Bug Summary

File:tools/clang/lib/CodeGen/CGExprConstant.cpp
Warning:line 1710, column 21
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 -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-8/lib/clang/8.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/clang/lib/CodeGen -I /build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen -I /build/llvm-toolchain-snapshot-8~svn345461/tools/clang/include -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn345461/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/8.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-8/lib/clang/8.0.0/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-8~svn345461/build-llvm/tools/clang/lib/CodeGen -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -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-2018-10-27-211344-32123-1 -x c++ /build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp -faddrsig
1//===--- CGExprConstant.cpp - Emit LLVM Code from Constant Expressions ----===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This contains code to emit Constant Expr nodes as LLVM code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
15#include "CGCXXABI.h"
16#include "CGObjCRuntime.h"
17#include "CGRecordLayout.h"
18#include "CodeGenModule.h"
19#include "ConstantEmitter.h"
20#include "TargetInfo.h"
21#include "clang/AST/APValue.h"
22#include "clang/AST/ASTContext.h"
23#include "clang/AST/RecordLayout.h"
24#include "clang/AST/StmtVisitor.h"
25#include "clang/Basic/Builtins.h"
26#include "llvm/IR/Constants.h"
27#include "llvm/IR/DataLayout.h"
28#include "llvm/IR/Function.h"
29#include "llvm/IR/GlobalVariable.h"
30using namespace clang;
31using namespace CodeGen;
32
33//===----------------------------------------------------------------------===//
34// ConstStructBuilder
35//===----------------------------------------------------------------------===//
36
37namespace {
38class ConstExprEmitter;
39class ConstStructBuilder {
40 CodeGenModule &CGM;
41 ConstantEmitter &Emitter;
42
43 bool Packed;
44 CharUnits NextFieldOffsetInChars;
45 CharUnits LLVMStructAlignment;
46 SmallVector<llvm::Constant *, 32> Elements;
47public:
48 static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
49 ConstExprEmitter *ExprEmitter,
50 llvm::ConstantStruct *Base,
51 InitListExpr *Updater,
52 QualType ValTy);
53 static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
54 InitListExpr *ILE, QualType StructTy);
55 static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
56 const APValue &Value, QualType ValTy);
57
58private:
59 ConstStructBuilder(ConstantEmitter &emitter)
60 : CGM(emitter.CGM), Emitter(emitter), Packed(false),
61 NextFieldOffsetInChars(CharUnits::Zero()),
62 LLVMStructAlignment(CharUnits::One()) { }
63
64 void AppendField(const FieldDecl *Field, uint64_t FieldOffset,
65 llvm::Constant *InitExpr);
66
67 void AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst);
68
69 void AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
70 llvm::ConstantInt *InitExpr);
71
72 void AppendPadding(CharUnits PadSize);
73
74 void AppendTailPadding(CharUnits RecordSize);
75
76 void ConvertStructToPacked();
77
78 bool Build(InitListExpr *ILE);
79 bool Build(ConstExprEmitter *Emitter, llvm::ConstantStruct *Base,
80 InitListExpr *Updater);
81 bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase,
82 const CXXRecordDecl *VTableClass, CharUnits BaseOffset);
83 llvm::Constant *Finalize(QualType Ty);
84
85 CharUnits getAlignment(const llvm::Constant *C) const {
86 if (Packed) return CharUnits::One();
87 return CharUnits::fromQuantity(
88 CGM.getDataLayout().getABITypeAlignment(C->getType()));
89 }
90
91 CharUnits getSizeInChars(const llvm::Constant *C) const {
92 return CharUnits::fromQuantity(
93 CGM.getDataLayout().getTypeAllocSize(C->getType()));
94 }
95};
96
97void ConstStructBuilder::
98AppendField(const FieldDecl *Field, uint64_t FieldOffset,
99 llvm::Constant *InitCst) {
100 const ASTContext &Context = CGM.getContext();
101
102 CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
103
104 AppendBytes(FieldOffsetInChars, InitCst);
105}
106
107void ConstStructBuilder::
108AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst) {
109
110 assert(NextFieldOffsetInChars <= FieldOffsetInChars((NextFieldOffsetInChars <= FieldOffsetInChars && "Field offset mismatch!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= FieldOffsetInChars && \"Field offset mismatch!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 111, __PRETTY_FUNCTION__))
111 && "Field offset mismatch!")((NextFieldOffsetInChars <= FieldOffsetInChars && "Field offset mismatch!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= FieldOffsetInChars && \"Field offset mismatch!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 111, __PRETTY_FUNCTION__))
;
112
113 CharUnits FieldAlignment = getAlignment(InitCst);
114
115 // Round up the field offset to the alignment of the field type.
116 CharUnits AlignedNextFieldOffsetInChars =
117 NextFieldOffsetInChars.alignTo(FieldAlignment);
118
119 if (AlignedNextFieldOffsetInChars < FieldOffsetInChars) {
120 // We need to append padding.
121 AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars);
122
123 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 124, __PRETTY_FUNCTION__))
124 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 124, __PRETTY_FUNCTION__))
;
125
126 AlignedNextFieldOffsetInChars =
127 NextFieldOffsetInChars.alignTo(FieldAlignment);
128 }
129
130 if (AlignedNextFieldOffsetInChars > FieldOffsetInChars) {
131 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 131, __PRETTY_FUNCTION__))
;
132
133 // Convert the struct to a packed struct.
134 ConvertStructToPacked();
135
136 // After we pack the struct, we may need to insert padding.
137 if (NextFieldOffsetInChars < FieldOffsetInChars) {
138 // We need to append padding.
139 AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars);
140
141 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 142, __PRETTY_FUNCTION__))
142 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 142, __PRETTY_FUNCTION__))
;
143 }
144 AlignedNextFieldOffsetInChars = NextFieldOffsetInChars;
145 }
146
147 // Add the field.
148 Elements.push_back(InitCst);
149 NextFieldOffsetInChars = AlignedNextFieldOffsetInChars +
150 getSizeInChars(InitCst);
151
152 if (Packed)
153 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 154, __PRETTY_FUNCTION__))
154 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 154, __PRETTY_FUNCTION__))
;
155 else
156 LLVMStructAlignment = std::max(LLVMStructAlignment, FieldAlignment);
157}
158
159void ConstStructBuilder::AppendBitField(const FieldDecl *Field,
160 uint64_t FieldOffset,
161 llvm::ConstantInt *CI) {
162 const ASTContext &Context = CGM.getContext();
163 const uint64_t CharWidth = Context.getCharWidth();
164 uint64_t NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
165 if (FieldOffset > NextFieldOffsetInBits) {
166 // We need to add padding.
167 CharUnits PadSize = Context.toCharUnitsFromBits(
168 llvm::alignTo(FieldOffset - NextFieldOffsetInBits,
169 Context.getTargetInfo().getCharAlign()));
170
171 AppendPadding(PadSize);
172 }
173
174 uint64_t FieldSize = Field->getBitWidthValue(Context);
175
176 llvm::APInt FieldValue = CI->getValue();
177
178 // Promote the size of FieldValue if necessary
179 // FIXME: This should never occur, but currently it can because initializer
180 // constants are cast to bool, and because clang is not enforcing bitfield
181 // width limits.
182 if (FieldSize > FieldValue.getBitWidth())
183 FieldValue = FieldValue.zext(FieldSize);
184
185 // Truncate the size of FieldValue to the bit field size.
186 if (FieldSize < FieldValue.getBitWidth())
187 FieldValue = FieldValue.trunc(FieldSize);
188
189 NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
190 if (FieldOffset < NextFieldOffsetInBits) {
191 // Either part of the field or the entire field can go into the previous
192 // byte.
193 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 193, __PRETTY_FUNCTION__))
;
194
195 unsigned BitsInPreviousByte = NextFieldOffsetInBits - FieldOffset;
196
197 bool FitsCompletelyInPreviousByte =
198 BitsInPreviousByte >= FieldValue.getBitWidth();
199
200 llvm::APInt Tmp = FieldValue;
201
202 if (!FitsCompletelyInPreviousByte) {
203 unsigned NewFieldWidth = FieldSize - BitsInPreviousByte;
204
205 if (CGM.getDataLayout().isBigEndian()) {
206 Tmp.lshrInPlace(NewFieldWidth);
207 Tmp = Tmp.trunc(BitsInPreviousByte);
208
209 // We want the remaining high bits.
210 FieldValue = FieldValue.trunc(NewFieldWidth);
211 } else {
212 Tmp = Tmp.trunc(BitsInPreviousByte);
213
214 // We want the remaining low bits.
215 FieldValue.lshrInPlace(BitsInPreviousByte);
216 FieldValue = FieldValue.trunc(NewFieldWidth);
217 }
218 }
219
220 Tmp = Tmp.zext(CharWidth);
221 if (CGM.getDataLayout().isBigEndian()) {
222 if (FitsCompletelyInPreviousByte)
223 Tmp = Tmp.shl(BitsInPreviousByte - FieldValue.getBitWidth());
224 } else {
225 Tmp = Tmp.shl(CharWidth - BitsInPreviousByte);
226 }
227
228 // 'or' in the bits that go into the previous byte.
229 llvm::Value *LastElt = Elements.back();
230 if (llvm::ConstantInt *Val = dyn_cast<llvm::ConstantInt>(LastElt))
231 Tmp |= Val->getValue();
232 else {
233 assert(isa<llvm::UndefValue>(LastElt))((isa<llvm::UndefValue>(LastElt)) ? static_cast<void
> (0) : __assert_fail ("isa<llvm::UndefValue>(LastElt)"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 233, __PRETTY_FUNCTION__))
;
234 // If there is an undef field that we're adding to, it can either be a
235 // scalar undef (in which case, we just replace it with our field) or it
236 // is an array. If it is an array, we have to pull one byte off the
237 // array so that the other undef bytes stay around.
238 if (!isa<llvm::IntegerType>(LastElt->getType())) {
239 // The undef padding will be a multibyte array, create a new smaller
240 // padding and then an hole for our i8 to get plopped into.
241 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 242, __PRETTY_FUNCTION__))
242 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 242, __PRETTY_FUNCTION__))
;
243 llvm::ArrayType *AT = cast<llvm::ArrayType>(LastElt->getType());
244 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 246, __PRETTY_FUNCTION__))
245 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 246, __PRETTY_FUNCTION__))
246 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 246, __PRETTY_FUNCTION__))
;
247
248 // Remove the padding array.
249 NextFieldOffsetInChars -= CharUnits::fromQuantity(AT->getNumElements());
250 Elements.pop_back();
251
252 // Add the padding back in two chunks.
253 AppendPadding(CharUnits::fromQuantity(AT->getNumElements()-1));
254 AppendPadding(CharUnits::One());
255 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 257, __PRETTY_FUNCTION__))
256 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 257, __PRETTY_FUNCTION__))
257 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 257, __PRETTY_FUNCTION__))
;
258 }
259 }
260
261 Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp);
262
263 if (FitsCompletelyInPreviousByte)
264 return;
265 }
266
267 while (FieldValue.getBitWidth() > CharWidth) {
268 llvm::APInt Tmp;
269
270 if (CGM.getDataLayout().isBigEndian()) {
271 // We want the high bits.
