Clang Project

clang_source_code/lib/CodeGen/CGDeclCXX.cpp
1//===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This contains code dealing with code generation of C++ declarations
10//
11//===----------------------------------------------------------------------===//
12
13#include "CodeGenFunction.h"
14#include "CGCXXABI.h"
15#include "CGObjCRuntime.h"
16#include "CGOpenMPRuntime.h"
17#include "clang/Basic/CodeGenOptions.h"
18#include "llvm/ADT/StringExtras.h"
19#include "llvm/IR/Intrinsics.h"
20#include "llvm/IR/MDBuilder.h"
21#include "llvm/Support/Path.h"
22
23using namespace clang;
24using namespace CodeGen;
25
26static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
27                         ConstantAddress DeclPtr) {
28   (0) . __assert_fail ("(D.hasGlobalStorage() || (D.hasLocalStorage() && CGF.getContext().getLangOpts().OpenCLCPlusPlus)) && \"VarDecl must have global or local (in the case of OpenCL) storage!\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 31, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(
29 (0) . __assert_fail ("(D.hasGlobalStorage() || (D.hasLocalStorage() && CGF.getContext().getLangOpts().OpenCLCPlusPlus)) && \"VarDecl must have global or local (in the case of OpenCL) storage!\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 31, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">      (D.hasGlobalStorage() ||
30 (0) . __assert_fail ("(D.hasGlobalStorage() || (D.hasLocalStorage() && CGF.getContext().getLangOpts().OpenCLCPlusPlus)) && \"VarDecl must have global or local (in the case of OpenCL) storage!\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 31, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">       (D.hasLocalStorage() && CGF.getContext().getLangOpts().OpenCLCPlusPlus)) &&
31 (0) . __assert_fail ("(D.hasGlobalStorage() || (D.hasLocalStorage() && CGF.getContext().getLangOpts().OpenCLCPlusPlus)) && \"VarDecl must have global or local (in the case of OpenCL) storage!\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 31, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">      "VarDecl must have global or local (in the case of OpenCL) storage!");
32   (0) . __assert_fail ("!D.getType()->isReferenceType() && \"Should not call EmitDeclInit on a reference!\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 33, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(!D.getType()->isReferenceType() &&
33 (0) . __assert_fail ("!D.getType()->isReferenceType() && \"Should not call EmitDeclInit on a reference!\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 33, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">         "Should not call EmitDeclInit on a reference!");
34
35  QualType type = D.getType();
36  LValue lv = CGF.MakeAddrLValue(DeclPtr, type);
37
38  const Expr *Init = D.getInit();
39  switch (CGF.getEvaluationKind(type)) {
40  case TEK_Scalar: {
41    CodeGenModule &CGM = CGF.CGM;
42    if (lv.isObjCStrong())
43      CGM.getObjCRuntime().EmitObjCGlobalAssign(CGF, CGF.EmitScalarExpr(Init),
44                                                DeclPtr, D.getTLSKind());
45    else if (lv.isObjCWeak())
46      CGM.getObjCRuntime().EmitObjCWeakAssign(CGF, CGF.EmitScalarExpr(Init),
47                                              DeclPtr);
48    else
49      CGF.EmitScalarInit(Init, &D, lv, false);
50    return;
51  }
52  case TEK_Complex:
53    CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
54    return;
55  case TEK_Aggregate:
56    CGF.EmitAggExpr(Init, AggValueSlot::forLValue(lv,AggValueSlot::IsDestructed,
57                                          AggValueSlot::DoesNotNeedGCBarriers,
58                                                  AggValueSlot::IsNotAliased,
59                                                  AggValueSlot::DoesNotOverlap));
60    return;
61  }
62  llvm_unreachable("bad evaluation kind");
63}
64
65/// Emit code to cause the destruction of the given variable with
66/// static storage duration.
67static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
68                            ConstantAddress Addr) {
69  // Honor __attribute__((no_destroy)) and bail instead of attempting
70  // to emit a reference to a possibly nonexistent destructor, which
71  // in turn can cause a crash. This will result in a global constructor
72  // that isn't balanced out by a destructor call as intended by the
73  // attribute. This also checks for -fno-c++-static-destructors and
74  // bails even if the attribute is not present.
