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Anders Carlsson3b1d57b2008-01-26 01:36:00 +00001//===--- 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 "CodeGenModule.h"
John McCall4c40d982010-08-31 07:33:07 +000016#include "CGCXXABI.h"
Daniel Dunbaraf2f62c2008-08-13 00:59:25 +000017#include "CGObjCRuntime.h"
Daniel Dunbar2924ade2010-03-30 22:26:10 +000018#include "CGRecordLayout.h"
Chris Lattnerf6b24ea2008-10-06 05:59:01 +000019#include "clang/AST/APValue.h"
Daniel Dunbarde7fb842008-08-11 05:00:27 +000020#include "clang/AST/ASTContext.h"
Anders Carlsson4c98efd2009-07-24 15:20:52 +000021#include "clang/AST/RecordLayout.h"
Daniel Dunbarde7fb842008-08-11 05:00:27 +000022#include "clang/AST/StmtVisitor.h"
Chris Lattner1b63e4f2009-06-14 01:54:56 +000023#include "clang/Basic/Builtins.h"
Anders Carlsson3b1d57b2008-01-26 01:36:00 +000024#include "llvm/Constants.h"
25#include "llvm/Function.h"
26#include "llvm/GlobalVariable.h"
Eli Friedmana8234002008-05-30 10:24:46 +000027#include "llvm/Target/TargetData.h"
Anders Carlsson3b1d57b2008-01-26 01:36:00 +000028using namespace clang;
29using namespace CodeGen;
30
Chris Lattnereba3e5a2010-04-13 17:45:57 +000031//===----------------------------------------------------------------------===//
32// ConstStructBuilder
33//===----------------------------------------------------------------------===//
34
35namespace {
Benjamin Kramer85b45212009-11-28 19:45:26 +000036class ConstStructBuilder {
Anders Carlsson4c98efd2009-07-24 15:20:52 +000037 CodeGenModule &CGM;
38 CodeGenFunction *CGF;
39
Mike Stump1eb44332009-09-09 15:08:12 +000040 bool Packed;
Ken Dyckdc496392011-03-17 01:33:18 +000041 CharUnits NextFieldOffsetInChars;
Ken Dyck7d2f9d52011-03-18 01:26:17 +000042 CharUnits LLVMStructAlignment;
Anders Carlsson4c98efd2009-07-24 15:20:52 +000043 std::vector<llvm::Constant *> Elements;
Chris Lattnereba3e5a2010-04-13 17:45:57 +000044public:
45 static llvm::Constant *BuildStruct(CodeGenModule &CGM, CodeGenFunction *CGF,
46 InitListExpr *ILE);
47
48private:
Anders Carlsson4c98efd2009-07-24 15:20:52 +000049 ConstStructBuilder(CodeGenModule &CGM, CodeGenFunction *CGF)
Ken Dyckdc496392011-03-17 01:33:18 +000050 : CGM(CGM), CGF(CGF), Packed(false),
51 NextFieldOffsetInChars(CharUnits::Zero()),
Ken Dyck7d2f9d52011-03-18 01:26:17 +000052 LLVMStructAlignment(CharUnits::One()) { }
Anders Carlsson4c98efd2009-07-24 15:20:52 +000053
Mike Stump1eb44332009-09-09 15:08:12 +000054 bool AppendField(const FieldDecl *Field, uint64_t FieldOffset,
Chris Lattner8ce9e452010-04-13 18:16:19 +000055 llvm::Constant *InitExpr);
Mike Stump1eb44332009-09-09 15:08:12 +000056
Chris Lattner18806662010-07-05 17:04:23 +000057 void AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
58 llvm::ConstantInt *InitExpr);
Mike Stump1eb44332009-09-09 15:08:12 +000059
Ken Dyckc29ea8f2011-03-11 23:42:54 +000060 void AppendPadding(CharUnits PadSize);
Mike Stump1eb44332009-09-09 15:08:12 +000061
Ken Dyck106ca042011-03-11 02:17:05 +000062 void AppendTailPadding(CharUnits RecordSize);
Anders Carlssond24393b2009-07-27 01:23:51 +000063
Chris Lattnereba3e5a2010-04-13 17:45:57 +000064 void ConvertStructToPacked();
Anders Carlsson31f2f9c2009-10-02 02:15:20 +000065
Chris Lattnereba3e5a2010-04-13 17:45:57 +000066 bool Build(InitListExpr *ILE);
Mike Stump1eb44332009-09-09 15:08:12 +000067
Ken Dyck7d2f9d52011-03-18 01:26:17 +000068 CharUnits getAlignment(const llvm::Constant *C) const {
69 if (Packed) return CharUnits::One();
70 return CharUnits::fromQuantity(
71 CGM.getTargetData().getABITypeAlignment(C->getType()));
Anders Carlsson4c98efd2009-07-24 15:20:52 +000072 }
Mike Stump1eb44332009-09-09 15:08:12 +000073
Ken Dyck15c152e2011-03-18 01:12:13 +000074 CharUnits getSizeInChars(const llvm::Constant *C) const {
75 return CharUnits::fromQuantity(
76 CGM.getTargetData().getTypeAllocSize(C->getType()));
Anders Carlsson4c98efd2009-07-24 15:20:52 +000077 }
Anders Carlsson4c98efd2009-07-24 15:20:52 +000078};
Mike Stump1eb44332009-09-09 15:08:12 +000079
Chris Lattnereba3e5a2010-04-13 17:45:57 +000080bool ConstStructBuilder::
Chris Lattner8ce9e452010-04-13 18:16:19 +000081AppendField(const FieldDecl *Field, uint64_t FieldOffset,
82 llvm::Constant *InitCst) {
Ken Dyck6925cc42011-03-15 01:09:02 +000083
84 const ASTContext &Context = CGM.getContext();
85
86 CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
Chris Lattnereba3e5a2010-04-13 17:45:57 +000087
Ken Dyckdc496392011-03-17 01:33:18 +000088 assert(NextFieldOffsetInChars <= FieldOffsetInChars
Chris Lattnereba3e5a2010-04-13 17:45:57 +000089 && "Field offset mismatch!");
90
Ken Dyck7d2f9d52011-03-18 01:26:17 +000091 CharUnits FieldAlignment = getAlignment(InitCst);
Chris Lattnereba3e5a2010-04-13 17:45:57 +000092
93 // Round up the field offset to the alignment of the field type.
Ken Dyckdc496392011-03-17 01:33:18 +000094 CharUnits AlignedNextFieldOffsetInChars =
Ken Dyck7d2f9d52011-03-18 01:26:17 +000095 NextFieldOffsetInChars.RoundUpToAlignment(FieldAlignment);
Chris Lattnereba3e5a2010-04-13 17:45:57 +000096
Ken Dyckdc496392011-03-17 01:33:18 +000097 if (AlignedNextFieldOffsetInChars > FieldOffsetInChars) {
Chris Lattnereba3e5a2010-04-13 17:45:57 +000098 assert(!Packed && "Alignment is wrong even with a packed struct!");
99
100 // Convert the struct to a packed struct.
101 ConvertStructToPacked();
102
Ken Dyckdc496392011-03-17 01:33:18 +0000103 AlignedNextFieldOffsetInChars = NextFieldOffsetInChars;
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000104 }
105
Ken Dyckdc496392011-03-17 01:33:18 +0000106 if (AlignedNextFieldOffsetInChars < FieldOffsetInChars) {
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000107 // We need to append padding.
Ken Dyckc29ea8f2011-03-11 23:42:54 +0000108 AppendPadding(
Ken Dyckdc496392011-03-17 01:33:18 +0000109 FieldOffsetInChars - NextFieldOffsetInChars);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000110
Ken Dyckdc496392011-03-17 01:33:18 +0000111 assert(NextFieldOffsetInChars == FieldOffsetInChars &&
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000112 "Did not add enough padding!");
113
Ken Dyckdc496392011-03-17 01:33:18 +0000114 AlignedNextFieldOffsetInChars = NextFieldOffsetInChars;
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000115 }
116
117 // Add the field.
Chris Lattner8ce9e452010-04-13 18:16:19 +0000118 Elements.push_back(InitCst);
Ken Dyckdc496392011-03-17 01:33:18 +0000119 NextFieldOffsetInChars = AlignedNextFieldOffsetInChars +
Ken Dyck15c152e2011-03-18 01:12:13 +0000120 getSizeInChars(InitCst);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000121
122 if (Packed)
Ken Dyck7d2f9d52011-03-18 01:26:17 +0000123 assert(LLVMStructAlignment == CharUnits::One() &&
124 "Packed struct not byte-aligned!");
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000125 else
126 LLVMStructAlignment = std::max(LLVMStructAlignment, FieldAlignment);
127
128 return true;
129}
130
Chris Lattner18806662010-07-05 17:04:23 +0000131void ConstStructBuilder::AppendBitField(const FieldDecl *Field,
132 uint64_t FieldOffset,
133 llvm::ConstantInt *CI) {
Ken Dyckf004da42011-03-12 12:03:11 +0000134 const ASTContext &Context = CGM.getContext();
Ken Dyck4f318c02011-03-19 00:57:28 +0000135 const uint64_t CharWidth = Context.getCharWidth();
Ken Dyckdc496392011-03-17 01:33:18 +0000136 uint64_t NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
137 if (FieldOffset > NextFieldOffsetInBits) {
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000138 // We need to add padding.
Ken Dyckf004da42011-03-12 12:03:11 +0000139 CharUnits PadSize = Context.toCharUnitsFromBits(
Ken Dyckdc496392011-03-17 01:33:18 +0000140 llvm::RoundUpToAlignment(FieldOffset - NextFieldOffsetInBits,
Ken Dyckf004da42011-03-12 12:03:11 +0000141 Context.Target.getCharAlign()));
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000142
Ken Dyckf004da42011-03-12 12:03:11 +0000143 AppendPadding(PadSize);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000144 }
145
146 uint64_t FieldSize =
Ken Dyckf004da42011-03-12 12:03:11 +0000147 Field->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000148
149 llvm::APInt FieldValue = CI->getValue();
150
151 // Promote the size of FieldValue if necessary
152 // FIXME: This should never occur, but currently it can because initializer
153 // constants are cast to bool, and because clang is not enforcing bitfield
154 // width limits.
