Bug Summary

File:tools/clang/lib/CodeGen/CGExprConstant.cpp
Warning:line 1711, column 19
Value stored to 'C' during its initialization is never read

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name CGExprConstant.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 -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -relaxed-aliasing -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-9/lib/clang/9.0.0 -D CLANG_VENDOR="Debian " -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-9~svn358860/build-llvm/tools/clang/lib/CodeGen -I /build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen -I /build/llvm-toolchain-snapshot-9~svn358860/tools/clang/include -I /build/llvm-toolchain-snapshot-9~svn358860/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-9~svn358860/build-llvm/include -I /build/llvm-toolchain-snapshot-9~svn358860/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/9.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-9/lib/clang/9.0.0/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-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-9~svn358860/build-llvm/tools/clang/lib/CodeGen -fdebug-prefix-map=/build/llvm-toolchain-snapshot-9~svn358860=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fobjc-runtime=gcc -fno-common -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2019-04-22-050718-5320-1 -x c++ /build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp -faddrsig
1//===--- CGExprConstant.cpp - Emit LLVM Code from Constant Expressions ----===//
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 to emit Constant Expr nodes as LLVM code.
10//
11//===----------------------------------------------------------------------===//
12
13#include "CodeGenFunction.h"
14#include "CGCXXABI.h"
15#include "CGObjCRuntime.h"
16#include "CGRecordLayout.h"
17#include "CodeGenModule.h"
18#include "ConstantEmitter.h"
19#include "TargetInfo.h"
20#include "clang/AST/APValue.h"
21#include "clang/AST/ASTContext.h"
22#include "clang/AST/RecordLayout.h"
23#include "clang/AST/StmtVisitor.h"
24#include "clang/Basic/Builtins.h"
25#include "llvm/IR/Constants.h"
26#include "llvm/IR/DataLayout.h"
27#include "llvm/IR/Function.h"
28#include "llvm/IR/GlobalVariable.h"
29using namespace clang;
30using namespace CodeGen;
31
32//===----------------------------------------------------------------------===//
33// ConstStructBuilder
34//===----------------------------------------------------------------------===//
35
36namespace {
37class ConstExprEmitter;
38class ConstStructBuilder {
39 CodeGenModule &CGM;
40 ConstantEmitter &Emitter;
41
42 bool Packed;
43 CharUnits NextFieldOffsetInChars;
44 CharUnits LLVMStructAlignment;
45 SmallVector<llvm::Constant *, 32> Elements;
46public:
47 static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
48 ConstExprEmitter *ExprEmitter,
49 llvm::Constant *Base,
50 InitListExpr *Updater,
51 QualType ValTy);
52 static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
53 InitListExpr *ILE, QualType StructTy);
54 static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
55 const APValue &Value, QualType ValTy);
56
57private:
58 ConstStructBuilder(ConstantEmitter &emitter)
59 : CGM(emitter.CGM), Emitter(emitter), Packed(false),
60 NextFieldOffsetInChars(CharUnits::Zero()),
61 LLVMStructAlignment(CharUnits::One()) { }
62
63 void AppendField(const FieldDecl *Field, uint64_t FieldOffset,
64 llvm::Constant *InitExpr);
65
66 void AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst);
67
68 void AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
69 llvm::ConstantInt *InitExpr);
70
71 void AppendPadding(CharUnits PadSize);
72
73 void AppendTailPadding(CharUnits RecordSize);
74
75 void ConvertStructToPacked();
76
77 bool Build(InitListExpr *ILE);
78 bool Build(ConstExprEmitter *Emitter, llvm::Constant *Base,
79 InitListExpr *Updater);
80 bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase,
81 const CXXRecordDecl *VTableClass, CharUnits BaseOffset);
82 llvm::Constant *Finalize(QualType Ty);
83
84 CharUnits getAlignment(const llvm::Constant *C) const {
85 if (Packed) return CharUnits::One();
86 return CharUnits::fromQuantity(
87 CGM.getDataLayout().getABITypeAlignment(C->getType()));
88 }
89
90 CharUnits getSizeInChars(const llvm::Constant *C) const {
91 return CharUnits::fromQuantity(
92 CGM.getDataLayout().getTypeAllocSize(C->getType()));
93 }
94};
95
96void ConstStructBuilder::
97AppendField(const FieldDecl *Field, uint64_t FieldOffset,
98 llvm::Constant *InitCst) {
99 const ASTContext &Context = CGM.getContext();
100
101 CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
102
103 AppendBytes(FieldOffsetInChars, InitCst);
104}
105
106void ConstStructBuilder::
107AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst) {
108
109 assert(NextFieldOffsetInChars <= FieldOffsetInChars((NextFieldOffsetInChars <= FieldOffsetInChars && "Field offset mismatch!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= FieldOffsetInChars && \"Field offset mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 110, __PRETTY_FUNCTION__))
110 && "Field offset mismatch!")((NextFieldOffsetInChars <= FieldOffsetInChars && "Field offset mismatch!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= FieldOffsetInChars && \"Field offset mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 110, __PRETTY_FUNCTION__))
;
111
112 CharUnits FieldAlignment = getAlignment(InitCst);
113
114 // Round up the field offset to the alignment of the field type.
115 CharUnits AlignedNextFieldOffsetInChars =
116 NextFieldOffsetInChars.alignTo(FieldAlignment);
117
118 if (AlignedNextFieldOffsetInChars < FieldOffsetInChars) {
119 // We need to append padding.
120 AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars);
121
122 assert(NextFieldOffsetInChars == FieldOffsetInChars &&((NextFieldOffsetInChars == FieldOffsetInChars && "Did not add enough padding!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars == FieldOffsetInChars && \"Did not add enough padding!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 123, __PRETTY_FUNCTION__))
123 "Did not add enough padding!")((NextFieldOffsetInChars == FieldOffsetInChars && "Did not add enough padding!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars == FieldOffsetInChars && \"Did not add enough padding!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 123, __PRETTY_FUNCTION__))
;
124
125 AlignedNextFieldOffsetInChars =
126 NextFieldOffsetInChars.alignTo(FieldAlignment);
127 }
128
129 if (AlignedNextFieldOffsetInChars > FieldOffsetInChars) {
130 assert(!Packed && "Alignment is wrong even with a packed struct!")((!Packed && "Alignment is wrong even with a packed struct!"
) ? static_cast<void> (0) : __assert_fail ("!Packed && \"Alignment is wrong even with a packed struct!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 130, __PRETTY_FUNCTION__))
;
131
132 // Convert the struct to a packed struct.
133 ConvertStructToPacked();
134
135 // After we pack the struct, we may need to insert padding.
136 if (NextFieldOffsetInChars < FieldOffsetInChars) {
137 // We need to append padding.
138 AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars);
139
140 assert(NextFieldOffsetInChars == FieldOffsetInChars &&((NextFieldOffsetInChars == FieldOffsetInChars && "Did not add enough padding!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars == FieldOffsetInChars && \"Did not add enough padding!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 141, __PRETTY_FUNCTION__))
141 "Did not add enough padding!")((NextFieldOffsetInChars == FieldOffsetInChars && "Did not add enough padding!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars == FieldOffsetInChars && \"Did not add enough padding!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 141, __PRETTY_FUNCTION__))
;
142 }
143 AlignedNextFieldOffsetInChars = NextFieldOffsetInChars;
144 }
145
146 // Add the field.
147 Elements.push_back(InitCst);
148 NextFieldOffsetInChars = AlignedNextFieldOffsetInChars +
149 getSizeInChars(InitCst);
150
151 if (Packed)
152 assert(LLVMStructAlignment == CharUnits::One() &&((LLVMStructAlignment == CharUnits::One() && "Packed struct not byte-aligned!"
) ? static_cast<void> (0) : __assert_fail ("LLVMStructAlignment == CharUnits::One() && \"Packed struct not byte-aligned!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 153, __PRETTY_FUNCTION__))
153 "Packed struct not byte-aligned!")((LLVMStructAlignment == CharUnits::One() && "Packed struct not byte-aligned!"
) ? static_cast<void> (0) : __assert_fail ("LLVMStructAlignment == CharUnits::One() && \"Packed struct not byte-aligned!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 153, __PRETTY_FUNCTION__))
;
154 else
155 LLVMStructAlignment = std::max(LLVMStructAlignment, FieldAlignment);
156}
157
158void ConstStructBuilder::AppendBitField(const FieldDecl *Field,
159 uint64_t FieldOffset,
160 llvm::ConstantInt *CI) {
161 const ASTContext &Context = CGM.getContext();
162 const uint64_t CharWidth = Context.getCharWidth();
163 uint64_t NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
164 if (FieldOffset > NextFieldOffsetInBits) {
165 // We need to add padding.
166 CharUnits PadSize = Context.toCharUnitsFromBits(
167 llvm::alignTo(FieldOffset - NextFieldOffsetInBits,
168 Context.getTargetInfo().getCharAlign()));
169
170 AppendPadding(PadSize);
171 }
172
173 uint64_t FieldSize = Field->getBitWidthValue(Context);
174
175 llvm::APInt FieldValue = CI->getValue();
176
177 // Promote the size of FieldValue if necessary
178 // FIXME: This should never occur, but currently it can because initializer
179 // constants are cast to bool, and because clang is not enforcing bitfield
180 // width limits.
181 if (FieldSize > FieldValue.getBitWidth())
182 FieldValue = FieldValue.zext(FieldSize);
183
184 // Truncate the size of FieldValue to the bit field size.
185 if (FieldSize < FieldValue.getBitWidth())
186 FieldValue = FieldValue.trunc(FieldSize);
187
188 NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
189 if (FieldOffset < NextFieldOffsetInBits) {
190 // Either part of the field or the entire field can go into the previous
191 // byte.
192 assert(!Elements.empty() && "Elements can't be empty!")((!Elements.empty() && "Elements can't be empty!") ? static_cast
<void> (0) : __assert_fail ("!Elements.empty() && \"Elements can't be empty!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 192, __PRETTY_FUNCTION__))
;
193
194 unsigned BitsInPreviousByte = NextFieldOffsetInBits - FieldOffset;
195
196 bool FitsCompletelyInPreviousByte =
197 BitsInPreviousByte >= FieldValue.getBitWidth();
198
199 llvm::APInt Tmp = FieldValue;
200
201 if (!FitsCompletelyInPreviousByte) {
202 unsigned NewFieldWidth = FieldSize - BitsInPreviousByte;
203
204 if (CGM.getDataLayout().isBigEndian()) {
205 Tmp.lshrInPlace(NewFieldWidth);
206 Tmp = Tmp.trunc(BitsInPreviousByte);
207
208 // We want the remaining high bits.
209 FieldValue = FieldValue.trunc(NewFieldWidth);
210 } else {
211 Tmp = Tmp.trunc(BitsInPreviousByte);
212
213 // We want the remaining low bits.
214 FieldValue.lshrInPlace(BitsInPreviousByte);
215 FieldValue = FieldValue.trunc(NewFieldWidth);
216 }
217 }
218
219 Tmp = Tmp.zext(CharWidth);
220 if (CGM.getDataLayout().isBigEndian()) {
221 if (FitsCompletelyInPreviousByte)
222 Tmp = Tmp.shl(BitsInPreviousByte - FieldValue.getBitWidth());
223 } else {
224 Tmp = Tmp.shl(CharWidth - BitsInPreviousByte);
225 }
226
227 // 'or' in the bits that go into the previous byte.
228 llvm::Value *LastElt = Elements.back();
229 if (llvm::ConstantInt *Val = dyn_cast<llvm::ConstantInt>(LastElt))
230 Tmp |= Val->getValue();
231 else {
232 assert(isa<llvm::UndefValue>(LastElt))((isa<llvm::UndefValue>(LastElt)) ? static_cast<void
> (0) : __assert_fail ("isa<llvm::UndefValue>(LastElt)"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 232, __PRETTY_FUNCTION__))
;
233 // If there is an undef field that we're adding to, it can either be a
234 // scalar undef (in which case, we just replace it with our field) or it
235 // is an array. If it is an array, we have to pull one byte off the
236 // array so that the other undef bytes stay around.
237 if (!isa<llvm::IntegerType>(LastElt->getType())) {
238 // The undef padding will be a multibyte array, create a new smaller
239 // padding and then an hole for our i8 to get plopped into.
240 assert(isa<llvm::ArrayType>(LastElt->getType()) &&((isa<llvm::ArrayType>(LastElt->getType()) &&
"Expected array padding of undefs") ? static_cast<void>
(0) : __assert_fail ("isa<llvm::ArrayType>(LastElt->getType()) && \"Expected array padding of undefs\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 241, __PRETTY_FUNCTION__))
241 "Expected array padding of undefs")((isa<llvm::ArrayType>(LastElt->getType()) &&
"Expected array padding of undefs") ? static_cast<void>
(0) : __assert_fail ("isa<llvm::ArrayType>(LastElt->getType()) && \"Expected array padding of undefs\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 241, __PRETTY_FUNCTION__))
;
242 llvm::ArrayType *AT = cast<llvm::ArrayType>(LastElt->getType());
243 assert(AT->getElementType()->isIntegerTy(CharWidth) &&((AT->getElementType()->isIntegerTy(CharWidth) &&
AT->getNumElements() != 0 && "Expected non-empty array padding of undefs"
) ? static_cast<void> (0) : __assert_fail ("AT->getElementType()->isIntegerTy(CharWidth) && AT->getNumElements() != 0 && \"Expected non-empty array padding of undefs\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 245, __PRETTY_FUNCTION__))
244 AT->getNumElements() != 0 &&((AT->getElementType()->isIntegerTy(CharWidth) &&
AT->getNumElements() != 0 && "Expected non-empty array padding of undefs"
) ? static_cast<void> (0) : __assert_fail ("AT->getElementType()->isIntegerTy(CharWidth) && AT->getNumElements() != 0 && \"Expected non-empty array padding of undefs\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 245, __PRETTY_FUNCTION__))
245 "Expected non-empty array padding of undefs")((AT->getElementType()->isIntegerTy(CharWidth) &&
AT->getNumElements() != 0 && "Expected non-empty array padding of undefs"
) ? static_cast<void> (0) : __assert_fail ("AT->getElementType()->isIntegerTy(CharWidth) && AT->getNumElements() != 0 && \"Expected non-empty array padding of undefs\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 245, __PRETTY_FUNCTION__))
;
246
247 // Remove the padding array.
