 HasCatchAll |= Handlers[I - 1].isCatchAll();
1243 llvm::BasicBlock *CatchBlock = Handlers[I-1].Block;
1244 EmitBlockAfterUses(CatchBlock);
1245
1246 // Catch the exception if this isn't a catch-all.
1247 const CXXCatchStmt *C = S.getHandler(I-1);
1248
1249 // Enter a cleanup scope, including the catch variable and the
1250 // end-catch.
1251 RunCleanupsScope CatchScope(*this);
1252
1253 // Initialize the catch variable and set up the cleanups.
1254 SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1255 CurrentFuncletPad);
1256 CGM.getCXXABI().emitBeginCatch(*this, C);
1257
1258 // Emit the PGO counter increment.
1259 incrementProfileCounter(C);
1260
1261 // Perform the body of the catch.
1262 EmitStmt(C->getHandlerBlock());
1263
1264 // [except.handle]p11:
1265 // The currently handled exception is rethrown if control
1266 // reaches the end of a handler of the function-try-block of a
1267 // constructor or destructor.
1268
1269 // It is important that we only do this on fallthrough and not on
1270 // return. Note that it's illegal to put a return in a
1271 // constructor function-try-block's catch handler (p14), so this
1272 // really only applies to destructors.
1273 if (doImplicitRethrow && HaveInsertPoint()) {
1274 CGM.getCXXABI().emitRethrow(*this, /*isNoReturn*/false);
1275 Builder.CreateUnreachable();
1276 Builder.ClearInsertionPoint();
1277 }
1278
1279 // Fall out through the catch cleanups.
1280 CatchScope.ForceCleanup();
1281
1282 // Branch out of the try.
1283 if (HaveInsertPoint())
1284 Builder.CreateBr(ContBB);
1285 }
1286
1287 // Because in wasm we merge all catch clauses into one big catchpad, in case
1288 // none of the types in catch handlers matches after we test against each of
1289 // them, we should unwind to the next EH enclosing scope. We generate a call
1290 // to rethrow function here to do that.
1291 if (EHPersonality::get(*this).isWasmPersonality() && !HasCatchAll
18.1
'HasCatchAll' is false
18.1
'HasCatchAll' is false
18.1
'HasCatchAll' is false
) {
18
Assuming the condition is true
19
Taking true branch
1292 assert(WasmCatchStartBlock)(static_cast<void> (0));
1293 // Navigate for the "rethrow" block we created in emitWasmCatchPadBlock().
1294 // Wasm uses landingpad-style conditional branches to compare selectors, so
1295 // we follow the false destination for each of the cond branches to reach
1296 // the rethrow block.
1297 llvm::BasicBlock *RethrowBlock = WasmCatchStartBlock;
20
'RethrowBlock' initialized to a null pointer value
1298 while (llvm::Instruction *TI = RethrowBlock->getTerminator()) {
21
Called C++ object pointer is null
1299 auto *BI = cast<llvm::BranchInst>(TI);
1300 assert(BI->isConditional())(static_cast<void> (0));
1301 RethrowBlock = BI->getSuccessor(1);
1302 }
1303 assert(RethrowBlock != WasmCatchStartBlock && RethrowBlock->empty())(static_cast<void> (0));
1304 Builder.SetInsertPoint(RethrowBlock);
1305 llvm::Function *RethrowInCatchFn =
1306 CGM.getIntrinsic(llvm::Intrinsic::wasm_rethrow);
1307 EmitNoreturnRuntimeCallOrInvoke(RethrowInCatchFn, {});
1308 }
1309
1310 EmitBlock(ContBB);
1311 incrementProfileCounter(&S);
1312}
1313
1314namespace {
1315 struct CallEndCatchForFinally final : EHScopeStack::Cleanup {
1316 llvm::Value *ForEHVar;
1317 llvm::FunctionCallee EndCatchFn;
1318 CallEndCatchForFinally(llvm::Value *ForEHVar,
1319 llvm::FunctionCallee EndCatchFn)
1320 : ForEHVar(ForEHVar), EndCatchFn(EndCatchFn) {}
1321
1322 void Emit(CodeGenFunction &CGF, Flags flags) override {
1323 llvm::BasicBlock *EndCatchBB = CGF.createBasicBlock("finally.endcatch");
1324 llvm::BasicBlock *CleanupContBB =
1325 CGF.createBasicBlock("finally.cleanup.cont");
1326
1327 llvm::Value *ShouldEndCatch =
1328 CGF.Builder.CreateFlagLoad(ForEHVar, "finally.endcatch");
1329 CGF.Builder.CreateCondBr(ShouldEndCatch, EndCatchBB, CleanupContBB);
1330 CGF.EmitBlock(EndCatchBB);
1331 CGF.EmitRuntimeCallOrInvoke(EndCatchFn); // catch-all, so might throw
1332 CGF.EmitBlock(CleanupContBB);
1333 }
1334 };
1335
1336 struct PerformFinally final : EHScopeStack::Cleanup {
1337 const Stmt *Body;
1338 llvm::Value *ForEHVar;
1339 llvm::FunctionCallee EndCatchFn;
1340 llvm::FunctionCallee RethrowFn;
1341 llvm::Value *SavedExnVar;
1342
1343 PerformFinally(const Stmt *Body, llvm::Value *ForEHVar,
1344 llvm::FunctionCallee EndCatchFn,
1345 llvm::FunctionCallee RethrowFn, llvm::Value *SavedExnVar)
1346 : Body(Body), ForEHVar(ForEHVar), EndCatchFn(EndCatchFn),
1347 RethrowFn(RethrowFn), SavedExnVar(SavedExnVar) {}
1348
1349 void Emit(CodeGenFunction &CGF, Flags flags) override {
1350 // Enter a cleanup to call the end-catch function if one was provided.
1351 if (EndCatchFn)
1352 CGF.EHStack.pushCleanup<CallEndCatchForFinally>(NormalAndEHCleanup,
1353 ForEHVar, EndCatchFn);
1354
1355 // Save the current cleanup destination in case there are
1356 // cleanups in the finally block.
1357 llvm::Value *SavedCleanupDest =
1358 CGF.Builder.CreateLoad(CGF.getNormalCleanupDestSlot(),
1359 "cleanup.dest.saved");
1360
1361 // Emit the finally block.
1362 CGF.EmitStmt(Body);
1363
1364 // If the end of the finally is reachable, check whether this was
1365 // for EH. If so, rethrow.
1366 if (CGF.HaveInsertPoint()) {
1367 llvm::BasicBlock *RethrowBB = CGF.createBasicBlock("finally.rethrow");
1368 llvm::BasicBlock *ContBB = CGF.createBasicBlock("finally.cont");
1369
1370 llvm::Value *ShouldRethrow =
1371 CGF.Builder.CreateFlagLoad(ForEHVar, "finally.shouldthrow");
1372 CGF.Builder.CreateCondBr(ShouldRethrow, RethrowBB, ContBB);
1373
1374 CGF.EmitBlock(RethrowBB);
1375 if (SavedExnVar) {
1376 CGF.EmitRuntimeCallOrInvoke(RethrowFn,
1377 CGF.Builder.CreateAlignedLoad(CGF.Int8PtrTy, SavedExnVar,
1378 CGF.getPointerAlign()));
1379 } else {
1380 CGF.EmitRuntimeCallOrInvoke(RethrowFn);
1381 }
1382 CGF.Builder.CreateUnreachable();
1383
1384 CGF.EmitBlock(ContBB);
1385
1386 // Restore the cleanup destination.
1387 CGF.Builder.CreateStore(SavedCleanupDest,
1388 CGF.getNormalCleanupDestSlot());
1389 }
1390
1391 // Leave the end-catch cleanup. As an optimization, pretend that
1392 // the fallthrough path was inaccessible; we've dynamically proven
1393 // that we're not in the EH case along that path.
1394 if (EndCatchFn) {
1395 CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
1396 CGF.PopCleanupBlock();
1397 CGF.Builder.restoreIP(SavedIP);
1398 }
1399
1400 // Now make sure we actually have an insertion point or the
1401 // cleanup gods will hate us.
1402 CGF.EnsureInsertPoint();
1403 }
1404 };
1405} // end anonymous namespace
1406
1407/// Enters a finally block for an implementation using zero-cost
1408/// exceptions. This is mostly general, but hard-codes some
1409/// language/ABI-specific behavior in the catch-all sections.
1410void CodeGenFunction::FinallyInfo::enter(CodeGenFunction &CGF, const Stmt *body,
1411 llvm::FunctionCallee beginCatchFn,
1412 llvm::FunctionCallee endCatchFn,
1413 llvm::FunctionCallee rethrowFn) {
1414 assert((!!beginCatchFn) == (!!endCatchFn) &&(static_cast<void> (0))
1415 "begin/end catch functions not paired")(static_cast<void> (0));
1416 assert(rethrowFn && "rethrow function is required")(static_cast<void> (0));
1417
1418 BeginCatchFn = beginCatchFn;
1419
1420 // The rethrow function has one of the following two types:
1421 // void (*)()
1422 // void (*)(void*)
1423 // In the latter case we need to pass it the exception object.
1424 // But we can't use the exception slot because the @finally might
1425 // have a landing pad (which would overwrite the exception slot).
1426 llvm::FunctionType *rethrowFnTy = rethrowFn.getFunctionType();
1427 SavedExnVar = nullptr;
1428 if (rethrowFnTy->getNumParams())
1429 SavedExnVar = CGF.CreateTempAlloca(CGF.Int8PtrTy, "finally.exn");
1430
1431 // A finally block is a statement which must be executed on any edge
1432 // out of a given scope. Unlike a cleanup, the finally block may
1433 // contain arbitrary control flow leading out of itself. In
1434 // addition, finally blocks should always be executed, even if there
1435 // are no catch handlers higher on the stack. Therefore, we
1436 // surround the protected scope with a combination of a normal
1437 // cleanup (to catch attempts to break out of the block via normal
1438 // control flow) and an EH catch-all (semantically "outside" any try
1439 // statement to which the finally block might have been attached).
1440 // The finally block itself is generated in the context of a cleanup
1441 // which conditionally leaves the catch-all.
1442
1443 // Jump destination for performing the finally block on an exception
1444 // edge. We'll never actually reach this block, so unreachable is
1445 // fine.
1446 RethrowDest = CGF.getJumpDestInCurrentScope(CGF.getUnreachableBlock());
1447
1448 // Whether the finally block is being executed for EH purposes.
1449 ForEHVar = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), "finally.for-eh");
1450 CGF.Builder.CreateFlagStore(false, ForEHVar);
1451
1452 // Enter a normal cleanup which will perform the @finally block.
1453 CGF.EHStack.pushCleanup<PerformFinally>(NormalCleanup, body,
1454 ForEHVar, endCatchFn,
1455 rethrowFn, SavedExnVar);
1456
1457 // Enter a catch-all scope.
1458 llvm::BasicBlock *catchBB = CGF.createBasicBlock("finally.catchall");
1459 EHCatchScope *catchScope = CGF.EHStack.pushCatch(1);
1460 catchScope->setCatchAllHandler(0, catchBB);
1461}
1462
1463void CodeGenFunction::FinallyInfo::exit(CodeGenFunction &CGF) {
1464 // Leave the finally catch-all.
1465 EHCatchScope &catchScope = cast<EHCatchScope>(*CGF.EHStack.begin());
1466 llvm::BasicBlock *catchBB = catchScope.getHandler(0).Block;
1467
1468 CGF.popCatchScope();
1469
1470 // If there are any references to the catch-all block, emit it.
1471 if (catchBB->use_empty()) {
1472 delete catchBB;
1473 } else {
1474 CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveAndClearIP();
1475 CGF.EmitBlock(catchBB);
1476
1477 llvm::Value *exn = nullptr;
1478
1479 // If there's a begin-catch function, call it.
1480 if (BeginCatchFn) {
1481 exn = CGF.getExceptionFromSlot();
1482 CGF.EmitNounwindRuntimeCall(BeginCatchFn, exn);
1483 }
1484
1485 // If we need to remember the exception pointer to rethrow later, do so.
1486 if (SavedExnVar) {
1487 if (!exn) exn = CGF.getExceptionFromSlot();
1488 CGF.Builder.CreateAlignedStore(exn, SavedExnVar, CGF.getPointerAlign());
1489 }
1490
1491 // Tell the cleanups in the finally block that we're do this for EH.
1492 CGF.Builder.CreateFlagStore(true, ForEHVar);
1493
1494 // Thread a jump through the finally cleanup.
1495 CGF.EmitBranchThroughCleanup(RethrowDest);
1496
1497 CGF.Builder.restoreIP(savedIP);
1498 }
1499
1500 // Finally, leave the @finally cleanup.
1501 CGF.PopCleanupBlock();
1502}
1503
1504llvm::BasicBlock *CodeGenFunction::getTerminateLandingPad() {
1505 if (TerminateLandingPad)
1506 return TerminateLandingPad;
1507
1508 CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1509
1510 // This will get inserted at the end of the function.
1511 TerminateLandingPad = createBasicBlock("terminate.lpad");
1512 Builder.SetInsertPoint(TerminateLandingPad);
1513
1514 // Tell the backend that this is a landing pad.
1515 const EHPersonality &Personality = EHPersonality::get(*this);
1516
1517 if (!CurFn->hasPersonalityFn())
1518 CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
1519
1520 llvm::LandingPadInst *LPadInst =
1521 Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
1522 LPadInst->addClause(getCatchAllValue(*this));
1523
1524 llvm::Value *Exn = nullptr;
1525 if (getLangOpts().CPlusPlus)
1526 Exn = Builder.CreateExtractValue(LPadInst, 0);
1527 llvm::CallInst *terminateCall =
1528 CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1529 terminateCall->setDoesNotReturn();
1530 Builder.CreateUnreachable();
1531
1532 // Restore the saved insertion state.