155 if (FieldSize > FieldValue.getBitWidth())
Jay Foad9f71a8f2010-12-07 08:25:34 +0000156 FieldValue = FieldValue.zext(FieldSize);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000157
158 // Truncate the size of FieldValue to the bit field size.
159 if (FieldSize < FieldValue.getBitWidth())
Jay Foad9f71a8f2010-12-07 08:25:34 +0000160 FieldValue = FieldValue.trunc(FieldSize);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000161
Ken Dyckdc496392011-03-17 01:33:18 +0000162 NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
163 if (FieldOffset < NextFieldOffsetInBits) {
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000164 // Either part of the field or the entire field can go into the previous
165 // byte.
166 assert(!Elements.empty() && "Elements can't be empty!");
167
Ken Dyckdc496392011-03-17 01:33:18 +0000168 unsigned BitsInPreviousByte = NextFieldOffsetInBits - FieldOffset;
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000169
170 bool FitsCompletelyInPreviousByte =
171 BitsInPreviousByte >= FieldValue.getBitWidth();
172
173 llvm::APInt Tmp = FieldValue;
174
175 if (!FitsCompletelyInPreviousByte) {
176 unsigned NewFieldWidth = FieldSize - BitsInPreviousByte;
177
178 if (CGM.getTargetData().isBigEndian()) {
179 Tmp = Tmp.lshr(NewFieldWidth);
Jay Foad9f71a8f2010-12-07 08:25:34 +0000180 Tmp = Tmp.trunc(BitsInPreviousByte);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000181
182 // We want the remaining high bits.
Jay Foad9f71a8f2010-12-07 08:25:34 +0000183 FieldValue = FieldValue.trunc(NewFieldWidth);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000184 } else {
Jay Foad9f71a8f2010-12-07 08:25:34 +0000185 Tmp = Tmp.trunc(BitsInPreviousByte);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000186
187 // We want the remaining low bits.
188 FieldValue = FieldValue.lshr(BitsInPreviousByte);
Jay Foad9f71a8f2010-12-07 08:25:34 +0000189 FieldValue = FieldValue.trunc(NewFieldWidth);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000190 }
191 }
192
Ken Dyck4f318c02011-03-19 00:57:28 +0000193 Tmp = Tmp.zext(CharWidth);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000194 if (CGM.getTargetData().isBigEndian()) {
195 if (FitsCompletelyInPreviousByte)
196 Tmp = Tmp.shl(BitsInPreviousByte - FieldValue.getBitWidth());
197 } else {
Ken Dyck4f318c02011-03-19 00:57:28 +0000198 Tmp = Tmp.shl(CharWidth - BitsInPreviousByte);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000199 }
200
Chris Lattner2bc00252010-07-05 18:03:30 +0000201 // 'or' in the bits that go into the previous byte.
202 llvm::Value *LastElt = Elements.back();
203 if (llvm::ConstantInt *Val = dyn_cast<llvm::ConstantInt>(LastElt))
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000204 Tmp |= Val->getValue();
Chris Lattner2bc00252010-07-05 18:03:30 +0000205 else {
206 assert(isa<llvm::UndefValue>(LastElt));
207 // If there is an undef field that we're adding to, it can either be a
208 // scalar undef (in which case, we just replace it with our field) or it
209 // is an array. If it is an array, we have to pull one byte off the
210 // array so that the other undef bytes stay around.
211 if (!isa<llvm::IntegerType>(LastElt->getType())) {
212 // The undef padding will be a multibyte array, create a new smaller
213 // padding and then an hole for our i8 to get plopped into.
214 assert(isa<llvm::ArrayType>(LastElt->getType()) &&
215 "Expected array padding of undefs");
216 const llvm::ArrayType *AT = cast<llvm::ArrayType>(LastElt->getType());
Ken Dyck4f318c02011-03-19 00:57:28 +0000217 assert(AT->getElementType()->isIntegerTy(CharWidth) &&
Chris Lattner2bc00252010-07-05 18:03:30 +0000218 AT->getNumElements() != 0 &&
219 "Expected non-empty array padding of undefs");
220
221 // Remove the padding array.
Ken Dyckdc496392011-03-17 01:33:18 +0000222 NextFieldOffsetInChars -= CharUnits::fromQuantity(AT->getNumElements());
Chris Lattner2bc00252010-07-05 18:03:30 +0000223 Elements.pop_back();
224
225 // Add the padding back in two chunks.
Ken Dyckc29ea8f2011-03-11 23:42:54 +0000226 AppendPadding(CharUnits::fromQuantity(AT->getNumElements()-1));
227 AppendPadding(CharUnits::One());
Chris Lattner2bc00252010-07-05 18:03:30 +0000228 assert(isa<llvm::UndefValue>(Elements.back()) &&
Ken Dyck4f318c02011-03-19 00:57:28 +0000229 Elements.back()->getType()->isIntegerTy(CharWidth) &&
Chris Lattner2bc00252010-07-05 18:03:30 +0000230 "Padding addition didn't work right");
231 }
232 }
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000233
234 Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp);
235
236 if (FitsCompletelyInPreviousByte)
Chris Lattner18806662010-07-05 17:04:23 +0000237 return;
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000238 }
239
Ken Dyck4f318c02011-03-19 00:57:28 +0000240 while (FieldValue.getBitWidth() > CharWidth) {
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000241 llvm::APInt Tmp;
242
243 if (CGM.getTargetData().isBigEndian()) {
244 // We want the high bits.
Ken Dyck4f318c02011-03-19 00:57:28 +0000245 Tmp =
246 FieldValue.lshr(FieldValue.getBitWidth() - CharWidth).trunc(CharWidth);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000247 } else {
248 // We want the low bits.
Ken Dyck4f318c02011-03-19 00:57:28 +0000249 Tmp = FieldValue.trunc(CharWidth);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000250
Ken Dyck4f318c02011-03-19 00:57:28 +0000251 FieldValue = FieldValue.lshr(CharWidth);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000252 }
253
254 Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp));
Ken Dyck199c1892011-03-19 01:28:06 +0000255 ++NextFieldOffsetInChars;
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000256
Ken Dyck4f318c02011-03-19 00:57:28 +0000257 FieldValue = FieldValue.trunc(FieldValue.getBitWidth() - CharWidth);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000258 }
259
260 assert(FieldValue.getBitWidth() > 0 &&
261 "Should have at least one bit left!");
Ken Dyck4f318c02011-03-19 00:57:28 +0000262 assert(FieldValue.getBitWidth() <= CharWidth &&
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000263 "Should not have more than a byte left!");
264
Ken Dyck4f318c02011-03-19 00:57:28 +0000265 if (FieldValue.getBitWidth() < CharWidth) {
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000266 if (CGM.getTargetData().isBigEndian()) {
267 unsigned BitWidth = FieldValue.getBitWidth();
268
Ken Dyck4f318c02011-03-19 00:57:28 +0000269 FieldValue = FieldValue.zext(CharWidth) << (CharWidth - BitWidth);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000270 } else
Ken Dyck4f318c02011-03-19 00:57:28 +0000271 FieldValue = FieldValue.zext(CharWidth);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000272 }
273
274 // Append the last element.
275 Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(),
276 FieldValue));
Ken Dyck199c1892011-03-19 01:28:06 +0000277 ++NextFieldOffsetInChars;
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000278}
279
Ken Dyckc29ea8f2011-03-11 23:42:54 +0000280void ConstStructBuilder::AppendPadding(CharUnits PadSize) {
281 if (PadSize.isZero())
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000282 return;
283
284 const llvm::Type *Ty = llvm::Type::getInt8Ty(CGM.getLLVMContext());
Ken Dyckc29ea8f2011-03-11 23:42:54 +0000285 if (PadSize > CharUnits::One())
286 Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity());
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000287
Nuno Lopescdb30b42010-04-16 20:56:35 +0000288 llvm::Constant *C = llvm::UndefValue::get(Ty);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000289 Elements.push_back(C);
Ken Dyck7d2f9d52011-03-18 01:26:17 +0000290 assert(getAlignment(C) == CharUnits::One() &&
291 "Padding must have 1 byte alignment!");
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000292
Ken Dyck15c152e2011-03-18 01:12:13 +0000293 NextFieldOffsetInChars += getSizeInChars(C);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000294}
295
Ken Dyck106ca042011-03-11 02:17:05 +0000296void ConstStructBuilder::AppendTailPadding(CharUnits RecordSize) {
Ken Dyckdc496392011-03-17 01:33:18 +0000297 assert(NextFieldOffsetInChars <= RecordSize &&
Ken Dyck106ca042011-03-11 02:17:05 +0000298 "Size mismatch!");
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000299
Ken Dyckdc496392011-03-17 01:33:18 +0000300 AppendPadding(RecordSize - NextFieldOffsetInChars);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000301}
302
303void ConstStructBuilder::ConvertStructToPacked() {
304 std::vector<llvm::Constant *> PackedElements;
Ken Dyck4a5c87e2011-03-18 00:55:06 +0000305 CharUnits ElementOffsetInChars = CharUnits::Zero();
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000306
307 for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
308 llvm::Constant *C = Elements[i];
309
Ken Dyck7d2f9d52011-03-18 01:26:17 +0000310 CharUnits ElementAlign = CharUnits::fromQuantity(
311 CGM.getTargetData().getABITypeAlignment(C->getType()));
Ken Dyck4a5c87e2011-03-18 00:55:06 +0000312 CharUnits AlignedElementOffsetInChars =
Ken Dyck7d2f9d52011-03-18 01:26:17 +0000313 ElementOffsetInChars.RoundUpToAlignment(ElementAlign);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000314
Ken Dyck4a5c87e2011-03-18 00:55:06 +0000315 if (AlignedElementOffsetInChars > ElementOffsetInChars) {
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000316 // We need some padding.
