1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
|
//===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code dealing with code generation of C++ declarations
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "clang/CodeGen/CodeGenOptions.h"
using namespace clang;
using namespace CodeGen;
static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
llvm::Constant *DeclPtr) {
assert(D.hasGlobalStorage() && "VarDecl must have global storage!");
assert(!D.getType()->isReferenceType() &&
"Should not call EmitDeclInit on a reference!");
CodeGenModule &CGM = CGF.CGM;
ASTContext &Context = CGF.getContext();
const Expr *Init = D.getInit();
QualType T = D.getType();
bool isVolatile = Context.getCanonicalType(T).isVolatileQualified();
if (!CGF.hasAggregateLLVMType(T)) {
llvm::Value *V = CGF.EmitScalarExpr(Init);
CGF.EmitStoreOfScalar(V, DeclPtr, isVolatile, T);
} else if (T->isAnyComplexType()) {
CGF.EmitComplexExprIntoAddr(Init, DeclPtr, isVolatile);
} else {
CGF.EmitAggExpr(Init, DeclPtr, isVolatile);
// Avoid generating destructor(s) for initialized objects.
if (!isa<CXXConstructExpr>(Init))
return;
const ConstantArrayType *Array = Context.getAsConstantArrayType(T);
if (Array)
T = Context.getBaseElementType(Array);
const RecordType *RT = T->getAs<RecordType>();
if (!RT)
return;
CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
if (RD->hasTrivialDestructor())
return;
CXXDestructorDecl *Dtor = RD->getDestructor(Context);
llvm::Constant *DtorFn;
if (Array) {
DtorFn =
CodeGenFunction(CGM).GenerateCXXAggrDestructorHelper(Dtor,
Array,
DeclPtr);
const llvm::Type *Int8PtrTy =
llvm::Type::getInt8PtrTy(CGM.getLLVMContext());
DeclPtr = llvm::Constant::getNullValue(Int8PtrTy);
} else
DtorFn = CGM.GetAddrOfCXXDestructor(Dtor, Dtor_Complete);
CGF.EmitCXXGlobalDtorRegistration(DtorFn, DeclPtr);
}
}
void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
llvm::Constant *DeclPtr) {
const Expr *Init = D.getInit();
QualType T = D.getType();
if (!T->isReferenceType()) {
EmitDeclInit(*this, D, DeclPtr);
return;
}
if (Init->isLvalue(getContext()) == Expr::LV_Valid) {
RValue RV = EmitReferenceBindingToExpr(Init, /*IsInitializer=*/true);
EmitStoreOfScalar(RV.getScalarVal(), DeclPtr, false, T);
return;
}
ErrorUnsupported(Init,
"global variable that binds reference to a non-lvalue");
}
void
CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *DtorFn,
llvm::Constant *DeclPtr) {
// Generate a global destructor entry if not using __cxa_atexit.
if (!CGM.getCodeGenOpts().CXAAtExit) {
CGM.AddCXXDtorEntry(DtorFn, DeclPtr);
return;
}
const llvm::Type *Int8PtrTy =
llvm::Type::getInt8Ty(VMContext)->getPointerTo();
std::vector<const llvm::Type *> Params;
Params.push_back(Int8PtrTy);
// Get the destructor function type
const llvm::Type *DtorFnTy =
llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), Params, false);
DtorFnTy = llvm::PointerType::getUnqual(DtorFnTy);
Params.clear();
Params.push_back(DtorFnTy);
Params.push_back(Int8PtrTy);
Params.push_back(Int8PtrTy);
// Get the __cxa_atexit function type
// extern "C" int __cxa_atexit ( void (*f)(void *), void *p, void *d );
const llvm::FunctionType *AtExitFnTy =
llvm::FunctionType::get(ConvertType(getContext().IntTy), Params, false);
llvm::Constant *AtExitFn = CGM.CreateRuntimeFunction(AtExitFnTy,
"__cxa_atexit");
llvm::Constant *Handle = CGM.CreateRuntimeVariable(Int8PtrTy,
"__dso_handle");
llvm::Value *Args[3] = { llvm::ConstantExpr::getBitCast(DtorFn, DtorFnTy),
llvm::ConstantExpr::getBitCast(DeclPtr, Int8PtrTy),
llvm::ConstantExpr::getBitCast(Handle, Int8PtrTy) };
Builder.CreateCall(AtExitFn, &Args[0], llvm::array_endof(Args));
}
void
CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D) {
const llvm::FunctionType *FTy
= llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
false);
// Create a variable initialization function.
llvm::Function *Fn =
llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
"__cxx_global_var_init", &TheModule);
CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D);
CXXGlobalInits.push_back(Fn);
}
void
CodeGenModule::EmitCXXGlobalInitFunc() {
if (CXXGlobalInits.empty())
return;
const llvm::FunctionType *FTy
= llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
false);
// Create our global initialization function.
llvm::Function *Fn =
llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
"_GLOBAL__I_a", &TheModule);
CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn,
&CXXGlobalInits[0],
CXXGlobalInits.size());
AddGlobalCtor(Fn);
}
void CodeGenModule::AddCXXDtorEntry(llvm::Constant *DtorFn,
llvm::Constant *Object) {
CXXGlobalDtors.push_back(std::make_pair(DtorFn, Object));
}
void CodeGenModule::EmitCXXGlobalDtorFunc() {
if (CXXGlobalDtors.empty())
return;
const llvm::FunctionType *FTy
= llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
false);
// Create our global destructor function.