1533 Builder.restoreIP(SavedIP);
1534
1535 return TerminateLandingPad;
1536}
1537
1538llvm::BasicBlock *CodeGenFunction::getTerminateHandler() {
1539 if (TerminateHandler)
1540 return TerminateHandler;
1541
1542 // Set up the terminate handler. This block is inserted at the very
1543 // end of the function by FinishFunction.
1544 TerminateHandler = createBasicBlock("terminate.handler");
1545 CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1546 Builder.SetInsertPoint(TerminateHandler);
1547
1548 llvm::Value *Exn = nullptr;
1549 if (getLangOpts().CPlusPlus)
1550 Exn = getExceptionFromSlot();
1551 llvm::CallInst *terminateCall =
1552 CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1553 terminateCall->setDoesNotReturn();
1554 Builder.CreateUnreachable();
1555
1556 // Restore the saved insertion state.
1557 Builder.restoreIP(SavedIP);
1558
1559 return TerminateHandler;
1560}
1561
1562llvm::BasicBlock *CodeGenFunction::getTerminateFunclet() {
1563 assert(EHPersonality::get(*this).usesFuncletPads() &&(static_cast<void> (0))
1564 "use getTerminateLandingPad for non-funclet EH")(static_cast<void> (0));
1565
1566 llvm::BasicBlock *&TerminateFunclet = TerminateFunclets[CurrentFuncletPad];
1567 if (TerminateFunclet)
1568 return TerminateFunclet;
1569
1570 CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1571
1572 // Set up the terminate handler. This block is inserted at the very
1573 // end of the function by FinishFunction.
1574 TerminateFunclet = createBasicBlock("terminate.handler");
1575 Builder.SetInsertPoint(TerminateFunclet);
1576
1577 // Create the cleanuppad using the current parent pad as its token. Use 'none'
1578 // if this is a top-level terminate scope, which is the common case.
1579 SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1580 CurrentFuncletPad);
1581 llvm::Value *ParentPad = CurrentFuncletPad;
1582 if (!ParentPad)
1583 ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
1584 CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
1585
1586 // Emit the __std_terminate call.
1587 llvm::CallInst *terminateCall =
1588 CGM.getCXXABI().emitTerminateForUnexpectedException(*this, nullptr);
1589 terminateCall->setDoesNotReturn();
1590 Builder.CreateUnreachable();
1591
1592 // Restore the saved insertion state.
1593 Builder.restoreIP(SavedIP);
1594
1595 return TerminateFunclet;
1596}
1597
1598llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
1599 if (EHResumeBlock) return EHResumeBlock;
1600
1601 CGBuilderTy::InsertPoint SavedIP = Builder.saveIP();
1602
1603 // We emit a jump to a notional label at the outermost unwind state.
1604 EHResumeBlock = createBasicBlock("eh.resume");
1605 Builder.SetInsertPoint(EHResumeBlock);
1606
1607 const EHPersonality &Personality = EHPersonality::get(*this);
1608
1609 // This can always be a call because we necessarily didn't find
1610 // anything on the EH stack which needs our help.
1611 const char *RethrowName = Personality.CatchallRethrowFn;
1612 if (RethrowName != nullptr && !isCleanup) {
1613 EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
1614 getExceptionFromSlot())->setDoesNotReturn();
1615 Builder.CreateUnreachable();
1616 Builder.restoreIP(SavedIP);
1617 return EHResumeBlock;
1618 }
1619
1620 // Recreate the landingpad's return value for the 'resume' instruction.
1621 llvm::Value *Exn = getExceptionFromSlot();
1622 llvm::Value *Sel = getSelectorFromSlot();
1623
1624 llvm::Type *LPadType = llvm::StructType::get(Exn->getType(), Sel->getType());
1625 llvm::Value *LPadVal = llvm::UndefValue::get(LPadType);
1626 LPadVal = Builder.CreateInsertValue(LPadVal, Exn, 0, "lpad.val");
1627 LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
1628
1629 Builder.CreateResume(LPadVal);
1630 Builder.restoreIP(SavedIP);
1631 return EHResumeBlock;
1632}
1633
1634void CodeGenFunction::EmitSEHTryStmt(const SEHTryStmt &S) {
1635 EnterSEHTryStmt(S);
1636 {
1637 JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
1638
1639 SEHTryEpilogueStack.push_back(&TryExit);
1640
1641 llvm::BasicBlock *TryBB = nullptr;
1642 // IsEHa: emit an invoke to _seh_try_begin() runtime for -EHa
1643 if (getLangOpts().EHAsynch) {
1644 EmitRuntimeCallOrInvoke(getSehTryBeginFn(CGM));
1645 if (SEHTryEpilogueStack.size() == 1) // outermost only
1646 TryBB = Builder.GetInsertBlock();
1647 }
1648
1649 EmitStmt(S.getTryBlock());
1650
1651 // Volatilize all blocks in Try, till current insert point
1652 if (TryBB) {
1653 llvm::SmallPtrSet<llvm::BasicBlock *, 10> Visited;
1654 VolatilizeTryBlocks(TryBB, Visited);
1655 }
1656
1657 SEHTryEpilogueStack.pop_back();
1658
1659 if (!TryExit.getBlock()->use_empty())
1660 EmitBlock(TryExit.getBlock(), /*IsFinished=*/true);
1661 else
1662 delete TryExit.getBlock();
1663 }
1664 ExitSEHTryStmt(S);
1665}
1666
1667// Recursively walk through blocks in a _try
1668// and make all memory instructions volatile
1669void CodeGenFunction::VolatilizeTryBlocks(
1670 llvm::BasicBlock *BB, llvm::SmallPtrSet<llvm::BasicBlock *, 10> &V) {
1671 if (BB == SEHTryEpilogueStack.back()->getBlock() /* end of Try */ ||
1672 !V.insert(BB).second /* already visited */ ||
1673 !BB->getParent() /* not emitted */ || BB->empty())
1674 return;
1675
1676 if (!BB->isEHPad()) {
1677 for (llvm::BasicBlock::iterator J = BB->begin(), JE = BB->end(); J != JE;
1678 ++J) {
1679 if (auto LI = dyn_cast<llvm::LoadInst>(J)) {
1680 LI->setVolatile(true);
1681 } else if (auto SI = dyn_cast<llvm::StoreInst>(J)) {
1682 SI->setVolatile(true);
1683 } else if (auto* MCI = dyn_cast<llvm::MemIntrinsic>(J)) {
1684 MCI->setVolatile(llvm::ConstantInt::get(Builder.getInt1Ty(), 1));
1685 }
1686 }
1687 }
1688 const llvm::Instruction *TI = BB->getTerminator();
1689 if (TI) {
1690 unsigned N = TI->getNumSuccessors();
1691 for (unsigned I = 0; I < N; I++)
1692 VolatilizeTryBlocks(TI->getSuccessor(I), V);
1693 }
1694}
1695
1696namespace {
1697struct PerformSEHFinally final : EHScopeStack::Cleanup {
1698 llvm::Function *OutlinedFinally;
1699 PerformSEHFinally(llvm::Function *OutlinedFinally)
1700 : OutlinedFinally(OutlinedFinally) {}
1701
1702 void Emit(CodeGenFunction &CGF, Flags F) override {
1703 ASTContext &Context = CGF.getContext();
1704 CodeGenModule &CGM = CGF.CGM;
1705
1706 CallArgList Args;
1707
1708 // Compute the two argument values.
1709 QualType ArgTys[2] = {Context.UnsignedCharTy, Context.VoidPtrTy};
1710 llvm::Value *FP = nullptr;
1711 // If CFG.IsOutlinedSEHHelper is true, then we are within a finally block.
1712 if (CGF.IsOutlinedSEHHelper) {
1713 FP = &CGF.CurFn->arg_begin()[1];
1714 } else {
1715 llvm::Function *LocalAddrFn =
1716 CGM.getIntrinsic(llvm::Intrinsic::localaddress);
1717 FP = CGF.Builder.CreateCall(LocalAddrFn);
1718 }
1719
1720 llvm::Value *IsForEH =
1721 llvm::ConstantInt::get(CGF.ConvertType(ArgTys[0]), F.isForEHCleanup());
1722
1723 // Except _leave and fall-through at the end, all other exits in a _try
1724 // (return/goto/continue/break) are considered as abnormal terminations
1725 // since _leave/fall-through is always Indexed 0,
1726 // just use NormalCleanupDestSlot (>= 1 for goto/return/..),
1727 // as 1st Arg to indicate abnormal termination
1728 if (!F.isForEHCleanup() && F.hasExitSwitch()) {
1729 Address Addr = CGF.getNormalCleanupDestSlot();
1730 llvm::Value *Load = CGF.Builder.CreateLoad(Addr, "cleanup.dest");
1731 llvm::Value *Zero = llvm::Constant::getNullValue(CGM.Int32Ty);
1732 IsForEH = CGF.Builder.CreateICmpNE(Load, Zero);
1733 }
1734
1735 Args.add(RValue::get(IsForEH), ArgTys[0]);
1736 Args.add(RValue::get(FP), ArgTys[1]);
1737
1738 // Arrange a two-arg function info and type.
1739 const CGFunctionInfo &FnInfo =
1740 CGM.getTypes().arrangeBuiltinFunctionCall(Context.VoidTy, Args);
1741
1742 auto Callee = CGCallee::forDirect(OutlinedFinally);
1743 CGF.EmitCall(FnInfo, Callee, ReturnValueSlot(), Args);
1744 }
1745};
1746} // end anonymous namespace
1747
1748namespace {
1749/// Find all local variable captures in the statement.
1750struct CaptureFinder : ConstStmtVisitor<CaptureFinder> {
1751 CodeGenFunction &ParentCGF;
1752 const VarDecl *ParentThis;
1753 llvm::SmallSetVector<const VarDecl *, 4> Captures;
1754 Address SEHCodeSlot = Address::invalid();
1755 CaptureFinder(CodeGenFunction &ParentCGF, const VarDecl *ParentThis)
1756 : ParentCGF(ParentCGF), ParentThis(ParentThis) {}
1757
1758 // Return true if we need to do any capturing work.
1759 bool foundCaptures() {
1760 return !Captures.empty() || SEHCodeSlot.isValid();
1761 }
1762
1763 void Visit(const Stmt *S) {
1764 // See if this is a capture, then recurse.
1765 ConstStmtVisitor<CaptureFinder>::Visit(S);
1766 for (const Stmt *Child : S->children())
1767 if (Child)
1768 Visit(Child);
1769 }
1770
1771 void VisitDeclRefExpr(const DeclRefExpr *E) {
1772 // If this is already a capture, just make sure we capture 'this'.
1773 if (E->refersToEnclosingVariableOrCapture())
1774 Captures.insert(ParentThis);
1775
1776 const auto *D = dyn_cast<VarDecl>(E->getDecl());
1777 if (D && D->isLocalVarDeclOrParm() && D->hasLocalStorage())
1778 Captures.insert(D);
1779 }
1780
1781 void VisitCXXThisExpr(const CXXThisExpr *E) {
1782 Captures.insert(ParentThis);
1783 }
1784
1785 void VisitCallExpr(const CallExpr *E) {
1786 // We only need to add parent frame allocations for these builtins in x86.
1787 if (ParentCGF.getTarget().getTriple().getArch() != llvm::Triple::x86)
1788 return;
1789
1790 unsigned ID = E->getBuiltinCallee();
1791 switch (ID) {
1792 case Builtin::BI__exception_code:
1793 case Builtin::BI_exception_code:
1794 // This is the simple case where we are the outermost finally. All we
1795 // have to do here is make sure we escape this and recover it in the
1796 // outlined handler.
1797 if (!SEHCodeSlot.isValid())
1798 SEHCodeSlot = ParentCGF.SEHCodeSlotStack.back();
1799 break;
1800 }
1801 }
1802};
1803} // end anonymous namespace
1804
1805Address CodeGenFunction::recoverAddrOfEscapedLocal(CodeGenFunction &ParentCGF,
1806 Address ParentVar,
1807 llvm::Value *ParentFP) {
1808 llvm::CallInst *RecoverCall = nullptr;
1809 CGBuilderTy Builder(*this, AllocaInsertPt);
1810 if (auto *ParentAlloca = dyn_cast<llvm::AllocaInst>(ParentVar.getPointer())) {
1811 // Mark the variable escaped if nobody else referenced it and compute the
1812 // localescape index.
1813 auto InsertPair = ParentCGF.EscapedLocals.insert(
1814 std::make_pair(ParentAlloca, ParentCGF.EscapedLocals.size()));
1815 int FrameEscapeIdx = InsertPair.first->second;
1816 // call i8* @llvm.localrecover(i8* bitcast(@parentFn), i8* %fp, i32 N)
1817 llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
1818 &CGM.getModule(), llvm::Intrinsic::localrecover);
1819 llvm::Constant *ParentI8Fn =
1820 llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1821 RecoverCall = Builder.CreateCall(
1822 FrameRecoverFn, {ParentI8Fn, ParentFP,
1823 llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
1824
1825 } else {
1826 // If the parent didn't have an alloca, we're doing some nested outlining.
1827 // Just clone the existing localrecover call, but tweak the FP argument to
1828 // use our FP value. All other arguments are constants.
1829 auto *ParentRecover =
1830 cast<llvm::IntrinsicInst>(ParentVar.getPointer()->stripPointerCasts());
1831 assert(ParentRecover->getIntrinsicID() == llvm::Intrinsic::localrecover &&(static_cast<void> (0))
1832 "expected alloca or localrecover in parent LocalDeclMap")(static_cast<void> (0));
1833 RecoverCall = cast<llvm::CallInst>(ParentRecover->clone());
1834 RecoverCall->setArgOperand(1, ParentFP);
1835 RecoverCall->insertBefore(AllocaInsertPt);
1836 }
1837
1838 // Bitcast the variable, rename it, and insert it in the local decl map.