Ken Dyck4a5c87e2011-03-18 00:55:06 +0000317 CharUnits NumChars =
318 AlignedElementOffsetInChars - ElementOffsetInChars;
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000319
320 const llvm::Type *Ty = llvm::Type::getInt8Ty(CGM.getLLVMContext());
Ken Dyck4a5c87e2011-03-18 00:55:06 +0000321 if (NumChars > CharUnits::One())
322 Ty = llvm::ArrayType::get(Ty, NumChars.getQuantity());
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000323
Nuno Lopescdb30b42010-04-16 20:56:35 +0000324 llvm::Constant *Padding = llvm::UndefValue::get(Ty);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000325 PackedElements.push_back(Padding);
Ken Dyck15c152e2011-03-18 01:12:13 +0000326 ElementOffsetInChars += getSizeInChars(Padding);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000327 }
328
329 PackedElements.push_back(C);
Ken Dyck15c152e2011-03-18 01:12:13 +0000330 ElementOffsetInChars += getSizeInChars(C);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000331 }
332
Ken Dyck4a5c87e2011-03-18 00:55:06 +0000333 assert(ElementOffsetInChars == NextFieldOffsetInChars &&
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000334 "Packing the struct changed its size!");
335
336 Elements = PackedElements;
Ken Dyck7d2f9d52011-03-18 01:26:17 +0000337 LLVMStructAlignment = CharUnits::One();
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000338 Packed = true;
339}
340
341bool ConstStructBuilder::Build(InitListExpr *ILE) {
342 RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
343 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
344
345 unsigned FieldNo = 0;
346 unsigned ElementNo = 0;
347 for (RecordDecl::field_iterator Field = RD->field_begin(),
Chris Lattner8ce9e452010-04-13 18:16:19 +0000348 FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
349
350 // If this is a union, skip all the fields that aren't being initialized.
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000351 if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field)
352 continue;
353
Chris Lattner8ce9e452010-04-13 18:16:19 +0000354 // Don't emit anonymous bitfields, they just affect layout.
355 if (Field->isBitField() && !Field->getIdentifier())
356 continue;
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000357
Chris Lattner8ce9e452010-04-13 18:16:19 +0000358 // Get the initializer. A struct can include fields without initializers,
359 // we just use explicit null values for them.
360 llvm::Constant *EltInit;
361 if (ElementNo < ILE->getNumInits())
362 EltInit = CGM.EmitConstantExpr(ILE->getInit(ElementNo++),
363 Field->getType(), CGF);
364 else
365 EltInit = CGM.EmitNullConstant(Field->getType());
Eli Friedmanf0ca0ee2010-07-17 23:55:01 +0000366
367 if (!EltInit)
368 return false;
Chris Lattner8ce9e452010-04-13 18:16:19 +0000369
370 if (!Field->isBitField()) {
371 // Handle non-bitfield members.
372 if (!AppendField(*Field, Layout.getFieldOffset(FieldNo), EltInit))
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000373 return false;
374 } else {
Chris Lattner8ce9e452010-04-13 18:16:19 +0000375 // Otherwise we have a bitfield.
Chris Lattner18806662010-07-05 17:04:23 +0000376 AppendBitField(*Field, Layout.getFieldOffset(FieldNo),
377 cast<llvm::ConstantInt>(EltInit));
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000378 }
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000379 }
380
Ken Dyckdc496392011-03-17 01:33:18 +0000381 CharUnits LayoutSizeInChars = Layout.getSize();
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000382
Ken Dyckdc496392011-03-17 01:33:18 +0000383 if (NextFieldOffsetInChars > LayoutSizeInChars) {
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000384 // If the struct is bigger than the size of the record type,
385 // we must have a flexible array member at the end.
386 assert(RD->hasFlexibleArrayMember() &&
387 "Must have flexible array member if struct is bigger than type!");
388
389 // No tail padding is necessary.
390 return true;
391 }
392
Ken Dyckdc496392011-03-17 01:33:18 +0000393 CharUnits LLVMSizeInChars =
Ken Dyck7d2f9d52011-03-18 01:26:17 +0000394 NextFieldOffsetInChars.RoundUpToAlignment(LLVMStructAlignment);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000395
396 // Check if we need to convert the struct to a packed struct.
Ken Dyckdc496392011-03-17 01:33:18 +0000397 if (NextFieldOffsetInChars <= LayoutSizeInChars &&
398 LLVMSizeInChars > LayoutSizeInChars) {
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000399 assert(!Packed && "Size mismatch!");
400
401 ConvertStructToPacked();
Ken Dyckdc496392011-03-17 01:33:18 +0000402 assert(NextFieldOffsetInChars <= LayoutSizeInChars &&
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000403 "Converting to packed did not help!");
404 }
405
406 // Append tail padding if necessary.
Ken Dyckdc496392011-03-17 01:33:18 +0000407 AppendTailPadding(LayoutSizeInChars);
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000408
Ken Dyckdc496392011-03-17 01:33:18 +0000409 assert(LayoutSizeInChars == NextFieldOffsetInChars &&
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000410 "Tail padding mismatch!");
411
412 return true;
413}
414
415llvm::Constant *ConstStructBuilder::
416 BuildStruct(CodeGenModule &CGM, CodeGenFunction *CGF, InitListExpr *ILE) {
417 ConstStructBuilder Builder(CGM, CGF);
418
419 if (!Builder.Build(ILE))
420 return 0;
421
422 llvm::Constant *Result =
423 llvm::ConstantStruct::get(CGM.getLLVMContext(),
424 Builder.Elements, Builder.Packed);
425
Ken Dyck15c152e2011-03-18 01:12:13 +0000426 assert(Builder.NextFieldOffsetInChars.RoundUpToAlignment(
Ken Dyck7d2f9d52011-03-18 01:26:17 +0000427 Builder.getAlignment(Result)) ==
Ken Dyck15c152e2011-03-18 01:12:13 +0000428 Builder.getSizeInChars(Result) && "Size mismatch!");
Chris Lattnereba3e5a2010-04-13 17:45:57 +0000429
430 return Result;
431}
432
433
434//===----------------------------------------------------------------------===//
435// ConstExprEmitter
436//===----------------------------------------------------------------------===//
437
Benjamin Kramer85b45212009-11-28 19:45:26 +0000438class ConstExprEmitter :
Anders Carlsson84005b42008-01-26 04:30:23 +0000439 public StmtVisitor<ConstExprEmitter, llvm::Constant*> {
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000440 CodeGenModule &CGM;
Lauro Ramos Venancio81373352008-02-26 21:41:45 +0000441 CodeGenFunction *CGF;
Owen Andersona1cf15f2009-07-14 23:10:40 +0000442 llvm::LLVMContext &VMContext;
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000443public:
Lauro Ramos Venancio81373352008-02-26 21:41:45 +0000444 ConstExprEmitter(CodeGenModule &cgm, CodeGenFunction *cgf)
Owen Andersona1cf15f2009-07-14 23:10:40 +0000445 : CGM(cgm), CGF(cgf), VMContext(cgm.getLLVMContext()) {
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000446 }
Mike Stump1eb44332009-09-09 15:08:12 +0000447
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000448 //===--------------------------------------------------------------------===//
449 // Visitor Methods
450 //===--------------------------------------------------------------------===//
Mike Stump1eb44332009-09-09 15:08:12 +0000451
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000452 llvm::Constant *VisitStmt(Stmt *S) {
Anders Carlsson069880e2009-03-03 16:43:34 +0000453 return 0;
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000454 }
Mike Stump1eb44332009-09-09 15:08:12 +0000455
456 llvm::Constant *VisitParenExpr(ParenExpr *PE) {
457 return Visit(PE->getSubExpr());
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000458 }
Mike Stump1eb44332009-09-09 15:08:12 +0000459
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000460 llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
461 return Visit(E->getInitializer());
462 }
John McCall5808ce42011-02-03 08:15:49 +0000463
Anders Carlssonf57b4e42009-10-03 15:02:02 +0000464 llvm::Constant *VisitUnaryAddrOf(UnaryOperator *E) {
John McCall5808ce42011-02-03 08:15:49 +0000465 if (E->getType()->isMemberPointerType())
466 return CGM.getMemberPointerConstant(E);
Anders Carlsson45147d02010-02-02 03:37:46 +0000467
Anders Carlssonf57b4e42009-10-03 15:02:02 +0000468 return 0;
469 }
470
Chris Lattner3ae9f482009-10-13 07:14:16 +0000471 llvm::Constant *VisitBinSub(BinaryOperator *E) {
472 // This must be a pointer/pointer subtraction. This only happens for
473 // address of label.
474 if (!isa<AddrLabelExpr>(E->getLHS()->IgnoreParenNoopCasts(CGM.getContext())) ||
475 !isa<AddrLabelExpr>(E->getRHS()->IgnoreParenNoopCasts(CGM.getContext())))
476 return 0;
477
478 llvm::Constant *LHS = CGM.EmitConstantExpr(E->getLHS(),
479 E->getLHS()->getType(), CGF);
480 llvm::Constant *RHS = CGM.EmitConstantExpr(E->getRHS(),
481 E->getRHS()->getType(), CGF);
482
483 const llvm::Type *ResultType = ConvertType(E->getType());
484 LHS = llvm::ConstantExpr::getPtrToInt(LHS, ResultType);
485 RHS = llvm::ConstantExpr::getPtrToInt(RHS, ResultType);
486
487 // No need to divide by element size, since addr of label is always void*,
488 // which has size 1 in GNUish.