75  if (D.isNoDestroy(CGF.getContext()))
76    return;
77  
78  CodeGenModule &CGM = CGF.CGM;
79
80  // FIXME:  __attribute__((cleanup)) ?
81
82  QualType Type = D.getType();
83  QualType::DestructionKind DtorKind = Type.isDestructedType();
84
85  switch (DtorKind) {
86  case QualType::DK_none:
87    return;
88
89  case QualType::DK_cxx_destructor:
90    break;
91
92  case QualType::DK_objc_strong_lifetime:
93  case QualType::DK_objc_weak_lifetime:
94  case QualType::DK_nontrivial_c_struct:
95    // We don't care about releasing objects during process teardown.
96     (0) . __assert_fail ("!D.getTLSKind() && \"should have rejected this\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 96, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(!D.getTLSKind() && "should have rejected this");
97    return;
98  }
99
100  llvm::FunctionCallee Func;
101  llvm::Constant *Argument;
102
103  // Special-case non-array C++ destructors, if they have the right signature.
104  // Under some ABIs, destructors return this instead of void, and cannot be
105  // passed directly to __cxa_atexit if the target does not allow this
106  // mismatch.
107  const CXXRecordDecl *Record = Type->getAsCXXRecordDecl();
108  bool CanRegisterDestructor =
109      Record && (!CGM.getCXXABI().HasThisReturn(
110                     GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
111                 CGM.getCXXABI().canCallMismatchedFunctionType());
112  // If __cxa_atexit is disabled via a flag, a different helper function is
113  // generated elsewhere which uses atexit instead, and it takes the destructor
114  // directly.
115  bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
116  if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
117    hasTrivialDestructor()", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 117, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(!Record->hasTrivialDestructor());
118    CXXDestructorDecl *Dtor = Record->getDestructor();
119
120    Func = CGM.getAddrAndTypeOfCXXStructor(GlobalDecl(Dtor, Dtor_Complete));
121    Argument = llvm::ConstantExpr::getBitCast(
122        Addr.getPointer(), CGF.getTypes().ConvertType(Type)->getPointerTo());
123
124  // Otherwise, the standard logic requires a helper function.
125  } else {
126    Func = CodeGenFunction(CGM)
127           .generateDestroyHelper(Addr, Type, CGF.getDestroyer(DtorKind),
128                                  CGF.needsEHCleanup(DtorKind), &D);
129    Argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
130  }
131
132  CGM.getCXXABI().registerGlobalDtor(CGF, D, Func, Argument);
133}
134
135/// Emit code to cause the variable at the given address to be considered as
136/// constant from this point onwards.
137static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
138                              llvm::Constant *Addr) {
139  return CGF.EmitInvariantStart(
140      Addr, CGF.getContext().getTypeSizeInChars(D.getType()));
141}
142
143void CodeGenFunction::EmitInvariantStart(llvm::Constant *Addr, CharUnits Size) {
144  // Do not emit the intrinsic if we're not optimizing.
145  if (!CGM.getCodeGenOpts().OptimizationLevel)
146    return;
147
148  // Grab the llvm.invariant.start intrinsic.
149  llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
150  // Overloaded address space type.
151  llvm::Type *ObjectPtr[1] = {Int8PtrTy};
152  llvm::Function *InvariantStart = CGM.getIntrinsic(InvStartID, ObjectPtr);
153
154  // Emit a call with the size in bytes of the object.
155  uint64_t Width = Size.getQuantity();
156  llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(Int64Ty, Width),
157                           llvm::ConstantExpr::getBitCast(Addr, Int8PtrTy)};
158  Builder.CreateCall(InvariantStart, Args);
159}
160
161void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
162                                               llvm::Constant *DeclPtr,
163                                               bool PerformInit) {
164
165  const Expr *Init = D.getInit();
166  QualType T = D.getType();
167
168  // The address space of a static local variable (DeclPtr) may be different
169  // from the address space of the "this" argument of the constructor. In that
170  // case, we need an addrspacecast before calling the constructor.