272 Tmp =
273 FieldValue.lshr(FieldValue.getBitWidth() - CharWidth).trunc(CharWidth);
274 } else {
275 // We want the low bits.
276 Tmp = FieldValue.trunc(CharWidth);
277
278 FieldValue.lshrInPlace(CharWidth);
279 }
280
281 Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp));
282 ++NextFieldOffsetInChars;
283
284 FieldValue = FieldValue.trunc(FieldValue.getBitWidth() - CharWidth);
285 }
286
287 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 288, __PRETTY_FUNCTION__))
288 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 288, __PRETTY_FUNCTION__))
;
289 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 290, __PRETTY_FUNCTION__))
290 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 290, __PRETTY_FUNCTION__))
;
291
292 if (FieldValue.getBitWidth() < CharWidth) {
293 if (CGM.getDataLayout().isBigEndian()) {
294 unsigned BitWidth = FieldValue.getBitWidth();
295
296 FieldValue = FieldValue.zext(CharWidth) << (CharWidth - BitWidth);
297 } else
298 FieldValue = FieldValue.zext(CharWidth);
299 }
300
301 // Append the last element.
302 Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(),
303 FieldValue));
304 ++NextFieldOffsetInChars;
305}
306
307void ConstStructBuilder::AppendPadding(CharUnits PadSize) {
308 if (PadSize.isZero())
309 return;
310
311 llvm::Type *Ty = CGM.Int8Ty;
312 if (PadSize > CharUnits::One())
313 Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity());
314
315 llvm::Constant *C = llvm::UndefValue::get(Ty);
316 Elements.push_back(C);
317 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 318, __PRETTY_FUNCTION__))
318 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 318, __PRETTY_FUNCTION__))
;
319
320 NextFieldOffsetInChars += getSizeInChars(C);
321}
322
323void ConstStructBuilder::AppendTailPadding(CharUnits RecordSize) {
324 assert(NextFieldOffsetInChars <= RecordSize &&((NextFieldOffsetInChars <= RecordSize && "Size mismatch!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= RecordSize && \"Size mismatch!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 325, __PRETTY_FUNCTION__))
325 "Size mismatch!")((NextFieldOffsetInChars <= RecordSize && "Size mismatch!"
) ? static_cast<void> (0) : __assert_fail ("NextFieldOffsetInChars <= RecordSize && \"Size mismatch!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 325, __PRETTY_FUNCTION__))
;
326
327 AppendPadding(RecordSize - NextFieldOffsetInChars);
328}
329
330void ConstStructBuilder::ConvertStructToPacked() {
331 SmallVector<llvm::Constant *, 16> PackedElements;
332 CharUnits ElementOffsetInChars = CharUnits::Zero();
333
334 for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
335 llvm::Constant *C = Elements[i];
336
337 CharUnits ElementAlign = CharUnits::fromQuantity(
338 CGM.getDataLayout().getABITypeAlignment(C->getType()));
339 CharUnits AlignedElementOffsetInChars =
340 ElementOffsetInChars.alignTo(ElementAlign);
341
342 if (AlignedElementOffsetInChars > ElementOffsetInChars) {
343 // We need some padding.
344 CharUnits NumChars =
345 AlignedElementOffsetInChars - ElementOffsetInChars;
346
347 llvm::Type *Ty = CGM.Int8Ty;
348 if (NumChars > CharUnits::One())
349 Ty = llvm::ArrayType::get(Ty, NumChars.getQuantity());
350
351 llvm::Constant *Padding = llvm::UndefValue::get(Ty);
352 PackedElements.push_back(Padding);
353 ElementOffsetInChars += getSizeInChars(Padding);
354 }
355
356 PackedElements.push_back(C);
357 ElementOffsetInChars += getSizeInChars(C);
358 }
359
360 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 361, __PRETTY_FUNCTION__))
361 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 361, __PRETTY_FUNCTION__))
;
362
363 Elements.swap(PackedElements);
364 LLVMStructAlignment = CharUnits::One();
365 Packed = true;
366}
367
368bool ConstStructBuilder::Build(InitListExpr *ILE) {
369 RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
370 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
371
372 unsigned FieldNo = 0;
373 unsigned ElementNo = 0;
374
375 // Bail out if we have base classes. We could support these, but they only
376 // arise in C++1z where we will have already constant folded most interesting
377 // cases. FIXME: There are still a few more cases we can handle this way.
378 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
379 if (CXXRD->getNumBases())
380 return false;
381
382 for (RecordDecl::field_iterator Field = RD->field_begin(),
383 FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
384 // If this is a union, skip all the fields that aren't being initialized.
385 if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field)
386 continue;
387
388 // Don't emit anonymous bitfields, they just affect layout.
389 if (Field->isUnnamedBitfield())
390 continue;
391
392 // Get the initializer. A struct can include fields without initializers,
393 // we just use explicit null values for them.
394 llvm::Constant *EltInit;
395 if (ElementNo < ILE->getNumInits())
396 EltInit = Emitter.tryEmitPrivateForMemory(ILE->getInit(ElementNo++),
397 Field->getType());
398 else
399 EltInit = Emitter.emitNullForMemory(Field->getType());
400
401 if (!EltInit)
402 return false;
403
404 if (!Field->isBitField()) {
405 // Handle non-bitfield members.
406 AppendField(*Field, Layout.getFieldOffset(FieldNo), EltInit);
407 } else {
408 // Otherwise we have a bitfield.
409 if (auto *CI = dyn_cast<llvm::ConstantInt>(EltInit)) {
410 AppendBitField(*Field, Layout.getFieldOffset(FieldNo), CI);
411 } else {
412 // We are trying to initialize a bitfield with a non-trivial constant,
413 // this must require run-time code.
414 return false;
415 }
416 }
417 }
418
419 return true;
420}
421
422namespace {
423struct BaseInfo {
424 BaseInfo(const CXXRecordDecl *Decl, CharUnits Offset, unsigned Index)
425 : Decl(Decl), Offset(Offset), Index(Index) {
426 }
427
428 const CXXRecordDecl *Decl;
429 CharUnits Offset;
430 unsigned Index;
431
432 bool operator<(const BaseInfo &O) const { return Offset < O.Offset; }
433};
434}
435
436bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
437 bool IsPrimaryBase,
438 const CXXRecordDecl *VTableClass,
439 CharUnits Offset) {
440 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
441
442 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
443 // Add a vtable pointer, if we need one and it hasn't already been added.
444 if (CD->isDynamicClass() && !IsPrimaryBase) {
445 llvm::Constant *VTableAddressPoint =
446 CGM.getCXXABI().getVTableAddressPointForConstExpr(
447 BaseSubobject(CD, Offset), VTableClass);
448 AppendBytes(Offset, VTableAddressPoint);
449 }
450
451 // Accumulate and sort bases, in order to visit them in address order, which
452 // may not be the same as declaration order.
453 SmallVector<BaseInfo, 8> Bases;
454 Bases.reserve(CD->getNumBases());
455 unsigned BaseNo = 0;
456 for (CXXRecordDecl::base_class_const_iterator Base = CD->bases_begin(),
457 BaseEnd = CD->bases_end(); Base != BaseEnd; ++Base, ++BaseNo) {
458 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 458, __PRETTY_FUNCTION__))
;
459 const CXXRecordDecl *BD = Base->getType()->getAsCXXRecordDecl();
460 CharUnits BaseOffset = Layout.getBaseClassOffset(BD);
461 Bases.push_back(BaseInfo(BD, BaseOffset, BaseNo));
462 }
463 std::stable_sort(Bases.begin(), Bases.end());
464
465 for (unsigned I = 0, N = Bases.size(); I != N; ++I) {
466 BaseInfo &Base = Bases[I];
467
468 bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl;
469 Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
470 VTableClass, Offset + Base.Offset);
471 }
472 }
473
474 unsigned FieldNo = 0;
475 uint64_t OffsetBits = CGM.getContext().toBits(Offset);
476
477 for (RecordDecl::field_iterator Field = RD->field_begin(),
478 FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
479 // If this is a union, skip all the fields that aren't being initialized.
480 if (RD->isUnion() && Val.getUnionField() != *Field)
481 continue;
482
483 // Don't emit anonymous bitfields, they just affect layout.
484 if (Field->isUnnamedBitfield())
485 continue;
486
487 // Emit the value of the initializer.
488 const APValue &FieldValue =
489 RD->isUnion() ? Val.getUnionValue() : Val.getStructField(FieldNo);
490 llvm::Constant *EltInit =
491 Emitter.tryEmitPrivateForMemory(FieldValue, Field->getType());
492 if (!EltInit)
493 return false;
494
495 if (!Field->isBitField()) {
496 // Handle non-bitfield members.
497 AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, EltInit);
498 } else {
499 // Otherwise we have a bitfield.
500 AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
501 cast<llvm::ConstantInt>(EltInit));
502 }
503 }
504
505 return true;
506}
507
508llvm::Constant *ConstStructBuilder::Finalize(QualType Ty) {
509 RecordDecl *RD = Ty->getAs<RecordType>()->getDecl();
510 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
511
512 CharUnits LayoutSizeInChars = Layout.getSize();
513
514 if (NextFieldOffsetInChars > LayoutSizeInChars) {
515 // If the struct is bigger than the size of the record type,
516 // we must have a flexible array member at the end.
517 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 518, __PRETTY_FUNCTION__))
518 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 518, __PRETTY_FUNCTION__))
;
519
520 // No tail padding is necessary.
521 } else {
522 // Append tail padding if necessary.
523 CharUnits LLVMSizeInChars =
524 NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
525
526 if (LLVMSizeInChars != LayoutSizeInChars)
527 AppendTailPadding(LayoutSizeInChars);
528
529 LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
530
531 // Check if we need to convert the struct to a packed struct.
532 if (NextFieldOffsetInChars <= LayoutSizeInChars &&
533 LLVMSizeInChars > LayoutSizeInChars) {
534 assert(!Packed && "Size mismatch!")((!Packed && "Size mismatch!") ? static_cast<void>
(0) : __assert_fail ("!Packed && \"Size mismatch!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 534, __PRETTY_FUNCTION__))
;
535
536 ConvertStructToPacked();
537 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 538, __PRETTY_FUNCTION__))
538 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 538, __PRETTY_FUNCTION__))
;
539 }
540
541 LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
542
543 assert(LayoutSizeInChars == LLVMSizeInChars &&((LayoutSizeInChars == LLVMSizeInChars && "Tail padding mismatch!"
) ? static_cast<void> (0) : __assert_fail ("LayoutSizeInChars == LLVMSizeInChars && \"Tail padding mismatch!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 544, __PRETTY_FUNCTION__))
544 "Tail padding mismatch!")((LayoutSizeInChars == LLVMSizeInChars && "Tail padding mismatch!"
) ? static_cast<void> (0) : __assert_fail ("LayoutSizeInChars == LLVMSizeInChars && \"Tail padding mismatch!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 544, __PRETTY_FUNCTION__))
;
545 }
546
547 // Pick the type to use. If the type is layout identical to the ConvertType
548 // type then use it, otherwise use whatever the builder produced for us.