489 return llvm::ConstantExpr::getSub(LHS, RHS);
490 }
491
Argyrios Kyrtzidis0835a3c2008-08-18 23:01:59 +0000492 llvm::Constant *VisitCastExpr(CastExpr* E) {
John McCall8bba1f42011-03-15 21:17:48 +0000493 Expr *subExpr = E->getSubExpr();
494 llvm::Constant *C = CGM.EmitConstantExpr(subExpr, subExpr->getType(), CGF);
495 if (!C) return 0;
496
497 const llvm::Type *destType = ConvertType(E->getType());
498
Anders Carlsson0086ccb2009-08-22 23:54:44 +0000499 switch (E->getCastKind()) {
John McCall2de56d12010-08-25 11:45:40 +0000500 case CK_ToUnion: {
Anders Carlsson0086ccb2009-08-22 23:54:44 +0000501 // GCC cast to union extension
502 assert(E->getType()->isUnionType() &&
503 "Destination type is not union type!");
Mike Stump1eb44332009-09-09 15:08:12 +0000504
Anders Carlssonaaed50d2009-07-31 21:38:39 +0000505 // Build a struct with the union sub-element as the first member,
506 // and padded to the appropriate size
507 std::vector<llvm::Constant*> Elts;
508 std::vector<const llvm::Type*> Types;
509 Elts.push_back(C);
510 Types.push_back(C->getType());
511 unsigned CurSize = CGM.getTargetData().getTypeAllocSize(C->getType());
John McCall8bba1f42011-03-15 21:17:48 +0000512 unsigned TotalSize = CGM.getTargetData().getTypeAllocSize(destType);
Mike Stump1eb44332009-09-09 15:08:12 +0000513
Anders Carlssonaaed50d2009-07-31 21:38:39 +0000514 assert(CurSize <= TotalSize && "Union size mismatch!");
515 if (unsigned NumPadBytes = TotalSize - CurSize) {
Owen Anderson0032b272009-08-13 21:57:51 +0000516 const llvm::Type *Ty = llvm::Type::getInt8Ty(VMContext);
Anders Carlssonaaed50d2009-07-31 21:38:39 +0000517 if (NumPadBytes > 1)
518 Ty = llvm::ArrayType::get(Ty, NumPadBytes);
Anders Carlsson0086ccb2009-08-22 23:54:44 +0000519
Nuno Lopescdb30b42010-04-16 20:56:35 +0000520 Elts.push_back(llvm::UndefValue::get(Ty));
Anders Carlssonaaed50d2009-07-31 21:38:39 +0000521 Types.push_back(Ty);
522 }
Mike Stump1eb44332009-09-09 15:08:12 +0000523
Anders Carlsson0086ccb2009-08-22 23:54:44 +0000524 llvm::StructType* STy =
525 llvm::StructType::get(C->getType()->getContext(), Types, false);
Anders Carlssonaaed50d2009-07-31 21:38:39 +0000526 return llvm::ConstantStruct::get(STy, Elts);
Nuno Lopes81e51e22009-01-17 00:48:48 +0000527 }
John McCall2de56d12010-08-25 11:45:40 +0000528 case CK_NullToMemberPointer: {
John McCalld608cdb2010-08-22 10:59:02 +0000529 const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>();
John McCall0bab0cd2010-08-23 01:21:21 +0000530 return CGM.getCXXABI().EmitNullMemberPointer(MPT);
John McCalld608cdb2010-08-22 10:59:02 +0000531 }
Anders Carlsson2c51f092009-10-03 15:13:22 +0000532
John McCall8bba1f42011-03-15 21:17:48 +0000533 case CK_DerivedToBaseMemberPointer:
534 case CK_BaseToDerivedMemberPointer:
John McCall0bab0cd2010-08-23 01:21:21 +0000535 return CGM.getCXXABI().EmitMemberPointerConversion(C, E);
Anders Carlssonbb378cb2009-10-18 20:31:03 +0000536
John McCall8bba1f42011-03-15 21:17:48 +0000537 case CK_LValueToRValue:
538 case CK_NoOp:
539 return C;
Anders Carlssonbb378cb2009-10-18 20:31:03 +0000540
John McCall8bba1f42011-03-15 21:17:48 +0000541 case CK_AnyPointerToObjCPointerCast:
542 case CK_AnyPointerToBlockPointerCast:
543 case CK_LValueBitCast:
544 case CK_BitCast:
545 if (C->getType() == destType) return C;
546 return llvm::ConstantExpr::getBitCast(C, destType);
Chris Lattner430656e2009-10-13 22:12:09 +0000547
John McCall8bba1f42011-03-15 21:17:48 +0000548 case CK_Dependent: llvm_unreachable("saw dependent cast!");
549
550 // These will never be supported.
551 case CK_ObjCObjectLValueCast:
552 case CK_GetObjCProperty:
553 case CK_ToVoid:
554 case CK_Dynamic:
Anders Carlsson0086ccb2009-08-22 23:54:44 +0000555 return 0;
John McCall8bba1f42011-03-15 21:17:48 +0000556
557 // These might need to be supported for constexpr.
558 case CK_UserDefinedConversion:
559 case CK_ConstructorConversion:
560 return 0;
561
562 // These should eventually be supported.
563 case CK_ArrayToPointerDecay:
564 case CK_FunctionToPointerDecay:
565 case CK_BaseToDerived:
566 case CK_DerivedToBase:
567 case CK_UncheckedDerivedToBase:
568 case CK_MemberPointerToBoolean:
569 case CK_VectorSplat:
570 case CK_FloatingRealToComplex:
571 case CK_FloatingComplexToReal:
572 case CK_FloatingComplexToBoolean:
573 case CK_FloatingComplexCast:
574 case CK_FloatingComplexToIntegralComplex:
575 case CK_IntegralRealToComplex:
576 case CK_IntegralComplexToReal:
577 case CK_IntegralComplexToBoolean:
578 case CK_IntegralComplexCast:
579 case CK_IntegralComplexToFloatingComplex:
580 return 0;
581
582 case CK_PointerToIntegral:
583 if (!E->getType()->isBooleanType())
584 return llvm::ConstantExpr::getPtrToInt(C, destType);
585 // fallthrough
586
587 case CK_PointerToBoolean:
588 return llvm::ConstantExpr::getICmp(llvm::CmpInst::ICMP_EQ, C,
589 llvm::ConstantPointerNull::get(cast<llvm::PointerType>(C->getType())));
590
591 case CK_NullToPointer:
592 return llvm::ConstantPointerNull::get(cast<llvm::PointerType>(destType));
593
594 case CK_IntegralCast: {
595 bool isSigned = subExpr->getType()->isSignedIntegerType();
596 return llvm::ConstantExpr::getIntegerCast(C, destType, isSigned);
Eli Friedmanddd2b6e2009-02-22 07:29:04 +0000597 }
John McCall8bba1f42011-03-15 21:17:48 +0000598
599 case CK_IntegralToPointer: {
600 bool isSigned = subExpr->getType()->isSignedIntegerType();
601 C = llvm::ConstantExpr::getIntegerCast(C, CGM.IntPtrTy, isSigned);
602 return llvm::ConstantExpr::getIntToPtr(C, destType);
603 }
604
605 case CK_IntegralToBoolean:
606 return llvm::ConstantExpr::getICmp(llvm::CmpInst::ICMP_EQ, C,
607 llvm::Constant::getNullValue(C->getType()));
608
609 case CK_IntegralToFloating:
610 if (subExpr->getType()->isSignedIntegerType())
611 return llvm::ConstantExpr::getSIToFP(C, destType);
612 else
613 return llvm::ConstantExpr::getUIToFP(C, destType);
614
615 case CK_FloatingToIntegral:
616 if (E->getType()->isSignedIntegerType())
617 return llvm::ConstantExpr::getFPToSI(C, destType);
618 else
619 return llvm::ConstantExpr::getFPToUI(C, destType);
620
621 case CK_FloatingToBoolean:
622 return llvm::ConstantExpr::getFCmp(llvm::CmpInst::FCMP_UNE, C,
623 llvm::Constant::getNullValue(C->getType()));
624
625 case CK_FloatingCast:
626 return llvm::ConstantExpr::getFPCast(C, destType);
Anders Carlsson0086ccb2009-08-22 23:54:44 +0000627 }
Matt Beaumont-Gay17d12fe2011-03-17 00:46:34 +0000628 llvm_unreachable("Invalid CastKind");
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000629 }
Devang Pateleae15602008-02-05 02:39:50 +0000630
Chris Lattner04421082008-04-08 04:40:51 +0000631 llvm::Constant *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
632 return Visit(DAE->getExpr());
633 }
634
Eli Friedmana8234002008-05-30 10:24:46 +0000635 llvm::Constant *EmitArrayInitialization(InitListExpr *ILE) {
Nuno Lopesa75b71f2010-04-18 19:06:43 +0000636 unsigned NumInitElements = ILE->getNumInits();
Benjamin Kramer0483a6f2011-03-02 21:27:44 +0000637 if (NumInitElements == 1 && ILE->getType() == ILE->getInit(0)->getType() &&
Nuno Lopesa75b71f2010-04-18 19:06:43 +0000638 (isa<StringLiteral>(ILE->getInit(0)) ||
639 isa<ObjCEncodeExpr>(ILE->getInit(0))))
640 return Visit(ILE->getInit(0));
641
Nuno Lopes67847042010-04-16 23:19:41 +0000642 std::vector<llvm::Constant*> Elts;
643 const llvm::ArrayType *AType =
644 cast<llvm::ArrayType>(ConvertType(ILE->getType()));
Devang Pateleae15602008-02-05 02:39:50 +0000645 const llvm::Type *ElemTy = AType->getElementType();
646 unsigned NumElements = AType->getNumElements();
647
Mike Stump1eb44332009-09-09 15:08:12 +0000648 // Initialising an array requires us to automatically
Devang Pateleae15602008-02-05 02:39:50 +0000649 // initialise any elements that have not been initialised explicitly
650 unsigned NumInitableElts = std::min(NumInitElements, NumElements);
651
652 // Copy initializer elements.
653 unsigned i = 0;
Eli Friedmana04a1532008-05-30 19:58:50 +0000654 bool RewriteType = false;
Devang Pateleae15602008-02-05 02:39:50 +0000655 for (; i < NumInitableElts; ++i) {
Anders Carlssone9352cc2009-04-08 04:48:15 +0000656 Expr *Init = ILE->getInit(i);
657 llvm::Constant *C = CGM.EmitConstantExpr(Init, Init->getType(), CGF);
Daniel Dunbard60f2fb2009-02-17 18:43:32 +0000658 if (!C)
659 return 0;
Eli Friedmana04a1532008-05-30 19:58:50 +0000660 RewriteType |= (C->getType() != ElemTy);
Devang Pateleae15602008-02-05 02:39:50 +0000661 Elts.push_back(C);
662 }
Eli Friedmana04a1532008-05-30 19:58:50 +0000663
Devang Pateleae15602008-02-05 02:39:50 +0000664 // Initialize remaining array elements.
Eli Friedman0f593122009-04-13 21:47:26 +0000665 // FIXME: This doesn't handle member pointers correctly!