248 NextFieldOffsetInChars -= CharUnits::fromQuantity(AT->getNumElements());
249 Elements.pop_back();
250
251 // Add the padding back in two chunks.
252 AppendPadding(CharUnits::fromQuantity(AT->getNumElements()-1));
253 AppendPadding(CharUnits::One());
254 assert(isa<llvm::UndefValue>(Elements.back()) &&((isa<llvm::UndefValue>(Elements.back()) && Elements
.back()->getType()->isIntegerTy(CharWidth) && "Padding addition didn't work right"
) ? static_cast<void> (0) : __assert_fail ("isa<llvm::UndefValue>(Elements.back()) && Elements.back()->getType()->isIntegerTy(CharWidth) && \"Padding addition didn't work right\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 256, __PRETTY_FUNCTION__))
255 Elements.back()->getType()->isIntegerTy(CharWidth) &&((isa<llvm::UndefValue>(Elements.back()) && Elements
.back()->getType()->isIntegerTy(CharWidth) && "Padding addition didn't work right"
) ? static_cast<void> (0) : __assert_fail ("isa<llvm::UndefValue>(Elements.back()) && Elements.back()->getType()->isIntegerTy(CharWidth) && \"Padding addition didn't work right\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 256, __PRETTY_FUNCTION__))
256 "Padding addition didn't work right")((isa<llvm::UndefValue>(Elements.back()) && Elements
.back()->getType()->isIntegerTy(CharWidth) && "Padding addition didn't work right"
) ? static_cast<void> (0) : __assert_fail ("isa<llvm::UndefValue>(Elements.back()) && Elements.back()->getType()->isIntegerTy(CharWidth) && \"Padding addition didn't work right\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 256, __PRETTY_FUNCTION__))
;
257 }
258 }
259
260 Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp);
261
262 if (FitsCompletelyInPreviousByte)
263 return;
264 }
265
266 while (FieldValue.getBitWidth() > CharWidth) {
267 llvm::APInt Tmp;
268
269 if (CGM.getDataLayout().isBigEndian()) {
270 // We want the high bits.
271 Tmp =
272 FieldValue.lshr(FieldValue.getBitWidth() - CharWidth).trunc(CharWidth);
273 } else {
274 // We want the low bits.
275 Tmp = FieldValue.trunc(CharWidth);
276
277 FieldValue.lshrInPlace(CharWidth);
278 }
279
280 Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp));
281 ++NextFieldOffsetInChars;
282
283 FieldValue = FieldValue.trunc(FieldValue.getBitWidth() - CharWidth);
284 }
285
286 assert(FieldValue.getBitWidth() > 0 &&((FieldValue.getBitWidth() > 0 && "Should have at least one bit left!"
) ? static_cast<void> (0) : __assert_fail ("FieldValue.getBitWidth() > 0 && \"Should have at least one bit left!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 287, __PRETTY_FUNCTION__))
287 "Should have at least one bit left!")((FieldValue.getBitWidth() > 0 && "Should have at least one bit left!"
) ? static_cast<void> (0) : __assert_fail ("FieldValue.getBitWidth() > 0 && \"Should have at least one bit left!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 287, __PRETTY_FUNCTION__))
;
288 assert(FieldValue.getBitWidth() <= CharWidth &&((FieldValue.getBitWidth() <= CharWidth && "Should not have more than a byte left!"
) ? static_cast<void> (0) : __assert_fail ("FieldValue.getBitWidth() <= CharWidth && \"Should not have more than a byte left!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 289, __PRETTY_FUNCTION__))
289 "Should not have more than a byte left!")((FieldValue.getBitWidth() <= CharWidth && "Should not have more than a byte left!"
) ? static_cast<void> (0) : __assert_fail ("FieldValue.getBitWidth() <= CharWidth && \"Should not have more than a byte left!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 289, __PRETTY_FUNCTION__))
;
290
291 if (FieldValue.getBitWidth() < CharWidth) {
292 if (CGM.getDataLayout().isBigEndian()) {
293 unsigned BitWidth = FieldValue.getBitWidth();
294
295 FieldValue = FieldValue.zext(CharWidth) << (CharWidth - BitWidth);
296 } else
297 FieldValue = FieldValue.zext(CharWidth);
298 }
299
300 // Append the last element.
301 Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(),
302 FieldValue));
303 ++NextFieldOffsetInChars;
304}
305
306void ConstStructBuilder::AppendPadding(CharUnits PadSize) {
307 if (PadSize.isZero())
308 return;
309
310 llvm::Type *Ty = CGM.Int8Ty;
311 if (PadSize > CharUnits::One())
312 Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity());
313
314 llvm::Constant *C = llvm::UndefValue::get(Ty);
315 Elements.push_back(C);
316 assert(getAlignment(C) == CharUnits::One() &&((getAlignment(C) == CharUnits::One() && "Padding must have 1 byte alignment!"
) ? static_cast<void> (0) : __assert_fail ("getAlignment(C) == CharUnits::One() && \"Padding must have 1 byte alignment!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 317, __PRETTY_FUNCTION__))
317 "Padding must have 1 byte alignment!")((getAlignment(C) == CharUnits::One() && "Padding must have 1 byte alignment!"
) ? static_cast<void> (0) : __assert_fail ("getAlignment(C) == CharUnits::One() && \"Padding must have 1 byte alignment!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 317, __PRETTY_FUNCTION__))
;
318
319 NextFieldOffsetInChars += getSizeInChars(C);
320}
321
322void ConstStructBuilder::AppendTailPadding(CharUnits RecordSize) {
323 assert(NextFieldOffsetInChars <= RecordSize &&((NextFieldOffsetInChars <= RecordSize && "Size mismatch!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= RecordSize && \"Size mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 324, __PRETTY_FUNCTION__))
324 "Size mismatch!")((NextFieldOffsetInChars <= RecordSize && "Size mismatch!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= RecordSize && \"Size mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 324, __PRETTY_FUNCTION__))
;
325
326 AppendPadding(RecordSize - NextFieldOffsetInChars);
327}
328
329void ConstStructBuilder::ConvertStructToPacked() {
330 SmallVector<llvm::Constant *, 16> PackedElements;
331 CharUnits ElementOffsetInChars = CharUnits::Zero();
332
333 for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
334 llvm::Constant *C = Elements[i];
335
336 CharUnits ElementAlign = CharUnits::fromQuantity(
337 CGM.getDataLayout().getABITypeAlignment(C->getType()));
338 CharUnits AlignedElementOffsetInChars =
339 ElementOffsetInChars.alignTo(ElementAlign);
340
341 if (AlignedElementOffsetInChars > ElementOffsetInChars) {
342 // We need some padding.
343 CharUnits NumChars =
344 AlignedElementOffsetInChars - ElementOffsetInChars;
345
346 llvm::Type *Ty = CGM.Int8Ty;
347 if (NumChars > CharUnits::One())
348 Ty = llvm::ArrayType::get(Ty, NumChars.getQuantity());
349
350 llvm::Constant *Padding = llvm::UndefValue::get(Ty);
351 PackedElements.push_back(Padding);
352 ElementOffsetInChars += getSizeInChars(Padding);
353 }
354
355 PackedElements.push_back(C);
356 ElementOffsetInChars += getSizeInChars(C);
357 }
358
359 assert(ElementOffsetInChars == NextFieldOffsetInChars &&((ElementOffsetInChars == NextFieldOffsetInChars && "Packing the struct changed its size!"
) ? static_cast<void> (0) : __assert_fail ("ElementOffsetInChars == NextFieldOffsetInChars && \"Packing the struct changed its size!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 360, __PRETTY_FUNCTION__))
360 "Packing the struct changed its size!")((ElementOffsetInChars == NextFieldOffsetInChars && "Packing the struct changed its size!"
) ? static_cast<void> (0) : __assert_fail ("ElementOffsetInChars == NextFieldOffsetInChars && \"Packing the struct changed its size!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 360, __PRETTY_FUNCTION__))
;
361
362 Elements.swap(PackedElements);
363 LLVMStructAlignment = CharUnits::One();
364 Packed = true;
365}
366
367bool ConstStructBuilder::Build(InitListExpr *ILE) {
368 RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
369 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
370
371 unsigned FieldNo = 0;
372 unsigned ElementNo = 0;
373
374 // Bail out if we have base classes. We could support these, but they only
375 // arise in C++1z where we will have already constant folded most interesting
376 // cases. FIXME: There are still a few more cases we can handle this way.
377 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
378 if (CXXRD->getNumBases())
379 return false;
380
381 for (RecordDecl::field_iterator Field = RD->field_begin(),
382 FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
383 // If this is a union, skip all the fields that aren't being initialized.
384 if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field)
385 continue;
386
387 // Don't emit anonymous bitfields, they just affect layout.
388 if (Field->isUnnamedBitfield())
389 continue;
390
391 // Get the initializer. A struct can include fields without initializers,
392 // we just use explicit null values for them.
393 llvm::Constant *EltInit;
394 if (ElementNo < ILE->getNumInits())
395 EltInit = Emitter.tryEmitPrivateForMemory(ILE->getInit(ElementNo++),
396 Field->getType());
397 else
398 EltInit = Emitter.emitNullForMemory(Field->getType());
399
400 if (!EltInit)
401 return false;
402
403 if (!Field->isBitField()) {
404 // Handle non-bitfield members.
405 AppendField(*Field, Layout.getFieldOffset(FieldNo), EltInit);
406 } else {
407 // Otherwise we have a bitfield.
408 if (auto *CI = dyn_cast<llvm::ConstantInt>(EltInit)) {
409 AppendBitField(*Field, Layout.getFieldOffset(FieldNo), CI);
410 } else {
411 // We are trying to initialize a bitfield with a non-trivial constant,
412 // this must require run-time code.
413 return false;
414 }
415 }
416 }
417
418 return true;
419}
420
421namespace {
422struct BaseInfo {
423 BaseInfo(const CXXRecordDecl *Decl, CharUnits Offset, unsigned Index)
424 : Decl(Decl), Offset(Offset), Index(Index) {
425 }
426
427 const CXXRecordDecl *Decl;
428 CharUnits Offset;
429 unsigned Index;
430
431 bool operator<(const BaseInfo &O) const { return Offset < O.Offset; }
432};
433}
434
435bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
436 bool IsPrimaryBase,
437 const CXXRecordDecl *VTableClass,
438 CharUnits Offset) {
439 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
440
441 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
442 // Add a vtable pointer, if we need one and it hasn't already been added.
443 if (CD->isDynamicClass() && !IsPrimaryBase) {
444 llvm::Constant *VTableAddressPoint =
445 CGM.getCXXABI().getVTableAddressPointForConstExpr(
446 BaseSubobject(CD, Offset), VTableClass);
447 AppendBytes(Offset, VTableAddressPoint);
448 }
449
450 // Accumulate and sort bases, in order to visit them in address order, which
451 // may not be the same as declaration order.
452 SmallVector<BaseInfo, 8> Bases;
453 Bases.reserve(CD->getNumBases());
454 unsigned BaseNo = 0;
455 for (CXXRecordDecl::base_class_const_iterator Base = CD->bases_begin(),
456 BaseEnd = CD->bases_end(); Base != BaseEnd; ++Base, ++BaseNo) {
457 assert(!Base->isVirtual() && "should not have virtual bases here")((!Base->isVirtual() && "should not have virtual bases here"
) ? static_cast<void> (0) : __assert_fail ("!Base->isVirtual() && \"should not have virtual bases here\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 457, __PRETTY_FUNCTION__))
;
458 const CXXRecordDecl *BD = Base->getType()->getAsCXXRecordDecl();
459 CharUnits BaseOffset = Layout.getBaseClassOffset(BD);
460 Bases.push_back(BaseInfo(BD, BaseOffset, BaseNo));
461 }
462 std::stable_sort(Bases.begin(), Bases.end());
463
464 for (unsigned I = 0, N = Bases.size(); I != N; ++I) {
465 BaseInfo &Base = Bases[I];
466
467 bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl;
468 Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
469 VTableClass, Offset + Base.Offset);
470 }
471 }
472
473 unsigned FieldNo = 0;
474 uint64_t OffsetBits = CGM.getContext().toBits(Offset);
475
476 for (RecordDecl::field_iterator Field = RD->field_begin(),
477 FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
478 // If this is a union, skip all the fields that aren't being initialized.
479 if (RD->isUnion() && Val.getUnionField() != *Field)
480 continue;
481
482 // Don't emit anonymous bitfields, they just affect layout.
483 if (Field->isUnnamedBitfield())
484 continue;
485
486 // Emit the value of the initializer.
487 const APValue &FieldValue =
488 RD->isUnion() ? Val.getUnionValue() : Val.getStructField(FieldNo);
489 llvm::Constant *EltInit =
490 Emitter.tryEmitPrivateForMemory(FieldValue, Field->getType());
491 if (!EltInit)
492 return false;
493
494 if (!Field->isBitField()) {
495 // Handle non-bitfield members.
496 AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, EltInit);
497 } else {
498 // Otherwise we have a bitfield.