1839 llvm::Value *ChildVar =
1840 Builder.CreateBitCast(RecoverCall, ParentVar.getType());
1841 ChildVar->setName(ParentVar.getName());
1842 return Address(ChildVar, ParentVar.getAlignment());
1843}
1844
1845void CodeGenFunction::EmitCapturedLocals(CodeGenFunction &ParentCGF,
1846 const Stmt *OutlinedStmt,
1847 bool IsFilter) {
1848 // Find all captures in the Stmt.
1849 CaptureFinder Finder(ParentCGF, ParentCGF.CXXABIThisDecl);
1850 Finder.Visit(OutlinedStmt);
1851
1852 // We can exit early on x86_64 when there are no captures. We just have to
1853 // save the exception code in filters so that __exception_code() works.
1854 if (!Finder.foundCaptures() &&
1855 CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1856 if (IsFilter)
1857 EmitSEHExceptionCodeSave(ParentCGF, nullptr, nullptr);
1858 return;
1859 }
1860
1861 llvm::Value *EntryFP = nullptr;
1862 CGBuilderTy Builder(CGM, AllocaInsertPt);
1863 if (IsFilter && CGM.getTarget().getTriple().getArch() == llvm::Triple::x86) {
1864 // 32-bit SEH filters need to be careful about FP recovery. The end of the
1865 // EH registration is passed in as the EBP physical register. We can
1866 // recover that with llvm.frameaddress(1).
1867 EntryFP = Builder.CreateCall(
1868 CGM.getIntrinsic(llvm::Intrinsic::frameaddress, AllocaInt8PtrTy),
1869 {Builder.getInt32(1)});
1870 } else {
1871 // Otherwise, for x64 and 32-bit finally functions, the parent FP is the
1872 // second parameter.
1873 auto AI = CurFn->arg_begin();
1874 ++AI;
1875 EntryFP = &*AI;
1876 }
1877
1878 llvm::Value *ParentFP = EntryFP;
1879 if (IsFilter) {
1880 // Given whatever FP the runtime provided us in EntryFP, recover the true
1881 // frame pointer of the parent function. We only need to do this in filters,
1882 // since finally funclets recover the parent FP for us.
1883 llvm::Function *RecoverFPIntrin =
1884 CGM.getIntrinsic(llvm::Intrinsic::eh_recoverfp);
1885 llvm::Constant *ParentI8Fn =
1886 llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1887 ParentFP = Builder.CreateCall(RecoverFPIntrin, {ParentI8Fn, EntryFP});
1888
1889 // if the parent is a _finally, the passed-in ParentFP is the FP
1890 // of parent _finally, not Establisher's FP (FP of outermost function).
1891 // Establkisher FP is 2nd paramenter passed into parent _finally.
1892 // Fortunately, it's always saved in parent's frame. The following
1893 // code retrieves it, and escapes it so that spill instruction won't be
1894 // optimized away.
1895 if (ParentCGF.ParentCGF != nullptr) {
1896 // Locate and escape Parent's frame_pointer.addr alloca
1897 // Depending on target, should be 1st/2nd one in LocalDeclMap.
1898 // Let's just scan for ImplicitParamDecl with VoidPtrTy.
1899 llvm::AllocaInst *FramePtrAddrAlloca = nullptr;
1900 for (auto &I : ParentCGF.LocalDeclMap) {
1901 const VarDecl *D = cast<VarDecl>(I.first);
1902 if (isa<ImplicitParamDecl>(D) &&
1903 D->getType() == getContext().VoidPtrTy) {
1904 assert(D->getName().startswith("frame_pointer"))(static_cast<void> (0));
1905 FramePtrAddrAlloca = cast<llvm::AllocaInst>(I.second.getPointer());
1906 break;
1907 }
1908 }
1909 assert(FramePtrAddrAlloca)(static_cast<void> (0));
1910 auto InsertPair = ParentCGF.EscapedLocals.insert(
1911 std::make_pair(FramePtrAddrAlloca, ParentCGF.EscapedLocals.size()));
1912 int FrameEscapeIdx = InsertPair.first->second;
1913
1914 // an example of a filter's prolog::
1915 // %0 = call i8* @llvm.eh.recoverfp(bitcast(@"?fin$0@0@main@@"),..)
1916 // %1 = call i8* @llvm.localrecover(bitcast(@"?fin$0@0@main@@"),..)
1917 // %2 = bitcast i8* %1 to i8**
1918 // %3 = load i8*, i8* *%2, align 8
1919 // ==> %3 is the frame-pointer of outermost host function
1920 llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
1921 &CGM.getModule(), llvm::Intrinsic::localrecover);
1922 llvm::Constant *ParentI8Fn =
1923 llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1924 ParentFP = Builder.CreateCall(
1925 FrameRecoverFn, {ParentI8Fn, ParentFP,
1926 llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
1927 ParentFP = Builder.CreateBitCast(ParentFP, CGM.VoidPtrPtrTy);
1928 ParentFP = Builder.CreateLoad(Address(ParentFP, getPointerAlign()));
1929 }
1930 }
1931
1932 // Create llvm.localrecover calls for all captures.
1933 for (const VarDecl *VD : Finder.Captures) {
1934 if (VD->getType()->isVariablyModifiedType()) {
1935 CGM.ErrorUnsupported(VD, "VLA captured by SEH");
1936 continue;
1937 }
1938 assert((isa<ImplicitParamDecl>(VD) || VD->isLocalVarDeclOrParm()) &&(static_cast<void> (0))
1939 "captured non-local variable")(static_cast<void> (0));
1940
1941 auto L = ParentCGF.LambdaCaptureFields.find(VD);
1942 if (L != ParentCGF.LambdaCaptureFields.end()) {
1943 LambdaCaptureFields[VD] = L->second;
1944 continue;
1945 }
1946
1947 // If this decl hasn't been declared yet, it will be declared in the
1948 // OutlinedStmt.
1949 auto I = ParentCGF.LocalDeclMap.find(VD);
1950 if (I == ParentCGF.LocalDeclMap.end())
1951 continue;
1952
1953 Address ParentVar = I->second;
1954 Address Recovered =
1955 recoverAddrOfEscapedLocal(ParentCGF, ParentVar, ParentFP);
1956 setAddrOfLocalVar(VD, Recovered);
1957
1958 if (isa<ImplicitParamDecl>(VD)) {
1959 CXXABIThisAlignment = ParentCGF.CXXABIThisAlignment;
1960 CXXThisAlignment = ParentCGF.CXXThisAlignment;
1961 CXXABIThisValue = Builder.CreateLoad(Recovered, "this");
1962 if (ParentCGF.LambdaThisCaptureField) {
1963 LambdaThisCaptureField = ParentCGF.LambdaThisCaptureField;
1964 // We are in a lambda function where "this" is captured so the
1965 // CXXThisValue need to be loaded from the lambda capture
1966 LValue ThisFieldLValue =
1967 EmitLValueForLambdaField(LambdaThisCaptureField);
1968 if (!LambdaThisCaptureField->getType()->isPointerType()) {
1969 CXXThisValue = ThisFieldLValue.getAddress(*this).getPointer();
1970 } else {
1971 CXXThisValue = EmitLoadOfLValue(ThisFieldLValue, SourceLocation())
1972 .getScalarVal();
1973 }
1974 } else {
1975 CXXThisValue = CXXABIThisValue;
1976 }
1977 }
1978 }
1979
1980 if (Finder.SEHCodeSlot.isValid()) {
1981 SEHCodeSlotStack.push_back(
1982 recoverAddrOfEscapedLocal(ParentCGF, Finder.SEHCodeSlot, ParentFP));
1983 }
1984
1985 if (IsFilter)
1986 EmitSEHExceptionCodeSave(ParentCGF, ParentFP, EntryFP);
1987}
1988
1989/// Arrange a function prototype that can be called by Windows exception
1990/// handling personalities. On Win64, the prototype looks like:
1991/// RetTy func(void *EHPtrs, void *ParentFP);
1992void CodeGenFunction::startOutlinedSEHHelper(CodeGenFunction &ParentCGF,
1993 bool IsFilter,
1994 const Stmt *OutlinedStmt) {
1995 SourceLocation StartLoc = OutlinedStmt->getBeginLoc();
1996
1997 // Get the mangled function name.
1998 SmallString<128> Name;
1999 {
2000 llvm::raw_svector_ostream OS(Name);
2001 const NamedDecl *ParentSEHFn = ParentCGF.CurSEHParent;
2002 assert(ParentSEHFn && "No CurSEHParent!")(static_cast<void> (0));
2003 MangleContext &Mangler = CGM.getCXXABI().getMangleContext();
2004 if (IsFilter)
2005 Mangler.mangleSEHFilterExpression(ParentSEHFn, OS);
2006 else
2007 Mangler.mangleSEHFinallyBlock(ParentSEHFn, OS);
2008 }
2009
2010 FunctionArgList Args;
2011 if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 || !IsFilter) {
2012 // All SEH finally functions take two parameters. Win64 filters take two
2013 // parameters. Win32 filters take no parameters.
2014 if (IsFilter) {
2015 Args.push_back(ImplicitParamDecl::Create(
2016 getContext(), /*DC=*/nullptr, StartLoc,
2017 &getContext().Idents.get("exception_pointers"),
2018 getContext().VoidPtrTy, ImplicitParamDecl::Other));
2019 } else {
2020 Args.push_back(ImplicitParamDecl::Create(
2021 getContext(), /*DC=*/nullptr, StartLoc,
2022 &getContext().Idents.get("abnormal_termination"),
2023 getContext().UnsignedCharTy, ImplicitParamDecl::Other));
2024 }
2025 Args.push_back(ImplicitParamDecl::Create(
2026 getContext(), /*DC=*/nullptr, StartLoc,
2027 &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy,
2028 ImplicitParamDecl::Other));
2029 }
2030
2031 QualType RetTy = IsFilter ? getContext().LongTy : getContext().VoidTy;
2032
2033 const CGFunctionInfo &FnInfo =
2034 CGM.getTypes().arrangeBuiltinFunctionDeclaration(RetTy, Args);
2035
2036 llvm::FunctionType *FnTy = CGM.getTypes().GetFunctionType(FnInfo);
2037 llvm::Function *Fn = llvm::Function::Create(
2038 FnTy, llvm::GlobalValue::InternalLinkage, Name.str(), &CGM.getModule());
2039
2040 IsOutlinedSEHHelper = true;
2041
2042 StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
2043 OutlinedStmt->getBeginLoc(), OutlinedStmt->getBeginLoc());
2044 CurSEHParent = ParentCGF.CurSEHParent;
2045
2046 CGM.SetInternalFunctionAttributes(GlobalDecl(), CurFn, FnInfo);
2047 EmitCapturedLocals(ParentCGF, OutlinedStmt, IsFilter);
2048}
2049
2050/// Create a stub filter function that will ultimately hold the code of the
2051/// filter expression. The EH preparation passes in LLVM will outline the code
2052/// from the main function body into this stub.
2053llvm::Function *
2054CodeGenFunction::GenerateSEHFilterFunction(CodeGenFunction &ParentCGF,
2055 const SEHExceptStmt &Except) {
2056 const Expr *FilterExpr = Except.getFilterExpr();
2057 startOutlinedSEHHelper(ParentCGF, true, FilterExpr);
2058
2059 // Emit the original filter expression, convert to i32, and return.
2060 llvm::Value *R = EmitScalarExpr(FilterExpr);
2061 R = Builder.CreateIntCast(R, ConvertType(getContext().LongTy),
2062 FilterExpr->getType()->isSignedIntegerType());
2063 Builder.CreateStore(R, ReturnValue);
2064
2065 FinishFunction(FilterExpr->getEndLoc());
2066
2067 return CurFn;
2068}
2069
2070llvm::Function *
2071CodeGenFunction::GenerateSEHFinallyFunction(CodeGenFunction &ParentCGF,
2072 const SEHFinallyStmt &Finally) {
2073 const Stmt *FinallyBlock = Finally.getBlock();
2074 startOutlinedSEHHelper(ParentCGF, false, FinallyBlock);
2075
2076 // Emit the original filter expression, convert to i32, and return.
2077 EmitStmt(FinallyBlock);
2078
2079 FinishFunction(FinallyBlock->getEndLoc());
2080
2081 return CurFn;
2082}
2083
2084void CodeGenFunction::EmitSEHExceptionCodeSave(CodeGenFunction &ParentCGF,
2085 llvm::Value *ParentFP,
2086 llvm::Value *EntryFP) {
2087 // Get the pointer to the EXCEPTION_POINTERS struct. This is returned by the
2088 // __exception_info intrinsic.
2089 if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
2090 // On Win64, the info is passed as the first parameter to the filter.
2091 SEHInfo = &*CurFn->arg_begin();
2092 SEHCodeSlotStack.push_back(
2093 CreateMemTemp(getContext().IntTy, "__exception_code"));
2094 } else {
2095 // On Win32, the EBP on entry to the filter points to the end of an
2096 // exception registration object. It contains 6 32-bit fields, and the info
2097 // pointer is stored in the second field. So, GEP 20 bytes backwards and
2098 // load the pointer.
2099 SEHInfo = Builder.CreateConstInBoundsGEP1_32(Int8Ty, EntryFP, -20);
2100 SEHInfo = Builder.CreateBitCast(SEHInfo, Int8PtrTy->getPointerTo());
2101 SEHInfo = Builder.CreateAlignedLoad(Int8PtrTy, SEHInfo, getPointerAlign());
2102 SEHCodeSlotStack.push_back(recoverAddrOfEscapedLocal(
2103 ParentCGF, ParentCGF.SEHCodeSlotStack.back(), ParentFP));
2104 }
2105
2106 // Save the exception code in the exception slot to unify exception access in
2107 // the filter function and the landing pad.