Devang Pateleae15602008-02-05 02:39:50 +0000666 for (; i < NumElements; ++i)
Owen Andersonc9c88b42009-07-31 20:28:54 +0000667 Elts.push_back(llvm::Constant::getNullValue(ElemTy));
Devang Pateleae15602008-02-05 02:39:50 +0000668
Eli Friedmana04a1532008-05-30 19:58:50 +0000669 if (RewriteType) {
670 // FIXME: Try to avoid packing the array
671 std::vector<const llvm::Type*> Types;
672 for (unsigned i = 0; i < Elts.size(); ++i)
673 Types.push_back(Elts[i]->getType());
Mike Stump1eb44332009-09-09 15:08:12 +0000674 const llvm::StructType *SType = llvm::StructType::get(AType->getContext(),
Owen Anderson47a434f2009-08-05 23:18:46 +0000675 Types, true);
Owen Anderson08e25242009-07-27 22:29:56 +0000676 return llvm::ConstantStruct::get(SType, Elts);
Eli Friedmana04a1532008-05-30 19:58:50 +0000677 }
678
Mike Stump1eb44332009-09-09 15:08:12 +0000679 return llvm::ConstantArray::get(AType, Elts);
Devang Pateleae15602008-02-05 02:39:50 +0000680 }
681
Eli Friedmana8234002008-05-30 10:24:46 +0000682 llvm::Constant *EmitStructInitialization(InitListExpr *ILE) {
Anders Carlsson8dca3b32009-07-27 05:54:15 +0000683 return ConstStructBuilder::BuildStruct(CGM, CGF, ILE);
Devang Pateleae15602008-02-05 02:39:50 +0000684 }
Mike Stump1eb44332009-09-09 15:08:12 +0000685
Eli Friedmana8234002008-05-30 10:24:46 +0000686 llvm::Constant *EmitUnionInitialization(InitListExpr *ILE) {
Anders Carlssonf6c43962009-07-31 21:34:04 +0000687 return ConstStructBuilder::BuildStruct(CGM, CGF, ILE);
Eli Friedmana8234002008-05-30 10:24:46 +0000688 }
689
Anders Carlsson7d801ea2009-01-30 06:13:25 +0000690 llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E) {
Eli Friedman0f593122009-04-13 21:47:26 +0000691 return CGM.EmitNullConstant(E->getType());
Anders Carlsson7d801ea2009-01-30 06:13:25 +0000692 }
Mike Stump1eb44332009-09-09 15:08:12 +0000693
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000694 llvm::Constant *VisitInitListExpr(InitListExpr *ILE) {
Eli Friedmana8234002008-05-30 10:24:46 +0000695 if (ILE->getType()->isScalarType()) {
696 // We have a scalar in braces. Just use the first element.
Anders Carlssone9352cc2009-04-08 04:48:15 +0000697 if (ILE->getNumInits() > 0) {
698 Expr *Init = ILE->getInit(0);
699 return CGM.EmitConstantExpr(Init, Init->getType(), CGF);
700 }
Eli Friedman0f593122009-04-13 21:47:26 +0000701 return CGM.EmitNullConstant(ILE->getType());
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000702 }
Mike Stump1eb44332009-09-09 15:08:12 +0000703
Eli Friedmana8234002008-05-30 10:24:46 +0000704 if (ILE->getType()->isArrayType())
705 return EmitArrayInitialization(ILE);
Devang Patel47fb6972008-01-29 23:23:18 +0000706
Anders Carlsson01a79ac2009-11-21 23:56:04 +0000707 if (ILE->getType()->isRecordType())
Eli Friedmana8234002008-05-30 10:24:46 +0000708 return EmitStructInitialization(ILE);
709
710 if (ILE->getType()->isUnionType())
711 return EmitUnionInitialization(ILE);
712
Eli Friedman8ac55492010-01-02 23:43:59 +0000713 // If ILE was a constant vector, we would have handled it already.
Eli Friedmana8234002008-05-30 10:24:46 +0000714 if (ILE->getType()->isVectorType())
Eli Friedman8ac55492010-01-02 23:43:59 +0000715 return 0;
Eli Friedmana8234002008-05-30 10:24:46 +0000716
Devang Pateleae15602008-02-05 02:39:50 +0000717 assert(0 && "Unable to handle InitListExpr");
Chris Lattner2b94fe32008-03-01 08:45:05 +0000718 // Get rid of control reaches end of void function warning.
719 // Not reached.
720 return 0;
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000721 }
Eli Friedman3b707e72008-02-21 17:57:49 +0000722
John McCallfb8b69a2010-02-02 08:02:49 +0000723 llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E) {
724 if (!E->getConstructor()->isTrivial())
725 return 0;
726
Anders Carlsson2ca4f632010-02-05 18:38:45 +0000727 QualType Ty = E->getType();
728
729 // FIXME: We should not have to call getBaseElementType here.
730 const RecordType *RT =
731 CGM.getContext().getBaseElementType(Ty)->getAs<RecordType>();
732 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
733
734 // If the class doesn't have a trivial destructor, we can't emit it as a
735 // constant expr.
736 if (!RD->hasTrivialDestructor())
737 return 0;
738
John McCallfb8b69a2010-02-02 08:02:49 +0000739 // Only copy and default constructors can be trivial.
740
John McCallfb8b69a2010-02-02 08:02:49 +0000741
742 if (E->getNumArgs()) {
743 assert(E->getNumArgs() == 1 && "trivial ctor with > 1 argument");
744 assert(E->getConstructor()->isCopyConstructor() &&
745 "trivial ctor has argument but isn't a copy ctor");
746
747 Expr *Arg = E->getArg(0);
748 assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) &&
749 "argument to copy ctor is of wrong type");
750
Chandler Carruth878b55c2010-02-02 12:15:55 +0000751 return Visit(Arg);
John McCallfb8b69a2010-02-02 08:02:49 +0000752 }
753
754 return CGM.EmitNullConstant(Ty);
755 }
756
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000757 llvm::Constant *VisitStringLiteral(StringLiteral *E) {
Chris Lattnera7ad98f2008-02-11 00:02:17 +0000758 assert(!E->getType()->isPointerType() && "Strings are always arrays");
Mike Stump1eb44332009-09-09 15:08:12 +0000759
Chris Lattnereaf2bb82009-02-24 22:18:39 +0000760 // This must be a string initializing an array in a static initializer.
761 // Don't emit it as the address of the string, emit the string data itself
762 // as an inline array.
Owen Anderson0032b272009-08-13 21:57:51 +0000763 return llvm::ConstantArray::get(VMContext,
764 CGM.GetStringForStringLiteral(E), false);
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000765 }
766
Chris Lattnereaf2bb82009-02-24 22:18:39 +0000767 llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E) {
768 // This must be an @encode initializing an array in a static initializer.
769 // Don't emit it as the address of the string, emit the string data itself
770 // as an inline array.
771 std::string Str;
772 CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str);
773 const ConstantArrayType *CAT = cast<ConstantArrayType>(E->getType());
Mike Stump1eb44332009-09-09 15:08:12 +0000774
Chris Lattnereaf2bb82009-02-24 22:18:39 +0000775 // Resize the string to the right size, adding zeros at the end, or
776 // truncating as needed.
777 Str.resize(CAT->getSize().getZExtValue(), '\0');
Owen Anderson0032b272009-08-13 21:57:51 +0000778 return llvm::ConstantArray::get(VMContext, Str, false);
Chris Lattnereaf2bb82009-02-24 22:18:39 +0000779 }
Mike Stump1eb44332009-09-09 15:08:12 +0000780
Eli Friedmanbc5ed6e2008-05-29 11:22:45 +0000781 llvm::Constant *VisitUnaryExtension(const UnaryOperator *E) {
782 return Visit(E->getSubExpr());
783 }
Mike Stumpb83d2872009-02-19 22:01:56 +0000784
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000785 // Utility methods
786 const llvm::Type *ConvertType(QualType T) {
787 return CGM.getTypes().ConvertType(T);
788 }
Anders Carlsson84005b42008-01-26 04:30:23 +0000789
Anders Carlsson5ea7d072008-11-16 06:23:45 +0000790public:
Anders Carlsson84005b42008-01-26 04:30:23 +0000791 llvm::Constant *EmitLValue(Expr *E) {
Anders Carlssone3d3b7d2008-01-26 02:08:50 +0000792 switch (E->getStmtClass()) {
Eli Friedman546d94c2008-02-11 00:23:10 +0000793 default: break;
Anders Carlssone3d3b7d2008-01-26 02:08:50 +0000794 case Expr::CompoundLiteralExprClass: {
795 // Note that due to the nature of compound literals, this is guaranteed
796 // to be the only use of the variable, so we just generate it here.
Anders Carlsson84005b42008-01-26 04:30:23 +0000797 CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
798 llvm::Constant* C = Visit(CLE->getInitializer());
Daniel Dunbard60f2fb2009-02-17 18:43:32 +0000799 // FIXME: "Leaked" on failure.
800 if (C)
Owen Anderson1c431b32009-07-08 19:05:04 +0000801 C = new llvm::GlobalVariable(CGM.getModule(), C->getType(),
Eli Friedmand15d8c62009-08-26 20:01:39 +0000802 E->getType().isConstant(CGM.getContext()),
Daniel Dunbard60f2fb2009-02-17 18:43:32 +0000803 llvm::GlobalValue::InternalLinkage,
Eli Friedmand15d8c62009-08-26 20:01:39 +0000804 C, ".compoundliteral", 0, false,
Peter Collingbourne207f4d82011-03-18 22:38:29 +0000805 CGM.getContext().getTargetAddressSpace(E->getType()));
Anders Carlssone3d3b7d2008-01-26 02:08:50 +0000806 return C;
Anders Carlsson84005b42008-01-26 04:30:23 +0000807 }
Douglas Gregora2813ce2009-10-23 18:54:35 +0000808 case Expr::DeclRefExprClass: {
Rafael Espindolada182612010-03-04 21:26:03 +0000809 ValueDecl *Decl = cast<DeclRefExpr>(E)->getDecl();
810 if (Decl->hasAttr<WeakRefAttr>())
Eli Friedmana7e68452010-08-22 01:00:03 +0000811 return CGM.GetWeakRefReference(Decl);
Anders Carlssone3d3b7d2008-01-26 02:08:50 +0000812 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Decl))
Anders Carlsson555b4bb2009-09-10 23:43:36 +0000813 return CGM.GetAddrOfFunction(FD);
Steve Naroff248a7532008-04-15 22:42:06 +0000814 if (const VarDecl* VD = dyn_cast<VarDecl>(Decl)) {
Daniel Dunbard01b6692009-02-24 18:41:57 +0000815 // We can never refer to a variable with local storage.