549 llvm::StructType *STy =
550 llvm::ConstantStruct::getTypeForElements(CGM.getLLVMContext(),
551 Elements, Packed);
552 llvm::Type *ValTy = CGM.getTypes().ConvertType(Ty);
553 if (llvm::StructType *ValSTy = dyn_cast<llvm::StructType>(ValTy)) {
554 if (ValSTy->isLayoutIdentical(STy))
555 STy = ValSTy;
556 }
557
558 llvm::Constant *Result = llvm::ConstantStruct::get(STy, Elements);
559
560 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 562, __PRETTY_FUNCTION__))
561 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 562, __PRETTY_FUNCTION__))
562 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 562, __PRETTY_FUNCTION__))
;
563
564 return Result;
565}
566
567llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
568 ConstExprEmitter *ExprEmitter,
569 llvm::ConstantStruct *Base,
570 InitListExpr *Updater,
571 QualType ValTy) {
572 ConstStructBuilder Builder(Emitter);
573 if (!Builder.Build(ExprEmitter, Base, Updater))
574 return nullptr;
575 return Builder.Finalize(ValTy);
576}
577
578llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
579 InitListExpr *ILE,
580 QualType ValTy) {
581 ConstStructBuilder Builder(Emitter);
582
583 if (!Builder.Build(ILE))
584 return nullptr;
585
586 return Builder.Finalize(ValTy);
587}
588
589llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
590 const APValue &Val,
591 QualType ValTy) {
592 ConstStructBuilder Builder(Emitter);
593
594 const RecordDecl *RD = ValTy->castAs<RecordType>()->getDecl();
595 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
596 if (!Builder.Build(Val, RD, false, CD, CharUnits::Zero()))
597 return nullptr;
598
599 return Builder.Finalize(ValTy);
600}
601
602
603//===----------------------------------------------------------------------===//
604// ConstExprEmitter
605//===----------------------------------------------------------------------===//
606
607static ConstantAddress tryEmitGlobalCompoundLiteral(CodeGenModule &CGM,
608 CodeGenFunction *CGF,
609 const CompoundLiteralExpr *E) {
610 CharUnits Align = CGM.getContext().getTypeAlignInChars(E->getType());
611 if (llvm::GlobalVariable *Addr =
612 CGM.getAddrOfConstantCompoundLiteralIfEmitted(E))
613 return ConstantAddress(Addr, Align);
614
615 LangAS addressSpace = E->getType().getAddressSpace();
616
617 ConstantEmitter emitter(CGM, CGF);
618 llvm::Constant *C = emitter.tryEmitForInitializer(E->getInitializer(),
619 addressSpace, E->getType());
620 if (!C) {
621 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 622, __PRETTY_FUNCTION__))
622 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 622, __PRETTY_FUNCTION__))
;
623 return ConstantAddress::invalid();
624 }
625
626 auto GV = new llvm::GlobalVariable(CGM.getModule(), C->getType(),
627 CGM.isTypeConstant(E->getType(), true),
628 llvm::GlobalValue::InternalLinkage,
629 C, ".compoundliteral", nullptr,
630 llvm::GlobalVariable::NotThreadLocal,
631 CGM.getContext().getTargetAddressSpace(addressSpace));
632 emitter.finalize(GV);
633 GV->setAlignment(Align.getQuantity());
634 CGM.setAddrOfConstantCompoundLiteral(E, GV);
635 return ConstantAddress(GV, Align);
636}
637
638static llvm::Constant *
639EmitArrayConstant(CodeGenModule &CGM, const ConstantArrayType *DestType,
640 llvm::Type *CommonElementType, unsigned ArrayBound,
641 SmallVectorImpl<llvm::Constant *> &Elements,
642 llvm::Constant *Filler) {
643 // Figure out how long the initial prefix of non-zero elements is.
644 unsigned NonzeroLength = ArrayBound;
645 if (Elements.size() < NonzeroLength && Filler->isNullValue())
646 NonzeroLength = Elements.size();
647 if (NonzeroLength == Elements.size()) {
648 while (NonzeroLength > 0 && Elements[NonzeroLength - 1]->isNullValue())
649 --NonzeroLength;
650 }
651
652 if (NonzeroLength == 0) {
653 return llvm::ConstantAggregateZero::get(
654 CGM.getTypes().ConvertType(QualType(DestType, 0)));
655 }
656
657 // Add a zeroinitializer array filler if we have lots of trailing zeroes.
658 unsigned TrailingZeroes = ArrayBound - NonzeroLength;
659 if (TrailingZeroes >= 8) {
660 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 661, __PRETTY_FUNCTION__))
661 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 661, __PRETTY_FUNCTION__))
;
662
663 // If all the elements had the same type up to the trailing zeroes, emit a
664 // struct of two arrays (the nonzero data and the zeroinitializer).
665 if (CommonElementType && NonzeroLength >= 8) {
666 llvm::Constant *Initial = llvm::ConstantArray::get(
667 llvm::ArrayType::get(CommonElementType, NonzeroLength),
668 makeArrayRef(Elements).take_front(NonzeroLength));
669 Elements.resize(2);
670 Elements[0] = Initial;
671 } else {
672 Elements.resize(NonzeroLength + 1);
673 }
674
675 auto *FillerType =
676 CommonElementType
677 ? CommonElementType
678 : CGM.getTypes().ConvertType(DestType->getElementType());
679 FillerType = llvm::ArrayType::get(FillerType, TrailingZeroes);
680 Elements.back() = llvm::ConstantAggregateZero::get(FillerType);
681 CommonElementType = nullptr;
682 } else if (Elements.size() != ArrayBound) {
683 // Otherwise pad to the right size with the filler if necessary.
684 Elements.resize(ArrayBound, Filler);
685 if (Filler->getType() != CommonElementType)
686 CommonElementType = nullptr;
687 }
688
689 // If all elements have the same type, just emit an array constant.
690 if (CommonElementType)
691 return llvm::ConstantArray::get(
692 llvm::ArrayType::get(CommonElementType, ArrayBound), Elements);
693
694 // We have mixed types. Use a packed struct.
695 llvm::SmallVector<llvm::Type *, 16> Types;
696 Types.reserve(Elements.size());
697 for (llvm::Constant *Elt : Elements)
698 Types.push_back(Elt->getType());
699 llvm::StructType *SType =
700 llvm::StructType::get(CGM.getLLVMContext(), Types, true);
701 return llvm::ConstantStruct::get(SType, Elements);
702}
703
704/// This class only needs to handle two cases:
705/// 1) Literals (this is used by APValue emission to emit literals).
706/// 2) Arrays, structs and unions (outside C++11 mode, we don't currently
707/// constant fold these types).
708class ConstExprEmitter :
709 public StmtVisitor<ConstExprEmitter, llvm::Constant*, QualType> {
710 CodeGenModule &CGM;
711 ConstantEmitter &Emitter;
712 llvm::LLVMContext &VMContext;
713public:
714 ConstExprEmitter(ConstantEmitter &emitter)
715 : CGM(emitter.CGM), Emitter(emitter), VMContext(CGM.getLLVMContext()) {
716 }
717
718 //===--------------------------------------------------------------------===//
719 // Visitor Methods
720 //===--------------------------------------------------------------------===//
721
722 llvm::Constant *VisitStmt(Stmt *S, QualType T) {
723 return nullptr;
724 }
725
726 llvm::Constant *VisitParenExpr(ParenExpr *PE, QualType T) {
727 return Visit(PE->getSubExpr(), T);
728 }
729
730 llvm::Constant *
731 VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *PE,
732 QualType T) {
733 return Visit(PE->getReplacement(), T);
734 }
735
736 llvm::Constant *VisitGenericSelectionExpr(GenericSelectionExpr *GE,
737 QualType T) {
738 return Visit(GE->getResultExpr(), T);
739 }
740
741 llvm::Constant *VisitChooseExpr(ChooseExpr *CE, QualType T) {
742 return Visit(CE->getChosenSubExpr(), T);
743 }
744
745 llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E, QualType T) {
746 return Visit(E->getInitializer(), T);
747 }
748
749 llvm::Constant *VisitCastExpr(CastExpr *E, QualType destType) {
750 if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
751 CGM.EmitExplicitCastExprType(ECE, Emitter.CGF);
752 Expr *subExpr = E->getSubExpr();
753
754 switch (E->getCastKind()) {
755 case CK_ToUnion: {
756 // GCC cast to union extension
757 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 758, __PRETTY_FUNCTION__))
758 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 758, __PRETTY_FUNCTION__))
;
759
760 auto field = E->getTargetUnionField();
761
762 auto C = Emitter.tryEmitPrivateForMemory(subExpr, field->getType());
763 if (!C) return nullptr;
764
765 auto destTy = ConvertType(destType);
766 if (C->getType() == destTy) return C;
767
768 // Build a struct with the union sub-element as the first member,
769 // and padded to the appropriate size.
770 SmallVector<llvm::Constant*, 2> Elts;
771 SmallVector<llvm::Type*, 2> Types;
772 Elts.push_back(C);
773 Types.push_back(C->getType());
774 unsigned CurSize = CGM.getDataLayout().getTypeAllocSize(C->getType());
775 unsigned TotalSize = CGM.getDataLayout().getTypeAllocSize(destTy);
776
777 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 777, __PRETTY_FUNCTION__))
;
778 if (unsigned NumPadBytes = TotalSize - CurSize) {
779 llvm::Type *Ty = CGM.Int8Ty;
780 if (NumPadBytes > 1)
781 Ty = llvm::ArrayType::get(Ty, NumPadBytes);
782
783 Elts.push_back(llvm::UndefValue::get(Ty));
784 Types.push_back(Ty);
785 }
786
787 llvm::StructType *STy = llvm::StructType::get(VMContext, Types, false);
788 return llvm::ConstantStruct::get(STy, Elts);
789 }
790
791 case CK_AddressSpaceConversion: {
792 auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
793 if (!C) return nullptr;
794 LangAS destAS = E->getType()->getPointeeType().getAddressSpace();
795 LangAS srcAS = subExpr->getType()->getPointeeType().getAddressSpace();
796 llvm::Type *destTy = ConvertType(E->getType());
797 return CGM.getTargetCodeGenInfo().performAddrSpaceCast(CGM, C, srcAS,
798 destAS, destTy);
799 }
800
801 case CK_LValueToRValue:
802 case CK_AtomicToNonAtomic:
803 case CK_NonAtomicToAtomic:
804 case CK_NoOp:
805 case CK_ConstructorConversion:
806 return Visit(subExpr, destType);
807
808 case CK_IntToOCLSampler:
809 llvm_unreachable("global sampler variables are not generated")::llvm::llvm_unreachable_internal("global sampler variables are not generated"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 809)
;
810
811 case CK_Dependent: llvm_unreachable("saw dependent cast!")::llvm::llvm_unreachable_internal("saw dependent cast!", "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 811)
;
812
813 case CK_BuiltinFnToFnPtr:
814 llvm_unreachable("builtin functions are handled elsewhere")::llvm::llvm_unreachable_internal("builtin functions are handled elsewhere"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 814)
;
815
816 case CK_ReinterpretMemberPointer:
817 case CK_DerivedToBaseMemberPointer:
818 case CK_BaseToDerivedMemberPointer: {
819 auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
820 if (!C) return nullptr;
821 return CGM.getCXXABI().EmitMemberPointerConversion(E, C);
822 }
823
824 // These will never be supported.