2108 // struct EXCEPTION_POINTERS {
2109 // EXCEPTION_RECORD *ExceptionRecord;
2110 // CONTEXT *ContextRecord;
2111 // };
2112 // int exceptioncode = exception_pointers->ExceptionRecord->ExceptionCode;
2113 llvm::Type *RecordTy = CGM.Int32Ty->getPointerTo();
2114 llvm::Type *PtrsTy = llvm::StructType::get(RecordTy, CGM.VoidPtrTy);
2115 llvm::Value *Ptrs = Builder.CreateBitCast(SEHInfo, PtrsTy->getPointerTo());
2116 llvm::Value *Rec = Builder.CreateStructGEP(PtrsTy, Ptrs, 0);
2117 Rec = Builder.CreateAlignedLoad(RecordTy, Rec, getPointerAlign());
2118 llvm::Value *Code = Builder.CreateAlignedLoad(Int32Ty, Rec, getIntAlign());
2119 assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except")(static_cast<void> (0));
2120 Builder.CreateStore(Code, SEHCodeSlotStack.back());
2121}
2122
2123llvm::Value *CodeGenFunction::EmitSEHExceptionInfo() {
2124 // Sema should diagnose calling this builtin outside of a filter context, but
2125 // don't crash if we screw up.
2126 if (!SEHInfo)
2127 return llvm::UndefValue::get(Int8PtrTy);
2128 assert(SEHInfo->getType() == Int8PtrTy)(static_cast<void> (0));
2129 return SEHInfo;
2130}
2131
2132llvm::Value *CodeGenFunction::EmitSEHExceptionCode() {
2133 assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except")(static_cast<void> (0));
2134 return Builder.CreateLoad(SEHCodeSlotStack.back());
2135}
2136
2137llvm::Value *CodeGenFunction::EmitSEHAbnormalTermination() {
2138 // Abnormal termination is just the first parameter to the outlined finally
2139 // helper.
2140 auto AI = CurFn->arg_begin();
2141 return Builder.CreateZExt(&*AI, Int32Ty);
2142}
2143
2144void CodeGenFunction::pushSEHCleanup(CleanupKind Kind,
2145 llvm::Function *FinallyFunc) {
2146 EHStack.pushCleanup<PerformSEHFinally>(Kind, FinallyFunc);
2147}
2148
2149void CodeGenFunction::EnterSEHTryStmt(const SEHTryStmt &S) {
2150 CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
2151 HelperCGF.ParentCGF = this;
2152 if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
2153 // Outline the finally block.
2154 llvm::Function *FinallyFunc =
2155 HelperCGF.GenerateSEHFinallyFunction(*this, *Finally);
2156
2157 // Push a cleanup for __finally blocks.
2158 EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc);
2159 return;
2160 }
2161
2162 // Otherwise, we must have an __except block.
2163 const SEHExceptStmt *Except = S.getExceptHandler();
2164 assert(Except)(static_cast<void> (0));
2165 EHCatchScope *CatchScope = EHStack.pushCatch(1);
2166 SEHCodeSlotStack.push_back(
2167 CreateMemTemp(getContext().IntTy, "__exception_code"));
2168
2169 // If the filter is known to evaluate to 1, then we can use the clause
2170 // "catch i8* null". We can't do this on x86 because the filter has to save
2171 // the exception code.
2172 llvm::Constant *C =
2173 ConstantEmitter(*this).tryEmitAbstract(Except->getFilterExpr(),
2174 getContext().IntTy);
2175 if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 && C &&
2176 C->isOneValue()) {
2177 CatchScope->setCatchAllHandler(0, createBasicBlock("__except"));
2178 return;
2179 }
2180
2181 // In general, we have to emit an outlined filter function. Use the function
2182 // in place of the RTTI typeinfo global that C++ EH uses.
2183 llvm::Function *FilterFunc =
2184 HelperCGF.GenerateSEHFilterFunction(*this, *Except);
2185 llvm::Constant *OpaqueFunc =
2186 llvm::ConstantExpr::getBitCast(FilterFunc, Int8PtrTy);
2187 CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except.ret"));
2188}
2189
2190void CodeGenFunction::ExitSEHTryStmt(const SEHTryStmt &S) {
2191 // Just pop the cleanup if it's a __finally block.
2192 if (S.getFinallyHandler()) {
2193 PopCleanupBlock();
2194 return;
2195 }
2196
2197 // IsEHa: emit an invoke _seh_try_end() to mark end of FT flow
2198 if (getLangOpts().EHAsynch && Builder.GetInsertBlock()) {
2199 llvm::FunctionCallee SehTryEnd = getSehTryEndFn(CGM);
2200 EmitRuntimeCallOrInvoke(SehTryEnd);
2201 }
2202
2203 // Otherwise, we must have an __except block.
2204 const SEHExceptStmt *Except = S.getExceptHandler();
2205 assert(Except && "__try must have __finally xor __except")(static_cast<void> (0));
2206 EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
2207
2208 // Don't emit the __except block if the __try block lacked invokes.
2209 // TODO: Model unwind edges from instructions, either with iload / istore or
2210 // a try body function.
2211 if (!CatchScope.hasEHBranches()) {
2212 CatchScope.clearHandlerBlocks();
2213 EHStack.popCatch();
2214 SEHCodeSlotStack.pop_back();
2215 return;
2216 }
2217
2218 // The fall-through block.
2219 llvm::BasicBlock *ContBB = createBasicBlock("__try.cont");
2220
2221 // We just emitted the body of the __try; jump to the continue block.
2222 if (HaveInsertPoint())
2223 Builder.CreateBr(ContBB);
2224
2225 // Check if our filter function returned true.
2226 emitCatchDispatchBlock(*this, CatchScope);
2227
2228 // Grab the block before we pop the handler.
2229 llvm::BasicBlock *CatchPadBB = CatchScope.getHandler(0).Block;
2230 EHStack.popCatch();
2231
2232 EmitBlockAfterUses(CatchPadBB);
2233
2234 // __except blocks don't get outlined into funclets, so immediately do a
2235 // catchret.
2236 llvm::CatchPadInst *CPI =
2237 cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
2238 llvm::BasicBlock *ExceptBB = createBasicBlock("__except");
2239 Builder.CreateCatchRet(CPI, ExceptBB);
2240 EmitBlock(ExceptBB);
2241
2242 // On Win64, the exception code is returned in EAX. Copy it into the slot.
2243 if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
2244 llvm::Function *SEHCodeIntrin =
2245 CGM.getIntrinsic(llvm::Intrinsic::eh_exceptioncode);
2246 llvm::Value *Code = Builder.CreateCall(SEHCodeIntrin, {CPI});
2247 Builder.CreateStore(Code, SEHCodeSlotStack.back());
2248 }
2249
2250 // Emit the __except body.
2251 EmitStmt(Except->getBlock());
2252
2253 // End the lifetime of the exception code.
2254 SEHCodeSlotStack.pop_back();
2255
2256 if (HaveInsertPoint())
2257 Builder.CreateBr(ContBB);
2258
2259 EmitBlock(ContBB);
2260}
2261
2262void CodeGenFunction::EmitSEHLeaveStmt(const SEHLeaveStmt &S) {
2263 // If this code is reachable then emit a stop point (if generating
2264 // debug info). We have to do this ourselves because we are on the
2265 // "simple" statement path.
2266 if (HaveInsertPoint())
2267 EmitStopPoint(&S);
2268
2269 // This must be a __leave from a __finally block, which we warn on and is UB.
2270 // Just emit unreachable.
2271 if (!isSEHTryScope()) {
2272 Builder.CreateUnreachable();
2273 Builder.ClearInsertionPoint();
2274 return;
2275 }
2276
2277 EmitBranchThroughCleanup(*SEHTryEpilogueStack.back());
2278}

/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/CodeGen/CGCleanup.h

1//===-- CGCleanup.h - Classes for cleanups IR generation --------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// These classes support the generation of LLVM IR for cleanups.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_CLANG_LIB_CODEGEN_CGCLEANUP_H
14#define LLVM_CLANG_LIB_CODEGEN_CGCLEANUP_H
15
16#include "EHScopeStack.h"
17
18#include "Address.h"
19#include "llvm/ADT/SmallPtrSet.h"
20#include "llvm/ADT/SmallVector.h"
21
22namespace llvm {
23class BasicBlock;
24class Value;
25class ConstantInt;
26class AllocaInst;
27}
28
29namespace clang {
30class FunctionDecl;
31namespace CodeGen {
32class CodeGenModule;
33class CodeGenFunction;
34
35/// The MS C++ ABI needs a pointer to RTTI data plus some flags to describe the
36/// type of a catch handler, so we use this wrapper.
37struct CatchTypeInfo {
38 llvm::Constant *RTTI;
39 unsigned Flags;
40};
41
42/// A protected scope for zero-cost EH handling.
43class EHScope {
44 llvm::BasicBlock *CachedLandingPad;
45 llvm::BasicBlock *CachedEHDispatchBlock;
46
47 EHScopeStack::stable_iterator EnclosingEHScope;
48
49 class CommonBitFields {
50 friend class EHScope;
51 unsigned Kind : 3;
52 };
53 enum { NumCommonBits = 3 };
54
55protected:
56 class CatchBitFields {
57 friend class EHCatchScope;
58 unsigned : NumCommonBits;
59
60 unsigned NumHandlers : 32 - NumCommonBits;
61 };
62
63 class CleanupBitFields {
64 friend class EHCleanupScope;
65 unsigned : NumCommonBits;
66
67 /// Whether this cleanup needs to be run along normal edges.
68 unsigned IsNormalCleanup : 1;
69
70 /// Whether this cleanup needs to be run along exception edges.
71 unsigned IsEHCleanup : 1;
72
73 /// Whether this cleanup is currently active.
74 unsigned IsActive : 1;
75
76 /// Whether this cleanup is a lifetime marker
77 unsigned IsLifetimeMarker : 1;
78
79 /// Whether the normal cleanup should test the activation flag.
80 unsigned TestFlagInNormalCleanup : 1;
81
82 /// Whether the EH cleanup should test the activation flag.
83 unsigned TestFlagInEHCleanup : 1;
84
85 /// The amount of extra storage needed by the Cleanup.
86 /// Always a multiple of the scope-stack alignment.
87 unsigned CleanupSize : 12;
88 };
89
90 class FilterBitFields {
91 friend class EHFilterScope;
92 unsigned : NumCommonBits;
93
94 unsigned NumFilters : 32 - NumCommonBits;
95 };
96
97 union {
98 CommonBitFields CommonBits;
99 CatchBitFields CatchBits;
100 CleanupBitFields CleanupBits;
101 FilterBitFields FilterBits;
102 };
103
104public:
105 enum Kind { Cleanup, Catch, Terminate, Filter };
106
107 EHScope(Kind kind, EHScopeStack::stable_iterator enclosingEHScope)
108 : CachedLandingPad(nullptr), CachedEHDispatchBlock(nullptr),
109 EnclosingEHScope(enclosingEHScope) {
110 CommonBits.Kind = kind;
111 }
112
113 Kind getKind() const { return static_cast<Kind>(CommonBits.Kind); }
114
115 llvm::BasicBlock *getCachedLandingPad() const {
116 return CachedLandingPad;
117 }
118
119 void setCachedLandingPad(llvm::BasicBlock *block) {
120 CachedLandingPad = block;
121 }
122
123 llvm::BasicBlock *getCachedEHDispatchBlock() const {
124 return CachedEHDispatchBlock;
125 }
126
127 void setCachedEHDispatchBlock(llvm::BasicBlock *block) {
128 CachedEHDispatchBlock = block;
129 }
130
131 bool hasEHBranches() const {
132 if (llvm::BasicBlock *block = getCachedEHDispatchBlock())
4
Assuming 'block' is non-null
5
Taking true branch
133 return !block->use_empty();
6
Calling 'Value::use_empty'
9
Returning from 'Value::use_empty'
10
Returning the value 1, which participates in a condition later
134 return false;
135 }
136
137 EHScopeStack::stable_iterator getEnclosingEHScope() const {
138 return EnclosingEHScope;
139 }
140};
141
142/// A scope which attempts to handle some, possibly all, types of
143/// exceptions.
144///
145/// Objective C \@finally blocks are represented using a cleanup scope
146/// after the catch scope.
147class EHCatchScope : public EHScope {
148 // In effect, we have a flexible array member
149 // Handler Handlers[0];
150 // But that's only standard in C99, not C++, so we have to do
151 // annoying pointer arithmetic instead.
152
153public:
154 struct Handler {
155 /// A type info value, or null (C++ null, not an LLVM null pointer)
156 /// for a catch-all.
157 CatchTypeInfo Type;
158
159 /// The catch handler for this type.
160 llvm::BasicBlock *Block;
161
162 bool isCatchAll() const { return Type.RTTI == nullptr; }
163 };
164
165private:
166 friend class EHScopeStack;
167
168 Handler *getHandlers() {
169 return reinterpret_cast<Handler*>(this+1);
170 }
171
172 const Handler *getHandlers() const {
173 return reinterpret_cast<const Handler*>(this+1);
174 }
175
176public:
177 static size_t getSizeForNumHandlers(unsigned N) {
178 return sizeof(EHCatchScope) + N * sizeof(Handler);
179 }
180
181 EHCatchScope(unsigned numHandlers,
182 EHScopeStack::stable_iterator enclosingEHScope)
183 : EHScope(Catch, enclosingEHScope) {
184 CatchBits.NumHandlers = numHandlers;
185 assert(CatchBits.NumHandlers == numHandlers && "NumHandlers overflow?")(static_cast<void> (0));
186 }
187
188 unsigned getNumHandlers() const {
189 return CatchBits.NumHandlers;
190 }
191
192 void setCatchAllHandler(unsigned I, llvm::BasicBlock *Block) {
193 setHandler(I, CatchTypeInfo{nullptr, 0}, Block);
194 }
195
196 void setHandler(unsigned I, llvm::Constant *Type, llvm::BasicBlock *Block) {
197 assert(I < getNumHandlers())(static_cast<void> (0));
198 getHandlers()[I].Type = CatchTypeInfo{Type, 0};
199 getHandlers()[I].Block = Block;
200 }
201
202 void setHandler(unsigned I, CatchTypeInfo Type, llvm::BasicBlock *Block) {
203 assert(I < getNumHandlers())(static_cast<void> (0));
204 getHandlers()[I].Type = Type;
205 getHandlers()[I].Block = Block;
206 }
207
208 const Handler &getHandler(unsigned I) const {
209 assert(I < getNumHandlers())(static_cast<void> (0));
210 return getHandlers()[I];
211 }
212
213 // Clear all handler blocks.