Mike Stump1eb44332009-09-09 15:08:12 +0000816 if (!VD->hasLocalStorage()) {
Daniel Dunbard01b6692009-02-24 18:41:57 +0000817 if (VD->isFileVarDecl() || VD->hasExternalStorage())
818 return CGM.GetAddrOfGlobalVar(VD);
John McCallb6bbcc92010-10-15 04:57:14 +0000819 else if (VD->isLocalVarDecl()) {
Daniel Dunbard01b6692009-02-24 18:41:57 +0000820 assert(CGF && "Can't access static local vars without CGF");
821 return CGF->GetAddrOfStaticLocalVar(VD);
822 }
Steve Naroff248a7532008-04-15 22:42:06 +0000823 }
Lauro Ramos Venancio81373352008-02-26 21:41:45 +0000824 }
Eli Friedman546d94c2008-02-11 00:23:10 +0000825 break;
Anders Carlssone3d3b7d2008-01-26 02:08:50 +0000826 }
Daniel Dunbar61432932008-08-13 23:20:05 +0000827 case Expr::StringLiteralClass:
828 return CGM.GetAddrOfConstantStringFromLiteral(cast<StringLiteral>(E));
Chris Lattnereaf2bb82009-02-24 22:18:39 +0000829 case Expr::ObjCEncodeExprClass:
830 return CGM.GetAddrOfConstantStringFromObjCEncode(cast<ObjCEncodeExpr>(E));
Anders Carlsson5ea7d072008-11-16 06:23:45 +0000831 case Expr::ObjCStringLiteralClass: {
832 ObjCStringLiteral* SL = cast<ObjCStringLiteral>(E);
David Chisnall0d13f6f2010-01-23 02:40:42 +0000833 llvm::Constant *C =
834 CGM.getObjCRuntime().GenerateConstantString(SL->getString());
Owen Anderson3c4972d2009-07-29 18:54:39 +0000835 return llvm::ConstantExpr::getBitCast(C, ConvertType(E->getType()));
Anders Carlsson5ea7d072008-11-16 06:23:45 +0000836 }
Chris Lattner35345642008-12-12 05:18:02 +0000837 case Expr::PredefinedExprClass: {
Eli Friedmanf70b24e2009-11-14 08:37:13 +0000838 unsigned Type = cast<PredefinedExpr>(E)->getIdentType();
839 if (CGF) {
Daniel Dunbar3ec0baf2010-08-21 03:01:12 +0000840 LValue Res = CGF->EmitPredefinedLValue(cast<PredefinedExpr>(E));
Eli Friedmanf70b24e2009-11-14 08:37:13 +0000841 return cast<llvm::Constant>(Res.getAddress());
842 } else if (Type == PredefinedExpr::PrettyFunction) {
843 return CGM.GetAddrOfConstantCString("top level", ".tmp");
844 }
Mike Stump1eb44332009-09-09 15:08:12 +0000845
Eli Friedmanf70b24e2009-11-14 08:37:13 +0000846 return CGM.GetAddrOfConstantCString("", ".tmp");
Chris Lattner35345642008-12-12 05:18:02 +0000847 }
Eli Friedmanf0115892009-01-25 01:21:06 +0000848 case Expr::AddrLabelExprClass: {
849 assert(CGF && "Invalid address of label expression outside function.");
Chris Lattnerd9becd12009-10-28 23:59:40 +0000850 llvm::Constant *Ptr =
851 CGF->GetAddrOfLabel(cast<AddrLabelExpr>(E)->getLabel());
852 return llvm::ConstantExpr::getBitCast(Ptr, ConvertType(E->getType()));
Eli Friedmanf0115892009-01-25 01:21:06 +0000853 }
Eli Friedman3941b182009-01-25 01:54:01 +0000854 case Expr::CallExprClass: {
855 CallExpr* CE = cast<CallExpr>(E);
David Chisnall0d13f6f2010-01-23 02:40:42 +0000856 unsigned builtin = CE->isBuiltinCall(CGM.getContext());
857 if (builtin !=
858 Builtin::BI__builtin___CFStringMakeConstantString &&
859 builtin !=
860 Builtin::BI__builtin___NSStringMakeConstantString)
Eli Friedman3941b182009-01-25 01:54:01 +0000861 break;
862 const Expr *Arg = CE->getArg(0)->IgnoreParenCasts();
863 const StringLiteral *Literal = cast<StringLiteral>(Arg);
David Chisnall0d13f6f2010-01-23 02:40:42 +0000864 if (builtin ==
865 Builtin::BI__builtin___NSStringMakeConstantString) {
866 return CGM.getObjCRuntime().GenerateConstantString(Literal);
867 }
Steve Naroff33fdb732009-03-31 16:53:37 +0000868 // FIXME: need to deal with UCN conversion issues.
Steve Naroff8d4141f2009-04-01 13:55:36 +0000869 return CGM.GetAddrOfConstantCFString(Literal);
Eli Friedman3941b182009-01-25 01:54:01 +0000870 }
Mike Stumpbd65cac2009-02-19 01:01:04 +0000871 case Expr::BlockExprClass: {
Anders Carlsson4de9fce2009-03-01 01:09:12 +0000872 std::string FunctionName;
873 if (CGF)
874 FunctionName = CGF->CurFn->getName();
875 else
876 FunctionName = "global";
877
878 return CGM.GetAddrOfGlobalBlock(cast<BlockExpr>(E), FunctionName.c_str());
Mike Stumpbd65cac2009-02-19 01:01:04 +0000879 }
Eli Friedman546d94c2008-02-11 00:23:10 +0000880 }
Daniel Dunbard60f2fb2009-02-17 18:43:32 +0000881
882 return 0;
Anders Carlssone3d3b7d2008-01-26 02:08:50 +0000883 }
Anders Carlssone3d3b7d2008-01-26 02:08:50 +0000884};
Mike Stump1eb44332009-09-09 15:08:12 +0000885
Anders Carlsson3b1d57b2008-01-26 01:36:00 +0000886} // end anonymous namespace.
887
Lauro Ramos Venancio81373352008-02-26 21:41:45 +0000888llvm::Constant *CodeGenModule::EmitConstantExpr(const Expr *E,
Anders Carlssone9352cc2009-04-08 04:48:15 +0000889 QualType DestType,
Chris Lattner96196622008-07-26 22:37:01 +0000890 CodeGenFunction *CGF) {
Anders Carlsson4b3f9c02008-12-01 02:42:14 +0000891 Expr::EvalResult Result;
Mike Stump1eb44332009-09-09 15:08:12 +0000892
Anders Carlsson1e5dc6e2009-04-11 01:08:03 +0000893 bool Success = false;
Mike Stump1eb44332009-09-09 15:08:12 +0000894
Eli Friedman50c39ea2009-05-27 06:04:58 +0000895 if (DestType->isReferenceType())
896 Success = E->EvaluateAsLValue(Result, Context);
Mike Stump1eb44332009-09-09 15:08:12 +0000897 else
Anders Carlsson1e5dc6e2009-04-11 01:08:03 +0000898 Success = E->Evaluate(Result, Context);
Mike Stump1eb44332009-09-09 15:08:12 +0000899
Eli Friedman55f9bdd2009-11-14 08:51:33 +0000900 if (Success && !Result.HasSideEffects) {
Anders Carlsson4b3f9c02008-12-01 02:42:14 +0000901 switch (Result.Val.getKind()) {
Daniel Dunbara5fd07b2009-01-28 22:24:07 +0000902 case APValue::Uninitialized:
Daniel Dunbard60f2fb2009-02-17 18:43:32 +0000903 assert(0 && "Constant expressions should be initialized.");
904 return 0;
Anders Carlsson5a9a4572008-11-15 20:45:50 +0000905 case APValue::LValue: {
Anders Carlsson1e5dc6e2009-04-11 01:08:03 +0000906 const llvm::Type *DestTy = getTypes().ConvertTypeForMem(DestType);
Mike Stump1eb44332009-09-09 15:08:12 +0000907 llvm::Constant *Offset =
908 llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext),
Ken Dycka7305832010-01-15 12:37:54 +0000909 Result.Val.getLValueOffset().getQuantity());
Mike Stump1eb44332009-09-09 15:08:12 +0000910
Daniel Dunbare20de512009-02-19 21:44:24 +0000911 llvm::Constant *C;
Anders Carlsson4b3f9c02008-12-01 02:42:14 +0000912 if (const Expr *LVBase = Result.Val.getLValueBase()) {
Daniel Dunbare20de512009-02-19 21:44:24 +0000913 C = ConstExprEmitter(*this, CGF).EmitLValue(const_cast<Expr*>(LVBase));
Anders Carlsson5ea7d072008-11-16 06:23:45 +0000914
Daniel Dunbare20de512009-02-19 21:44:24 +0000915 // Apply offset if necessary.
916 if (!Offset->isNullValue()) {
Benjamin Kramer3c0ef8c2009-10-13 10:07:13 +0000917 const llvm::Type *Type = llvm::Type::getInt8PtrTy(VMContext);
Owen Anderson3c4972d2009-07-29 18:54:39 +0000918 llvm::Constant *Casted = llvm::ConstantExpr::getBitCast(C, Type);
919 Casted = llvm::ConstantExpr::getGetElementPtr(Casted, &Offset, 1);
920 C = llvm::ConstantExpr::getBitCast(Casted, C->getType());
Daniel Dunbare20de512009-02-19 21:44:24 +0000921 }
922
923 // Convert to the appropriate type; this could be an lvalue for
924 // an integer.
Anders Carlsson12e330c2009-04-10 04:59:59 +0000925 if (isa<llvm::PointerType>(DestTy))
Owen Anderson3c4972d2009-07-29 18:54:39 +0000926 return llvm::ConstantExpr::getBitCast(C, DestTy);
Daniel Dunbare20de512009-02-19 21:44:24 +0000927
Owen Anderson3c4972d2009-07-29 18:54:39 +0000928 return llvm::ConstantExpr::getPtrToInt(C, DestTy);
Daniel Dunbare20de512009-02-19 21:44:24 +0000929 } else {
930 C = Offset;
931
932 // Convert to the appropriate type; this could be an lvalue for
933 // an integer.
Anders Carlsson12e330c2009-04-10 04:59:59 +0000934 if (isa<llvm::PointerType>(DestTy))
Owen Anderson3c4972d2009-07-29 18:54:39 +0000935 return llvm::ConstantExpr::getIntToPtr(C, DestTy);
Daniel Dunbare20de512009-02-19 21:44:24 +0000936
937 // If the types don't match this should only be a truncate.