825 case CK_ObjCObjectLValueCast:
826 case CK_ARCProduceObject:
827 case CK_ARCConsumeObject:
828 case CK_ARCReclaimReturnedObject:
829 case CK_ARCExtendBlockObject:
830 case CK_CopyAndAutoreleaseBlockObject:
831 return nullptr;
832
833 // These don't need to be handled here because Evaluate knows how to
834 // evaluate them in the cases where they can be folded.
835 case CK_BitCast:
836 case CK_ToVoid:
837 case CK_Dynamic:
838 case CK_LValueBitCast:
839 case CK_NullToMemberPointer:
840 case CK_UserDefinedConversion:
841 case CK_CPointerToObjCPointerCast:
842 case CK_BlockPointerToObjCPointerCast:
843 case CK_AnyPointerToBlockPointerCast:
844 case CK_ArrayToPointerDecay:
845 case CK_FunctionToPointerDecay:
846 case CK_BaseToDerived:
847 case CK_DerivedToBase:
848 case CK_UncheckedDerivedToBase:
849 case CK_MemberPointerToBoolean:
850 case CK_VectorSplat:
851 case CK_FloatingRealToComplex:
852 case CK_FloatingComplexToReal:
853 case CK_FloatingComplexToBoolean:
854 case CK_FloatingComplexCast:
855 case CK_FloatingComplexToIntegralComplex:
856 case CK_IntegralRealToComplex:
857 case CK_IntegralComplexToReal:
858 case CK_IntegralComplexToBoolean:
859 case CK_IntegralComplexCast:
860 case CK_IntegralComplexToFloatingComplex:
861 case CK_PointerToIntegral:
862 case CK_PointerToBoolean:
863 case CK_NullToPointer:
864 case CK_IntegralCast:
865 case CK_BooleanToSignedIntegral:
866 case CK_IntegralToPointer:
867 case CK_IntegralToBoolean:
868 case CK_IntegralToFloating:
869 case CK_FloatingToIntegral:
870 case CK_FloatingToBoolean:
871 case CK_FloatingCast:
872 case CK_FixedPointCast:
873 case CK_FixedPointToBoolean:
874 case CK_ZeroToOCLOpaqueType:
875 return nullptr;
876 }
877 llvm_unreachable("Invalid CastKind")::llvm::llvm_unreachable_internal("Invalid CastKind", "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 877)
;
878 }
879
880 llvm::Constant *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE, QualType T) {
881 return Visit(DAE->getExpr(), T);
882 }
883
884 llvm::Constant *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE, QualType T) {
885 // No need for a DefaultInitExprScope: we don't handle 'this' in a
886 // constant expression.
887 return Visit(DIE->getExpr(), T);
888 }
889
890 llvm::Constant *VisitExprWithCleanups(ExprWithCleanups *E, QualType T) {
891 if (!E->cleanupsHaveSideEffects())
892 return Visit(E->getSubExpr(), T);
893 return nullptr;
894 }
895
896 llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
897 QualType T) {
898 return Visit(E->GetTemporaryExpr(), T);
899 }
900
901 llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) {
902 auto *CAT = CGM.getContext().getAsConstantArrayType(ILE->getType());
903 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 903, __PRETTY_FUNCTION__))
;
904 unsigned NumInitElements = ILE->getNumInits();
905 unsigned NumElements = CAT->getSize().getZExtValue();
906
907 // Initialising an array requires us to automatically
908 // initialise any elements that have not been initialised explicitly
909 unsigned NumInitableElts = std::min(NumInitElements, NumElements);
910
911 QualType EltType = CAT->getElementType();
912
913 // Initialize remaining array elements.
914 llvm::Constant *fillC = nullptr;
915 if (Expr *filler = ILE->getArrayFiller()) {
916 fillC = Emitter.tryEmitAbstractForMemory(filler, EltType);
917 if (!fillC)
918 return nullptr;
919 }
920
921 // Copy initializer elements.
922 SmallVector<llvm::Constant*, 16> Elts;
923 if (fillC && fillC->isNullValue())
924 Elts.reserve(NumInitableElts + 1);
925 else
926 Elts.reserve(NumElements);
927
928 llvm::Type *CommonElementType = nullptr;
929 for (unsigned i = 0; i < NumInitableElts; ++i) {
930 Expr *Init = ILE->getInit(i);
931 llvm::Constant *C = Emitter.tryEmitPrivateForMemory(Init, EltType);
932 if (!C)
933 return nullptr;
934 if (i == 0)
935 CommonElementType = C->getType();
936 else if (C->getType() != CommonElementType)
937 CommonElementType = nullptr;
938 Elts.push_back(C);
939 }
940
941 return EmitArrayConstant(CGM, CAT, CommonElementType, NumElements, Elts,
942 fillC);
943 }
944
945 llvm::Constant *EmitRecordInitialization(InitListExpr *ILE, QualType T) {
946 return ConstStructBuilder::BuildStruct(Emitter, ILE, T);
947 }
948
949 llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E,
950 QualType T) {
951 return CGM.EmitNullConstant(T);
952 }
953
954 llvm::Constant *VisitInitListExpr(InitListExpr *ILE, QualType T) {
955 if (ILE->isTransparent())
956 return Visit(ILE->getInit(0), T);
957
958 if (ILE->getType()->isArrayType())
959 return EmitArrayInitialization(ILE, T);
960
961 if (ILE->getType()->isRecordType())
962 return EmitRecordInitialization(ILE, T);
963
964 return nullptr;
965 }
966
967 llvm::Constant *EmitDesignatedInitUpdater(llvm::Constant *Base,
968 InitListExpr *Updater,
969 QualType destType) {
970 if (auto destAT = CGM.getContext().getAsArrayType(destType)) {
971 llvm::ArrayType *AType = cast<llvm::ArrayType>(ConvertType(destType));
972 llvm::Type *ElemType = AType->getElementType();
973
974 unsigned NumInitElements = Updater->getNumInits();
975 unsigned NumElements = AType->getNumElements();
976
977 std::vector<llvm::Constant *> Elts;
978 Elts.reserve(NumElements);
979
980 QualType destElemType = destAT->getElementType();
981
982 if (auto DataArray = dyn_cast<llvm::ConstantDataArray>(Base))
983 for (unsigned i = 0; i != NumElements; ++i)
984 Elts.push_back(DataArray->getElementAsConstant(i));
985 else if (auto Array = dyn_cast<llvm::ConstantArray>(Base))
986 for (unsigned i = 0; i != NumElements; ++i)
987 Elts.push_back(Array->getOperand(i));
988 else
989 return nullptr; // FIXME: other array types not implemented
990
991 llvm::Constant *fillC = nullptr;
992 if (Expr *filler = Updater->getArrayFiller())
993 if (!isa<NoInitExpr>(filler))
994 fillC = Emitter.tryEmitAbstractForMemory(filler, destElemType);
995 bool RewriteType = (fillC && fillC->getType() != ElemType);
996
997 for (unsigned i = 0; i != NumElements; ++i) {
998 Expr *Init = nullptr;
999 if (i < NumInitElements)
1000 Init = Updater->getInit(i);
1001
1002 if (!Init && fillC)
1003 Elts[i] = fillC;
1004 else if (!Init || isa<NoInitExpr>(Init))
1005 ; // Do nothing.
1006 else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init))
1007 Elts[i] = EmitDesignatedInitUpdater(Elts[i], ChildILE, destElemType);
1008 else
1009 Elts[i] = Emitter.tryEmitPrivateForMemory(Init, destElemType);
1010
1011 if (!Elts[i])
1012 return nullptr;
1013 RewriteType |= (Elts[i]->getType() != ElemType);
1014 }
1015
1016 if (RewriteType) {
1017 std::vector<llvm::Type *> Types;
1018 Types.reserve(NumElements);
1019 for (unsigned i = 0; i != NumElements; ++i)
1020 Types.push_back(Elts[i]->getType());
1021 llvm::StructType *SType = llvm::StructType::get(AType->getContext(),
1022 Types, true);
1023 return llvm::ConstantStruct::get(SType, Elts);
1024 }
1025
1026 return llvm::ConstantArray::get(AType, Elts);
1027 }
1028
1029 if (destType->isRecordType())
1030 return ConstStructBuilder::BuildStruct(Emitter, this,
1031 dyn_cast<llvm::ConstantStruct>(Base), Updater, destType);
1032
1033 return nullptr;
1034 }
1035
1036 llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E,
1037 QualType destType) {
1038 auto C = Visit(E->getBase(), destType);
1039 if (!C) return nullptr;
1040 return EmitDesignatedInitUpdater(C, E->getUpdater(), destType);
1041 }
1042
1043 llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) {
1044 if (!E->getConstructor()->isTrivial())
1045 return nullptr;
1046
1047 // FIXME: We should not have to call getBaseElementType here.
1048 const RecordType *RT =
1049 CGM.getContext().getBaseElementType(Ty)->getAs<RecordType>();
1050 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1051
1052 // If the class doesn't have a trivial destructor, we can't emit it as a
1053 // constant expr.
1054 if (!RD->hasTrivialDestructor())
1055 return nullptr;
1056
1057 // Only copy and default constructors can be trivial.
1058
1059
1060 if (E->getNumArgs()) {
1061 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1061, __PRETTY_FUNCTION__))
;
1062 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1063, __PRETTY_FUNCTION__))
1063 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1063, __PRETTY_FUNCTION__))
;
1064
1065 Expr *Arg = E->getArg(0);
1066 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1067, __PRETTY_FUNCTION__))
1067 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1067, __PRETTY_FUNCTION__))
;
1068
1069 return Visit(Arg, Ty);
1070 }
1071
1072 return CGM.EmitNullConstant(Ty);
1073 }
1074
1075 llvm::Constant *VisitStringLiteral(StringLiteral *E, QualType T) {
1076 return CGM.GetConstantArrayFromStringLiteral(E);
1077 }
1078
1079 llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E, QualType T) {
1080 // This must be an @encode initializing an array in a static initializer.
1081 // Don't emit it as the address of the string, emit the string data itself
1082 // as an inline array.
1083 std::string Str;
1084 CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str);
1085 const ConstantArrayType *CAT = CGM.getContext().getAsConstantArrayType(T);
1086
1087 // Resize the string to the right size, adding zeros at the end, or
1088 // truncating as needed.
1089 Str.resize(CAT->getSize().getZExtValue(), '\0');
1090 return llvm::ConstantDataArray::getString(VMContext, Str, false);
1091 }
1092
1093 llvm::Constant *VisitUnaryExtension(const UnaryOperator *E, QualType T) {
1094 return Visit(E->getSubExpr(), T);
1095 }
1096
1097 // Utility methods
1098 llvm::Type *ConvertType(QualType T) {
1099 return CGM.getTypes().ConvertType(T);
1100 }
1101};
1102
1103} // end anonymous namespace.
1104
1105bool ConstStructBuilder::Build(ConstExprEmitter *ExprEmitter,
1106 llvm::ConstantStruct *Base,
1107 InitListExpr *Updater) {
1108 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1108, __PRETTY_FUNCTION__))
;
1109
1110 QualType ExprType = Updater->getType();
1111 RecordDecl *RD = ExprType->getAs<RecordType>()->getDecl();
1112 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
1113 const llvm::StructLayout *BaseLayout = CGM.getDataLayout().getStructLayout(
1114 Base->getType());
1115 unsigned FieldNo = -1;
1116 unsigned ElementNo = 0;
1117
1118 // Bail out if we have base classes. We could support these, but they only
1119 // arise in C++1z where we will have already constant folded most interesting
1120 // cases. FIXME: There are still a few more cases we can handle this way.