214 // FIXME: it's better to always call clearHandlerBlocks in DTOR and have a
215 // 'takeHandler' or some such function which removes ownership from the
216 // EHCatchScope object if the handlers should live longer than EHCatchScope.
217 void clearHandlerBlocks() {
218 for (unsigned I = 0, N = getNumHandlers(); I != N; ++I)
219 delete getHandler(I).Block;
220 }
221
222 typedef const Handler *iterator;
223 iterator begin() const { return getHandlers(); }
224 iterator end() const { return getHandlers() + getNumHandlers(); }
225
226 static bool classof(const EHScope *Scope) {
227 return Scope->getKind() == Catch;
228 }
229};
230
231/// A cleanup scope which generates the cleanup blocks lazily.
232class alignas(8) EHCleanupScope : public EHScope {
233 /// The nearest normal cleanup scope enclosing this one.
234 EHScopeStack::stable_iterator EnclosingNormal;
235
236 /// The nearest EH scope enclosing this one.
237 EHScopeStack::stable_iterator EnclosingEH;
238
239 /// The dual entry/exit block along the normal edge. This is lazily
240 /// created if needed before the cleanup is popped.
241 llvm::BasicBlock *NormalBlock;
242
243 /// An optional i1 variable indicating whether this cleanup has been
244 /// activated yet.
245 llvm::AllocaInst *ActiveFlag;
246
247 /// Extra information required for cleanups that have resolved
248 /// branches through them. This has to be allocated on the side
249 /// because everything on the cleanup stack has be trivially
250 /// movable.
251 struct ExtInfo {
252 /// The destinations of normal branch-afters and branch-throughs.
253 llvm::SmallPtrSet<llvm::BasicBlock*, 4> Branches;
254
255 /// Normal branch-afters.
256 SmallVector<std::pair<llvm::BasicBlock*,llvm::ConstantInt*>, 4>
257 BranchAfters;
258 };
259 mutable struct ExtInfo *ExtInfo;
260
261 /// The number of fixups required by enclosing scopes (not including
262 /// this one). If this is the top cleanup scope, all the fixups
263 /// from this index onwards belong to this scope.
264 unsigned FixupDepth;
265
266 struct ExtInfo &getExtInfo() {
267 if (!ExtInfo) ExtInfo = new struct ExtInfo();
268 return *ExtInfo;
269 }
270
271 const struct ExtInfo &getExtInfo() const {
272 if (!ExtInfo) ExtInfo = new struct ExtInfo();
273 return *ExtInfo;
274 }
275
276public:
277 /// Gets the size required for a lazy cleanup scope with the given
278 /// cleanup-data requirements.
279 static size_t getSizeForCleanupSize(size_t Size) {
280 return sizeof(EHCleanupScope) + Size;
281 }
282
283 size_t getAllocatedSize() const {
284 return sizeof(EHCleanupScope) + CleanupBits.CleanupSize;
285 }
286
287 EHCleanupScope(bool isNormal, bool isEH, unsigned cleanupSize,
288 unsigned fixupDepth,
289 EHScopeStack::stable_iterator enclosingNormal,
290 EHScopeStack::stable_iterator enclosingEH)
291 : EHScope(EHScope::Cleanup, enclosingEH),
292 EnclosingNormal(enclosingNormal), NormalBlock(nullptr),
293 ActiveFlag(nullptr), ExtInfo(nullptr), FixupDepth(fixupDepth) {
294 CleanupBits.IsNormalCleanup = isNormal;
295 CleanupBits.IsEHCleanup = isEH;
296 CleanupBits.IsActive = true;
297 CleanupBits.IsLifetimeMarker = false;
298 CleanupBits.TestFlagInNormalCleanup = false;
299 CleanupBits.TestFlagInEHCleanup = false;
300 CleanupBits.CleanupSize = cleanupSize;
301
302 assert(CleanupBits.CleanupSize == cleanupSize && "cleanup size overflow")(static_cast<void> (0));
303 }
304
305 void Destroy() {
306 delete ExtInfo;
307 }
308 // Objects of EHCleanupScope are not destructed. Use Destroy().
309 ~EHCleanupScope() = delete;
310
311 bool isNormalCleanup() const { return CleanupBits.IsNormalCleanup; }
312 llvm::BasicBlock *getNormalBlock() const { return NormalBlock; }
313 void setNormalBlock(llvm::BasicBlock *BB) { NormalBlock = BB; }
314
315 bool isEHCleanup() const { return CleanupBits.IsEHCleanup; }
316
317 bool isActive() const { return CleanupBits.IsActive; }
318 void setActive(bool A) { CleanupBits.IsActive = A; }
319
320 bool isLifetimeMarker() const { return CleanupBits.IsLifetimeMarker; }
321 void setLifetimeMarker() { CleanupBits.IsLifetimeMarker = true; }
322
323 bool hasActiveFlag() const { return ActiveFlag != nullptr; }
324 Address getActiveFlag() const {
325 return Address(ActiveFlag, CharUnits::One());
326 }
327 void setActiveFlag(Address Var) {
328 assert(Var.getAlignment().isOne())(static_cast<void> (0));
329 ActiveFlag = cast<llvm::AllocaInst>(Var.getPointer());
330 }
331
332 void setTestFlagInNormalCleanup() {
333 CleanupBits.TestFlagInNormalCleanup = true;
334 }
335 bool shouldTestFlagInNormalCleanup() const {
336 return CleanupBits.TestFlagInNormalCleanup;
337 }
338
339 void setTestFlagInEHCleanup() {
340 CleanupBits.TestFlagInEHCleanup = true;
341 }
342 bool shouldTestFlagInEHCleanup() const {
343 return CleanupBits.TestFlagInEHCleanup;
344 }
345
346 unsigned getFixupDepth() const { return FixupDepth; }
347 EHScopeStack::stable_iterator getEnclosingNormalCleanup() const {
348 return EnclosingNormal;
349 }
350
351 size_t getCleanupSize() const { return CleanupBits.CleanupSize; }
352 void *getCleanupBuffer() { return this + 1; }
353
354 EHScopeStack::Cleanup *getCleanup() {
355 return reinterpret_cast<EHScopeStack::Cleanup*>(getCleanupBuffer());
356 }
357
358 /// True if this cleanup scope has any branch-afters or branch-throughs.
359 bool hasBranches() const { return ExtInfo && !ExtInfo->Branches.empty(); }
360
361 /// Add a branch-after to this cleanup scope. A branch-after is a
362 /// branch from a point protected by this (normal) cleanup to a
363 /// point in the normal cleanup scope immediately containing it.
364 /// For example,
365 /// for (;;) { A a; break; }
366 /// contains a branch-after.
367 ///
368 /// Branch-afters each have their own destination out of the
369 /// cleanup, guaranteed distinct from anything else threaded through
370 /// it. Therefore branch-afters usually force a switch after the
371 /// cleanup.
372 void addBranchAfter(llvm::ConstantInt *Index,
373 llvm::BasicBlock *Block) {
374 struct ExtInfo &ExtInfo = getExtInfo();
375 if (ExtInfo.Branches.insert(Block).second)
376 ExtInfo.BranchAfters.push_back(std::make_pair(Block, Index));
377 }
378
379 /// Return the number of unique branch-afters on this scope.
380 unsigned getNumBranchAfters() const {
381 return ExtInfo ? ExtInfo->BranchAfters.size() : 0;
382 }
383
384 llvm::BasicBlock *getBranchAfterBlock(unsigned I) const {
385 assert(I < getNumBranchAfters())(static_cast<void> (0));
386 return ExtInfo->BranchAfters[I].first;
387 }
388
389 llvm::ConstantInt *getBranchAfterIndex(unsigned I) const {
390 assert(I < getNumBranchAfters())(static_cast<void> (0));
391 return ExtInfo->BranchAfters[I].second;
392 }
393
394 /// Add a branch-through to this cleanup scope. A branch-through is
395 /// a branch from a scope protected by this (normal) cleanup to an
396 /// enclosing scope other than the immediately-enclosing normal
397 /// cleanup scope.
398 ///
399 /// In the following example, the branch through B's scope is a
400 /// branch-through, while the branch through A's scope is a
401 /// branch-after:
402 /// for (;;) { A a; B b; break; }
403 ///
404 /// All branch-throughs have a common destination out of the
405 /// cleanup, one possibly shared with the fall-through. Therefore
406 /// branch-throughs usually don't force a switch after the cleanup.
407 ///
408 /// \return true if the branch-through was new to this scope
409 bool addBranchThrough(llvm::BasicBlock *Block) {
410 return getExtInfo().Branches.insert(Block).second;
411 }
412
413 /// Determines if this cleanup scope has any branch throughs.
414 bool hasBranchThroughs() const {
415 if (!ExtInfo) return false;
416 return (ExtInfo->BranchAfters.size() != ExtInfo->Branches.size());
417 }
418
419 static bool classof(const EHScope *Scope) {
420 return (Scope->getKind() == Cleanup);
421 }
422};
423// NOTE: there's a bunch of different data classes tacked on after an
424// EHCleanupScope. It is asserted (in EHScopeStack::pushCleanup*) that
425// they don't require greater alignment than ScopeStackAlignment. So,
426// EHCleanupScope ought to have alignment equal to that -- not more
427// (would be misaligned by the stack allocator), and not less (would
428// break the appended classes).
429static_assert(alignof(EHCleanupScope) == EHScopeStack::ScopeStackAlignment,
430 "EHCleanupScope expected alignment");
431
432/// An exceptions scope which filters exceptions thrown through it.
433/// Only exceptions matching the filter types will be permitted to be
434/// thrown.
435///
436/// This is used to implement C++ exception specifications.
437class EHFilterScope : public EHScope {
438 // Essentially ends in a flexible array member:
439 // llvm::Value *FilterTypes[0];
440
441 llvm::Value **getFilters() {
442 return reinterpret_cast<llvm::Value**>(this+1);
443 }
444
445 llvm::Value * const *getFilters() const {
446 return reinterpret_cast<llvm::Value* const *>(this+1);
447 }
448
449public:
450 EHFilterScope(unsigned numFilters)
451 : EHScope(Filter, EHScopeStack::stable_end()) {
452 FilterBits.NumFilters = numFilters;
453 assert(FilterBits.NumFilters == numFilters && "NumFilters overflow")(static_cast<void> (0));
454 }
455
456 static size_t getSizeForNumFilters(unsigned numFilters) {
457 return sizeof(EHFilterScope) + numFilters * sizeof(llvm::Value*);
458 }
459
460 unsigned getNumFilters() const { return FilterBits.NumFilters; }
461
462 void setFilter(unsigned i, llvm::Value *filterValue) {
463 assert(i < getNumFilters())(static_cast<void> (0));
464 getFilters()[i] = filterValue;
465 }
466
467 llvm::Value *getFilter(unsigned i) const {
468 assert(i < getNumFilters())(static_cast<void> (0));
469 return getFilters()[i];
470 }
471
472 static bool classof(const EHScope *scope) {
473 return scope->getKind() == Filter;
474 }
475};
476
477/// An exceptions scope which calls std::terminate if any exception
478/// reaches it.
479class EHTerminateScope : public EHScope {
480public:
481 EHTerminateScope(EHScopeStack::stable_iterator enclosingEHScope)
482 : EHScope(Terminate, enclosingEHScope) {}
483 static size_t getSize() { return sizeof(EHTerminateScope); }
484
485 static bool classof(const EHScope *scope) {
486 return scope->getKind() == Terminate;
487 }
488};
489
490/// A non-stable pointer into the scope stack.
491class EHScopeStack::iterator {
492 char *Ptr;
493
494 friend class EHScopeStack;
495 explicit iterator(char *Ptr) : Ptr(Ptr) {}
496
497public:
498 iterator() : Ptr(nullptr) {}
499
500 EHScope *get() const {
501 return reinterpret_cast<EHScope*>(Ptr);
502 }
503
504 EHScope *operator->() const { return get(); }
505 EHScope &operator*() const { return *get(); }
506
507 iterator &operator++() {
508 size_t Size;
509 switch (get()->getKind()) {
510 case EHScope::Catch:
511 Size = EHCatchScope::getSizeForNumHandlers(
512 static_cast<const EHCatchScope *>(get())->getNumHandlers());
513 break;
514
515 case EHScope::Filter:
516 Size = EHFilterScope::getSizeForNumFilters(
517 static_cast<const EHFilterScope *>(get())->getNumFilters());
518 break;
519
520 case EHScope::Cleanup:
521 Size = static_cast<const EHCleanupScope *>(get())->getAllocatedSize();
522 break;
523
524 case EHScope::Terminate:
525 Size = EHTerminateScope::getSize();
526 break;
527 }
528 Ptr += llvm::alignTo(Size, ScopeStackAlignment);
529 return *this;
530 }
531
532 iterator next() {
533 iterator copy = *this;
534 ++copy;
535 return copy;
536 }
537
538 iterator operator++(int) {
539 iterator copy = *this;
540 operator++();
541 return copy;
542 }
543
544 bool encloses(iterator other) const { return Ptr >= other.Ptr; }
545 bool strictlyEncloses(iterator other) const { return Ptr > other.Ptr; }
546
547 bool operator==(iterator other) const { return Ptr == other.Ptr; }
548 bool operator!=(iterator other) const { return Ptr != other.Ptr; }
549};
550
551inline EHScopeStack::iterator EHScopeStack::begin() const {
552 return iterator(StartOfData);
553}
554
555inline EHScopeStack::iterator EHScopeStack::end() const {
556 return iterator(EndOfBuffer);
557}
558
559inline void EHScopeStack::popCatch() {
560 assert(!empty() && "popping exception stack when not empty")(static_cast<void> (0));
561
562 EHCatchScope &scope = cast<EHCatchScope>(*begin());
563 InnermostEHScope = scope.getEnclosingEHScope();
564 deallocate(EHCatchScope::getSizeForNumHandlers(scope.getNumHandlers()));
565}
566
567inline void EHScopeStack::popTerminate() {
568 assert(!empty() && "popping exception stack when not empty")(static_cast<void> (0));
569
570 EHTerminateScope &scope = cast<EHTerminateScope>(*begin());
571 InnermostEHScope = scope.getEnclosingEHScope();
572 deallocate(EHTerminateScope::getSize());
573}
574
575inline EHScopeStack::iterator EHScopeStack::find(stable_iterator sp) const {
576 assert(sp.isValid() && "finding invalid savepoint")(static_cast<void> (0));
577 assert(sp.Size <= stable_begin().Size && "finding savepoint after pop")(static_cast<void> (0));
578 return iterator(EndOfBuffer - sp.Size);
579}
580
581inline EHScopeStack::stable_iterator
582EHScopeStack::stabilize(iterator ir) const {
583 assert(StartOfData <= ir.Ptr && ir.Ptr <= EndOfBuffer)(static_cast<void> (0));
584 return stable_iterator(EndOfBuffer - ir.Ptr);
585}
586
587/// The exceptions personality for a function.