Anders Carlsson12e330c2009-04-10 04:59:59 +0000938 if (C->getType() != DestTy)
Owen Anderson3c4972d2009-07-29 18:54:39 +0000939 return llvm::ConstantExpr::getTrunc(C, DestTy);
Daniel Dunbare20de512009-02-19 21:44:24 +0000940
941 return C;
Anders Carlsson5ea7d072008-11-16 06:23:45 +0000942 }
Anders Carlsson5a9a4572008-11-15 20:45:50 +0000943 }
Eli Friedman7b30b1c2008-11-17 03:57:28 +0000944 case APValue::Int: {
Mike Stump1eb44332009-09-09 15:08:12 +0000945 llvm::Constant *C = llvm::ConstantInt::get(VMContext,
Owen Anderson4a28d5d2009-07-24 23:12:58 +0000946 Result.Val.getInt());
Mike Stump1eb44332009-09-09 15:08:12 +0000947
Chris Lattner7f215c12010-06-26 21:52:32 +0000948 if (C->getType()->isIntegerTy(1)) {
Anders Carlsson5a9a4572008-11-15 20:45:50 +0000949 const llvm::Type *BoolTy = getTypes().ConvertTypeForMem(E->getType());
Owen Anderson3c4972d2009-07-29 18:54:39 +0000950 C = llvm::ConstantExpr::getZExt(C, BoolTy);
Anders Carlsson5a9a4572008-11-15 20:45:50 +0000951 }
952 return C;
Eli Friedman7b30b1c2008-11-17 03:57:28 +0000953 }
Daniel Dunbara5fd07b2009-01-28 22:24:07 +0000954 case APValue::ComplexInt: {
955 llvm::Constant *Complex[2];
Mike Stump1eb44332009-09-09 15:08:12 +0000956
Owen Anderson4a28d5d2009-07-24 23:12:58 +0000957 Complex[0] = llvm::ConstantInt::get(VMContext,
958 Result.Val.getComplexIntReal());
Mike Stump1eb44332009-09-09 15:08:12 +0000959 Complex[1] = llvm::ConstantInt::get(VMContext,
Owen Anderson4a28d5d2009-07-24 23:12:58 +0000960 Result.Val.getComplexIntImag());
Mike Stump1eb44332009-09-09 15:08:12 +0000961
Nick Lewycky0d36dd22009-09-19 20:00:52 +0000962 // FIXME: the target may want to specify that this is packed.
963 return llvm::ConstantStruct::get(VMContext, Complex, 2, false);
Daniel Dunbara5fd07b2009-01-28 22:24:07 +0000964 }
Anders Carlsson5a9a4572008-11-15 20:45:50 +0000965 case APValue::Float:
Owen Andersonbc0a2222009-07-27 21:00:51 +0000966 return llvm::ConstantFP::get(VMContext, Result.Val.getFloat());
Anders Carlssonaa432562008-11-17 01:58:55 +0000967 case APValue::ComplexFloat: {
968 llvm::Constant *Complex[2];
Mike Stump1eb44332009-09-09 15:08:12 +0000969
970 Complex[0] = llvm::ConstantFP::get(VMContext,
Owen Andersonbc0a2222009-07-27 21:00:51 +0000971 Result.Val.getComplexFloatReal());
972 Complex[1] = llvm::ConstantFP::get(VMContext,
973 Result.Val.getComplexFloatImag());
Mike Stump1eb44332009-09-09 15:08:12 +0000974
Nick Lewycky0d36dd22009-09-19 20:00:52 +0000975 // FIXME: the target may want to specify that this is packed.
976 return llvm::ConstantStruct::get(VMContext, Complex, 2, false);
Anders Carlssonaa432562008-11-17 01:58:55 +0000977 }
Nate Begeman3d309f92009-01-18 01:01:34 +0000978 case APValue::Vector: {
979 llvm::SmallVector<llvm::Constant *, 4> Inits;
980 unsigned NumElts = Result.Val.getVectorLength();
Mike Stump1eb44332009-09-09 15:08:12 +0000981
Anton Yartsevd06fea82011-03-27 09:32:40 +0000982 if (Context.getLangOptions().AltiVec &&
983 isa<CastExpr>(E) &&
984 cast<CastExpr>(E)->getCastKind() == CK_VectorSplat) {
985 // AltiVec vector initialization with a single literal
986 APValue &Elt = Result.Val.getVectorElt(0);
987
988 llvm::Constant* InitValue = Elt.isInt()
989 ? cast<llvm::Constant>
990 (llvm::ConstantInt::get(VMContext, Elt.getInt()))
991 : cast<llvm::Constant>
992 (llvm::ConstantFP::get(VMContext, Elt.getFloat()));
993
994 for (unsigned i = 0; i != NumElts; ++i)
995 Inits.push_back(InitValue);
996
997 } else {
998 for (unsigned i = 0; i != NumElts; ++i) {
999 APValue &Elt = Result.Val.getVectorElt(i);
1000 if (Elt.isInt())
1001 Inits.push_back(llvm::ConstantInt::get(VMContext, Elt.getInt()));
1002 else
1003 Inits.push_back(llvm::ConstantFP::get(VMContext, Elt.getFloat()));
1004 }
Nate Begeman3d309f92009-01-18 01:01:34 +00001005 }
Chris Lattnerfb018d12011-02-15 00:14:06 +00001006 return llvm::ConstantVector::get(Inits);
Nate Begeman3d309f92009-01-18 01:01:34 +00001007 }
Anders Carlsson5a9a4572008-11-15 20:45:50 +00001008 }
1009 }
Eli Friedman7dfa6392008-06-01 15:31:44 +00001010
1011 llvm::Constant* C = ConstExprEmitter(*this, CGF).Visit(const_cast<Expr*>(E));
Chris Lattner7f215c12010-06-26 21:52:32 +00001012 if (C && C->getType()->isIntegerTy(1)) {
Eli Friedman7dfa6392008-06-01 15:31:44 +00001013 const llvm::Type *BoolTy = getTypes().ConvertTypeForMem(E->getType());
Owen Anderson3c4972d2009-07-29 18:54:39 +00001014 C = llvm::ConstantExpr::getZExt(C, BoolTy);
Eli Friedman7dfa6392008-06-01 15:31:44 +00001015 }
1016 return C;
Anders Carlsson3b1d57b2008-01-26 01:36:00 +00001017}
Eli Friedman0f593122009-04-13 21:47:26 +00001018
John McCall5808ce42011-02-03 08:15:49 +00001019static uint64_t getFieldOffset(ASTContext &C, const FieldDecl *field) {
1020 const ASTRecordLayout &layout = C.getASTRecordLayout(field->getParent());
1021 return layout.getFieldOffset(field->getFieldIndex());
1022}
1023
1024llvm::Constant *
1025CodeGenModule::getMemberPointerConstant(const UnaryOperator *uo) {
1026 // Member pointer constants always have a very particular form.
1027 const MemberPointerType *type = cast<MemberPointerType>(uo->getType());
1028 const ValueDecl *decl = cast<DeclRefExpr>(uo->getSubExpr())->getDecl();
1029
1030 // A member function pointer.
1031 if (const CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(decl))
1032 return getCXXABI().EmitMemberPointer(method);
1033
1034 // Otherwise, a member data pointer.
1035 uint64_t fieldOffset;
1036 if (const FieldDecl *field = dyn_cast<FieldDecl>(decl))
1037 fieldOffset = getFieldOffset(getContext(), field);
1038 else {
1039 const IndirectFieldDecl *ifield = cast<IndirectFieldDecl>(decl);
1040
1041 fieldOffset = 0;
1042 for (IndirectFieldDecl::chain_iterator ci = ifield->chain_begin(),
1043 ce = ifield->chain_end(); ci != ce; ++ci)
1044 fieldOffset += getFieldOffset(getContext(), cast<FieldDecl>(*ci));
1045 }
1046
1047 CharUnits chars = getContext().toCharUnitsFromBits((int64_t) fieldOffset);
1048 return getCXXABI().EmitMemberDataPointer(type, chars);
1049}
1050
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001051static void
1052FillInNullDataMemberPointers(CodeGenModule &CGM, QualType T,
1053 std::vector<llvm::Constant *> &Elements,
1054 uint64_t StartOffset) {
Ken Dyckc4d68db2011-03-22 00:24:31 +00001055 assert(StartOffset % CGM.getContext().getCharWidth() == 0 &&
1056 "StartOffset not byte aligned!");
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001057
John McCallf16aa102010-08-22 21:01:12 +00001058 if (CGM.getTypes().isZeroInitializable(T))
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001059 return;
1060
1061 if (const ConstantArrayType *CAT =
1062 CGM.getContext().getAsConstantArrayType(T)) {
1063 QualType ElementTy = CAT->getElementType();
1064 uint64_t ElementSize = CGM.getContext().getTypeSize(ElementTy);
1065
1066 for (uint64_t I = 0, E = CAT->getSize().getZExtValue(); I != E; ++I) {
1067 FillInNullDataMemberPointers(CGM, ElementTy, Elements,
1068 StartOffset + I * ElementSize);
1069 }
1070 } else if (const RecordType *RT = T->getAs<RecordType>()) {
1071 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1072 const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
1073
1074 // Go through all bases and fill in any null pointer to data members.
1075 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
1076 E = RD->bases_end(); I != E; ++I) {
Anders Carlsson0a87b372010-05-27 18:51:01 +00001077 if (I->isVirtual()) {
Anders Carlssonada4b322010-11-22 18:42:14 +00001078 // Ignore virtual bases.
Anders Carlsson0a87b372010-05-27 18:51:01 +00001079 continue;
1080 }
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001081
1082 const CXXRecordDecl *BaseDecl =
1083 cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
1084
1085 // Ignore empty bases.
1086 if (BaseDecl->isEmpty())
1087 continue;
1088
1089 // Ignore bases that don't have any pointer to data members.
John McCallf16aa102010-08-22 21:01:12 +00001090 if (CGM.getTypes().isZeroInitializable(BaseDecl))
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001091 continue;
1092
Anders Carlssona14f5972010-10-31 23:22:37 +00001093 uint64_t BaseOffset = Layout.getBaseClassOffsetInBits(BaseDecl);
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001094 FillInNullDataMemberPointers(CGM, I->getType(),
1095 Elements, StartOffset + BaseOffset);
1096 }
1097
1098 // Visit all fields.