1121 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
1122 if (CXXRD->getNumBases())
1123 return false;
1124
1125 for (FieldDecl *Field : RD->fields()) {
1126 ++FieldNo;
1127
1128 if (RD->isUnion() && Updater->getInitializedFieldInUnion() != Field)
1129 continue;
1130
1131 // Skip anonymous bitfields.
1132 if (Field->isUnnamedBitfield())
1133 continue;
1134
1135 llvm::Constant *EltInit = Base->getOperand(ElementNo);
1136
1137 // Bail out if the type of the ConstantStruct does not have the same layout
1138 // as the type of the InitListExpr.
1139 if (CGM.getTypes().ConvertType(Field->getType()) != EltInit->getType() ||
1140 Layout.getFieldOffset(ElementNo) !=
1141 BaseLayout->getElementOffsetInBits(ElementNo))
1142 return false;
1143
1144 // Get the initializer. If we encounter an empty field or a NoInitExpr,
1145 // we use values from the base expression.
1146 Expr *Init = nullptr;
1147 if (ElementNo < Updater->getNumInits())
1148 Init = Updater->getInit(ElementNo);
1149
1150 if (!Init || isa<NoInitExpr>(Init))
1151 ; // Do nothing.
1152 else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init))
1153 EltInit = ExprEmitter->EmitDesignatedInitUpdater(EltInit, ChildILE,
1154 Field->getType());
1155 else
1156 EltInit = Emitter.tryEmitPrivateForMemory(Init, Field->getType());
1157
1158 ++ElementNo;
1159
1160 if (!EltInit)
1161 return false;
1162
1163 if (!Field->isBitField())
1164 AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit);
1165 else if (llvm::ConstantInt *CI = dyn_cast<llvm::ConstantInt>(EltInit))
1166 AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI);
1167 else
1168 // Initializing a bitfield with a non-trivial constant?
1169 return false;
1170 }
1171
1172 return true;
1173}
1174
1175llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C,
1176 AbstractState saved) {
1177 Abstract = saved.OldValue;
1178
1179 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1180, __PRETTY_FUNCTION__))
1180 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1180, __PRETTY_FUNCTION__))
;
1181
1182 // No validation necessary for now.
1183 // No cleanup to do for now.
1184 return C;
1185}
1186
1187llvm::Constant *
1188ConstantEmitter::tryEmitAbstractForInitializer(const VarDecl &D) {
1189 auto state = pushAbstract();
1190 auto C = tryEmitPrivateForVarInit(D);
1191 return validateAndPopAbstract(C, state);
1192}
1193
1194llvm::Constant *
1195ConstantEmitter::tryEmitAbstract(const Expr *E, QualType destType) {
1196 auto state = pushAbstract();
1197 auto C = tryEmitPrivate(E, destType);
1198 return validateAndPopAbstract(C, state);
1199}
1200
1201llvm::Constant *
1202ConstantEmitter::tryEmitAbstract(const APValue &value, QualType destType) {
1203 auto state = pushAbstract();
1204 auto C = tryEmitPrivate(value, destType);
1205 return validateAndPopAbstract(C, state);
1206}
1207
1208llvm::Constant *
1209ConstantEmitter::emitAbstract(const Expr *E, QualType destType) {
1210 auto state = pushAbstract();
1211 auto C = tryEmitPrivate(E, destType);
1212 C = validateAndPopAbstract(C, state);
1213 if (!C) {
1214 CGM.Error(E->getExprLoc(),
1215 "internal error: could not emit constant value \"abstractly\"");
1216 C = CGM.EmitNullConstant(destType);
1217 }
1218 return C;
1219}
1220
1221llvm::Constant *
1222ConstantEmitter::emitAbstract(SourceLocation loc, const APValue &value,
1223 QualType destType) {
1224 auto state = pushAbstract();
1225 auto C = tryEmitPrivate(value, destType);
1226 C = validateAndPopAbstract(C, state);
1227 if (!C) {
1228 CGM.Error(loc,
1229 "internal error: could not emit constant value \"abstractly\"");
1230 C = CGM.EmitNullConstant(destType);
1231 }
1232 return C;
1233}
1234
1235llvm::Constant *ConstantEmitter::tryEmitForInitializer(const VarDecl &D) {
1236 initializeNonAbstract(D.getType().getAddressSpace());
1237 return markIfFailed(tryEmitPrivateForVarInit(D));
1238}
1239
1240llvm::Constant *ConstantEmitter::tryEmitForInitializer(const Expr *E,
1241 LangAS destAddrSpace,
1242 QualType destType) {
1243 initializeNonAbstract(destAddrSpace);
1244 return markIfFailed(tryEmitPrivateForMemory(E, destType));
1245}
1246
1247llvm::Constant *ConstantEmitter::emitForInitializer(const APValue &value,
1248 LangAS destAddrSpace,
1249 QualType destType) {
1250 initializeNonAbstract(destAddrSpace);
1251 auto C = tryEmitPrivateForMemory(value, destType);
1252 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1252, __PRETTY_FUNCTION__))
;
1253 return C;
1254}
1255
1256llvm::GlobalValue *ConstantEmitter::getCurrentAddrPrivate() {
1257 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1257, __PRETTY_FUNCTION__))
;
1258
1259
1260
1261 // Make an obviously ill-formed global that should blow up compilation
1262 // if it survives.
1263 auto global = new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty, true,
1264 llvm::GlobalValue::PrivateLinkage,
1265 /*init*/ nullptr,
1266 /*name*/ "",
1267 /*before*/ nullptr,
1268 llvm::GlobalVariable::NotThreadLocal,
1269 CGM.getContext().getTargetAddressSpace(DestAddressSpace));
1270
1271 PlaceholderAddresses.push_back(std::make_pair(nullptr, global));
1272
1273 return global;
1274}
1275
1276void ConstantEmitter::registerCurrentAddrPrivate(llvm::Constant *signal,
1277 llvm::GlobalValue *placeholder) {
1278 assert(!PlaceholderAddresses.empty())((!PlaceholderAddresses.empty()) ? static_cast<void> (0
) : __assert_fail ("!PlaceholderAddresses.empty()", "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1278, __PRETTY_FUNCTION__))
;
1279 assert(PlaceholderAddresses.back().first == nullptr)((PlaceholderAddresses.back().first == nullptr) ? static_cast
<void> (0) : __assert_fail ("PlaceholderAddresses.back().first == nullptr"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1279, __PRETTY_FUNCTION__))
;
1280 assert(PlaceholderAddresses.back().second == placeholder)((PlaceholderAddresses.back().second == placeholder) ? static_cast
<void> (0) : __assert_fail ("PlaceholderAddresses.back().second == placeholder"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1280, __PRETTY_FUNCTION__))
;
1281 PlaceholderAddresses.back().first = signal;
1282}
1283
1284namespace {
1285 struct ReplacePlaceholders {
1286 CodeGenModule &CGM;
1287
1288 /// The base address of the global.
1289 llvm::Constant *Base;
1290 llvm::Type *BaseValueTy = nullptr;
1291
1292 /// The placeholder addresses that were registered during emission.
1293 llvm::DenseMap<llvm::Constant*, llvm::GlobalVariable*> PlaceholderAddresses;
1294
1295 /// The locations of the placeholder signals.
1296 llvm::DenseMap<llvm::GlobalVariable*, llvm::Constant*> Locations;
1297
1298 /// The current index stack. We use a simple unsigned stack because
1299 /// we assume that placeholders will be relatively sparse in the
1300 /// initializer, but we cache the index values we find just in case.
1301 llvm::SmallVector<unsigned, 8> Indices;
1302 llvm::SmallVector<llvm::Constant*, 8> IndexValues;
1303
1304 ReplacePlaceholders(CodeGenModule &CGM, llvm::Constant *base,
1305 ArrayRef<std::pair<llvm::Constant*,
1306 llvm::GlobalVariable*>> addresses)
1307 : CGM(CGM), Base(base),
1308 PlaceholderAddresses(addresses.begin(), addresses.end()) {
1309 }
1310
1311 void replaceInInitializer(llvm::Constant *init) {
1312 // Remember the type of the top-most initializer.
1313 BaseValueTy = init->getType();
1314
1315 // Initialize the stack.
1316 Indices.push_back(0);
1317 IndexValues.push_back(nullptr);
1318
1319 // Recurse into the initializer.
1320 findLocations(init);
1321
1322 // Check invariants.
1323 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1323, __PRETTY_FUNCTION__))
;
1324 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1324, __PRETTY_FUNCTION__))
;
1325
1326 // Do the replacement; this basically invalidates 'init'.
1327 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1328, __PRETTY_FUNCTION__))
1328 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1328, __PRETTY_FUNCTION__))
;
1329
1330 // We're iterating over a hashtable, so this would be a source of
1331 // non-determinism in compiler output *except* that we're just
1332 // messing around with llvm::Constant structures, which never itself
1333 // does anything that should be visible in compiler output.
1334 for (auto &entry : Locations) {
1335 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1335, __PRETTY_FUNCTION__))
;
1336 entry.first->replaceAllUsesWith(entry.second);
1337 entry.first->eraseFromParent();
1338 }
1339 }
1340
1341 private:
1342 void findLocations(llvm::Constant *init) {
1343 // Recurse into aggregates.
1344 if (auto agg = dyn_cast<llvm::ConstantAggregate>(init)) {
1345 for (unsigned i = 0, e = agg->getNumOperands(); i != e; ++i) {
1346 Indices.push_back(i);
1347 IndexValues.push_back(nullptr);
1348
1349 findLocations(agg->getOperand(i));
1350
1351 IndexValues.pop_back();
1352 Indices.pop_back();
1353 }
1354 return;
1355 }
1356
1357 // Otherwise, check for registered constants.
1358 while (true) {
1359 auto it = PlaceholderAddresses.find(init);
1360 if (it != PlaceholderAddresses.end()) {
1361 setLocation(it->second);
1362 break;
1363 }
1364
1365 // Look through bitcasts or other expressions.
1366 if (auto expr = dyn_cast<llvm::ConstantExpr>(init)) {
1367 init = expr->getOperand(0);
1368 } else {
1369 break;
1370 }
1371 }
1372 }
1373
1374 void setLocation(llvm::GlobalVariable *placeholder) {
1375 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1376, __PRETTY_FUNCTION__))
1376 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1376, __PRETTY_FUNCTION__))
;
1377
1378 // Lazily fill in IndexValues with the values from Indices.
1379 // We do this in reverse because we should always have a strict
1380 // prefix of indices from the start.