588struct EHPersonality {
589 const char *PersonalityFn;
590
591 // If this is non-null, this personality requires a non-standard
592 // function for rethrowing an exception after a catchall cleanup.
593 // This function must have prototype void(void*).
594 const char *CatchallRethrowFn;
595
596 static const EHPersonality &get(CodeGenModule &CGM, const FunctionDecl *FD);
597 static const EHPersonality &get(CodeGenFunction &CGF);
598
599 static const EHPersonality GNU_C;
600 static const EHPersonality GNU_C_SJLJ;
601 static const EHPersonality GNU_C_SEH;
602 static const EHPersonality GNU_ObjC;
603 static const EHPersonality GNU_ObjC_SJLJ;
604 static const EHPersonality GNU_ObjC_SEH;
605 static const EHPersonality GNUstep_ObjC;
606 static const EHPersonality GNU_ObjCXX;
607 static const EHPersonality NeXT_ObjC;
608 static const EHPersonality GNU_CPlusPlus;
609 static const EHPersonality GNU_CPlusPlus_SJLJ;
610 static const EHPersonality GNU_CPlusPlus_SEH;
611 static const EHPersonality MSVC_except_handler;
612 static const EHPersonality MSVC_C_specific_handler;
613 static const EHPersonality MSVC_CxxFrameHandler3;
614 static const EHPersonality GNU_Wasm_CPlusPlus;
615 static const EHPersonality XL_CPlusPlus;
616
617 /// Does this personality use landingpads or the family of pad instructions
618 /// designed to form funclets?
619 bool usesFuncletPads() const {
620 return isMSVCPersonality() || isWasmPersonality();
621 }
622
623 bool isMSVCPersonality() const {
624 return this == &MSVC_except_handler || this == &MSVC_C_specific_handler ||
625 this == &MSVC_CxxFrameHandler3;
626 }
627
628 bool isWasmPersonality() const { return this == &GNU_Wasm_CPlusPlus; }
629
630 bool isMSVCXXPersonality() const { return this == &MSVC_CxxFrameHandler3; }
631};
632}
633}
634
635#endif

/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include/llvm/IR/Value.h

1//===- llvm/Value.h - Definition of the Value class -------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file declares the Value class.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_IR_VALUE_H
14#define LLVM_IR_VALUE_H
15
16#include "llvm-c/Types.h"
17#include "llvm/ADT/STLExtras.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/ADT/iterator_range.h"
20#include "llvm/IR/Use.h"
21#include "llvm/Support/Alignment.h"
22#include "llvm/Support/CBindingWrapping.h"
23#include "llvm/Support/Casting.h"
24#include <cassert>
25#include <iterator>
26#include <memory>
27
28namespace llvm {
29
30class APInt;
31class Argument;
32class BasicBlock;
33class Constant;
34class ConstantData;
35class ConstantAggregate;
36class DataLayout;
37class Function;
38class GlobalAlias;
39class GlobalIFunc;
40class GlobalIndirectSymbol;
41class GlobalObject;
42class GlobalValue;
43class GlobalVariable;
44class InlineAsm;
45class Instruction;
46class LLVMContext;
47class MDNode;
48class Module;
49class ModuleSlotTracker;
50class raw_ostream;
51template<typename ValueTy> class StringMapEntry;
52class Twine;
53class Type;
54class User;
55
56using ValueName = StringMapEntry<Value *>;
57
58//===----------------------------------------------------------------------===//
59// Value Class
60//===----------------------------------------------------------------------===//
61
62/// LLVM Value Representation
63///
64/// This is a very important LLVM class. It is the base class of all values
65/// computed by a program that may be used as operands to other values. Value is
66/// the super class of other important classes such as Instruction and Function.
67/// All Values have a Type. Type is not a subclass of Value. Some values can
68/// have a name and they belong to some Module. Setting the name on the Value
69/// automatically updates the module's symbol table.
70///
71/// Every value has a "use list" that keeps track of which other Values are
72/// using this Value. A Value can also have an arbitrary number of ValueHandle
73/// objects that watch it and listen to RAUW and Destroy events. See
74/// llvm/IR/ValueHandle.h for details.
75class Value {
76 Type *VTy;
77 Use *UseList;
78
79 friend class ValueAsMetadata; // Allow access to IsUsedByMD.
80 friend class ValueHandleBase;
81
82 const unsigned char SubclassID; // Subclass identifier (for isa/dyn_cast)
83 unsigned char HasValueHandle : 1; // Has a ValueHandle pointing to this?
84
85protected:
86 /// Hold subclass data that can be dropped.
87 ///
88 /// This member is similar to SubclassData, however it is for holding
89 /// information which may be used to aid optimization, but which may be
90 /// cleared to zero without affecting conservative interpretation.
91 unsigned char SubclassOptionalData : 7;
92
93private:
94 /// Hold arbitrary subclass data.
95 ///
96 /// This member is defined by this class, but is not used for anything.
97 /// Subclasses can use it to hold whatever state they find useful. This
98 /// field is initialized to zero by the ctor.
99 unsigned short SubclassData;
100
101protected:
102 /// The number of operands in the subclass.
103 ///
104 /// This member is defined by this class, but not used for anything.
105 /// Subclasses can use it to store their number of operands, if they have
106 /// any.
107 ///
108 /// This is stored here to save space in User on 64-bit hosts. Since most
109 /// instances of Value have operands, 32-bit hosts aren't significantly
110 /// affected.
111 ///
112 /// Note, this should *NOT* be used directly by any class other than User.
113 /// User uses this value to find the Use list.
114 enum : unsigned { NumUserOperandsBits = 27 };
115 unsigned NumUserOperands : NumUserOperandsBits;
116
117 // Use the same type as the bitfield above so that MSVC will pack them.
118 unsigned IsUsedByMD : 1;
119 unsigned HasName : 1;
120 unsigned HasMetadata : 1; // Has metadata attached to this?
121 unsigned HasHungOffUses : 1;
122 unsigned HasDescriptor : 1;
123
124private:
125 template <typename UseT> // UseT == 'Use' or 'const Use'
126 class use_iterator_impl {
127 friend class Value;
128
129 UseT *U;
130
131 explicit use_iterator_impl(UseT *u) : U(u) {}
132
133 public:
134 using iterator_category = std::forward_iterator_tag;
135 using value_type = UseT *;
136 using difference_type = std::ptrdiff_t;
137 using pointer = value_type *;
138 using reference = value_type &;
139
140 use_iterator_impl() : U() {}
141
142 bool operator==(const use_iterator_impl &x) const { return U == x.U; }
143 bool operator!=(const use_iterator_impl &x) const { return !operator==(x); }
144
145 use_iterator_impl &operator++() { // Preincrement
146 assert(U && "Cannot increment end iterator!")(static_cast<void> (0));
147 U = U->getNext();
148 return *this;
149 }
150
151 use_iterator_impl operator++(int) { // Postincrement
152 auto tmp = *this;
153 ++*this;
154 return tmp;
155 }
156
157 UseT &operator*() const {
158 assert(U && "Cannot dereference end iterator!")(static_cast<void> (0));
159 return *U;
160 }
161
162 UseT *operator->() const { return &operator*(); }
163
164 operator use_iterator_impl<const UseT>() const {
165 return use_iterator_impl<const UseT>(U);
166 }
167 };
168
169 template <typename UserTy> // UserTy == 'User' or 'const User'
170 class user_iterator_impl {
171 use_iterator_impl<Use> UI;
172 explicit user_iterator_impl(Use *U) : UI(U) {}
173 friend class Value;
174
175 public:
176 using iterator_category = std::forward_iterator_tag;
177 using value_type = UserTy *;
178 using difference_type = std::ptrdiff_t;
179 using pointer = value_type *;
180 using reference = value_type &;
181
182 user_iterator_impl() = default;
183
184 bool operator==(const user_iterator_impl &x) const { return UI == x.UI; }
185 bool operator!=(const user_iterator_impl &x) const { return !operator==(x); }
186
187 /// Returns true if this iterator is equal to user_end() on the value.
188 bool atEnd() const { return *this == user_iterator_impl(); }
189
190 user_iterator_impl &operator++() { // Preincrement
191 ++UI;
192 return *this;
193 }
194
195 user_iterator_impl operator++(int) { // Postincrement
196 auto tmp = *this;
197 ++*this;
198 return tmp;
199 }
200
201 // Retrieve a pointer to the current User.
202 UserTy *operator*() const {
203 return UI->getUser();
204 }
205
206 UserTy *operator->() const { return operator*(); }
207
208 operator user_iterator_impl<const UserTy>() const {
209 return user_iterator_impl<const UserTy>(*UI);
210 }
211
212 Use &getUse() const { return *UI; }
213 };
214
215protected:
216 Value(Type *Ty, unsigned scid);
217
218 /// Value's destructor should be virtual by design, but that would require
219 /// that Value and all of its subclasses have a vtable that effectively
220 /// duplicates the information in the value ID. As a size optimization, the
221 /// destructor has been protected, and the caller should manually call
222 /// deleteValue.
223 ~Value(); // Use deleteValue() to delete a generic Value.
224
225public:
226 Value(const Value &) = delete;
227 Value &operator=(const Value &) = delete;
228
229 /// Delete a pointer to a generic Value.
230 void deleteValue();
231
232 /// Support for debugging, callable in GDB: V->dump()
233 void dump() const;
234
235 /// Implement operator<< on Value.
236 /// @{
237 void print(raw_ostream &O, bool IsForDebug = false) const;
238 void print(raw_ostream &O, ModuleSlotTracker &MST,
239 bool IsForDebug = false) const;
240 /// @}
241
242 /// Print the name of this Value out to the specified raw_ostream.
243 ///
244 /// This is useful when you just want to print 'int %reg126', not the
245 /// instruction that generated it. If you specify a Module for context, then
246 /// even constanst get pretty-printed; for example, the type of a null
247 /// pointer is printed symbolically.
248 /// @{
249 void printAsOperand(raw_ostream &O, bool PrintType = true,
250 const Module *M = nullptr) const;
251 void printAsOperand(raw_ostream &O, bool PrintType,
252 ModuleSlotTracker &MST) const;
253 /// @}
254
255 /// All values are typed, get the type of this value.
256 Type *getType() const { return VTy; }
257
258 /// All values hold a context through their type.
259 LLVMContext &getContext() const;
260
261 // All values can potentially be named.
262 bool hasName() const { return HasName; }
263 ValueName *getValueName() const;
264 void setValueName(ValueName *VN);
265
266private:
267 void destroyValueName();
268 enum class ReplaceMetadataUses { No, Yes };
269 void doRAUW(Value *New, ReplaceMetadataUses);
270 void setNameImpl(const Twine &Name);
271
272public:
273 /// Return a constant reference to the value's name.
274 ///
275 /// This guaranteed to return the same reference as long as the value is not
276 /// modified. If the value has a name, this does a hashtable lookup, so it's
277 /// not free.
278 StringRef getName() const;
279
280 /// Change the name of the value.
281 ///
282 /// Choose a new unique name if the provided name is taken.
283 ///
284 /// \param Name The new name; or "" if the value's name should be removed.
285 void setName(const Twine &Name);
286
287 /// Transfer the name from V to this value.
288 ///
289 /// After taking V's name, sets V's name to empty.
290 ///
291 /// \note It is an error to call V->takeName(V).
292 void takeName(Value *V);
293
294#ifndef NDEBUG1
295 std::string getNameOrAsOperand() const;
296#endif
297
298 /// Change all uses of this to point to a new Value.
299 ///
300 /// Go through the uses list for this definition and make each use point to
301 /// "V" instead of "this". After this completes, 'this's use list is
302 /// guaranteed to be empty.
303 void replaceAllUsesWith(Value *V);
304
305 /// Change non-metadata uses of this to point to a new Value.
306 ///
307 /// Go through the uses list for this definition and make each use point to
308 /// "V" instead of "this". This function skips metadata entries in the list.
309 void replaceNonMetadataUsesWith(Value *V);
310
311 /// Go through the uses list for this definition and make each use point
312 /// to "V" if the callback ShouldReplace returns true for the given Use.
313 /// Unlike replaceAllUsesWith() this function does not support basic block
314 /// values.
315 void replaceUsesWithIf(Value *New,
316 llvm::function_ref<bool(Use &U)> ShouldReplace);
317
318 /// replaceUsesOutsideBlock - Go through the uses list for this definition and
319 /// make each use point to "V" instead of "this" when the use is outside the
320 /// block. 'This's use list is expected to have at least one element.
321 /// Unlike replaceAllUsesWith() this function does not support basic block
322 /// values.