1099 unsigned FieldNo = 0;
1100 for (RecordDecl::field_iterator I = RD->field_begin(),
1101 E = RD->field_end(); I != E; ++I, ++FieldNo) {
1102 QualType FieldType = I->getType();
1103
John McCallf16aa102010-08-22 21:01:12 +00001104 if (CGM.getTypes().isZeroInitializable(FieldType))
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001105 continue;
1106
1107 uint64_t FieldOffset = StartOffset + Layout.getFieldOffset(FieldNo);
1108 FillInNullDataMemberPointers(CGM, FieldType, Elements, FieldOffset);
1109 }
1110 } else {
1111 assert(T->isMemberPointerType() && "Should only see member pointers here!");
1112 assert(!T->getAs<MemberPointerType>()->getPointeeType()->isFunctionType() &&
1113 "Should only see pointers to data members here!");
1114
Ken Dyckc4d68db2011-03-22 00:24:31 +00001115 CharUnits StartIndex = CGM.getContext().toCharUnitsFromBits(StartOffset);
1116 CharUnits EndIndex = StartIndex + CGM.getContext().getTypeSizeInChars(T);
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001117
John McCall5808ce42011-02-03 08:15:49 +00001118 // FIXME: hardcodes Itanium member pointer representation!
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001119 llvm::Constant *NegativeOne =
1120 llvm::ConstantInt::get(llvm::Type::getInt8Ty(CGM.getLLVMContext()),
John McCall5808ce42011-02-03 08:15:49 +00001121 -1ULL, /*isSigned*/true);
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001122
1123 // Fill in the null data member pointer.
Ken Dyckc4d68db2011-03-22 00:24:31 +00001124 for (CharUnits I = StartIndex; I != EndIndex; ++I)
1125 Elements[I.getQuantity()] = NegativeOne;
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001126 }
1127}
1128
John McCall9b7da1c2011-02-15 06:40:56 +00001129static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
1130 const llvm::Type *baseType,
1131 const CXXRecordDecl *base);
1132
Anders Carlssonada4b322010-11-22 18:42:14 +00001133static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
John McCall9b7da1c2011-02-15 06:40:56 +00001134 const CXXRecordDecl *record,
1135 bool asCompleteObject) {
1136 const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record);
1137 const llvm::StructType *structure =
1138 (asCompleteObject ? layout.getLLVMType()
1139 : layout.getBaseSubobjectLLVMType());
Anders Carlssonada4b322010-11-22 18:42:14 +00001140
John McCall9b7da1c2011-02-15 06:40:56 +00001141 unsigned numElements = structure->getNumElements();
1142 std::vector<llvm::Constant *> elements(numElements);
Anders Carlssonada4b322010-11-22 18:42:14 +00001143
John McCall9b7da1c2011-02-15 06:40:56 +00001144 // Fill in all the bases.
1145 for (CXXRecordDecl::base_class_const_iterator
1146 I = record->bases_begin(), E = record->bases_end(); I != E; ++I) {
Anders Carlssonada4b322010-11-22 18:42:14 +00001147 if (I->isVirtual()) {
John McCall9b7da1c2011-02-15 06:40:56 +00001148 // Ignore virtual bases; if we're laying out for a complete
1149 // object, we'll lay these out later.
Anders Carlssonada4b322010-11-22 18:42:14 +00001150 continue;
1151 }
1152
John McCall9b7da1c2011-02-15 06:40:56 +00001153 const CXXRecordDecl *base =
1154 cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
Anders Carlssonada4b322010-11-22 18:42:14 +00001155
1156 // Ignore empty bases.
John McCall9b7da1c2011-02-15 06:40:56 +00001157 if (base->isEmpty())
Anders Carlssonada4b322010-11-22 18:42:14 +00001158 continue;
1159
John McCall9b7da1c2011-02-15 06:40:56 +00001160 unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
1161 const llvm::Type *baseType = structure->getElementType(fieldIndex);
1162 elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
Anders Carlssonada4b322010-11-22 18:42:14 +00001163 }
1164
John McCall9b7da1c2011-02-15 06:40:56 +00001165 // Fill in all the fields.
1166 for (RecordDecl::field_iterator I = record->field_begin(),
1167 E = record->field_end(); I != E; ++I) {
1168 const FieldDecl *field = *I;
Anders Carlssonada4b322010-11-22 18:42:14 +00001169
1170 // Ignore bit fields.
John McCall9b7da1c2011-02-15 06:40:56 +00001171 if (field->isBitField())
Anders Carlssonada4b322010-11-22 18:42:14 +00001172 continue;
1173
John McCall9b7da1c2011-02-15 06:40:56 +00001174 unsigned fieldIndex = layout.getLLVMFieldNo(field);
1175 elements[fieldIndex] = CGM.EmitNullConstant(field->getType());
1176 }
1177
1178 // Fill in the virtual bases, if we're working with the complete object.
1179 if (asCompleteObject) {
1180 for (CXXRecordDecl::base_class_const_iterator
1181 I = record->vbases_begin(), E = record->vbases_end(); I != E; ++I) {
1182 const CXXRecordDecl *base =
1183 cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
1184
1185 // Ignore empty bases.
1186 if (base->isEmpty())
1187 continue;
1188
1189 unsigned fieldIndex = layout.getVirtualBaseIndex(base);
1190
1191 // We might have already laid this field out.
1192 if (elements[fieldIndex]) continue;
1193
1194 const llvm::Type *baseType = structure->getElementType(fieldIndex);
1195 elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
1196 }
Anders Carlssonada4b322010-11-22 18:42:14 +00001197 }
1198
1199 // Now go through all other fields and zero them out.
John McCall9b7da1c2011-02-15 06:40:56 +00001200 for (unsigned i = 0; i != numElements; ++i) {
1201 if (!elements[i])
1202 elements[i] = llvm::Constant::getNullValue(structure->getElementType(i));
Anders Carlssonada4b322010-11-22 18:42:14 +00001203 }
1204
John McCall9b7da1c2011-02-15 06:40:56 +00001205 return llvm::ConstantStruct::get(structure, elements);
1206}
1207
1208/// Emit the null constant for a base subobject.
1209static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
1210 const llvm::Type *baseType,
1211 const CXXRecordDecl *base) {
1212 const CGRecordLayout &baseLayout = CGM.getTypes().getCGRecordLayout(base);
1213
1214 // Just zero out bases that don't have any pointer to data members.
1215 if (baseLayout.isZeroInitializableAsBase())
1216 return llvm::Constant::getNullValue(baseType);
1217
1218 // If the base type is a struct, we can just use its null constant.
1219 if (isa<llvm::StructType>(baseType)) {
1220 return EmitNullConstant(CGM, base, /*complete*/ false);
1221 }
1222
1223 // Otherwise, some bases are represented as arrays of i8 if the size
1224 // of the base is smaller than its corresponding LLVM type. Figure
1225 // out how many elements this base array has.
1226 const llvm::ArrayType *baseArrayType = cast<llvm::ArrayType>(baseType);
1227 unsigned numBaseElements = baseArrayType->getNumElements();
1228
1229 // Fill in null data member pointers.
1230 std::vector<llvm::Constant *> baseElements(numBaseElements);
1231 FillInNullDataMemberPointers(CGM, CGM.getContext().getTypeDeclType(base),
1232 baseElements, 0);
1233
1234 // Now go through all other elements and zero them out.
1235 if (numBaseElements) {
1236 const llvm::Type *i8 = llvm::Type::getInt8Ty(CGM.getLLVMContext());
1237 llvm::Constant *i8_zero = llvm::Constant::getNullValue(i8);
1238 for (unsigned i = 0; i != numBaseElements; ++i) {
1239 if (!baseElements[i])
1240 baseElements[i] = i8_zero;
1241 }
1242 }
1243
1244 return llvm::ConstantArray::get(baseArrayType, baseElements);
Anders Carlssonada4b322010-11-22 18:42:14 +00001245}
1246
Eli Friedman0f593122009-04-13 21:47:26 +00001247llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
John McCallf16aa102010-08-22 21:01:12 +00001248 if (getTypes().isZeroInitializable(T))
Anders Carlssonad3e7112009-08-24 17:16:23 +00001249 return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
Anders Carlsson2c12d032010-02-02 05:17:25 +00001250
Anders Carlsson237957c2009-08-09 18:26:27 +00001251 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) {
Mike Stump1eb44332009-09-09 15:08:12 +00001252
Anders Carlsson237957c2009-08-09 18:26:27 +00001253 QualType ElementTy = CAT->getElementType();
1254
Anders Carlsson2c12d032010-02-02 05:17:25 +00001255 llvm::Constant *Element = EmitNullConstant(ElementTy);
1256 unsigned NumElements = CAT->getSize().getZExtValue();
1257 std::vector<llvm::Constant *> Array(NumElements);
1258 for (unsigned i = 0; i != NumElements; ++i)
1259 Array[i] = Element;
Mike Stump1eb44332009-09-09 15:08:12 +00001260
Anders Carlsson2c12d032010-02-02 05:17:25 +00001261 const llvm::ArrayType *ATy =
1262 cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T));
1263 return llvm::ConstantArray::get(ATy, Array);
Anders Carlsson237957c2009-08-09 18:26:27 +00001264 }
Anders Carlssonfc3eaa42009-08-23 01:25:01 +00001265
1266 if (const RecordType *RT = T->getAs<RecordType>()) {
Anders Carlsson2c12d032010-02-02 05:17:25 +00001267 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
John McCall9b7da1c2011-02-15 06:40:56 +00001268 return ::EmitNullConstant(*this, RD, /*complete object*/ true);
Anders Carlssonfc3eaa42009-08-23 01:25:01 +00001269 }
Mike Stump1eb44332009-09-09 15:08:12 +00001270
Anders Carlssona83fb4b2010-05-18 16:51:41 +00001271 assert(T->isMemberPointerType() && "Should only see member pointers here!");
Anders Carlsson2c12d032010-02-02 05:17:25 +00001272 assert(!T->getAs<MemberPointerType>()->getPointeeType()->isFunctionType() &&
1273 "Should only see pointers to data members here!");
1274
1275 // Itanium C++ ABI 2.3:
1276 // A NULL pointer is represented as -1.
John McCall5808ce42011-02-03 08:15:49 +00001277 return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>());
Eli Friedman0f593122009-04-13 21:47:26 +00001278}