499 AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
500 cast<llvm::ConstantInt>(EltInit));
501 }
502 }
503
504 return true;
505}
506
507llvm::Constant *ConstStructBuilder::Finalize(QualType Ty) {
508 RecordDecl *RD = Ty->getAs<RecordType>()->getDecl();
509 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
510
511 CharUnits LayoutSizeInChars = Layout.getSize();
512
513 if (NextFieldOffsetInChars > LayoutSizeInChars) {
514 // If the struct is bigger than the size of the record type,
515 // we must have a flexible array member at the end.
516 assert(RD->hasFlexibleArrayMember() &&((RD->hasFlexibleArrayMember() && "Must have flexible array member if struct is bigger than type!"
) ? static_cast<void> (0) : __assert_fail ("RD->hasFlexibleArrayMember() && \"Must have flexible array member if struct is bigger than type!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 517, __PRETTY_FUNCTION__))
517 "Must have flexible array member if struct is bigger than type!")((RD->hasFlexibleArrayMember() && "Must have flexible array member if struct is bigger than type!"
) ? static_cast<void> (0) : __assert_fail ("RD->hasFlexibleArrayMember() && \"Must have flexible array member if struct is bigger than type!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 517, __PRETTY_FUNCTION__))
;
518
519 // No tail padding is necessary.
520 } else {
521 // Append tail padding if necessary.
522 CharUnits LLVMSizeInChars =
523 NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
524
525 if (LLVMSizeInChars != LayoutSizeInChars)
526 AppendTailPadding(LayoutSizeInChars);
527
528 LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
529
530 // Check if we need to convert the struct to a packed struct.
531 if (NextFieldOffsetInChars <= LayoutSizeInChars &&
532 LLVMSizeInChars > LayoutSizeInChars) {
533 assert(!Packed && "Size mismatch!")((!Packed && "Size mismatch!") ? static_cast<void>
(0) : __assert_fail ("!Packed && \"Size mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 533, __PRETTY_FUNCTION__))
;
534
535 ConvertStructToPacked();
536 assert(NextFieldOffsetInChars <= LayoutSizeInChars &&((NextFieldOffsetInChars <= LayoutSizeInChars && "Converting to packed did not help!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= LayoutSizeInChars && \"Converting to packed did not help!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 537, __PRETTY_FUNCTION__))
537 "Converting to packed did not help!")((NextFieldOffsetInChars <= LayoutSizeInChars && "Converting to packed did not help!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= LayoutSizeInChars && \"Converting to packed did not help!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 537, __PRETTY_FUNCTION__))
;
538 }
539
540 LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
541
542 assert(LayoutSizeInChars == LLVMSizeInChars &&((LayoutSizeInChars == LLVMSizeInChars && "Tail padding mismatch!"
) ? static_cast<void> (0) : __assert_fail ("LayoutSizeInChars == LLVMSizeInChars && \"Tail padding mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 543, __PRETTY_FUNCTION__))
543 "Tail padding mismatch!")((LayoutSizeInChars == LLVMSizeInChars && "Tail padding mismatch!"
) ? static_cast<void> (0) : __assert_fail ("LayoutSizeInChars == LLVMSizeInChars && \"Tail padding mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 543, __PRETTY_FUNCTION__))
;
544 }
545
546 // Pick the type to use. If the type is layout identical to the ConvertType
547 // type then use it, otherwise use whatever the builder produced for us.
548 llvm::StructType *STy =
549 llvm::ConstantStruct::getTypeForElements(CGM.getLLVMContext(),
550 Elements, Packed);
551 llvm::Type *ValTy = CGM.getTypes().ConvertType(Ty);
552 if (llvm::StructType *ValSTy = dyn_cast<llvm::StructType>(ValTy)) {
553 if (ValSTy->isLayoutIdentical(STy))
554 STy = ValSTy;
555 }
556
557 llvm::Constant *Result = llvm::ConstantStruct::get(STy, Elements);
558
559 assert(NextFieldOffsetInChars.alignTo(getAlignment(Result)) ==((NextFieldOffsetInChars.alignTo(getAlignment(Result)) == getSizeInChars
(Result) && "Size mismatch!") ? static_cast<void>
(0) : __assert_fail ("NextFieldOffsetInChars.alignTo(getAlignment(Result)) == getSizeInChars(Result) && \"Size mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 561, __PRETTY_FUNCTION__))
560 getSizeInChars(Result) &&((NextFieldOffsetInChars.alignTo(getAlignment(Result)) == getSizeInChars
(Result) && "Size mismatch!") ? static_cast<void>
(0) : __assert_fail ("NextFieldOffsetInChars.alignTo(getAlignment(Result)) == getSizeInChars(Result) && \"Size mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 561, __PRETTY_FUNCTION__))
561 "Size mismatch!")((NextFieldOffsetInChars.alignTo(getAlignment(Result)) == getSizeInChars
(Result) && "Size mismatch!") ? static_cast<void>
(0) : __assert_fail ("NextFieldOffsetInChars.alignTo(getAlignment(Result)) == getSizeInChars(Result) && \"Size mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 561, __PRETTY_FUNCTION__))
;
562
563 return Result;
564}
565
566llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
567 ConstExprEmitter *ExprEmitter,
568 llvm::Constant *Base,
569 InitListExpr *Updater,
570 QualType ValTy) {
571 ConstStructBuilder Builder(Emitter);
572 if (!Builder.Build(ExprEmitter, Base, Updater))
573 return nullptr;
574 return Builder.Finalize(ValTy);
575}
576
577llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
578 InitListExpr *ILE,
579 QualType ValTy) {
580 ConstStructBuilder Builder(Emitter);
581
582 if (!Builder.Build(ILE))
583 return nullptr;
584
585 return Builder.Finalize(ValTy);
586}
587
588llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
589 const APValue &Val,
590 QualType ValTy) {
591 ConstStructBuilder Builder(Emitter);
592
593 const RecordDecl *RD = ValTy->castAs<RecordType>()->getDecl();
594 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
595 if (!Builder.Build(Val, RD, false, CD, CharUnits::Zero()))
596 return nullptr;
597
598 return Builder.Finalize(ValTy);
599}
600
601
602//===----------------------------------------------------------------------===//
603// ConstExprEmitter
604//===----------------------------------------------------------------------===//
605
606static ConstantAddress tryEmitGlobalCompoundLiteral(CodeGenModule &CGM,
607 CodeGenFunction *CGF,
608 const CompoundLiteralExpr *E) {
609 CharUnits Align = CGM.getContext().getTypeAlignInChars(E->getType());
610 if (llvm::GlobalVariable *Addr =
611 CGM.getAddrOfConstantCompoundLiteralIfEmitted(E))
612 return ConstantAddress(Addr, Align);
613
614 LangAS addressSpace = E->getType().getAddressSpace();
615
616 ConstantEmitter emitter(CGM, CGF);
617 llvm::Constant *C = emitter.tryEmitForInitializer(E->getInitializer(),
618 addressSpace, E->getType());
619 if (!C) {
620 assert(!E->isFileScope() &&((!E->isFileScope() && "file-scope compound literal did not have constant initializer!"
) ? static_cast<void> (0) : __assert_fail ("!E->isFileScope() && \"file-scope compound literal did not have constant initializer!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 621, __PRETTY_FUNCTION__))
621 "file-scope compound literal did not have constant initializer!")((!E->isFileScope() && "file-scope compound literal did not have constant initializer!"
) ? static_cast<void> (0) : __assert_fail ("!E->isFileScope() && \"file-scope compound literal did not have constant initializer!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 621, __PRETTY_FUNCTION__))
;
622 return ConstantAddress::invalid();
623 }
624
625 auto GV = new llvm::GlobalVariable(CGM.getModule(), C->getType(),
626 CGM.isTypeConstant(E->getType(), true),
627 llvm::GlobalValue::InternalLinkage,
628 C, ".compoundliteral", nullptr,
629 llvm::GlobalVariable::NotThreadLocal,
630 CGM.getContext().getTargetAddressSpace(addressSpace));
631 emitter.finalize(GV);
632 GV->setAlignment(Align.getQuantity());
633 CGM.setAddrOfConstantCompoundLiteral(E, GV);
634 return ConstantAddress(GV, Align);
635}
636
637static llvm::Constant *
638EmitArrayConstant(CodeGenModule &CGM, const ConstantArrayType *DestType,
639 llvm::Type *CommonElementType, unsigned ArrayBound,
640 SmallVectorImpl<llvm::Constant *> &Elements,
641 llvm::Constant *Filler) {
642 // Figure out how long the initial prefix of non-zero elements is.
643 unsigned NonzeroLength = ArrayBound;
644 if (Elements.size() < NonzeroLength && Filler->isNullValue())
645 NonzeroLength = Elements.size();
646 if (NonzeroLength == Elements.size()) {
647 while (NonzeroLength > 0 && Elements[NonzeroLength - 1]->isNullValue())
648 --NonzeroLength;
649 }
650
651 if (NonzeroLength == 0) {
652 return llvm::ConstantAggregateZero::get(
653 CGM.getTypes().ConvertType(QualType(DestType, 0)));
654 }
655
656 // Add a zeroinitializer array filler if we have lots of trailing zeroes.
657 unsigned TrailingZeroes = ArrayBound - NonzeroLength;
658 if (TrailingZeroes >= 8) {
659 assert(Elements.size() >= NonzeroLength &&((Elements.size() >= NonzeroLength && "missing initializer for non-zero element"
) ? static_cast<void> (0) : __assert_fail ("Elements.size() >= NonzeroLength && \"missing initializer for non-zero element\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 660, __PRETTY_FUNCTION__))
660 "missing initializer for non-zero element")((Elements.size() >= NonzeroLength && "missing initializer for non-zero element"
) ? static_cast<void> (0) : __assert_fail ("Elements.size() >= NonzeroLength && \"missing initializer for non-zero element\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 660, __PRETTY_FUNCTION__))
;
661
662 // If all the elements had the same type up to the trailing zeroes, emit a
663 // struct of two arrays (the nonzero data and the zeroinitializer).
664 if (CommonElementType && NonzeroLength >= 8) {
665 llvm::Constant *Initial = llvm::ConstantArray::get(
666 llvm::ArrayType::get(CommonElementType, NonzeroLength),
667 makeArrayRef(Elements).take_front(NonzeroLength));
668 Elements.resize(2);
669 Elements[0] = Initial;
670 } else {
671 Elements.resize(NonzeroLength + 1);
672 }
673
674 auto *FillerType =
675 CommonElementType
676 ? CommonElementType
677 : CGM.getTypes().ConvertType(DestType->getElementType());
678 FillerType = llvm::ArrayType::get(FillerType, TrailingZeroes);
679 Elements.back() = llvm::ConstantAggregateZero::get(FillerType);
680 CommonElementType = nullptr;
681 } else if (Elements.size() != ArrayBound) {
682 // Otherwise pad to the right size with the filler if necessary.
683 Elements.resize(ArrayBound, Filler);
684 if (Filler->getType() != CommonElementType)
685 CommonElementType = nullptr;
686 }
687
688 // If all elements have the same type, just emit an array constant.
689 if (CommonElementType)
690 return llvm::ConstantArray::get(
691 llvm::ArrayType::get(CommonElementType, ArrayBound), Elements);
692
693 // We have mixed types. Use a packed struct.
694 llvm::SmallVector<llvm::Type *, 16> Types;
695 Types.reserve(Elements.size());
696 for (llvm::Constant *Elt : Elements)
697 Types.push_back(Elt->getType());
698 llvm::StructType *SType =
699 llvm::StructType::get(CGM.getLLVMContext(), Types, true);
700 return llvm::ConstantStruct::get(SType, Elements);
701}
702
703// This class only needs to handle arrays, structs and unions. Outside C++11
704// mode, we don't currently constant fold those types. All other types are
705// handled by constant folding.
706//
707// Constant folding is currently missing support for a few features supported
708// here: CK_ToUnion, CK_ReinterpretMemberPointer, and DesignatedInitUpdateExpr.
709class ConstExprEmitter :
710 public StmtVisitor<ConstExprEmitter, llvm::Constant*, QualType> {
711 CodeGenModule &CGM;
712 ConstantEmitter &Emitter;
713 llvm::LLVMContext &VMContext;
714public:
715 ConstExprEmitter(ConstantEmitter &emitter)
716 : CGM(emitter.CGM), Emitter(emitter), VMContext(CGM.getLLVMContext()) {
717 }
718
719 //===--------------------------------------------------------------------===//
720 // Visitor Methods
721 //===--------------------------------------------------------------------===//
722
723 llvm::Constant *VisitStmt(Stmt *S, QualType T) {
724 return nullptr;
725 }
726
727 llvm::Constant *VisitConstantExpr(ConstantExpr *CE, QualType T) {
728 return Visit(CE->getSubExpr(), T);
729 }
730
731 llvm::Constant *VisitParenExpr(ParenExpr *PE, QualType T) {
732 return Visit(PE->getSubExpr(), T);
733 }
734
735 llvm::Constant *
736 VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *PE,
737 QualType T) {
738 return Visit(PE->getReplacement(), T);
739 }
740
741 llvm::Constant *VisitGenericSelectionExpr(GenericSelectionExpr *GE,
742 QualType T) {
743 return Visit(GE->getResultExpr(), T);
744 }
745
746 llvm::Constant *VisitChooseExpr(ChooseExpr *CE, QualType T) {
747 return Visit(CE->getChosenSubExpr(), T);
748 }
749
750 llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E, QualType T) {
751 return Visit(E->getInitializer(), T);
752 }
753
754 llvm::Constant *VisitCastExpr(CastExpr *E, QualType destType) {
755 if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
756 CGM.EmitExplicitCastExprType(ECE, Emitter.CGF);
757 Expr *subExpr = E->getSubExpr();
758
759 switch (E->getCastKind()) {
760 case CK_ToUnion: {
761 // GCC cast to union extension
762 assert(E->getType()->isUnionType() &&((E->getType()->isUnionType() && "Destination type is not union type!"