llvm::Function *Fn =
llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
"_GLOBAL__D_a", &TheModule);
CodeGenFunction(*this).GenerateCXXGlobalDtorFunc(Fn, CXXGlobalDtors);
AddGlobalDtor(Fn);
}
void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
const VarDecl *D) {
StartFunction(GlobalDecl(), getContext().VoidTy, Fn, FunctionArgList(),
SourceLocation());
llvm::Constant *DeclPtr = CGM.GetAddrOfGlobalVar(D);
EmitCXXGlobalVarDeclInit(*D, DeclPtr);
FinishFunction();
}
void CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
llvm::Constant **Decls,
unsigned NumDecls) {
StartFunction(GlobalDecl(), getContext().VoidTy, Fn, FunctionArgList(),
SourceLocation());
for (unsigned i = 0; i != NumDecls; ++i)
Builder.CreateCall(Decls[i]);
FinishFunction();
}
void CodeGenFunction::GenerateCXXGlobalDtorFunc(llvm::Function *Fn,
const std::vector<std::pair<llvm::Constant*, llvm::Constant*> >
&DtorsAndObjects) {
StartFunction(GlobalDecl(), getContext().VoidTy, Fn, FunctionArgList(),
SourceLocation());
// Emit the dtors, in reverse order from construction.
for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
llvm::Constant *Callee = DtorsAndObjects[e - i - 1].first;
llvm::CallInst *CI = Builder.CreateCall(Callee,
DtorsAndObjects[e - i - 1].second);
// Make sure the call and the callee agree on calling convention.
if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
CI->setCallingConv(F->getCallingConv());
}
FinishFunction();
}
static llvm::Constant *getGuardAcquireFn(CodeGenFunction &CGF) {
// int __cxa_guard_acquire(__int64_t *guard_object);
const llvm::Type *Int64PtrTy =
llvm::Type::getInt64PtrTy(CGF.getLLVMContext());
std::vector<const llvm::Type*> Args(1, Int64PtrTy);
const llvm::FunctionType *FTy =
llvm::FunctionType::get(CGF.ConvertType(CGF.getContext().IntTy),
Args, /*isVarArg=*/false);
return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_guard_acquire");
}
static llvm::Constant *getGuardReleaseFn(CodeGenFunction &CGF) {
// void __cxa_guard_release(__int64_t *guard_object);
const llvm::Type *Int64PtrTy =
llvm::Type::getInt64PtrTy(CGF.getLLVMContext());
std::vector<const llvm::Type*> Args(1, Int64PtrTy);
const llvm::FunctionType *FTy =
llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()),
Args, /*isVarArg=*/false);
return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_guard_release");
}
static llvm::Constant *getGuardAbortFn(CodeGenFunction &CGF) {
// void __cxa_guard_abort(__int64_t *guard_object);
const llvm::Type *Int64PtrTy =
llvm::Type::getInt64PtrTy(CGF.getLLVMContext());
std::vector<const llvm::Type*> Args(1, Int64PtrTy);
const llvm::FunctionType *FTy =
llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()),
Args, /*isVarArg=*/false);
return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_guard_abort");
}
void
CodeGenFunction::EmitStaticCXXBlockVarDeclInit(const VarDecl &D,
llvm::GlobalVariable *GV) {
bool ThreadsafeStatics = getContext().getLangOptions().ThreadsafeStatics;
llvm::SmallString<256> GuardVName;
CGM.getMangleContext().mangleGuardVariable(&D, GuardVName);
// Create the guard variable.
const llvm::Type *Int64Ty = llvm::Type::getInt64Ty(VMContext);
llvm::GlobalValue *GuardVariable =
new llvm::GlobalVariable(CGM.getModule(), Int64Ty,
false, GV->getLinkage(),
llvm::Constant::getNullValue(Int64Ty),
GuardVName.str());
// Load the first byte of the guard variable.
const llvm::Type *PtrTy
= llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext), 0);
llvm::Value *V =
Builder.CreateLoad(Builder.CreateBitCast(GuardVariable, PtrTy), "tmp");
llvm::BasicBlock *InitCheckBlock = createBasicBlock("init.check");
llvm::BasicBlock *EndBlock = createBasicBlock("init.end");
// Check if the first byte of the guard variable is zero.
Builder.CreateCondBr(Builder.CreateIsNull(V, "tobool"),
InitCheckBlock, EndBlock);
EmitBlock(InitCheckBlock);
if (ThreadsafeStatics) {
// Call __cxa_guard_acquire.
V = Builder.CreateCall(getGuardAcquireFn(*this), GuardVariable);
llvm::BasicBlock *InitBlock = createBasicBlock("init");
Builder.CreateCondBr(Builder.CreateIsNotNull(V, "tobool"),
InitBlock, EndBlock);
EmitBlock(InitBlock);
if (Exceptions) {
EHCleanupBlock Cleanup(*this);
// Call __cxa_guard_abort.
Builder.CreateCall(getGuardAbortFn(*this), GuardVariable);
}
}
if (D.getType()->isReferenceType()) {
QualType T = D.getType();
// We don't want to pass true for IsInitializer here, because a static
// reference to a temporary does not extend its lifetime.
RValue RV = EmitReferenceBindingToExpr(D.getInit(),
/*IsInitializer=*/false);
EmitStoreOfScalar(RV.getScalarVal(), GV, /*Volatile=*/false, T);
} else
EmitDeclInit(*this, D, GV);
if (ThreadsafeStatics) {
// Call __cxa_guard_release.
Builder.CreateCall(getGuardReleaseFn(*this), GuardVariable);
} else {
llvm::Value *One =
llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext), 1);
Builder.CreateStore(One, Builder.CreateBitCast(GuardVariable, PtrTy));
}
EmitBlock(EndBlock);
}
|