1381 assert(Indices.size() == IndexValues.size())((Indices.size() == IndexValues.size()) ? static_cast<void
> (0) : __assert_fail ("Indices.size() == IndexValues.size()"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1381, __PRETTY_FUNCTION__))
;
1382 for (size_t i = Indices.size() - 1; i != size_t(-1); --i) {
1383 if (IndexValues[i]) {
1384#ifndef NDEBUG
1385 for (size_t j = 0; j != i + 1; ++j) {
1386 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1389, __PRETTY_FUNCTION__))
1387 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1389, __PRETTY_FUNCTION__))
1388 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1389, __PRETTY_FUNCTION__))
1389 == 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1389, __PRETTY_FUNCTION__))
;
1390 }
1391#endif
1392 break;
1393 }
1394
1395 IndexValues[i] = llvm::ConstantInt::get(CGM.Int32Ty, Indices[i]);
1396 }
1397
1398 // Form a GEP and then bitcast to the placeholder type so that the
1399 // replacement will succeed.
1400 llvm::Constant *location =
1401 llvm::ConstantExpr::getInBoundsGetElementPtr(BaseValueTy,
1402 Base, IndexValues);
1403 location = llvm::ConstantExpr::getBitCast(location,
1404 placeholder->getType());
1405
1406 Locations.insert({placeholder, location});
1407 }
1408 };
1409}
1410
1411void ConstantEmitter::finalize(llvm::GlobalVariable *global) {
1412 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1413, __PRETTY_FUNCTION__))
1413 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1413, __PRETTY_FUNCTION__))
;
1414 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1414, __PRETTY_FUNCTION__))
;
1415 assert(global->getInitializer())((global->getInitializer()) ? static_cast<void> (0) :
__assert_fail ("global->getInitializer()", "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1415, __PRETTY_FUNCTION__))
;
1416
1417 // Note that we might also be Failed.
1418 Finalized = true;
1419
1420 if (!PlaceholderAddresses.empty()) {
1421 ReplacePlaceholders(CGM, global, PlaceholderAddresses)
1422 .replaceInInitializer(global->getInitializer());
1423 PlaceholderAddresses.clear(); // satisfy
1424 }
1425}
1426
1427ConstantEmitter::~ConstantEmitter() {
1428 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1429, __PRETTY_FUNCTION__))
1429 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1429, __PRETTY_FUNCTION__))
;
1430 assert(PlaceholderAddresses.empty() && "unhandled placeholders")((PlaceholderAddresses.empty() && "unhandled placeholders"
) ? static_cast<void> (0) : __assert_fail ("PlaceholderAddresses.empty() && \"unhandled placeholders\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1430, __PRETTY_FUNCTION__))
;
1431}
1432
1433static QualType getNonMemoryType(CodeGenModule &CGM, QualType type) {
1434 if (auto AT = type->getAs<AtomicType>()) {
1435 return CGM.getContext().getQualifiedType(AT->getValueType(),
1436 type.getQualifiers());
1437 }
1438 return type;
1439}
1440
1441llvm::Constant *ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &D) {
1442 // Make a quick check if variable can be default NULL initialized
1443 // and avoid going through rest of code which may do, for c++11,
1444 // initialization of memory to all NULLs.
1445 if (!D.hasLocalStorage()) {
1446 QualType Ty = CGM.getContext().getBaseElementType(D.getType());
1447 if (Ty->isRecordType())
1448 if (const CXXConstructExpr *E =
1449 dyn_cast_or_null<CXXConstructExpr>(D.getInit())) {
1450 const CXXConstructorDecl *CD = E->getConstructor();
1451 if (CD->isTrivial() && CD->isDefaultConstructor())
1452 return CGM.EmitNullConstant(D.getType());
1453 }
1454 }
1455
1456 QualType destType = D.getType();
1457
1458 // Try to emit the initializer. Note that this can allow some things that
1459 // are not allowed by tryEmitPrivateForMemory alone.
1460 if (auto value = D.evaluateValue()) {
1461 return tryEmitPrivateForMemory(*value, destType);
1462 }
1463
1464 // FIXME: Implement C++11 [basic.start.init]p2: if the initializer of a
1465 // reference is a constant expression, and the reference binds to a temporary,
1466 // then constant initialization is performed. ConstExprEmitter will
1467 // incorrectly emit a prvalue constant in this case, and the calling code
1468 // interprets that as the (pointer) value of the reference, rather than the
1469 // desired value of the referee.
1470 if (destType->isReferenceType())
1471 return nullptr;
1472
1473 const Expr *E = D.getInit();
1474 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1474, __PRETTY_FUNCTION__))
;
1475
1476 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1477 auto C =
1478 ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), nonMemoryDestType);
1479 return (C ? emitForMemory(C, destType) : nullptr);
1480}
1481
1482llvm::Constant *
1483ConstantEmitter::tryEmitAbstractForMemory(const Expr *E, QualType destType) {
1484 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1485 auto C = tryEmitAbstract(E, nonMemoryDestType);
1486 return (C ? emitForMemory(C, destType) : nullptr);
1487}
1488
1489llvm::Constant *
1490ConstantEmitter::tryEmitAbstractForMemory(const APValue &value,
1491 QualType destType) {
1492 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1493 auto C = tryEmitAbstract(value, nonMemoryDestType);
1494 return (C ? emitForMemory(C, destType) : nullptr);
1495}
1496
1497llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const Expr *E,
1498 QualType destType) {
1499 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1500 llvm::Constant *C = tryEmitPrivate(E, nonMemoryDestType);
1501 return (C ? emitForMemory(C, destType) : nullptr);
1502}
1503
1504llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const APValue &value,
1505 QualType destType) {
1506 auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1507 auto C = tryEmitPrivate(value, nonMemoryDestType);
1508 return (C ? emitForMemory(C, destType) : nullptr);
1509}
1510
1511llvm::Constant *ConstantEmitter::emitForMemory(CodeGenModule &CGM,
1512 llvm::Constant *C,
1513 QualType destType) {
1514 // For an _Atomic-qualified constant, we may need to add tail padding.
1515 if (auto AT = destType->getAs<AtomicType>()) {
1516 QualType destValueType = AT->getValueType();
1517 C = emitForMemory(CGM, C, destValueType);
1518
1519 uint64_t innerSize = CGM.getContext().getTypeSize(destValueType);
1520 uint64_t outerSize = CGM.getContext().getTypeSize(destType);
1521 if (innerSize == outerSize)
1522 return C;
1523
1524 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1524, __PRETTY_FUNCTION__))
;
1525 llvm::Constant *elts[] = {
1526 C,
1527 llvm::ConstantAggregateZero::get(
1528 llvm::ArrayType::get(CGM.Int8Ty, (outerSize - innerSize) / 8))
1529 };
1530 return llvm::ConstantStruct::getAnon(elts);
1531 }
1532
1533 // Zero-extend bool.
1534 if (C->getType()->isIntegerTy(1)) {
1535 llvm::Type *boolTy = CGM.getTypes().ConvertTypeForMem(destType);
1536 return llvm::ConstantExpr::getZExt(C, boolTy);
1537 }
1538
1539 return C;
1540}
1541
1542llvm::Constant *ConstantEmitter::tryEmitPrivate(const Expr *E,
1543 QualType destType) {
1544 Expr::EvalResult Result;
1545
1546 bool Success = false;
1547
1548 if (destType->isReferenceType())
1549 Success = E->EvaluateAsLValue(Result, CGM.getContext());
1550 else
1551 Success = E->EvaluateAsRValue(Result, CGM.getContext());
1552
1553 llvm::Constant *C;
1554 if (Success && !Result.HasSideEffects)
1555 C = tryEmitPrivate(Result.Val, destType);
1556 else
1557 C = ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), destType);
1558
1559 return C;
1560}
1561
1562llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) {
1563 return getTargetCodeGenInfo().getNullPointer(*this, T, QT);
1564}
1565
1566namespace {
1567/// A struct which can be used to peephole certain kinds of finalization
1568/// that normally happen during l-value emission.
1569struct ConstantLValue {
1570 llvm::Constant *Value;
1571 bool HasOffsetApplied;
1572
1573 /*implicit*/ ConstantLValue(llvm::Constant *value,
1574 bool hasOffsetApplied = false)
1575 : Value(value), HasOffsetApplied(false) {}
1576
1577 /*implicit*/ ConstantLValue(ConstantAddress address)
1578 : ConstantLValue(address.getPointer()) {}
1579};
1580
1581/// A helper class for emitting constant l-values.
1582class ConstantLValueEmitter : public ConstStmtVisitor<ConstantLValueEmitter,
1583 ConstantLValue> {
1584 CodeGenModule &CGM;
1585 ConstantEmitter &Emitter;
1586 const APValue &Value;
1587 QualType DestType;
1588
1589 // Befriend StmtVisitorBase so that we don't have to expose Visit*.
1590 friend StmtVisitorBase;
1591
1592public:
1593 ConstantLValueEmitter(ConstantEmitter &emitter, const APValue &value,
1594 QualType destType)
1595 : CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType) {}
1596
1597 llvm::Constant *tryEmit();
1598
1599private:
1600 llvm::Constant *tryEmitAbsolute(llvm::Type *destTy);
1601 ConstantLValue tryEmitBase(const APValue::LValueBase &base);
1602
1603 ConstantLValue VisitStmt(const Stmt *S) { return nullptr; }
1604 ConstantLValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
1605 ConstantLValue VisitStringLiteral(const StringLiteral *E);
1606 ConstantLValue VisitObjCEncodeExpr(const ObjCEncodeExpr *E);
1607 ConstantLValue VisitObjCStringLiteral(const ObjCStringLiteral *E);
1608 ConstantLValue VisitPredefinedExpr(const PredefinedExpr *E);
1609 ConstantLValue VisitAddrLabelExpr(const AddrLabelExpr *E);
1610 ConstantLValue VisitCallExpr(const CallExpr *E);
1611 ConstantLValue VisitBlockExpr(const BlockExpr *E);
1612 ConstantLValue VisitCXXTypeidExpr(const CXXTypeidExpr *E);
1613 ConstantLValue VisitCXXUuidofExpr(const CXXUuidofExpr *E);
1614 ConstantLValue VisitMaterializeTemporaryExpr(
1615 const MaterializeTemporaryExpr *E);
1616
1617 bool hasNonZeroOffset() const {
1618 return !Value.getLValueOffset().isZero();
1619 }
1620
1621 /// Return the value offset.
1622 llvm::Constant *getOffset() {
1623 return llvm::ConstantInt::get(CGM.Int64Ty,
1624 Value.getLValueOffset().getQuantity());
1625 }
1626
1627 /// Apply the value offset to the given constant.
1628 llvm::Constant *applyOffset(llvm::Constant *C) {
1629 if (!hasNonZeroOffset())
1630 return C;
1631
1632 llvm::Type *origPtrTy = C->getType();
1633 unsigned AS = origPtrTy->getPointerAddressSpace();
1634 llvm::Type *charPtrTy = CGM.Int8Ty->getPointerTo(AS);
1635 C = llvm::ConstantExpr::getBitCast(C, charPtrTy);
1636 C = llvm::ConstantExpr::getGetElementPtr(CGM.Int8Ty, C, getOffset());
1637 C = llvm::ConstantExpr::getPointerCast(C, origPtrTy);
1638 return C;
1639 }
1640};
1641
1642}
1643
1644llvm::Constant *ConstantLValueEmitter::tryEmit() {
1645 const APValue::LValueBase &base = Value.getLValueBase();
1646
1647 // Certain special array initializers are represented in APValue
1648 // as l-values referring to the base expression which generates the
1649 // array. This happens with e.g. string literals. These should
1650 // probably just get their own representation kind in APValue.