) ? static_cast<void> (0) : __assert_fail ("E->getType()->isUnionType() && \"Destination type is not union type!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 763, __PRETTY_FUNCTION__))
763 "Destination type is not union type!")((E->getType()->isUnionType() && "Destination type is not union type!"
) ? static_cast<void> (0) : __assert_fail ("E->getType()->isUnionType() && \"Destination type is not union type!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 763, __PRETTY_FUNCTION__))
;
764
765 auto field = E->getTargetUnionField();
766
767 auto C = Emitter.tryEmitPrivateForMemory(subExpr, field->getType());
768 if (!C) return nullptr;
769
770 auto destTy = ConvertType(destType);
771 if (C->getType() == destTy) return C;
772
773 // Build a struct with the union sub-element as the first member,
774 // and padded to the appropriate size.
775 SmallVector<llvm::Constant*, 2> Elts;
776 SmallVector<llvm::Type*, 2> Types;
777 Elts.push_back(C);
778 Types.push_back(C->getType());
779 unsigned CurSize = CGM.getDataLayout().getTypeAllocSize(C->getType());
780 unsigned TotalSize = CGM.getDataLayout().getTypeAllocSize(destTy);
781
782 assert(CurSize <= TotalSize && "Union size mismatch!")((CurSize <= TotalSize && "Union size mismatch!") ?
static_cast<void> (0) : __assert_fail ("CurSize <= TotalSize && \"Union size mismatch!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 782, __PRETTY_FUNCTION__))
;
783 if (unsigned NumPadBytes = TotalSize - CurSize) {
784 llvm::Type *Ty = CGM.Int8Ty;
785 if (NumPadBytes > 1)
786 Ty = llvm::ArrayType::get(Ty, NumPadBytes);
787
788 Elts.push_back(llvm::UndefValue::get(Ty));
789 Types.push_back(Ty);
790 }
791
792 llvm::StructType *STy = llvm::StructType::get(VMContext, Types, false);
793 return llvm::ConstantStruct::get(STy, Elts);
794 }
795
796 case CK_AddressSpaceConversion: {
797 auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
798 if (!C) return nullptr;
799 LangAS destAS = E->getType()->getPointeeType().getAddressSpace();
800 LangAS srcAS = subExpr->getType()->getPointeeType().getAddressSpace();
801 llvm::Type *destTy = ConvertType(E->getType());
802 return CGM.getTargetCodeGenInfo().performAddrSpaceCast(CGM, C, srcAS,
803 destAS, destTy);
804 }
805
806 case CK_LValueToRValue:
807 case CK_AtomicToNonAtomic:
808 case CK_NonAtomicToAtomic:
809 case CK_NoOp:
810 case CK_ConstructorConversion:
811 return Visit(subExpr, destType);
812
813 case CK_IntToOCLSampler:
814 llvm_unreachable("global sampler variables are not generated")::llvm::llvm_unreachable_internal("global sampler variables are not generated"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 814)
;
815
816 case CK_Dependent: llvm_unreachable("saw dependent cast!")::llvm::llvm_unreachable_internal("saw dependent cast!", "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 816)
;
817
818 case CK_BuiltinFnToFnPtr:
819 llvm_unreachable("builtin functions are handled elsewhere")::llvm::llvm_unreachable_internal("builtin functions are handled elsewhere"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 819)
;
820
821 case CK_ReinterpretMemberPointer:
822 case CK_DerivedToBaseMemberPointer:
823 case CK_BaseToDerivedMemberPointer: {
824 auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
825 if (!C) return nullptr;
826 return CGM.getCXXABI().EmitMemberPointerConversion(E, C);
827 }
828
829 // These will never be supported.
830 case CK_ObjCObjectLValueCast:
831 case CK_ARCProduceObject:
832 case CK_ARCConsumeObject:
833 case CK_ARCReclaimReturnedObject:
834 case CK_ARCExtendBlockObject:
835 case CK_CopyAndAutoreleaseBlockObject:
836 return nullptr;
837
838 // These don't need to be handled here because Evaluate knows how to
839 // evaluate them in the cases where they can be folded.
840 case CK_BitCast:
841 case CK_ToVoid:
842 case CK_Dynamic:
843 case CK_LValueBitCast:
844 case CK_NullToMemberPointer:
845 case CK_UserDefinedConversion:
846 case CK_CPointerToObjCPointerCast:
847 case CK_BlockPointerToObjCPointerCast:
848 case CK_AnyPointerToBlockPointerCast:
849 case CK_ArrayToPointerDecay:
850 case CK_FunctionToPointerDecay:
851 case CK_BaseToDerived:
852 case CK_DerivedToBase:
853 case CK_UncheckedDerivedToBase:
854 case CK_MemberPointerToBoolean:
855 case CK_VectorSplat:
856 case CK_FloatingRealToComplex:
857 case CK_FloatingComplexToReal:
858 case CK_FloatingComplexToBoolean:
859 case CK_FloatingComplexCast:
860 case CK_FloatingComplexToIntegralComplex:
861 case CK_IntegralRealToComplex:
862 case CK_IntegralComplexToReal:
863 case CK_IntegralComplexToBoolean:
864 case CK_IntegralComplexCast:
865 case CK_IntegralComplexToFloatingComplex:
866 case CK_PointerToIntegral:
867 case CK_PointerToBoolean:
868 case CK_NullToPointer:
869 case CK_IntegralCast:
870 case CK_BooleanToSignedIntegral:
871 case CK_IntegralToPointer:
872 case CK_IntegralToBoolean:
873 case CK_IntegralToFloating:
874 case CK_FloatingToIntegral:
875 case CK_FloatingToBoolean:
876 case CK_FloatingCast:
877 case CK_FixedPointCast:
878 case CK_FixedPointToBoolean:
879 case CK_FixedPointToIntegral:
880 case CK_IntegralToFixedPoint:
881 case CK_ZeroToOCLOpaqueType:
882 return nullptr;
883 }
884 llvm_unreachable("Invalid CastKind")::llvm::llvm_unreachable_internal("Invalid CastKind", "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 884)
;
885 }
886
887 llvm::Constant *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE, QualType T) {
888 return Visit(DAE->getExpr(), T);
889 }
890
891 llvm::Constant *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE, QualType T) {
892 // No need for a DefaultInitExprScope: we don't handle 'this' in a
893 // constant expression.
894 return Visit(DIE->getExpr(), T);
895 }
896
897 llvm::Constant *VisitExprWithCleanups(ExprWithCleanups *E, QualType T) {
898 if (!E->cleanupsHaveSideEffects())
899 return Visit(E->getSubExpr(), T);
900 return nullptr;
901 }
902
903 llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
904 QualType T) {
905 return Visit(E->GetTemporaryExpr(), T);
906 }
907
908 llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) {
909 auto *CAT = CGM.getContext().getAsConstantArrayType(ILE->getType());
910 assert(CAT && "can't emit array init for non-constant-bound array")((CAT && "can't emit array init for non-constant-bound array"
) ? static_cast<void> (0) : __assert_fail ("CAT && \"can't emit array init for non-constant-bound array\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 910, __PRETTY_FUNCTION__))
;
911 unsigned NumInitElements = ILE->getNumInits();
912 unsigned NumElements = CAT->getSize().getZExtValue();
913
914 // Initialising an array requires us to automatically
915 // initialise any elements that have not been initialised explicitly
916 unsigned NumInitableElts = std::min(NumInitElements, NumElements);
917
918 QualType EltType = CAT->getElementType();
919
920 // Initialize remaining array elements.
921 llvm::Constant *fillC = nullptr;
922 if (Expr *filler = ILE->getArrayFiller()) {
923 fillC = Emitter.tryEmitAbstractForMemory(filler, EltType);
924 if (!fillC)
925 return nullptr;
926 }
927
928 // Copy initializer elements.
929 SmallVector<llvm::Constant*, 16> Elts;
930 if (fillC && fillC->isNullValue())
931 Elts.reserve(NumInitableElts + 1);
932 else
933 Elts.reserve(NumElements);
934
935 llvm::Type *CommonElementType = nullptr;
936 for (unsigned i = 0; i < NumInitableElts; ++i) {
937 Expr *Init = ILE->getInit(i);
938 llvm::Constant *C = Emitter.tryEmitPrivateForMemory(Init, EltType);
939 if (!C)
940 return nullptr;
941 if (i == 0)
942 CommonElementType = C->getType();
943 else if (C->getType() != CommonElementType)
944 CommonElementType = nullptr;
945 Elts.push_back(C);
946 }
947
948 return EmitArrayConstant(CGM, CAT, CommonElementType, NumElements, Elts,
949 fillC);
950 }
951
952 llvm::Constant *EmitRecordInitialization(InitListExpr *ILE, QualType T) {
953 return ConstStructBuilder::BuildStruct(Emitter, ILE, T);
954 }
955
956 llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E,
957 QualType T) {
958 return CGM.EmitNullConstant(T);
959 }
960
961 llvm::Constant *VisitInitListExpr(InitListExpr *ILE, QualType T) {
962 if (ILE->isTransparent())
963 return Visit(ILE->getInit(0), T);
964
965 if (ILE->getType()->isArrayType())
966 return EmitArrayInitialization(ILE, T);
967
968 if (ILE->getType()->isRecordType())
969 return EmitRecordInitialization(ILE, T);
970
971 return nullptr;
972 }
973
974 llvm::Constant *EmitDesignatedInitUpdater(llvm::Constant *Base,
975 InitListExpr *Updater,
976 QualType destType) {
977 if (auto destAT = CGM.getContext().getAsArrayType(destType)) {
978 llvm::ArrayType *AType = cast<llvm::ArrayType>(ConvertType(destType));
979 llvm::Type *ElemType = AType->getElementType();
980
981 unsigned NumInitElements = Updater->getNumInits();
982 unsigned NumElements = AType->getNumElements();
983
984 std::vector<llvm::Constant *> Elts;
985 Elts.reserve(NumElements);
986
987 QualType destElemType = destAT->getElementType();
988
989 if (auto DataArray = dyn_cast<llvm::ConstantDataArray>(Base))
990 for (unsigned i = 0; i != NumElements; ++i)
991 Elts.push_back(DataArray->getElementAsConstant(i));
992 else if (auto Array = dyn_cast<llvm::ConstantArray>(Base))
993 for (unsigned i = 0; i != NumElements; ++i)
994 Elts.push_back(Array->getOperand(i));
995 else
996 return nullptr; // FIXME: other array types not implemented
997
998 llvm::Constant *fillC = nullptr;
999 if (Expr *filler = Updater->getArrayFiller())
1000 if (!isa<NoInitExpr>(filler))
1001 fillC = Emitter.tryEmitAbstractForMemory(filler, destElemType);
1002 bool RewriteType = (fillC && fillC->getType() != ElemType);
1003
1004 for (unsigned i = 0; i != NumElements; ++i) {
1005 Expr *Init = nullptr;
1006 if (i < NumInitElements)
1007 Init = Updater->getInit(i);
1008
1009 if (!Init && fillC)
1010 Elts[i] = fillC;
1011 else if (!Init || isa<NoInitExpr>(Init))
1012 ; // Do nothing.
1013 else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init))
1014 Elts[i] = EmitDesignatedInitUpdater(Elts[i], ChildILE, destElemType);
1015 else
1016 Elts[i] = Emitter.tryEmitPrivateForMemory(Init, destElemType);
1017
1018 if (!Elts[i])
1019 return nullptr;
1020 RewriteType |= (Elts[i]->getType() != ElemType);
1021 }
1022
1023 if (RewriteType) {
1024 std::vector<llvm::Type *> Types;
1025 Types.reserve(NumElements);
1026 for (unsigned i = 0; i != NumElements; ++i)
1027 Types.push_back(Elts[i]->getType());
1028 llvm::StructType *SType = llvm::StructType::get(AType->getContext(),
1029 Types, true);
1030 return llvm::ConstantStruct::get(SType, Elts);
1031 }
1032
1033 return llvm::ConstantArray::get(AType, Elts);
1034 }
1035
1036 if (destType->isRecordType())
1037 return ConstStructBuilder::BuildStruct(Emitter, this, Base, Updater,
1038 destType);
1039
1040 return nullptr;
1041 }
1042
1043 llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E,
1044 QualType destType) {
1045 auto C = Visit(E->getBase(), destType);
1046 if (!C) return nullptr;
1047 return EmitDesignatedInitUpdater(C, E->getUpdater(), destType);
1048 }
1049
1050 llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) {
1051 if (!E->getConstructor()->isTrivial())
1052 return nullptr;
1053
1054 // FIXME: We should not have to call getBaseElementType here.
1055 const RecordType *RT =
1056 CGM.getContext().getBaseElementType(Ty)->getAs<RecordType>();
1057 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1058
1059 // If the class doesn't have a trivial destructor, we can't emit it as a
1060 // constant expr.
1061 if (!RD->hasTrivialDestructor())
1062 return nullptr;
1063
1064 // Only copy and default constructors can be trivial.