323 void replaceUsesOutsideBlock(Value *V, BasicBlock *BB);
324
325 //----------------------------------------------------------------------
326 // Methods for handling the chain of uses of this Value.
327 //
328 // Materializing a function can introduce new uses, so these methods come in
329 // two variants:
330 // The methods that start with materialized_ check the uses that are
331 // currently known given which functions are materialized. Be very careful
332 // when using them since you might not get all uses.
333 // The methods that don't start with materialized_ assert that modules is
334 // fully materialized.
335 void assertModuleIsMaterializedImpl() const;
336 // This indirection exists so we can keep assertModuleIsMaterializedImpl()
337 // around in release builds of Value.cpp to be linked with other code built
338 // in debug mode. But this avoids calling it in any of the release built code.
339 void assertModuleIsMaterialized() const {
340#ifndef NDEBUG1
341 assertModuleIsMaterializedImpl();
342#endif
343 }
344
345 bool use_empty() const {
346 assertModuleIsMaterialized();
347 return UseList == nullptr;
7
Assuming the condition is false
8
Returning zero, which participates in a condition later
348 }
349
350 bool materialized_use_empty() const {
351 return UseList == nullptr;
352 }
353
354 using use_iterator = use_iterator_impl<Use>;
355 using const_use_iterator = use_iterator_impl<const Use>;
356
357 use_iterator materialized_use_begin() { return use_iterator(UseList); }
358 const_use_iterator materialized_use_begin() const {
359 return const_use_iterator(UseList);
360 }
361 use_iterator use_begin() {
362 assertModuleIsMaterialized();
363 return materialized_use_begin();
364 }
365 const_use_iterator use_begin() const {
366 assertModuleIsMaterialized();
367 return materialized_use_begin();
368 }
369 use_iterator use_end() { return use_iterator(); }
370 const_use_iterator use_end() const { return const_use_iterator(); }
371 iterator_range<use_iterator> materialized_uses() {
372 return make_range(materialized_use_begin(), use_end());
373 }
374 iterator_range<const_use_iterator> materialized_uses() const {
375 return make_range(materialized_use_begin(), use_end());
376 }
377 iterator_range<use_iterator> uses() {
378 assertModuleIsMaterialized();
379 return materialized_uses();
380 }
381 iterator_range<const_use_iterator> uses() const {
382 assertModuleIsMaterialized();
383 return materialized_uses();
384 }
385
386 bool user_empty() const {
387 assertModuleIsMaterialized();
388 return UseList == nullptr;
389 }
390
391 using user_iterator = user_iterator_impl<User>;
392 using const_user_iterator = user_iterator_impl<const User>;
393
394 user_iterator materialized_user_begin() { return user_iterator(UseList); }
395 const_user_iterator materialized_user_begin() const {
396 return const_user_iterator(UseList);
397 }
398 user_iterator user_begin() {
399 assertModuleIsMaterialized();
400 return materialized_user_begin();
401 }
402 const_user_iterator user_begin() const {
403 assertModuleIsMaterialized();
404 return materialized_user_begin();
405 }
406 user_iterator user_end() { return user_iterator(); }
407 const_user_iterator user_end() const { return const_user_iterator(); }
408 User *user_back() {
409 assertModuleIsMaterialized();
410 return *materialized_user_begin();
411 }
412 const User *user_back() const {
413 assertModuleIsMaterialized();
414 return *materialized_user_begin();
415 }
416 iterator_range<user_iterator> materialized_users() {
417 return make_range(materialized_user_begin(), user_end());
418 }
419 iterator_range<const_user_iterator> materialized_users() const {
420 return make_range(materialized_user_begin(), user_end());
421 }
422 iterator_range<user_iterator> users() {
423 assertModuleIsMaterialized();
424 return materialized_users();
425 }
426 iterator_range<const_user_iterator> users() const {
427 assertModuleIsMaterialized();
428 return materialized_users();
429 }
430
431 /// Return true if there is exactly one use of this value.
432 ///
433 /// This is specialized because it is a common request and does not require
434 /// traversing the whole use list.
435 bool hasOneUse() const { return hasSingleElement(uses()); }
436
437 /// Return true if this Value has exactly N uses.
438 bool hasNUses(unsigned N) const;
439
440 /// Return true if this value has N uses or more.
441 ///
442 /// This is logically equivalent to getNumUses() >= N.
443 bool hasNUsesOrMore(unsigned N) const;
444
445 /// Return true if there is exactly one user of this value.
446 ///
447 /// Note that this is not the same as "has one use". If a value has one use,
448 /// then there certainly is a single user. But if value has several uses,
449 /// it is possible that all uses are in a single user, or not.
450 ///
451 /// This check is potentially costly, since it requires traversing,
452 /// in the worst case, the whole use list of a value.
453 bool hasOneUser() const;
454
455 /// Return true if there is exactly one use of this value that cannot be
456 /// dropped.
457 ///
458 /// This is specialized because it is a common request and does not require
459 /// traversing the whole use list.
460 Use *getSingleUndroppableUse();
461 const Use *getSingleUndroppableUse() const {
462 return const_cast<Value *>(this)->getSingleUndroppableUse();
463 }
464
465 /// Return true if there this value.
466 ///
467 /// This is specialized because it is a common request and does not require
468 /// traversing the whole use list.
469 bool hasNUndroppableUses(unsigned N) const;
470
471 /// Return true if this value has N uses or more.
472 ///
473 /// This is logically equivalent to getNumUses() >= N.
474 bool hasNUndroppableUsesOrMore(unsigned N) const;
475
476 /// Remove every uses that can safely be removed.
477 ///
478 /// This will remove for example uses in llvm.assume.
479 /// This should be used when performing want to perform a tranformation but
480 /// some Droppable uses pervent it.
481 /// This function optionally takes a filter to only remove some droppable
482 /// uses.
483 void dropDroppableUses(llvm::function_ref<bool(const Use *)> ShouldDrop =
484 [](const Use *) { return true; });
485
486 /// Remove every use of this value in \p User that can safely be removed.
487 void dropDroppableUsesIn(User &Usr);
488
489 /// Remove the droppable use \p U.
490 static void dropDroppableUse(Use &U);
491
492 /// Check if this value is used in the specified basic block.
493 bool isUsedInBasicBlock(const BasicBlock *BB) const;
494
495 /// This method computes the number of uses of this Value.
496 ///
497 /// This is a linear time operation. Use hasOneUse, hasNUses, or
498 /// hasNUsesOrMore to check for specific values.
499 unsigned getNumUses() const;
500
501 /// This method should only be used by the Use class.
502 void addUse(Use &U) { U.addToList(&UseList); }
503
504 /// Concrete subclass of this.
505 ///
506 /// An enumeration for keeping track of the concrete subclass of Value that
507 /// is actually instantiated. Values of this enumeration are kept in the
508 /// Value classes SubclassID field. They are used for concrete type
509 /// identification.
510 enum ValueTy {
511#define HANDLE_VALUE(Name) Name##Val,
512#include "llvm/IR/Value.def"
513
514 // Markers:
515#define HANDLE_CONSTANT_MARKER(Marker, Constant) Marker = Constant##Val,
516#include "llvm/IR/Value.def"
517 };
518
519 /// Return an ID for the concrete type of this object.
520 ///
521 /// This is used to implement the classof checks. This should not be used
522 /// for any other purpose, as the values may change as LLVM evolves. Also,
523 /// note that for instructions, the Instruction's opcode is added to
524 /// InstructionVal. So this means three things:
525 /// # there is no value with code InstructionVal (no opcode==0).
526 /// # there are more possible values for the value type than in ValueTy enum.
527 /// # the InstructionVal enumerator must be the highest valued enumerator in
528 /// the ValueTy enum.
529 unsigned getValueID() const {
530 return SubclassID;
531 }
532
533 /// Return the raw optional flags value contained in this value.
534 ///
535 /// This should only be used when testing two Values for equivalence.
536 unsigned getRawSubclassOptionalData() const {
537 return SubclassOptionalData;
538 }
539
540 /// Clear the optional flags contained in this value.
541 void clearSubclassOptionalData() {
542 SubclassOptionalData = 0;
543 }
544
545 /// Check the optional flags for equality.
546 bool hasSameSubclassOptionalData(const Value *V) const {
547 return SubclassOptionalData == V->SubclassOptionalData;
548 }
549
550 /// Return true if there is a value handle associated with this value.
551 bool hasValueHandle() const { return HasValueHandle; }
552
553 /// Return true if there is metadata referencing this value.
554 bool isUsedByMetadata() const { return IsUsedByMD; }
555
556 // Return true if this value is only transitively referenced by metadata.
557 bool isTransitiveUsedByMetadataOnly() const;
558
559protected:
560 /// Get the current metadata attachments for the given kind, if any.
561 ///
562 /// These functions require that the value have at most a single attachment
563 /// of the given kind, and return \c nullptr if such an attachment is missing.
564 /// @{
565 MDNode *getMetadata(unsigned KindID) const;
566 MDNode *getMetadata(StringRef Kind) const;
567 /// @}
568
569 /// Appends all attachments with the given ID to \c MDs in insertion order.
570 /// If the Value has no attachments with the given ID, or if ID is invalid,
571 /// leaves MDs unchanged.
572 /// @{
573 void getMetadata(unsigned KindID, SmallVectorImpl<MDNode *> &MDs) const;
574 void getMetadata(StringRef Kind, SmallVectorImpl<MDNode *> &MDs) const;
575 /// @}
576
577 /// Appends all metadata attached to this value to \c MDs, sorting by
578 /// KindID. The first element of each pair returned is the KindID, the second
579 /// element is the metadata value. Attachments with the same ID appear in
580 /// insertion order.
581 void
582 getAllMetadata(SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const;
583
584 /// Return true if this value has any metadata attached to it.
585 bool hasMetadata() const { return (bool)HasMetadata; }
586
587 /// Return true if this value has the given type of metadata attached.
588 /// @{
589 bool hasMetadata(unsigned KindID) const {
590 return getMetadata(KindID) != nullptr;
591 }
592 bool hasMetadata(StringRef Kind) const {
593 return getMetadata(Kind) != nullptr;
594 }
595 /// @}
596
597 /// Set a particular kind of metadata attachment.
598 ///
599 /// Sets the given attachment to \c MD, erasing it if \c MD is \c nullptr or
600 /// replacing it if it already exists.
601 /// @{
602 void setMetadata(unsigned KindID, MDNode *Node);
603 void setMetadata(StringRef Kind, MDNode *Node);
604 /// @}
605
606 /// Add a metadata attachment.
607 /// @{
608 void addMetadata(unsigned KindID, MDNode &MD);
609 void addMetadata(StringRef Kind, MDNode &MD);
610 /// @}
611
612 /// Erase all metadata attachments with the given kind.
613 ///
614 /// \returns true if any metadata was removed.
615 bool eraseMetadata(unsigned KindID);
616
617 /// Erase all metadata attached to this Value.
618 void clearMetadata();
619
620public:
621 /// Return true if this value is a swifterror value.
622 ///
623 /// swifterror values can be either a function argument or an alloca with a
624 /// swifterror attribute.
625 bool isSwiftError() const;
626
627 /// Strip off pointer casts, all-zero GEPs and address space casts.
628 ///
629 /// Returns the original uncasted value. If this is called on a non-pointer
630 /// value, it returns 'this'.
631 const Value *stripPointerCasts() const;
632 Value *stripPointerCasts() {
633 return const_cast<Value *>(
634 static_cast<const Value *>(this)->stripPointerCasts());
635 }
636
637 /// Strip off pointer casts, all-zero GEPs, address space casts, and aliases.
638 ///
639 /// Returns the original uncasted value. If this is called on a non-pointer
640 /// value, it returns 'this'.
641 const Value *stripPointerCastsAndAliases() const;
642 Value *stripPointerCastsAndAliases() {
643 return const_cast<Value *>(
644 static_cast<const Value *>(this)->stripPointerCastsAndAliases());
645 }
646
647 /// Strip off pointer casts, all-zero GEPs and address space casts
648 /// but ensures the representation of the result stays the same.
649 ///
650 /// Returns the original uncasted value with the same representation. If this
651 /// is called on a non-pointer value, it returns 'this'.
652 const Value *stripPointerCastsSameRepresentation() const;
653 Value *stripPointerCastsSameRepresentation() {
654 return const_cast<Value *>(static_cast<const Value *>(this)
655 ->stripPointerCastsSameRepresentation());
656 }
657
658 /// Strip off pointer casts, all-zero GEPs, single-argument phi nodes and
659 /// invariant group info.
660 ///
661 /// Returns the original uncasted value. If this is called on a non-pointer
662 /// value, it returns 'this'. This function should be used only in
663 /// Alias analysis.
664 const Value *stripPointerCastsForAliasAnalysis() const;
665 Value *stripPointerCastsForAliasAnalysis() {
666 return const_cast<Value *>(static_cast<const Value *>(this)
667 ->stripPointerCastsForAliasAnalysis());
668 }
669
670 /// Strip off pointer casts and all-constant inbounds GEPs.
671 ///
672 /// Returns the original pointer value. If this is called on a non-pointer
673 /// value, it returns 'this'.
674 const Value *stripInBoundsConstantOffsets() const;
675 Value *stripInBoundsConstantOffsets() {
676 return const_cast<Value *>(
677 static_cast<const Value *>(this)->stripInBoundsConstantOffsets());
678 }
679
680 /// Accumulate the constant offset this value has compared to a base pointer.
681 /// Only 'getelementptr' instructions (GEPs) are accumulated but other
682 /// instructions, e.g., casts, are stripped away as well.
683 /// The accumulated constant offset is added to \p Offset and the base
684 /// pointer is returned.
685 ///
686 /// The APInt \p Offset has to have a bit-width equal to the IntPtr type for
687 /// the address space of 'this' pointer value, e.g., use
688 /// DataLayout::getIndexTypeSizeInBits(Ty).
689 ///
690 /// If \p AllowNonInbounds is true, offsets in GEPs are stripped and
691 /// accumulated even if the GEP is not "inbounds".