1651 if (DestType->isArrayType()) {
1652 assert(!hasNonZeroOffset() && "offset on array initializer")((!hasNonZeroOffset() && "offset on array initializer"
) ? static_cast<void> (0) : __assert_fail ("!hasNonZeroOffset() && \"offset on array initializer\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1652, __PRETTY_FUNCTION__))
;
1653 auto expr = const_cast<Expr*>(base.get<const Expr*>());
1654 return ConstExprEmitter(Emitter).Visit(expr, DestType);
1655 }
1656
1657 // Otherwise, the destination type should be a pointer or reference
1658 // type, but it might also be a cast thereof.
1659 //
1660 // FIXME: the chain of casts required should be reflected in the APValue.
1661 // We need this in order to correctly handle things like a ptrtoint of a
1662 // non-zero null pointer and addrspace casts that aren't trivially
1663 // represented in LLVM IR.
1664 auto destTy = CGM.getTypes().ConvertTypeForMem(DestType);
1665 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1665, __PRETTY_FUNCTION__))
;
1666
1667 // If there's no base at all, this is a null or absolute pointer,
1668 // possibly cast back to an integer type.
1669 if (!base) {
1670 return tryEmitAbsolute(destTy);
1671 }
1672
1673 // Otherwise, try to emit the base.
1674 ConstantLValue result = tryEmitBase(base);
1675
1676 // If that failed, we're done.
1677 llvm::Constant *value = result.Value;
1678 if (!value) return nullptr;
1679
1680 // Apply the offset if necessary and not already done.
1681 if (!result.HasOffsetApplied) {
1682 value = applyOffset(value);
1683 }
1684
1685 // Convert to the appropriate type; this could be an lvalue for
1686 // an integer. FIXME: performAddrSpaceCast
1687 if (isa<llvm::PointerType>(destTy))
1688 return llvm::ConstantExpr::getPointerCast(value, destTy);
1689
1690 return llvm::ConstantExpr::getPtrToInt(value, destTy);
1691}
1692
1693/// Try to emit an absolute l-value, such as a null pointer or an integer
1694/// bitcast to pointer type.
1695llvm::Constant *
1696ConstantLValueEmitter::tryEmitAbsolute(llvm::Type *destTy) {
1697 auto offset = getOffset();
1698
1699 // If we're producing a pointer, this is easy.
1700 if (auto destPtrTy = cast<llvm::PointerType>(destTy)) {
1701 if (Value.isNullPointer()) {
1702 // FIXME: integer offsets from non-zero null pointers.
1703 return CGM.getNullPointer(destPtrTy, DestType);
1704 }
1705
1706 // Convert the integer to a pointer-sized integer before converting it
1707 // to a pointer.
1708 // FIXME: signedness depends on the original integer type.
1709 auto intptrTy = CGM.getDataLayout().getIntPtrType(destPtrTy);
1710 llvm::Constant *C = offset;
Value stored to 'C' during its initialization is never read
1711 C = llvm::ConstantExpr::getIntegerCast(getOffset(), intptrTy,
1712 /*isSigned*/ false);
1713 C = llvm::ConstantExpr::getIntToPtr(C, destPtrTy);
1714 return C;
1715 }
1716
1717 // Otherwise, we're basically returning an integer constant.
1718
1719 // FIXME: this does the wrong thing with ptrtoint of a null pointer,
1720 // but since we don't know the original pointer type, there's not much
1721 // we can do about it.
1722
1723 auto C = getOffset();
1724 C = llvm::ConstantExpr::getIntegerCast(C, destTy, /*isSigned*/ false);
1725 return C;
1726}
1727
1728ConstantLValue
1729ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) {
1730 // Handle values.
1731 if (const ValueDecl *D = base.dyn_cast<const ValueDecl*>()) {
1732 if (D->hasAttr<WeakRefAttr>())
1733 return CGM.GetWeakRefReference(D).getPointer();
1734
1735 if (auto FD = dyn_cast<FunctionDecl>(D))
1736 return CGM.GetAddrOfFunction(FD);
1737
1738 if (auto VD = dyn_cast<VarDecl>(D)) {
1739 // We can never refer to a variable with local storage.
1740 if (!VD->hasLocalStorage()) {
1741 if (VD->isFileVarDecl() || VD->hasExternalStorage())
1742 return CGM.GetAddrOfGlobalVar(VD);
1743
1744 if (VD->isLocalVarDecl()) {
1745 return CGM.getOrCreateStaticVarDecl(
1746 *VD, CGM.getLLVMLinkageVarDefinition(VD, /*isConstant=*/false));
1747 }
1748 }
1749 }
1750
1751 return nullptr;
1752 }
1753
1754 // Otherwise, it must be an expression.
1755 return Visit(base.get<const Expr*>());
1756}
1757
1758ConstantLValue
1759ConstantLValueEmitter::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
1760 return tryEmitGlobalCompoundLiteral(CGM, Emitter.CGF, E);
1761}
1762
1763ConstantLValue
1764ConstantLValueEmitter::VisitStringLiteral(const StringLiteral *E) {
1765 return CGM.GetAddrOfConstantStringFromLiteral(E);
1766}
1767
1768ConstantLValue
1769ConstantLValueEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
1770 return CGM.GetAddrOfConstantStringFromObjCEncode(E);
1771}
1772
1773ConstantLValue
1774ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) {
1775 auto C = CGM.getObjCRuntime().GenerateConstantString(E->getString());
1776 return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(E->getType()));
1777}
1778
1779ConstantLValue
1780ConstantLValueEmitter::VisitPredefinedExpr(const PredefinedExpr *E) {
1781 if (auto CGF = Emitter.CGF) {
1782 LValue Res = CGF->EmitPredefinedLValue(E);
1783 return cast<ConstantAddress>(Res.getAddress());
1784 }
1785
1786 auto kind = E->getIdentKind();
1787 if (kind == PredefinedExpr::PrettyFunction) {
1788 return CGM.GetAddrOfConstantCString("top level", ".tmp");
1789 }
1790
1791 return CGM.GetAddrOfConstantCString("", ".tmp");
1792}
1793
1794ConstantLValue
1795ConstantLValueEmitter::VisitAddrLabelExpr(const AddrLabelExpr *E) {
1796 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1796, __PRETTY_FUNCTION__))
;
1797 llvm::Constant *Ptr = Emitter.CGF->GetAddrOfLabel(E->getLabel());
1798 Ptr = llvm::ConstantExpr::getBitCast(Ptr,
1799 CGM.getTypes().ConvertType(E->getType()));
1800 return Ptr;
1801}
1802
1803ConstantLValue
1804ConstantLValueEmitter::VisitCallExpr(const CallExpr *E) {
1805 unsigned builtin = E->getBuiltinCallee();
1806 if (builtin != Builtin::BI__builtin___CFStringMakeConstantString &&
1807 builtin != Builtin::BI__builtin___NSStringMakeConstantString)
1808 return nullptr;
1809
1810 auto literal = cast<StringLiteral>(E->getArg(0)->IgnoreParenCasts());
1811 if (builtin == Builtin::BI__builtin___NSStringMakeConstantString) {
1812 return CGM.getObjCRuntime().GenerateConstantString(literal);
1813 } else {
1814 // FIXME: need to deal with UCN conversion issues.
1815 return CGM.GetAddrOfConstantCFString(literal);
1816 }
1817}
1818
1819ConstantLValue
1820ConstantLValueEmitter::VisitBlockExpr(const BlockExpr *E) {
1821 StringRef functionName;
1822 if (auto CGF = Emitter.CGF)
1823 functionName = CGF->CurFn->getName();
1824 else
1825 functionName = "global";
1826
1827 return CGM.GetAddrOfGlobalBlock(E, functionName);
1828}
1829
1830ConstantLValue
1831ConstantLValueEmitter::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
1832 QualType T;
1833 if (E->isTypeOperand())
1834 T = E->getTypeOperand(CGM.getContext());
1835 else
1836 T = E->getExprOperand()->getType();
1837 return CGM.GetAddrOfRTTIDescriptor(T);
1838}
1839
1840ConstantLValue
1841ConstantLValueEmitter::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
1842 return CGM.GetAddrOfUuidDescriptor(E);
1843}
1844
1845ConstantLValue
1846ConstantLValueEmitter::VisitMaterializeTemporaryExpr(
1847 const MaterializeTemporaryExpr *E) {
1848 assert(E->getStorageDuration() == SD_Static)((E->getStorageDuration() == SD_Static) ? static_cast<void
> (0) : __assert_fail ("E->getStorageDuration() == SD_Static"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1848, __PRETTY_FUNCTION__))
;
1849 SmallVector<const Expr *, 2> CommaLHSs;
1850 SmallVector<SubobjectAdjustment, 2> Adjustments;
1851 const Expr *Inner = E->GetTemporaryExpr()
1852 ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
1853 return CGM.GetAddrOfGlobalTemporary(E, Inner);
1854}
1855
1856llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
1857 QualType DestType) {
1858 switch (Value.getKind()) {
1859 case APValue::Uninitialized:
1860 llvm_unreachable("Constant expressions should be initialized.")::llvm::llvm_unreachable_internal("Constant expressions should be initialized."
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1860)
;
1861 case APValue::LValue:
1862 return ConstantLValueEmitter(*this, Value, DestType).tryEmit();
1863 case APValue::Int:
1864 return llvm::ConstantInt::get(CGM.getLLVMContext(), Value.getInt());
1865 case APValue::ComplexInt: {
1866 llvm::Constant *Complex[2];
1867
1868 Complex[0] = llvm::ConstantInt::get(CGM.getLLVMContext(),
1869 Value.getComplexIntReal());
1870 Complex[1] = llvm::ConstantInt::get(CGM.getLLVMContext(),
1871 Value.getComplexIntImag());
1872
1873 // FIXME: the target may want to specify that this is packed.
1874 llvm::StructType *STy =
1875 llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
1876 return llvm::ConstantStruct::get(STy, Complex);
1877 }
1878 case APValue::Float: {
1879 const llvm::APFloat &Init = Value.getFloat();
1880 if (&Init.getSemantics() == &llvm::APFloat::IEEEhalf() &&
1881 !CGM.getContext().getLangOpts().NativeHalfType &&
1882 CGM.getContext().getTargetInfo().useFP16ConversionIntrinsics())
1883 return llvm::ConstantInt::get(CGM.getLLVMContext(),
1884 Init.bitcastToAPInt());
1885 else
1886 return llvm::ConstantFP::get(CGM.getLLVMContext(), Init);
1887 }
1888 case APValue::ComplexFloat: {
1889 llvm::Constant *Complex[2];
1890
1891 Complex[0] = llvm::ConstantFP::get(CGM.getLLVMContext(),
1892 Value.getComplexFloatReal());
1893 Complex[1] = llvm::ConstantFP::get(CGM.getLLVMContext(),
1894 Value.getComplexFloatImag());
1895
1896 // FIXME: the target may want to specify that this is packed.