1065
1066
1067 if (E->getNumArgs()) {
1068 assert(E->getNumArgs() == 1 && "trivial ctor with > 1 argument")((E->getNumArgs() == 1 && "trivial ctor with > 1 argument"
) ? static_cast<void> (0) : __assert_fail ("E->getNumArgs() == 1 && \"trivial ctor with > 1 argument\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1068, __PRETTY_FUNCTION__))
;
1069 assert(E->getConstructor()->isCopyOrMoveConstructor() &&((E->getConstructor()->isCopyOrMoveConstructor() &&
"trivial ctor has argument but isn't a copy/move ctor") ? static_cast
<void> (0) : __assert_fail ("E->getConstructor()->isCopyOrMoveConstructor() && \"trivial ctor has argument but isn't a copy/move ctor\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1070, __PRETTY_FUNCTION__))
1070 "trivial ctor has argument but isn't a copy/move ctor")((E->getConstructor()->isCopyOrMoveConstructor() &&
"trivial ctor has argument but isn't a copy/move ctor") ? static_cast
<void> (0) : __assert_fail ("E->getConstructor()->isCopyOrMoveConstructor() && \"trivial ctor has argument but isn't a copy/move ctor\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1070, __PRETTY_FUNCTION__))
;
1071
1072 Expr *Arg = E->getArg(0);
1073 assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) &&((CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType
()) && "argument to copy ctor is of wrong type") ? static_cast
<void> (0) : __assert_fail ("CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) && \"argument to copy ctor is of wrong type\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1074, __PRETTY_FUNCTION__))
1074 "argument to copy ctor is of wrong type")((CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType
()) && "argument to copy ctor is of wrong type") ? static_cast
<void> (0) : __assert_fail ("CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) && \"argument to copy ctor is of wrong type\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1074, __PRETTY_FUNCTION__))
;
1075
1076 return Visit(Arg, Ty);
1077 }
1078
1079 return CGM.EmitNullConstant(Ty);
1080 }
1081
1082 llvm::Constant *VisitStringLiteral(StringLiteral *E, QualType T) {
1083 // This is a string literal initializing an array in an initializer.
1084 return CGM.GetConstantArrayFromStringLiteral(E);
1085 }
1086
1087 llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E, QualType T) {
1088 // This must be an @encode initializing an array in a static initializer.
1089 // Don't emit it as the address of the string, emit the string data itself
1090 // as an inline array.
1091 std::string Str;
1092 CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str);
1093 const ConstantArrayType *CAT = CGM.getContext().getAsConstantArrayType(T);
1094
1095 // Resize the string to the right size, adding zeros at the end, or
1096 // truncating as needed.
1097 Str.resize(CAT->getSize().getZExtValue(), '\0');
1098 return llvm::ConstantDataArray::getString(VMContext, Str, false);
1099 }
1100
1101 llvm::Constant *VisitUnaryExtension(const UnaryOperator *E, QualType T) {
1102 return Visit(E->getSubExpr(), T);
1103 }
1104
1105 // Utility methods
1106 llvm::Type *ConvertType(QualType T) {
1107 return CGM.getTypes().ConvertType(T);
1108 }
1109};
1110
1111} // end anonymous namespace.
1112
1113bool ConstStructBuilder::Build(ConstExprEmitter *ExprEmitter,
1114 llvm::Constant *Base,
1115 InitListExpr *Updater) {
1116 assert(Base && "base expression should not be empty")((Base && "base expression should not be empty") ? static_cast
<void> (0) : __assert_fail ("Base && \"base expression should not be empty\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1116, __PRETTY_FUNCTION__))
;
1117
1118 QualType ExprType = Updater->getType();
1119 RecordDecl *RD = ExprType->getAs<RecordType>()->getDecl();
1120 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
1121 const llvm::StructLayout *BaseLayout = CGM.getDataLayout().getStructLayout(
1122 cast<llvm::StructType>(Base->getType()));
1123 unsigned FieldNo = -1;
1124 unsigned ElementNo = 0;
1125
1126 // Bail out if we have base classes. We could support these, but they only
1127 // arise in C++1z where we will have already constant folded most interesting
1128 // cases. FIXME: There are still a few more cases we can handle this way.
1129 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
1130 if (CXXRD->getNumBases())
1131 return false;
1132
1133 for (FieldDecl *Field : RD->fields()) {
1134 ++FieldNo;
1135
1136 if (RD->isUnion() && Updater->getInitializedFieldInUnion() != Field)
1137 continue;
1138
1139 // Skip anonymous bitfields.
1140 if (Field->isUnnamedBitfield())
1141 continue;
1142
1143 llvm::Constant *EltInit = Base->getAggregateElement(ElementNo);
1144
1145 // Bail out if the type of the ConstantStruct does not have the same layout
1146 // as the type of the InitListExpr.
1147 if (CGM.getTypes().ConvertType(Field->getType()) != EltInit->getType() ||
1148 Layout.getFieldOffset(ElementNo) !=
1149 BaseLayout->getElementOffsetInBits(ElementNo))
1150 return false;
1151
1152 // Get the initializer. If we encounter an empty field or a NoInitExpr,
1153 // we use values from the base expression.
1154 Expr *Init = nullptr;
1155 if (ElementNo < Updater->getNumInits())
1156 Init = Updater->getInit(ElementNo);
1157
1158 if (!Init || isa<NoInitExpr>(Init))
1159 ; // Do nothing.
1160 else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init))
1161 EltInit = ExprEmitter->EmitDesignatedInitUpdater(EltInit, ChildILE,
1162 Field->getType());
1163 else
1164 EltInit = Emitter.tryEmitPrivateForMemory(Init, Field->getType());
1165
1166 ++ElementNo;
1167
1168 if (!EltInit)
1169 return false;
1170
1171 if (!Field->isBitField())
1172 AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit);
1173 else if (llvm::ConstantInt *CI = dyn_cast<llvm::ConstantInt>(EltInit))
1174 AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI);
1175 else
1176 // Initializing a bitfield with a non-trivial constant?
1177 return false;
1178 }
1179
1180 return true;
1181}
1182
1183llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C,
1184 AbstractState saved) {
1185 Abstract = saved.OldValue;
1186
1187 assert(saved.OldPlaceholdersSize == PlaceholderAddresses.size() &&((saved.OldPlaceholdersSize == PlaceholderAddresses.size() &&
"created a placeholder while doing an abstract emission?") ?
static_cast<void> (0) : __assert_fail ("saved.OldPlaceholdersSize == PlaceholderAddresses.size() && \"created a placeholder while doing an abstract emission?\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1188, __PRETTY_FUNCTION__))
1188 "created a placeholder while doing an abstract emission?")((saved.OldPlaceholdersSize == PlaceholderAddresses.size() &&
"created a placeholder while doing an abstract emission?") ?
static_cast<void> (0) : __assert_fail ("saved.OldPlaceholdersSize == PlaceholderAddresses.size() && \"created a placeholder while doing an abstract emission?\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1188, __PRETTY_FUNCTION__))
;
1189
1190 // No validation necessary for now.
1191 // No cleanup to do for now.
1192 return C;
1193}
1194
1195llvm::Constant *
1196ConstantEmitter::tryEmitAbstractForInitializer(const VarDecl &D) {
1197 auto state = pushAbstract();
1198 auto C = tryEmitPrivateForVarInit(D);
1199 return validateAndPopAbstract(C, state);
1200}
1201
1202llvm::Constant *
1203ConstantEmitter::tryEmitAbstract(const Expr *E, QualType destType) {
1204 auto state = pushAbstract();
1205 auto C = tryEmitPrivate(E, destType);
1206 return validateAndPopAbstract(C, state);
1207}
1208
1209llvm::Constant *
1210ConstantEmitter::tryEmitAbstract(const APValue &value, QualType destType) {
1211 auto state = pushAbstract();
1212 auto C = tryEmitPrivate(value, destType);
1213 return validateAndPopAbstract(C, state);
1214}
1215
1216llvm::Constant *
1217ConstantEmitter::emitAbstract(const Expr *E, QualType destType) {
1218 auto state = pushAbstract();
1219 auto C = tryEmitPrivate(E, destType);
1220 C = validateAndPopAbstract(C, state);
1221 if (!C) {
1222 CGM.Error(E->getExprLoc(),
1223 "internal error: could not emit constant value \"abstractly\"");
1224 C = CGM.EmitNullConstant(destType);
1225 }
1226 return C;
1227}
1228
1229llvm::Constant *
1230ConstantEmitter::emitAbstract(SourceLocation loc, const APValue &value,
1231 QualType destType) {
1232 auto state = pushAbstract();
1233 auto C = tryEmitPrivate(value, destType);
1234 C = validateAndPopAbstract(C, state);
1235 if (!C) {
1236 CGM.Error(loc,
1237 "internal error: could not emit constant value \"abstractly\"");
1238 C = CGM.EmitNullConstant(destType);
1239 }
1240 return C;
1241}
1242
1243llvm::Constant *ConstantEmitter::tryEmitForInitializer(const VarDecl &D) {
1244 initializeNonAbstract(D.getType().getAddressSpace());
1245 return markIfFailed(tryEmitPrivateForVarInit(D));
1246}
1247
1248llvm::Constant *ConstantEmitter::tryEmitForInitializer(const Expr *E,
1249 LangAS destAddrSpace,
1250 QualType destType) {
1251 initializeNonAbstract(destAddrSpace);
1252 return markIfFailed(tryEmitPrivateForMemory(E, destType));
1253}
1254
1255llvm::Constant *ConstantEmitter::emitForInitializer(const APValue &value,
1256 LangAS destAddrSpace,
1257 QualType destType) {
1258 initializeNonAbstract(destAddrSpace);
1259 auto C = tryEmitPrivateForMemory(value, destType);
1260 assert(C && "couldn't emit constant value non-abstractly?")((C && "couldn't emit constant value non-abstractly?"
) ? static_cast<void> (0) : __assert_fail ("C && \"couldn't emit constant value non-abstractly?\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1260, __PRETTY_FUNCTION__))
;
1261 return C;
1262}
1263
1264llvm::GlobalValue *ConstantEmitter::getCurrentAddrPrivate() {
1265 assert(!Abstract && "cannot get current address for abstract constant")((!Abstract && "cannot get current address for abstract constant"
) ? static_cast<void> (0) : __assert_fail ("!Abstract && \"cannot get current address for abstract constant\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1265, __PRETTY_FUNCTION__))
;
1266
1267
1268
1269 // Make an obviously ill-formed global that should blow up compilation
1270 // if it survives.
1271 auto global = new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty, true,
1272 llvm::GlobalValue::PrivateLinkage,
1273 /*init*/ nullptr,
1274 /*name*/ "",
1275 /*before*/ nullptr,
1276 llvm::GlobalVariable::NotThreadLocal,
1277 CGM.getContext().getTargetAddressSpace(DestAddressSpace));
1278
1279 PlaceholderAddresses.push_back(std::make_pair(nullptr, global));
1280
1281 return global;
1282}
1283
1284void ConstantEmitter::registerCurrentAddrPrivate(llvm::Constant *signal,
1285 llvm::GlobalValue *placeholder) {
1286 assert(!PlaceholderAddresses.empty())((!PlaceholderAddresses.empty()) ? static_cast<void> (0
) : __assert_fail ("!PlaceholderAddresses.empty()", "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1286, __PRETTY_FUNCTION__))
;
1287 assert(PlaceholderAddresses.back().first == nullptr)((PlaceholderAddresses.back().first == nullptr) ? static_cast
<void> (0) : __assert_fail ("PlaceholderAddresses.back().first == nullptr"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1287, __PRETTY_FUNCTION__))
;
1288 assert(PlaceholderAddresses.back().second == placeholder)((PlaceholderAddresses.back().second == placeholder) ? static_cast
<void> (0) : __assert_fail ("PlaceholderAddresses.back().second == placeholder"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1288, __PRETTY_FUNCTION__))
;
1289 PlaceholderAddresses.back().first = signal;
1290}
1291
1292namespace {
1293 struct ReplacePlaceholders {
1294 CodeGenModule &CGM;
1295
1296 /// The base address of the global.
1297 llvm::Constant *Base;
1298 llvm::Type *BaseValueTy = nullptr;
1299
1300 /// The placeholder addresses that were registered during emission.
1301 llvm::DenseMap<llvm::Constant*, llvm::GlobalVariable*> PlaceholderAddresses;
1302
1303 /// The locations of the placeholder signals.
1304 llvm::DenseMap<llvm::GlobalVariable*, llvm::Constant*> Locations;
1305
1306 /// The current index stack. We use a simple unsigned stack because
1307 /// we assume that placeholders will be relatively sparse in the
1308 /// initializer, but we cache the index values we find just in case.
1309 llvm::SmallVector<unsigned, 8> Indices;
1310 llvm::SmallVector<llvm::Constant*, 8> IndexValues;
1311
1312 ReplacePlaceholders(CodeGenModule &CGM, llvm::Constant *base,
1313 ArrayRef<std::pair<llvm::Constant*,
1314 llvm::GlobalVariable*>> addresses)
1315 : CGM(CGM), Base(base),
1316 PlaceholderAddresses(addresses.begin(), addresses.end()) {
1317 }
1318
1319 void replaceInInitializer(llvm::Constant *init) {
1320 // Remember the type of the top-most initializer.
1321 BaseValueTy = init->getType();
1322
1323 // Initialize the stack.
1324 Indices.push_back(0);
1325 IndexValues.push_back(nullptr);
1326
1327 // Recurse into the initializer.
1328 findLocations(init);
1329
1330 // Check invariants.
1331 assert(IndexValues.size() == Indices.size() && "mismatch")((IndexValues.size() == Indices.size() && "mismatch")
? static_cast<void> (0) : __assert_fail ("IndexValues.size() == Indices.size() && \"mismatch\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1331, __PRETTY_FUNCTION__))
;
1332 assert(Indices.size() == 1 && "didn't pop all indices")((Indices.size() == 1 && "didn't pop all indices") ? static_cast
<void> (0) : __assert_fail ("Indices.size() == 1 && \"didn't pop all indices\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1332, __PRETTY_FUNCTION__))
;
1333
1334 // Do the replacement; this basically invalidates 'init'.
1335 assert(Locations.size() == PlaceholderAddresses.size() &&((Locations.size() == PlaceholderAddresses.size() && "missed a placeholder?"
) ? static_cast<void> (0) : __assert_fail ("Locations.size() == PlaceholderAddresses.size() && \"missed a placeholder?\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1336, __PRETTY_FUNCTION__))
1336 "missed a placeholder?")((Locations.size() == PlaceholderAddresses.size() && "missed a placeholder?"