692 ///
693 /// If \p ExternalAnalysis is provided it will be used to calculate a offset
694 /// when a operand of GEP is not constant.
695 /// For example, for a value \p ExternalAnalysis might try to calculate a
696 /// lower bound. If \p ExternalAnalysis is successful, it should return true.
697 ///
698 /// If this is called on a non-pointer value, it returns 'this' and the
699 /// \p Offset is not modified.
700 ///
701 /// Note that this function will never return a nullptr. It will also never
702 /// manipulate the \p Offset in a way that would not match the difference
703 /// between the underlying value and the returned one. Thus, if no constant
704 /// offset was found, the returned value is the underlying one and \p Offset
705 /// is unchanged.
706 const Value *stripAndAccumulateConstantOffsets(
707 const DataLayout &DL, APInt &Offset, bool AllowNonInbounds,
708 function_ref<bool(Value &Value, APInt &Offset)> ExternalAnalysis =
709 nullptr) const;
710 Value *stripAndAccumulateConstantOffsets(const DataLayout &DL, APInt &Offset,
711 bool AllowNonInbounds) {
712 return const_cast<Value *>(
713 static_cast<const Value *>(this)->stripAndAccumulateConstantOffsets(
714 DL, Offset, AllowNonInbounds));
715 }
716
717 /// This is a wrapper around stripAndAccumulateConstantOffsets with the
718 /// in-bounds requirement set to false.
719 const Value *stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
720 APInt &Offset) const {
721 return stripAndAccumulateConstantOffsets(DL, Offset,
722 /* AllowNonInbounds */ false);
723 }
724 Value *stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
725 APInt &Offset) {
726 return stripAndAccumulateConstantOffsets(DL, Offset,
727 /* AllowNonInbounds */ false);
728 }
729
730 /// Strip off pointer casts and inbounds GEPs.
731 ///
732 /// Returns the original pointer value. If this is called on a non-pointer
733 /// value, it returns 'this'.
734 const Value *stripInBoundsOffsets(function_ref<void(const Value *)> Func =
735 [](const Value *) {}) const;
736 inline Value *stripInBoundsOffsets(function_ref<void(const Value *)> Func =
737 [](const Value *) {}) {
738 return const_cast<Value *>(
739 static_cast<const Value *>(this)->stripInBoundsOffsets(Func));
740 }
741
742 /// Return true if the memory object referred to by V can by freed in the
743 /// scope for which the SSA value defining the allocation is statically
744 /// defined. E.g. deallocation after the static scope of a value does not
745 /// count, but a deallocation before that does.
746 bool canBeFreed() const;
747
748 /// Returns the number of bytes known to be dereferenceable for the
749 /// pointer value.
750 ///
751 /// If CanBeNull is set by this function the pointer can either be null or be
752 /// dereferenceable up to the returned number of bytes.
753 ///
754 /// IF CanBeFreed is true, the pointer is known to be dereferenceable at
755 /// point of definition only. Caller must prove that allocation is not
756 /// deallocated between point of definition and use.
757 uint64_t getPointerDereferenceableBytes(const DataLayout &DL,
758 bool &CanBeNull,
759 bool &CanBeFreed) const;
760
761 /// Returns an alignment of the pointer value.
762 ///
763 /// Returns an alignment which is either specified explicitly, e.g. via
764 /// align attribute of a function argument, or guaranteed by DataLayout.
765 Align getPointerAlignment(const DataLayout &DL) const;
766
767 /// Translate PHI node to its predecessor from the given basic block.
768 ///
769 /// If this value is a PHI node with CurBB as its parent, return the value in
770 /// the PHI node corresponding to PredBB. If not, return ourself. This is
771 /// useful if you want to know the value something has in a predecessor
772 /// block.
773 const Value *DoPHITranslation(const BasicBlock *CurBB,
774 const BasicBlock *PredBB) const;
775 Value *DoPHITranslation(const BasicBlock *CurBB, const BasicBlock *PredBB) {
776 return const_cast<Value *>(
777 static_cast<const Value *>(this)->DoPHITranslation(CurBB, PredBB));
778 }
779
780 /// The maximum alignment for instructions.
781 ///
782 /// This is the greatest alignment value supported by load, store, and alloca
783 /// instructions, and global values.
784 static constexpr unsigned MaxAlignmentExponent = 30;
785 static constexpr unsigned MaximumAlignment = 1u << MaxAlignmentExponent;
786
787 /// Mutate the type of this Value to be of the specified type.
788 ///
789 /// Note that this is an extremely dangerous operation which can create
790 /// completely invalid IR very easily. It is strongly recommended that you
791 /// recreate IR objects with the right types instead of mutating them in
792 /// place.
793 void mutateType(Type *Ty) {
794 VTy = Ty;
795 }
796
797 /// Sort the use-list.
798 ///
799 /// Sorts the Value's use-list by Cmp using a stable mergesort. Cmp is
800 /// expected to compare two \a Use references.
801 template <class Compare> void sortUseList(Compare Cmp);
802
803 /// Reverse the use-list.
804 void reverseUseList();
805
806private:
807 /// Merge two lists together.
808 ///
809 /// Merges \c L and \c R using \c Cmp. To enable stable sorts, always pushes
810 /// "equal" items from L before items from R.
811 ///
812 /// \return the first element in the list.
813 ///
814 /// \note Completely ignores \a Use::Prev (doesn't read, doesn't update).
815 template <class Compare>
816 static Use *mergeUseLists(Use *L, Use *R, Compare Cmp) {
817 Use *Merged;
818 Use **Next = &Merged;
819
820 while (true) {
821 if (!L) {
822 *Next = R;
823 break;
824 }
825 if (!R) {
826 *Next = L;
827 break;
828 }
829 if (Cmp(*R, *L)) {
830 *Next = R;
831 Next = &R->Next;
832 R = R->Next;
833 } else {
834 *Next = L;
835 Next = &L->Next;
836 L = L->Next;
837 }
838 }
839
840 return Merged;
841 }
842
843protected:
844 unsigned short getSubclassDataFromValue() const { return SubclassData; }
845 void setValueSubclassData(unsigned short D) { SubclassData = D; }
846};
847
848struct ValueDeleter { void operator()(Value *V) { V->deleteValue(); } };
849
850/// Use this instead of std::unique_ptr<Value> or std::unique_ptr<Instruction>.
851/// Those don't work because Value and Instruction's destructors are protected,
852/// aren't virtual, and won't destroy the complete object.
853using unique_value = std::unique_ptr<Value, ValueDeleter>;
854
855inline raw_ostream &operator<<(raw_ostream &OS, const Value &V) {
856 V.print(OS);
857 return OS;
858}
859
860void Use::set(Value *V) {
861 if (Val) removeFromList();
862 Val = V;
863 if (V) V->addUse(*this);
864}
865
866Value *Use::operator=(Value *RHS) {
867 set(RHS);
868 return RHS;
869}
870
871const Use &Use::operator=(const Use &RHS) {
872 set(RHS.Val);
873 return *this;
874}
875
876template <class Compare> void Value::sortUseList(Compare Cmp) {
877 if (!UseList || !UseList->Next)
878 // No need to sort 0 or 1 uses.
879 return;
880
881 // Note: this function completely ignores Prev pointers until the end when
882 // they're fixed en masse.
883
884 // Create a binomial vector of sorted lists, visiting uses one at a time and
885 // merging lists as necessary.
886 const unsigned MaxSlots = 32;
887 Use *Slots[MaxSlots];
888
889 // Collect the first use, turning it into a single-item list.
890 Use *Next = UseList->Next;
891 UseList->Next = nullptr;
892 unsigned NumSlots = 1;
893 Slots[0] = UseList;
894
895 // Collect all but the last use.
896 while (Next->Next) {
897 Use *Current = Next;
898 Next = Current->Next;
899
900 // Turn Current into a single-item list.
901 Current->Next = nullptr;
902
903 // Save Current in the first available slot, merging on collisions.
904 unsigned I;
905 for (I = 0; I < NumSlots; ++I) {
906 if (!Slots[I])
907 break;
908
909 // Merge two lists, doubling the size of Current and emptying slot I.
910 //
911 // Since the uses in Slots[I] originally preceded those in Current, send
912 // Slots[I] in as the left parameter to maintain a stable sort.
913 Current = mergeUseLists(Slots[I], Current, Cmp);
914 Slots[I] = nullptr;
915 }
916 // Check if this is a new slot.
917 if (I == NumSlots) {
918 ++NumSlots;
919 assert(NumSlots <= MaxSlots && "Use list bigger than 2^32")(static_cast<void> (0));
920 }
921
922 // Found an open slot.
923 Slots[I] = Current;
924 }
925
926 // Merge all the lists together.
927 assert(Next && "Expected one more Use")(static_cast<void> (0));
928 assert(!Next->Next && "Expected only one Use")(static_cast<void> (0));
929 UseList = Next;
930 for (unsigned I = 0; I < NumSlots; ++I)
931 if (Slots[I])
932 // Since the uses in Slots[I] originally preceded those in UseList, send
933 // Slots[I] in as the left parameter to maintain a stable sort.
934 UseList = mergeUseLists(Slots[I], UseList, Cmp);
935
936 // Fix the Prev pointers.
937 for (Use *I = UseList, **Prev = &UseList; I; I = I->Next) {
938 I->Prev = Prev;
939 Prev = &I->Next;
940 }
941}
942
943// isa - Provide some specializations of isa so that we don't have to include
944// the subtype header files to test to see if the value is a subclass...
945//
946template <> struct isa_impl<Constant, Value> {
947 static inline bool doit(const Value &Val) {
948 static_assert(Value::ConstantFirstVal == 0, "Val.getValueID() >= Value::ConstantFirstVal");
949 return Val.getValueID() <= Value::ConstantLastVal;
950 }
951};
952
953template <> struct isa_impl<ConstantData, Value> {
954 static inline bool doit(const Value &Val) {
955 return Val.getValueID() >= Value::ConstantDataFirstVal &&
956 Val.getValueID() <= Value::ConstantDataLastVal;
957 }
958};
959
960template <> struct isa_impl<ConstantAggregate, Value> {
961 static inline bool doit(const Value &Val) {
962 return Val.getValueID() >= Value::ConstantAggregateFirstVal &&
963 Val.getValueID() <= Value::ConstantAggregateLastVal;
964 }
965};
966
967template <> struct isa_impl<Argument, Value> {
968 static inline bool doit (const Value &Val) {
969 return Val.getValueID() == Value::ArgumentVal;
970 }
971};
972
973template <> struct isa_impl<InlineAsm, Value> {
974 static inline bool doit(const Value &Val) {
975 return Val.getValueID() == Value::InlineAsmVal;
976 }
977};
978
979template <> struct isa_impl<Instruction, Value> {
980 static inline bool doit(const Value &Val) {
981 return Val.getValueID() >= Value::InstructionVal;
982 }
983};
984
985template <> struct isa_impl<BasicBlock, Value> {
986 static inline bool doit(const Value &Val) {
987 return Val.getValueID() == Value::BasicBlockVal;
988 }
989};
990
991template <> struct isa_impl<Function, Value> {
992 static inline bool doit(const Value &Val) {
993 return Val.getValueID() == Value::FunctionVal;
994 }
995};
996
997template <> struct isa_impl<GlobalVariable, Value> {
998 static inline bool doit(const Value &Val) {
999 return Val.getValueID() == Value::GlobalVariableVal;
1000 }
1001};
1002
1003template <> struct isa_impl<GlobalAlias, Value> {
1004 static inline bool doit(const Value &Val) {
1005 return Val.getValueID() == Value::GlobalAliasVal;
1006 }
1007};
1008
1009template <> struct isa_impl<GlobalIFunc, Value> {
1010 static inline bool doit(const Value &Val) {
1011 return Val.getValueID() == Value::GlobalIFuncVal;
1012 }
1013};
1014
1015template <> struct isa_impl<GlobalIndirectSymbol, Value> {
1016 static inline bool doit(const Value &Val) {
1017 return isa<GlobalAlias>(Val) || isa<GlobalIFunc>(Val);
1018 }
1019};
1020
1021template <> struct isa_impl<GlobalValue, Value> {
1022 static inline bool doit(const Value &Val) {
1023 return isa<GlobalObject>(Val) || isa<GlobalIndirectSymbol>(Val);
1024 }
1025};
1026
1027template <> struct isa_impl<GlobalObject, Value> {
1028 static inline bool doit(const Value &Val) {
1029 return isa<GlobalVariable>(Val) || isa<Function>(Val);
1030 }
1031};
1032
1033// Create wrappers for C Binding types (see CBindingWrapping.h).
1034DEFINE_ISA_CONVERSION_FUNCTIONS(Value, LLVMValueRef)inline Value *unwrap(LLVMValueRef P) { return reinterpret_cast
<Value*>(P); } inline LLVMValueRef wrap(const Value *P)
{ return reinterpret_cast<LLVMValueRef>(const_cast<
Value*>(P)); } template<typename T> inline T *unwrap
(LLVMValueRef P) { return cast<T>(unwrap(P)); }
1035
1036// Specialized opaque value conversions.
1037inline Value **unwrap(LLVMValueRef *Vals) {
1038 return reinterpret_cast<Value**>(Vals);
1039}
1040
1041template<typename T>
1042inline T **unwrap(LLVMValueRef *Vals, unsigned Length) {
1043#ifndef NDEBUG1
1044 for (LLVMValueRef *I = Vals, *E = Vals + Length; I != E; ++I)
1045 unwrap<T>(*I); // For side effect of calling assert on invalid usage.
1046#endif
1047 (void)Length;
1048 return reinterpret_cast<T**>(Vals);
1049}
1050
1051inline LLVMValueRef *wrap(const Value **Vals) {
1052 return reinterpret_cast<LLVMValueRef*>(const_cast<Value**>(Vals));
1053}
1054
1055} // end namespace llvm
1056
1057#endif // LLVM_IR_VALUE_H