1897 llvm::StructType *STy =
1898 llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
1899 return llvm::ConstantStruct::get(STy, Complex);
1900 }
1901 case APValue::Vector: {
1902 unsigned NumElts = Value.getVectorLength();
1903 SmallVector<llvm::Constant *, 4> Inits(NumElts);
1904
1905 for (unsigned I = 0; I != NumElts; ++I) {
1906 const APValue &Elt = Value.getVectorElt(I);
1907 if (Elt.isInt())
1908 Inits[I] = llvm::ConstantInt::get(CGM.getLLVMContext(), Elt.getInt());
1909 else if (Elt.isFloat())
1910 Inits[I] = llvm::ConstantFP::get(CGM.getLLVMContext(), Elt.getFloat());
1911 else
1912 llvm_unreachable("unsupported vector element type")::llvm::llvm_unreachable_internal("unsupported vector element type"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1912)
;
1913 }
1914 return llvm::ConstantVector::get(Inits);
1915 }
1916 case APValue::AddrLabelDiff: {
1917 const AddrLabelExpr *LHSExpr = Value.getAddrLabelDiffLHS();
1918 const AddrLabelExpr *RHSExpr = Value.getAddrLabelDiffRHS();
1919 llvm::Constant *LHS = tryEmitPrivate(LHSExpr, LHSExpr->getType());
1920 llvm::Constant *RHS = tryEmitPrivate(RHSExpr, RHSExpr->getType());
1921 if (!LHS || !RHS) return nullptr;
1922
1923 // Compute difference
1924 llvm::Type *ResultType = CGM.getTypes().ConvertType(DestType);
1925 LHS = llvm::ConstantExpr::getPtrToInt(LHS, CGM.IntPtrTy);
1926 RHS = llvm::ConstantExpr::getPtrToInt(RHS, CGM.IntPtrTy);
1927 llvm::Constant *AddrLabelDiff = llvm::ConstantExpr::getSub(LHS, RHS);
1928
1929 // LLVM is a bit sensitive about the exact format of the
1930 // address-of-label difference; make sure to truncate after
1931 // the subtraction.
1932 return llvm::ConstantExpr::getTruncOrBitCast(AddrLabelDiff, ResultType);
1933 }
1934 case APValue::Struct:
1935 case APValue::Union:
1936 return ConstStructBuilder::BuildStruct(*this, Value, DestType);
1937 case APValue::Array: {
1938 const ConstantArrayType *CAT =
1939 CGM.getContext().getAsConstantArrayType(DestType);
1940 unsigned NumElements = Value.getArraySize();
1941 unsigned NumInitElts = Value.getArrayInitializedElts();
1942
1943 // Emit array filler, if there is one.
1944 llvm::Constant *Filler = nullptr;
1945 if (Value.hasArrayFiller()) {
1946 Filler = tryEmitAbstractForMemory(Value.getArrayFiller(),
1947 CAT->getElementType());
1948 if (!Filler)
1949 return nullptr;
1950 }
1951
1952 // Emit initializer elements.
1953 SmallVector<llvm::Constant*, 16> Elts;
1954 if (Filler && Filler->isNullValue())
1955 Elts.reserve(NumInitElts + 1);
1956 else
1957 Elts.reserve(NumElements);
1958
1959 llvm::Type *CommonElementType = nullptr;
1960 for (unsigned I = 0; I < NumInitElts; ++I) {
1961 llvm::Constant *C = tryEmitPrivateForMemory(
1962 Value.getArrayInitializedElt(I), CAT->getElementType());
1963 if (!C) return nullptr;
1964
1965 if (I == 0)
1966 CommonElementType = C->getType();
1967 else if (C->getType() != CommonElementType)
1968 CommonElementType = nullptr;
1969 Elts.push_back(C);
1970 }
1971
1972 // This means that the array type is probably "IncompleteType" or some
1973 // type that is not ConstantArray.
1974 if (CAT == nullptr && CommonElementType == nullptr && !NumInitElts) {
1975 const ArrayType *AT = CGM.getContext().getAsArrayType(DestType);
1976 CommonElementType = CGM.getTypes().ConvertType(AT->getElementType());
1977 llvm::ArrayType *AType = llvm::ArrayType::get(CommonElementType,
1978 NumElements);
1979 return llvm::ConstantAggregateZero::get(AType);
1980 }
1981
1982 return EmitArrayConstant(CGM, CAT, CommonElementType, NumElements, Elts,
1983 Filler);
1984 }
1985 case APValue::MemberPointer:
1986 return CGM.getCXXABI().EmitMemberPointer(Value, DestType);
1987 }
1988 llvm_unreachable("Unknown APValue kind")::llvm::llvm_unreachable_internal("Unknown APValue kind", "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 1988)
;
1989}
1990
1991llvm::GlobalVariable *CodeGenModule::getAddrOfConstantCompoundLiteralIfEmitted(
1992 const CompoundLiteralExpr *E) {
1993 return EmittedCompoundLiterals.lookup(E);
1994}
1995
1996void CodeGenModule::setAddrOfConstantCompoundLiteral(
1997 const CompoundLiteralExpr *CLE, llvm::GlobalVariable *GV) {
1998 bool Ok = EmittedCompoundLiterals.insert(std::make_pair(CLE, GV)).second;
1999 (void)Ok;
2000 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 2000, __PRETTY_FUNCTION__))
;
2001}
2002
2003ConstantAddress
2004CodeGenModule::GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr *E) {
2005 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 2005, __PRETTY_FUNCTION__))
;
2006 return tryEmitGlobalCompoundLiteral(*this, nullptr, E);
2007}
2008
2009llvm::Constant *
2010CodeGenModule::getMemberPointerConstant(const UnaryOperator *uo) {
2011 // Member pointer constants always have a very particular form.
2012 const MemberPointerType *type = cast<MemberPointerType>(uo->getType());
2013 const ValueDecl *decl = cast<DeclRefExpr>(uo->getSubExpr())->getDecl();
2014
2015 // A member function pointer.
2016 if (const CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(decl))
2017 return getCXXABI().EmitMemberFunctionPointer(method);
2018
2019 // Otherwise, a member data pointer.
2020 uint64_t fieldOffset = getContext().getFieldOffset(decl);
2021 CharUnits chars = getContext().toCharUnitsFromBits((int64_t) fieldOffset);
2022 return getCXXABI().EmitMemberDataPointer(type, chars);
2023}
2024
2025static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
2026 llvm::Type *baseType,
2027 const CXXRecordDecl *base);
2028
2029static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
2030 const RecordDecl *record,
2031 bool asCompleteObject) {
2032 const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record);
2033 llvm::StructType *structure =
2034 (asCompleteObject ? layout.getLLVMType()
2035 : layout.getBaseSubobjectLLVMType());
2036
2037 unsigned numElements = structure->getNumElements();
2038 std::vector<llvm::Constant *> elements(numElements);
2039
2040 auto CXXR = dyn_cast<CXXRecordDecl>(record);
2041 // Fill in all the bases.
2042 if (CXXR) {
2043 for (const auto &I : CXXR->bases()) {
2044 if (I.isVirtual()) {
2045 // Ignore virtual bases; if we're laying out for a complete
2046 // object, we'll lay these out later.
2047 continue;
2048 }
2049
2050 const CXXRecordDecl *base =
2051 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
2052
2053 // Ignore empty bases.
2054 if (base->isEmpty() ||
2055 CGM.getContext().getASTRecordLayout(base).getNonVirtualSize()
2056 .isZero())
2057 continue;
2058
2059 unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
2060 llvm::Type *baseType = structure->getElementType(fieldIndex);
2061 elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
2062 }
2063 }
2064
2065 // Fill in all the fields.
2066 for (const auto *Field : record->fields()) {
2067 // Fill in non-bitfields. (Bitfields always use a zero pattern, which we
2068 // will fill in later.)
2069 if (!Field->isBitField()) {
2070 unsigned fieldIndex = layout.getLLVMFieldNo(Field);
2071 elements[fieldIndex] = CGM.EmitNullConstant(Field->getType());
2072 }
2073
2074 // For unions, stop after the first named field.
2075 if (record->isUnion()) {
2076 if (Field->getIdentifier())
2077 break;
2078 if (const auto *FieldRD = Field->getType()->getAsRecordDecl())
2079 if (FieldRD->findFirstNamedDataMember())
2080 break;
2081 }
2082 }
2083
2084 // Fill in the virtual bases, if we're working with the complete object.
2085 if (CXXR && asCompleteObject) {
2086 for (const auto &I : CXXR->vbases()) {
2087 const CXXRecordDecl *base =
2088 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
2089
2090 // Ignore empty bases.
2091 if (base->isEmpty())
2092 continue;
2093
2094 unsigned fieldIndex = layout.getVirtualBaseIndex(base);
2095
2096 // We might have already laid this field out.
2097 if (elements[fieldIndex]) continue;
2098
2099 llvm::Type *baseType = structure->getElementType(fieldIndex);
2100 elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
2101 }
2102 }
2103
2104 // Now go through all other fields and zero them out.
2105 for (unsigned i = 0; i != numElements; ++i) {
2106 if (!elements[i])
2107 elements[i] = llvm::Constant::getNullValue(structure->getElementType(i));
2108 }
2109
2110 return llvm::ConstantStruct::get(structure, elements);
2111}
2112
2113/// Emit the null constant for a base subobject.
2114static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
2115 llvm::Type *baseType,
2116 const CXXRecordDecl *base) {
2117 const CGRecordLayout &baseLayout = CGM.getTypes().getCGRecordLayout(base);
2118
2119 // Just zero out bases that don't have any pointer to data members.
2120 if (baseLayout.isZeroInitializableAsBase())
2121 return llvm::Constant::getNullValue(baseType);
2122
2123 // Otherwise, we can just use its null constant.
2124 return EmitNullConstant(CGM, base, /*asCompleteObject=*/false);
2125}
2126
2127llvm::Constant *ConstantEmitter::emitNullForMemory(CodeGenModule &CGM,
2128 QualType T) {
2129 return emitForMemory(CGM, CGM.EmitNullConstant(T), T);
2130}
2131
2132llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
2133 if (T->getAs<PointerType>())
2134 return getNullPointer(
2135 cast<llvm::PointerType>(getTypes().ConvertTypeForMem(T)), T);
2136
2137 if (getTypes().isZeroInitializable(T))
2138 return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
2139
2140 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) {
2141 llvm::ArrayType *ATy =
2142 cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T));
2143
2144 QualType ElementTy = CAT->getElementType();
2145
2146 llvm::Constant *Element =
2147 ConstantEmitter::emitNullForMemory(*this, ElementTy);
2148 unsigned NumElements = CAT->getSize().getZExtValue();
2149 SmallVector<llvm::Constant *, 8> Array(NumElements, Element);
2150 return llvm::ConstantArray::get(ATy, Array);
2151 }
2152
2153 if (const RecordType *RT = T->getAs<RecordType>())
2154 return ::EmitNullConstant(*this, RT->getDecl(), /*complete object*/ true);
2155
2156 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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 2157, __PRETTY_FUNCTION__))
2157 "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-8~svn345461/tools/clang/lib/CodeGen/CGExprConstant.cpp"
, 2157, __PRETTY_FUNCTION__))
;
2158
2159 return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>());
2160}
2161
2162llvm::Constant *
2163CodeGenModule::EmitNullConstantForBase(const CXXRecordDecl *Record) {
2164 return ::EmitNullConstant(*this, Record, false);
2165}