) ? static_cast<void> (0) : __assert_fail ("Locations.size() == PlaceholderAddresses.size() && \"missed a placeholder?\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1336, __PRETTY_FUNCTION__))
;
1337
1338 // We're iterating over a hashtable, so this would be a source of
1339 // non-determinism in compiler output *except* that we're just
1340 // messing around with llvm::Constant structures, which never itself
1341 // does anything that should be visible in compiler output.
1342 for (auto &entry : Locations) {
1343 assert(entry.first->getParent() == nullptr && "not a placeholder!")((entry.first->getParent() == nullptr && "not a placeholder!"
) ? static_cast<void> (0) : __assert_fail ("entry.first->getParent() == nullptr && \"not a placeholder!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1343, __PRETTY_FUNCTION__))
;
1344 entry.first->replaceAllUsesWith(entry.second);
1345 entry.first->eraseFromParent();
1346 }
1347 }
1348
1349 private:
1350 void findLocations(llvm::Constant *init) {
1351 // Recurse into aggregates.
1352 if (auto agg = dyn_cast<llvm::ConstantAggregate>(init)) {
1353 for (unsigned i = 0, e = agg->getNumOperands(); i != e; ++i) {
1354 Indices.push_back(i);
1355 IndexValues.push_back(nullptr);
1356
1357 findLocations(agg->getOperand(i));
1358
1359 IndexValues.pop_back();
1360 Indices.pop_back();
1361 }
1362 return;
1363 }
1364
1365 // Otherwise, check for registered constants.
1366 while (true) {
1367 auto it = PlaceholderAddresses.find(init);
1368 if (it != PlaceholderAddresses.end()) {
1369 setLocation(it->second);
1370 break;
1371 }
1372
1373 // Look through bitcasts or other expressions.
1374 if (auto expr = dyn_cast<llvm::ConstantExpr>(init)) {
1375 init = expr->getOperand(0);
1376 } else {
1377 break;
1378 }
1379 }
1380 }
1381
1382 void setLocation(llvm::GlobalVariable *placeholder) {
1383 assert(Locations.find(placeholder) == Locations.end() &&((Locations.find(placeholder) == Locations.end() && "already found location for placeholder!"
) ? static_cast<void> (0) : __assert_fail ("Locations.find(placeholder) == Locations.end() && \"already found location for placeholder!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1384, __PRETTY_FUNCTION__))
1384 "already found location for placeholder!")((Locations.find(placeholder) == Locations.end() && "already found location for placeholder!"
) ? static_cast<void> (0) : __assert_fail ("Locations.find(placeholder) == Locations.end() && \"already found location for placeholder!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1384, __PRETTY_FUNCTION__))
;
1385
1386 // Lazily fill in IndexValues with the values from Indices.
1387 // We do this in reverse because we should always have a strict
1388 // prefix of indices from the start.
1389 assert(Indices.size() == IndexValues.size())((Indices.size() == IndexValues.size()) ? static_cast<void
> (0) : __assert_fail ("Indices.size() == IndexValues.size()"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1389, __PRETTY_FUNCTION__))
;
1390 for (size_t i = Indices.size() - 1; i != size_t(-1); --i) {
1391 if (IndexValues[i]) {
1392#ifndef NDEBUG
1393 for (size_t j = 0; j != i + 1; ++j) {
1394 assert(IndexValues[j] &&((IndexValues[j] && isa<llvm::ConstantInt>(IndexValues
[j]) && cast<llvm::ConstantInt>(IndexValues[j])
->getZExtValue() == Indices[j]) ? static_cast<void> (
0) : __assert_fail ("IndexValues[j] && isa<llvm::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue() == Indices[j]"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1397, __PRETTY_FUNCTION__))
1395 isa<llvm::ConstantInt>(IndexValues[j]) &&((IndexValues[j] && isa<llvm::ConstantInt>(IndexValues
[j]) && cast<llvm::ConstantInt>(IndexValues[j])
->getZExtValue() == Indices[j]) ? static_cast<void> (
0) : __assert_fail ("IndexValues[j] && isa<llvm::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue() == Indices[j]"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1397, __PRETTY_FUNCTION__))
1396 cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue()((IndexValues[j] && isa<llvm::ConstantInt>(IndexValues
[j]) && cast<llvm::ConstantInt>(IndexValues[j])
->getZExtValue() == Indices[j]) ? static_cast<void> (
0) : __assert_fail ("IndexValues[j] && isa<llvm::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue() == Indices[j]"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1397, __PRETTY_FUNCTION__))
1397 == Indices[j])((IndexValues[j] && isa<llvm::ConstantInt>(IndexValues
[j]) && cast<llvm::ConstantInt>(IndexValues[j])
->getZExtValue() == Indices[j]) ? static_cast<void> (
0) : __assert_fail ("IndexValues[j] && isa<llvm::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue() == Indices[j]"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1397, __PRETTY_FUNCTION__))
;
1398 }
1399#endif
1400 break;
1401 }
1402
1403 IndexValues[i] = llvm::ConstantInt::get(CGM.Int32Ty, Indices[i]);
1404 }
1405
1406 // Form a GEP and then bitcast to the placeholder type so that the
1407 // replacement will succeed.
1408 llvm::Constant *location =
1409 llvm::ConstantExpr::getInBoundsGetElementPtr(BaseValueTy,
1410 Base, IndexValues);
1411 location = llvm::ConstantExpr::getBitCast(location,
1412 placeholder->getType());
1413
1414 Locations.insert({placeholder, location});
1415 }
1416 };
1417}
1418
1419void ConstantEmitter::finalize(llvm::GlobalVariable *global) {
1420 assert(InitializedNonAbstract &&((InitializedNonAbstract && "finalizing emitter that was used for abstract emission?"
) ? static_cast<void> (0) : __assert_fail ("InitializedNonAbstract && \"finalizing emitter that was used for abstract emission?\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1421, __PRETTY_FUNCTION__))
1421 "finalizing emitter that was used for abstract emission?")((InitializedNonAbstract && "finalizing emitter that was used for abstract emission?"
) ? static_cast<void> (0) : __assert_fail ("InitializedNonAbstract && \"finalizing emitter that was used for abstract emission?\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1421, __PRETTY_FUNCTION__))
;
1422 assert(!Finalized && "finalizing emitter multiple times")((!Finalized && "finalizing emitter multiple times") ?
static_cast<void> (0) : __assert_fail ("!Finalized && \"finalizing emitter multiple times\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1422, __PRETTY_FUNCTION__))
;
1423 assert(global->getInitializer())((global->getInitializer()) ? static_cast<void> (0) :
__assert_fail ("global->getInitializer()", "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1423, __PRETTY_FUNCTION__))
;
1424
1425 // Note that we might also be Failed.
1426 Finalized = true;
1427
1428 if (!PlaceholderAddresses.empty()) {
1429 ReplacePlaceholders(CGM, global, PlaceholderAddresses)
1430 .replaceInInitializer(global->getInitializer());
1431 PlaceholderAddresses.clear(); // satisfy
1432 }
1433}
1434
1435ConstantEmitter::~ConstantEmitter() {
1436 assert((!InitializedNonAbstract || Finalized || Failed) &&(((!InitializedNonAbstract || Finalized || Failed) &&
"not finalized after being initialized for non-abstract emission"
) ? static_cast<void> (0) : __assert_fail ("(!InitializedNonAbstract || Finalized || Failed) && \"not finalized after being initialized for non-abstract emission\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1437, __PRETTY_FUNCTION__))
1437 "not finalized after being initialized for non-abstract emission")(((!InitializedNonAbstract || Finalized || Failed) &&
"not finalized after being initialized for non-abstract emission"
) ? static_cast<void> (0) : __assert_fail ("(!InitializedNonAbstract || Finalized || Failed) && \"not finalized after being initialized for non-abstract emission\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1437, __PRETTY_FUNCTION__))
;
1438 assert(PlaceholderAddresses.empty() && "unhandled placeholders")((PlaceholderAddresses.empty() && "unhandled placeholders"
) ? static_cast<void> (0) : __assert_fail ("PlaceholderAddresses.empty() && \"unhandled placeholders\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1438, __PRETTY_FUNCTION__))
;
1439}
1440
1441static QualType getNonMemoryType(CodeGenModule &CGM, QualType type) {
1442 if (auto AT = type->getAs<AtomicType>()) {
1443 return CGM.getContext().getQualifiedType(AT->getValueType(),
1444 type.getQualifiers());
1445 }
1446 return type;
1447}
1448
1449llvm::Constant *ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &D) {
1450 // Make a quick check if variable can be default NULL initialized
1451 // and avoid going through rest of code which may do, for c++11,
1452 // initialization of memory to all NULLs.
1453 if (!D.hasLocalStorage()) {
1454 QualType Ty = CGM.getContext().getBaseElementType(D.getType());
1455 if (Ty->isRecordType())
1456 if (const CXXConstructExpr *E =
1457 dyn_cast_or_null<CXXConstructExpr>(D.getInit())) {
1458 const CXXConstructorDecl *CD = E->getConstructor();
1459 if (CD->isTrivial() && CD->isDefaultConstructor())
1460 return CGM.EmitNullConstant(D.getType());
1461 }
1462 InConstantContext = true;
1463 }
1464
1465 QualType destType = D.getType();
1466
1467 // Try to emit the initializer. Note that this can allow some things that
1468 // are not allowed by tryEmitPrivateForMemory alone.
1469 if (auto value = D.evaluateValue()) {
1470 return tryEmitPrivateForMemory(*value, destType);
1471 }
1472
1473 // FIXME: Implement C++11 [basic.start.init]p2: if the initializer of a
1474 // reference is a constant expression, and the reference binds to a temporary,
1475 // then constant initialization is performed. ConstExprEmitter will
1476 // incorrectly emit a prvalue constant in this case, and the calling code
1477 // interprets that as the (pointer) value of the reference, rather than the
1478 // desired value of the referee.
1479 if (destType->isReferenceType())
1480 return nullptr;
1481
1482 const Expr *E = D.getInit();
1483 assert(E && "No initializer to emit")((E && "No initializer to emit") ? static_cast<void
> (0) : __assert_fail ("E && \"No initializer to emit\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1483, __PRETTY_FUNCTION__))
;
1484
1485 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1486 auto C =
1487 ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), nonMemoryDestType);
1488 return (C ? emitForMemory(C, destType) : nullptr);
1489}
1490
1491llvm::Constant *
1492ConstantEmitter::tryEmitAbstractForMemory(const Expr *E, QualType destType) {
1493 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1494 auto C = tryEmitAbstract(E, nonMemoryDestType);
1495 return (C ? emitForMemory(C, destType) : nullptr);
1496}
1497
1498llvm::Constant *
1499ConstantEmitter::tryEmitAbstractForMemory(const APValue &value,
1500 QualType destType) {
1501 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1502 auto C = tryEmitAbstract(value, nonMemoryDestType);
1503 return (C ? emitForMemory(C, destType) : nullptr);
1504}
1505
1506llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const Expr *E,
1507 QualType destType) {
1508 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1509 llvm::Constant *C = tryEmitPrivate(E, nonMemoryDestType);
1510 return (C ? emitForMemory(C, destType) : nullptr);
1511}
1512
1513llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const APValue &value,
1514 QualType destType) {
1515 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1516 auto C = tryEmitPrivate(value, nonMemoryDestType);
1517 return (C ? emitForMemory(C, destType) : nullptr);
1518}
1519
1520llvm::Constant *ConstantEmitter::emitForMemory(CodeGenModule &CGM,
1521 llvm::Constant *C,
1522 QualType destType) {
1523 // For an _Atomic-qualified constant, we may need to add tail padding.
1524 if (auto AT = destType->getAs<AtomicType>()) {
1525 QualType destValueType = AT->getValueType();
1526 C = emitForMemory(CGM, C, destValueType);
1527
1528 uint64_t innerSize = CGM.getContext().getTypeSize(destValueType);
1529 uint64_t outerSize = CGM.getContext().getTypeSize(destType);
1530 if (innerSize == outerSize)
1531 return C;
1532
1533 assert(innerSize < outerSize && "emitted over-large constant for atomic")((innerSize < outerSize && "emitted over-large constant for atomic"
) ? static_cast<void> (0) : __assert_fail ("innerSize < outerSize && \"emitted over-large constant for atomic\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1533, __PRETTY_FUNCTION__))
;
1534 llvm::Constant *elts[] = {
1535 C,
1536 llvm::ConstantAggregateZero::get(
1537 llvm::ArrayType::get(CGM.Int8Ty, (outerSize - innerSize) / 8))
1538 };
1539 return llvm::ConstantStruct::getAnon(elts);
1540 }
1541
1542 // Zero-extend bool.
1543 if (C->getType()->isIntegerTy(1)) {
1544 llvm::Type *boolTy = CGM.getTypes().ConvertTypeForMem(destType);
1545 return llvm::ConstantExpr::getZExt(C, boolTy);
1546 }
1547
1548 return C;
1549}
1550
1551llvm::Constant *ConstantEmitter::tryEmitPrivate(const Expr *E,
1552 QualType destType) {
1553 Expr::EvalResult Result;
1554
1555 bool Success = false;
1556
1557 if (destType->isReferenceType())
1558 Success = E->EvaluateAsLValue(Result, CGM.getContext());
1559 else
1560 Success = E->EvaluateAsRValue(Result, CGM.getContext(), InConstantContext);
1561
1562 llvm::Constant *C;
1563 if (Success && !Result.HasSideEffects)
1564 C = tryEmitPrivate(Result.Val, destType);
1565 else
1566 C = ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), destType);
1567
1568 return C;
1569}
1570
1571llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) {
1572 return getTargetCodeGenInfo().getNullPointer(*this, T, QT);
1573}
1574
1575namespace {
1576/// A struct which can be used to peephole certain kinds of finalization
1577/// that normally happen during l-value emission.
1578struct ConstantLValue {
1579 llvm::Constant *Value;
1580 bool HasOffsetApplied;
1581
1582 /*implicit*/ ConstantLValue(llvm::Constant *value,
1583 bool hasOffsetApplied = false)
1584 : Value(value), HasOffsetApplied(false) {}
1585
1586 /*implicit*/ ConstantLValue(ConstantAddress address)
1587 : ConstantLValue(address.getPointer()) {}
1588};
1589
1590/// A helper class for emitting constant l-values.
1591class ConstantLValueEmitter : public ConstStmtVisitor<ConstantLValueEmitter,
1592 ConstantLValue> {
1593 CodeGenModule &CGM;
1594 ConstantEmitter &Emitter;
1595 const APValue &Value;
1596 QualType DestType;
1597
1598 // Befriend StmtVisitorBase so that we don't have to expose Visit*.
1599 friend StmtVisitorBase;
1600
1601public:
1602 ConstantLValueEmitter(ConstantEmitter &emitter, const APValue &value,
1603 QualType destType)
1604 : CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType) {}
1605
1606 llvm::Constant *tryEmit();
1607
1608private:
1609 llvm::Constant *tryEmitAbsolute(llvm::Type *destTy);
1610 ConstantLValue tryEmitBase(const APValue::LValueBase &base);
1611
1612 ConstantLValue VisitStmt(const Stmt *S) { return nullptr; }
1613 ConstantLValue VisitConstantExpr(const ConstantExpr *E);
1614 ConstantLValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
1615 ConstantLValue VisitStringLiteral(const StringLiteral *E);
1616 ConstantLValue VisitObjCBoxedExpr(const ObjCBoxedExpr *E);
1617 ConstantLValue VisitObjCEncodeExpr(const ObjCEncodeExpr *E);
1618 ConstantLValue VisitObjCStringLiteral(const ObjCStringLiteral *E);
1619 ConstantLValue VisitPredefinedExpr(const PredefinedExpr *E);
1620 ConstantLValue VisitAddrLabelExpr(const AddrLabelExpr *E);
1621 ConstantLValue VisitCallExpr(const CallExpr *E);
1622 ConstantLValue VisitBlockExpr(const BlockExpr *E);
1623 ConstantLValue VisitCXXTypeidExpr(const CXXTypeidExpr *E);
1624 ConstantLValue VisitCXXUuidofExpr(const CXXUuidofExpr *E);
1625 ConstantLValue VisitMaterializeTemporaryExpr(
1626 const MaterializeTemporaryExpr *E);
1627
1628 bool hasNonZeroOffset() const {
1629 return !Value.getLValueOffset().isZero();
1630 }
1631
1632 /// Return the value offset.
1633 llvm::Constant *getOffset() {
1634 return llvm::ConstantInt::get(CGM.Int64Ty,
1635 Value.getLValueOffset().getQuantity());
1636 }
1637
1638 /// Apply the value offset to the given constant.
1639 llvm::Constant *applyOffset(llvm::Constant *C) {
1640 if (!hasNonZeroOffset())
1641 return C;
1642
1643 llvm::Type *origPtrTy = C->getType();
1644 unsigned AS = origPtrTy->getPointerAddressSpace();
1645 llvm::Type *charPtrTy = CGM.Int8Ty->getPointerTo(AS);
1646 C = llvm::ConstantExpr::getBitCast(C, charPtrTy);
1647 C = llvm::ConstantExpr::getGetElementPtr(CGM.Int8Ty, C, getOffset());
1648 C = llvm::ConstantExpr::getPointerCast(C, origPtrTy);
1649 return C;
1650 }
1651};
1652
1653}
1654
1655llvm::Constant *ConstantLValueEmitter::tryEmit() {
1656 const APValue::LValueBase &base = Value.getLValueBase();
1657
1658 // The destination type should be a pointer or reference
1659 // type, but it might also be a cast thereof.
1660 //
1661 // FIXME: the chain of casts required should be reflected in the APValue.
1662 // We need this in order to correctly handle things like a ptrtoint of a
1663 // non-zero null pointer and addrspace casts that aren't trivially
1664 // represented in LLVM IR.
1665 auto destTy = CGM.getTypes().ConvertTypeForMem(DestType);
1666 assert(isa<llvm::IntegerType>(destTy) || isa<llvm::PointerType>(destTy))((isa<llvm::IntegerType>(destTy) || isa<llvm::PointerType
>(destTy)) ? static_cast<void> (0) : __assert_fail (
"isa<llvm::IntegerType>(destTy) || isa<llvm::PointerType>(destTy)"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1666, __PRETTY_FUNCTION__))
;
1667
1668 // If there's no base at all, this is a null or absolute pointer,
1669 // possibly cast back to an integer type.
1670 if (!base) {
1671 return tryEmitAbsolute(destTy);
1672 }
1673
1674 // Otherwise, try to emit the base.
1675 ConstantLValue result = tryEmitBase(base);
1676
1677 // If that failed, we're done.
1678 llvm::Constant *value = result.Value;
1679 if (!value) return nullptr;
1680
1681 // Apply the offset if necessary and not already done.
1682 if (!result.HasOffsetApplied) {
1683 value = applyOffset(value);
1684 }
1685
1686 // Convert to the appropriate type; this could be an lvalue for
1687 // an integer. FIXME: performAddrSpaceCast
1688 if (isa<llvm::PointerType>(destTy))
1689 return llvm::ConstantExpr::getPointerCast(value, destTy);
1690
1691 return llvm::ConstantExpr::getPtrToInt(value, destTy);
1692}
1693
1694/// Try to emit an absolute l-value, such as a null pointer or an integer
1695/// bitcast to pointer type.
1696llvm::Constant *
1697ConstantLValueEmitter::tryEmitAbsolute(llvm::Type *destTy) {
1698 auto offset = getOffset();
1699
1700 // If we're producing a pointer, this is easy.
1701 auto destPtrTy = cast<llvm::PointerType>(destTy);
1702 if (Value.isNullPointer()) {
1703 // FIXME: integer offsets from non-zero null pointers.
1704 return CGM.getNullPointer(destPtrTy, DestType);
1705 }
1706
1707 // Convert the integer to a pointer-sized integer before converting it
1708 // to a pointer.
1709 // FIXME: signedness depends on the original integer type.
1710 auto intptrTy = CGM.getDataLayout().getIntPtrType(destPtrTy);
1711 llvm::Constant *C = offset;
Value stored to 'C' during its initialization is never read
1712 C = llvm::ConstantExpr::getIntegerCast(getOffset(), intptrTy,
1713 /*isSigned*/ false);
1714 C = llvm::ConstantExpr::getIntToPtr(C, destPtrTy);
1715 return C;
1716}
1717
1718ConstantLValue
1719ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) {
1720 // Handle values.
1721 if (const ValueDecl *D = base.dyn_cast<const ValueDecl*>()) {
1722 if (D->hasAttr<WeakRefAttr>())
1723 return CGM.GetWeakRefReference(D).getPointer();
1724
1725 if (auto FD = dyn_cast<FunctionDecl>(D))
1726 return CGM.GetAddrOfFunction(FD);
1727
1728 if (auto VD = dyn_cast<VarDecl>(D)) {
1729 // We can never refer to a variable with local storage.
1730 if (!VD->hasLocalStorage()) {
1731 if (VD->isFileVarDecl() || VD->hasExternalStorage())
1732 return CGM.GetAddrOfGlobalVar(VD);
1733
1734 if (VD->isLocalVarDecl()) {
1735 return CGM.getOrCreateStaticVarDecl(
1736 *VD, CGM.getLLVMLinkageVarDefinition(VD, /*isConstant=*/false));
1737 }
1738 }
1739 }
1740
1741 return nullptr;
1742 }
1743
1744 // Otherwise, it must be an expression.
1745 return Visit(base.get<const Expr*>());
1746}
1747
1748ConstantLValue
1749ConstantLValueEmitter::VisitConstantExpr(const ConstantExpr *E) {
1750 return Visit(E->getSubExpr());
1751}
1752
1753ConstantLValue
1754ConstantLValueEmitter::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
1755 return tryEmitGlobalCompoundLiteral(CGM, Emitter.CGF, E);
1756}
1757
1758ConstantLValue
1759ConstantLValueEmitter::VisitStringLiteral(const StringLiteral *E) {
1760 return CGM.GetAddrOfConstantStringFromLiteral(E);
1761}
1762
1763ConstantLValue
1764ConstantLValueEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
1765 return CGM.GetAddrOfConstantStringFromObjCEncode(E);
1766}
1767
1768static ConstantLValue emitConstantObjCStringLiteral(const StringLiteral *S,
1769 QualType T,
1770 CodeGenModule &CGM) {
1771 auto C = CGM.getObjCRuntime().GenerateConstantString(S);
1772 return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(T));
1773}
1774
1775ConstantLValue
1776ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) {
1777 return emitConstantObjCStringLiteral(E->getString(), E->getType(), CGM);
1778}
1779
1780ConstantLValue
1781ConstantLValueEmitter::VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
1782 assert(E->isExpressibleAsConstantInitializer() &&((E->isExpressibleAsConstantInitializer() && "this boxed expression can't be emitted as a compile-time constant"
) ? static_cast<void> (0) : __assert_fail ("E->isExpressibleAsConstantInitializer() && \"this boxed expression can't be emitted as a compile-time constant\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1783, __PRETTY_FUNCTION__))
1783 "this boxed expression can't be emitted as a compile-time constant")((E->isExpressibleAsConstantInitializer() && "this boxed expression can't be emitted as a compile-time constant"
) ? static_cast<void> (0) : __assert_fail ("E->isExpressibleAsConstantInitializer() && \"this boxed expression can't be emitted as a compile-time constant\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1783, __PRETTY_FUNCTION__))
;
1784 auto *SL = cast<StringLiteral>(E->getSubExpr()->IgnoreParenCasts());
1785 return emitConstantObjCStringLiteral(SL, E->getType(), CGM);
1786}
1787
1788ConstantLValue
1789ConstantLValueEmitter::VisitPredefinedExpr(const PredefinedExpr *E) {
1790 return CGM.GetAddrOfConstantStringFromLiteral(E->getFunctionName());
1791}
1792
1793ConstantLValue
1794ConstantLValueEmitter::VisitAddrLabelExpr(const AddrLabelExpr *E) {
1795 assert(Emitter.CGF && "Invalid address of label expression outside function")((Emitter.CGF && "Invalid address of label expression outside function"
) ? static_cast<void> (0) : __assert_fail ("Emitter.CGF && \"Invalid address of label expression outside function\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1795, __PRETTY_FUNCTION__))
;
1796 llvm::Constant *Ptr = Emitter.CGF->GetAddrOfLabel(E->getLabel());
1797 Ptr = llvm::ConstantExpr::getBitCast(Ptr,
1798 CGM.getTypes().ConvertType(E->getType()));
1799 return Ptr;
1800}
1801
1802ConstantLValue
1803ConstantLValueEmitter::VisitCallExpr(const CallExpr *E) {
1804 unsigned builtin = E->getBuiltinCallee();
1805 if (builtin != Builtin::BI__builtin___CFStringMakeConstantString &&
1806 builtin != Builtin::BI__builtin___NSStringMakeConstantString)
1807 return nullptr;
1808
1809 auto literal = cast<StringLiteral>(E->getArg(0)->IgnoreParenCasts());
1810 if (builtin == Builtin::BI__builtin___NSStringMakeConstantString) {
1811 return CGM.getObjCRuntime().GenerateConstantString(literal);
1812 } else {
1813 // FIXME: need to deal with UCN conversion issues.
1814 return CGM.GetAddrOfConstantCFString(literal);
1815 }
1816}
1817
1818ConstantLValue
1819ConstantLValueEmitter::VisitBlockExpr(const BlockExpr *E) {
1820 StringRef functionName;
1821 if (auto CGF = Emitter.CGF)
1822 functionName = CGF->CurFn->getName();
1823 else
1824 functionName = "global";
1825
1826 return CGM.GetAddrOfGlobalBlock(E, functionName);
1827}
1828
1829ConstantLValue
1830ConstantLValueEmitter::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
1831 QualType T;
1832 if (E->isTypeOperand())
1833 T = E->getTypeOperand(CGM.getContext());
1834 else
1835 T = E->getExprOperand()->getType();
1836 return CGM.GetAddrOfRTTIDescriptor(T);
1837}
1838
1839ConstantLValue
1840ConstantLValueEmitter::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
1841 return CGM.GetAddrOfUuidDescriptor(E);
1842}
1843
1844ConstantLValue
1845ConstantLValueEmitter::VisitMaterializeTemporaryExpr(
1846 const MaterializeTemporaryExpr *E) {
1847 assert(E->getStorageDuration() == SD_Static)((E->getStorageDuration() == SD_Static) ? static_cast<void
> (0) : __assert_fail ("E->getStorageDuration() == SD_Static"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1847, __PRETTY_FUNCTION__))
;
1848 SmallVector<const Expr *, 2> CommaLHSs;
1849 SmallVector<SubobjectAdjustment, 2> Adjustments;
1850 const Expr *Inner = E->GetTemporaryExpr()
1851 ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
1852 return CGM.GetAddrOfGlobalTemporary(E, Inner);
1853}
1854
1855llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
1856 QualType DestType) {
1857 switch (Value.getKind()) {
1858 case APValue::Uninitialized:
1859 llvm_unreachable("Constant expressions should be initialized.")::llvm::llvm_unreachable_internal("Constant expressions should be initialized."
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1859)
;
1860 case APValue::LValue:
1861 return ConstantLValueEmitter(*this, Value, DestType).tryEmit();
1862 case APValue::Int:
1863 return llvm::ConstantInt::get(CGM.getLLVMContext(), Value.getInt());
1864 case APValue::FixedPoint:
1865 return llvm::ConstantInt::get(CGM.getLLVMContext(),
1866 Value.getFixedPoint().getValue());
1867 case APValue::ComplexInt: {
1868 llvm::Constant *Complex[2];
1869
1870 Complex[0] = llvm::ConstantInt::get(CGM.getLLVMContext(),
1871 Value.getComplexIntReal());
1872 Complex[1] = llvm::ConstantInt::get(CGM.getLLVMContext(),
1873 Value.getComplexIntImag());
1874
1875 // FIXME: the target may want to specify that this is packed.
1876 llvm::StructType *STy =
1877 llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
1878 return llvm::ConstantStruct::get(STy, Complex);
1879 }
1880 case APValue::Float: {
1881 const llvm::APFloat &Init = Value.getFloat();
1882 if (&Init.getSemantics() == &llvm::APFloat::IEEEhalf() &&
1883 !CGM.getContext().getLangOpts().NativeHalfType &&
1884 CGM.getContext().getTargetInfo().useFP16ConversionIntrinsics())
1885 return llvm::ConstantInt::get(CGM.getLLVMContext(),
1886 Init.bitcastToAPInt());
1887 else
1888 return llvm::ConstantFP::get(CGM.getLLVMContext(), Init);
1889 }
1890 case APValue::ComplexFloat: {
1891 llvm::Constant *Complex[2];
1892
1893 Complex[0] = llvm::ConstantFP::get(CGM.getLLVMContext(),
1894 Value.getComplexFloatReal());
1895 Complex[1] = llvm::ConstantFP::get(CGM.getLLVMContext(),
1896 Value.getComplexFloatImag());
1897
1898 // FIXME: the target may want to specify that this is packed.
1899 llvm::StructType *STy =
1900 llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
1901 return llvm::ConstantStruct::get(STy, Complex);
1902 }
1903 case APValue::Vector: {
1904 unsigned NumElts = Value.getVectorLength();
1905 SmallVector<llvm::Constant *, 4> Inits(NumElts);
1906
1907 for (unsigned I = 0; I != NumElts; ++I) {
1908 const APValue &Elt = Value.getVectorElt(I);
1909 if (Elt.isInt())
1910 Inits[I] = llvm::ConstantInt::get(CGM.getLLVMContext(), Elt.getInt());
1911 else if (Elt.isFloat())
1912 Inits[I] = llvm::ConstantFP::get(CGM.getLLVMContext(), Elt.getFloat());
1913 else
1914 llvm_unreachable("unsupported vector element type")::llvm::llvm_unreachable_internal("unsupported vector element type"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1914)
;
1915 }
1916 return llvm::ConstantVector::get(Inits);
1917 }
1918 case APValue::AddrLabelDiff: {
1919 const AddrLabelExpr *LHSExpr = Value.getAddrLabelDiffLHS();
1920 const AddrLabelExpr *RHSExpr = Value.getAddrLabelDiffRHS();
1921 llvm::Constant *LHS = tryEmitPrivate(LHSExpr, LHSExpr->getType());
1922 llvm::Constant *RHS = tryEmitPrivate(RHSExpr, RHSExpr->getType());
1923 if (!LHS || !RHS) return nullptr;
1924
1925 // Compute difference
1926 llvm::Type *ResultType = CGM.getTypes().ConvertType(DestType);
1927 LHS = llvm::ConstantExpr::getPtrToInt(LHS, CGM.IntPtrTy);
1928 RHS = llvm::ConstantExpr::getPtrToInt(RHS, CGM.IntPtrTy);
1929 llvm::Constant *AddrLabelDiff = llvm::ConstantExpr::getSub(LHS, RHS);
1930
1931 // LLVM is a bit sensitive about the exact format of the
1932 // address-of-label difference; make sure to truncate after
1933 // the subtraction.
1934 return llvm::ConstantExpr::getTruncOrBitCast(AddrLabelDiff, ResultType);
1935 }
1936 case APValue::Struct:
1937 case APValue::Union:
1938 return ConstStructBuilder::BuildStruct(*this, Value, DestType);
1939 case APValue::Array: {
1940 const ConstantArrayType *CAT =
1941 CGM.getContext().getAsConstantArrayType(DestType);
1942 unsigned NumElements = Value.getArraySize();
1943 unsigned NumInitElts = Value.getArrayInitializedElts();
1944
1945 // Emit array filler, if there is one.
1946 llvm::Constant *Filler = nullptr;
1947 if (Value.hasArrayFiller()) {
1948 Filler = tryEmitAbstractForMemory(Value.getArrayFiller(),
1949 CAT->getElementType());
1950 if (!Filler)
1951 return nullptr;
1952 }
1953
1954 // Emit initializer elements.
1955 SmallVector<llvm::Constant*, 16> Elts;
1956 if (Filler && Filler->isNullValue())
1957 Elts.reserve(NumInitElts + 1);
1958 else
1959 Elts.reserve(NumElements);
1960
1961 llvm::Type *CommonElementType = nullptr;
1962 for (unsigned I = 0; I < NumInitElts; ++I) {
1963 llvm::Constant *C = tryEmitPrivateForMemory(
1964 Value.getArrayInitializedElt(I), CAT->getElementType());
1965 if (!C) return nullptr;
1966
1967 if (I == 0)
1968 CommonElementType = C->getType();
1969 else if (C->getType() != CommonElementType)
1970 CommonElementType = nullptr;
1971 Elts.push_back(C);
1972 }
1973
1974 // This means that the array type is probably "IncompleteType" or some
1975 // type that is not ConstantArray.
1976 if (CAT == nullptr && CommonElementType == nullptr && !NumInitElts) {
1977 const ArrayType *AT = CGM.getContext().getAsArrayType(DestType);
1978 CommonElementType = CGM.getTypes().ConvertType(AT->getElementType());
1979 llvm::ArrayType *AType = llvm::ArrayType::get(CommonElementType,
1980 NumElements);
1981 return llvm::ConstantAggregateZero::get(AType);
1982 }
1983
1984 return EmitArrayConstant(CGM, CAT, CommonElementType, NumElements, Elts,
1985 Filler);
1986 }
1987 case APValue::MemberPointer:
1988 return CGM.getCXXABI().EmitMemberPointer(Value, DestType);
1989 }
1990 llvm_unreachable("Unknown APValue kind")::llvm::llvm_unreachable_internal("Unknown APValue kind", "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1990)
;
1991}
1992
1993llvm::GlobalVariable *CodeGenModule::getAddrOfConstantCompoundLiteralIfEmitted(
1994 const CompoundLiteralExpr *E) {
1995 return EmittedCompoundLiterals.lookup(E);
1996}
1997
1998void CodeGenModule::setAddrOfConstantCompoundLiteral(
1999 const CompoundLiteralExpr *CLE, llvm::GlobalVariable *GV) {
2000 bool Ok = EmittedCompoundLiterals.insert(std::make_pair(CLE, GV)).second;
2001 (void)Ok;
2002 assert(Ok && "CLE has already been emitted!")((Ok && "CLE has already been emitted!") ? static_cast
<void> (0) : __assert_fail ("Ok && \"CLE has already been emitted!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 2002, __PRETTY_FUNCTION__))
;
2003}
2004
2005ConstantAddress
2006CodeGenModule::GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr *E) {
2007 assert(E->isFileScope() && "not a file-scope compound literal expr")((E->isFileScope() && "not a file-scope compound literal expr"
) ? static_cast<void> (0) : __assert_fail ("E->isFileScope() && \"not a file-scope compound literal expr\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 2007, __PRETTY_FUNCTION__))
;
2008 return tryEmitGlobalCompoundLiteral(*this, nullptr, E);
2009}
2010
2011llvm::Constant *
2012CodeGenModule::getMemberPointerConstant(const UnaryOperator *uo) {
2013 // Member pointer constants always have a very particular form.
2014 const MemberPointerType *type = cast<MemberPointerType>(uo->getType());
2015 const ValueDecl *decl = cast<DeclRefExpr>(uo->getSubExpr())->getDecl();
2016
2017 // A member function pointer.
2018 if (const CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(decl))
2019 return getCXXABI().EmitMemberFunctionPointer(method);
2020
2021 // Otherwise, a member data pointer.
2022 uint64_t fieldOffset = getContext().getFieldOffset(decl);
2023 CharUnits chars = getContext().toCharUnitsFromBits((int64_t) fieldOffset);
2024 return getCXXABI().EmitMemberDataPointer(type, chars);
2025}
2026
2027static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
2028 llvm::Type *baseType,
2029 const CXXRecordDecl *base);
2030
2031static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
2032 const RecordDecl *record,
2033 bool asCompleteObject) {
2034 const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record);
2035 llvm::StructType *structure =
2036 (asCompleteObject ? layout.getLLVMType()
2037 : layout.getBaseSubobjectLLVMType());
2038
2039 unsigned numElements = structure->getNumElements();
2040 std::vector<llvm::Constant *> elements(numElements);
2041
2042 auto CXXR = dyn_cast<CXXRecordDecl>(record);
2043 // Fill in all the bases.
2044 if (CXXR) {
2045 for (const auto &I : CXXR->bases()) {
2046 if (I.isVirtual()) {
2047 // Ignore virtual bases; if we're laying out for a complete
2048 // object, we'll lay these out later.
2049 continue;
2050 }
2051
2052 const CXXRecordDecl *base =
2053 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
2054
2055 // Ignore empty bases.
2056 if (base->isEmpty() ||
2057 CGM.getContext().getASTRecordLayout(base).getNonVirtualSize()
2058 .isZero())
2059 continue;
2060
2061 unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
2062 llvm::Type *baseType = structure->getElementType(fieldIndex);
2063 elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
2064 }
2065 }
2066
2067 // Fill in all the fields.
2068 for (const auto *Field : record->fields()) {
2069 // Fill in non-bitfields. (Bitfields always use a zero pattern, which we
2070 // will fill in later.)
2071 if (!Field->isBitField()) {
2072 unsigned fieldIndex = layout.getLLVMFieldNo(Field);
2073 elements[fieldIndex] = CGM.EmitNullConstant(Field->getType());
2074 }
2075
2076 // For unions, stop after the first named field.
2077 if (record->isUnion()) {
2078 if (Field->getIdentifier())
2079 break;
2080 if (const auto *FieldRD = Field->getType()->getAsRecordDecl())
2081 if (FieldRD->findFirstNamedDataMember())
2082 break;
2083 }
2084 }
2085
2086 // Fill in the virtual bases, if we're working with the complete object.
2087 if (CXXR && asCompleteObject) {
2088 for (const auto &I : CXXR->vbases()) {
2089 const CXXRecordDecl *base =
2090 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
2091
2092 // Ignore empty bases.
2093 if (base->isEmpty())
2094 continue;
2095
2096 unsigned fieldIndex = layout.getVirtualBaseIndex(base);
2097
2098 // We might have already laid this field out.
2099 if (elements[fieldIndex]) continue;
2100
2101 llvm::Type *baseType = structure->getElementType(fieldIndex);
2102 elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
2103 }
2104 }
2105
2106 // Now go through all other fields and zero them out.
2107 for (unsigned i = 0; i != numElements; ++i) {
2108 if (!elements[i])
2109 elements[i] = llvm::Constant::getNullValue(structure->getElementType(i));
2110 }
2111
2112 return llvm::ConstantStruct::get(structure, elements);
2113}
2114
2115/// Emit the null constant for a base subobject.
2116static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
2117 llvm::Type *baseType,
2118 const CXXRecordDecl *base) {
2119 const CGRecordLayout &baseLayout = CGM.getTypes().getCGRecordLayout(base);
2120
2121 // Just zero out bases that don't have any pointer to data members.
2122 if (baseLayout.isZeroInitializableAsBase())
2123 return llvm::Constant::getNullValue(baseType);
2124
2125 // Otherwise, we can just use its null constant.
2126 return EmitNullConstant(CGM, base, /*asCompleteObject=*/false);
2127}
2128
2129llvm::Constant *ConstantEmitter::emitNullForMemory(CodeGenModule &CGM,
2130 QualType T) {
2131 return emitForMemory(CGM, CGM.EmitNullConstant(T), T);
2132}
2133
2134llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
2135 if (T->getAs<PointerType>())
2136 return getNullPointer(
2137 cast<llvm::PointerType>(getTypes().ConvertTypeForMem(T)), T);
2138
2139 if (getTypes().isZeroInitializable(T))
2140 return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
2141
2142 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) {
2143 llvm::ArrayType *ATy =
2144 cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T));
2145
2146 QualType ElementTy = CAT->getElementType();
2147
2148 llvm::Constant *Element =
2149 ConstantEmitter::emitNullForMemory(*this, ElementTy);
2150 unsigned NumElements = CAT->getSize().getZExtValue();
2151 SmallVector<llvm::Constant *, 8> Array(NumElements, Element);
2152 return llvm::ConstantArray::get(ATy, Array);
2153 }
2154
2155 if (const RecordType *RT = T->getAs<RecordType>())
2156 return ::EmitNullConstant(*this, RT->getDecl(), /*complete object*/ true);
2157
2158 assert(T->isMemberDataPointerType() &&((T->isMemberDataPointerType() && "Should only see pointers to data members here!"
) ? static_cast<void> (0) : __assert_fail ("T->isMemberDataPointerType() && \"Should only see pointers to data members here!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 2159, __PRETTY_FUNCTION__))
2159 "Should only see pointers to data members here!")((T->isMemberDataPointerType() && "Should only see pointers to data members here!"
) ? static_cast<void> (0) : __assert_fail ("T->isMemberDataPointerType() && \"Should only see pointers to data members here!\""
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 2159, __PRETTY_FUNCTION__))
;
2160
2161 return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>());
2162}
2163
2164llvm::Constant *
2165CodeGenModule::EmitNullConstantForBase(const CXXRecordDecl *Record) {
2166 return ::EmitNullConstant(*this, Record, false);
2167}