171  //
172  // struct StructWithCtor {
173  //   __device__ StructWithCtor() {...}
174  // };
175  // __device__ void foo() {
176  //   __shared__ StructWithCtor s;
177  //   ...
178  // }
179  //
180  // For example, in the above CUDA code, the static local variable s has a
181  // "shared" address space qualifier, but the constructor of StructWithCtor
182  // expects "this" in the "generic" address space.
183  unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
184  unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
185  if (ActualAddrSpace != ExpectedAddrSpace) {
186    llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(T);
187    llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
188    DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
189  }
190
191  ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
192
193  if (!T->isReferenceType()) {
194    if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
195        D.hasAttr<OMPThreadPrivateDeclAttr>()) {
196      (void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
197          &D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
198          PerformInit, this);
199    }
200    if (PerformInit)
201      EmitDeclInit(*this, D, DeclAddr);
202    if (CGM.isTypeConstant(D.getType(), true))
203      EmitDeclInvariant(*this, D, DeclPtr);
204    else
205      EmitDeclDestroy(*this, D, DeclAddr);
206    return;
207  }
208
209   (0) . __assert_fail ("PerformInit && \"cannot have constant initializer which needs \" \"destruction for reference\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 210, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(PerformInit && "cannot have constant initializer which needs "
210 (0) . __assert_fail ("PerformInit && \"cannot have constant initializer which needs \" \"destruction for reference\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 210, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">         "destruction for reference");
211  RValue RV = EmitReferenceBindingToExpr(Init);
212  EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
213}
214
215/// Create a stub function, suitable for being passed to atexit,
216/// which passes the given address to the given destructor function.
217llvm::Function *CodeGenFunction::createAtExitStub(const VarDecl &VD,
218                                                  llvm::FunctionCallee dtor,
219                                                  llvm::Constant *addr) {
220  // Get the destructor function type, void(*)(void).
221  llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
222  SmallString<256> FnName;
223  {
224    llvm::raw_svector_ostream Out(FnName);
225    CGM.getCXXABI().getMangleContext().mangleDynamicAtExitDestructor(&VD, Out);
226  }
227
228  const CGFunctionInfo &FI = CGM.getTypes().arrangeNullaryFunction();
229  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(ty, FnName.str(),
230                                                              FI,
231                                                              VD.getLocation());
232
233  CodeGenFunction CGF(CGM);
234
235  CGF.StartFunction(&VD, CGM.getContext().VoidTy, fn, FI, FunctionArgList());
236
237  llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
238
239 // Make sure the call and the callee agree on calling convention.
240  if (llvm::Function *dtorFn =
241          dyn_cast<llvm::Function>(dtor.getCallee()->stripPointerCasts()))
242    call->setCallingConv(dtorFn->getCallingConv());
243
244  CGF.FinishFunction();
245
246  return fn;
247}
248
249/// Register a global destructor using the C atexit runtime function.
250void CodeGenFunction::registerGlobalDtorWithAtExit(const VarDecl &VD,
251                                                   llvm::FunctionCallee dtor,
252                                                   llvm::Constant *addr) {
253  // Create a function which calls the destructor.
254  llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
255  registerGlobalDtorWithAtExit(dtorStub);
256}
257
258void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
259  // extern "C" int atexit(void (*f)(void));
260  llvm::FunctionType *atexitTy =
261    llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
262
263  llvm::FunctionCallee atexit =
264      CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
265                                /*Local=*/true);
266  if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit.getCallee()))
267    atexitFn->setDoesNotThrow();
268
269  EmitNounwindRuntimeCall(atexit, dtorStub);
270}
271
272void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
273                                         llvm::GlobalVariable *DeclPtr,
274                                         bool PerformInit) {
275  // If we've been asked to forbid guard variables, emit an error now.
276  // This diagnostic is hard-coded for Darwin's use case;  we can find
277  // better phrasing if someone else needs it.
278  if (CGM.getCodeGenOpts().ForbidGuardVariables)
279    CGM.Error(D.getLocation(),
280              "this initialization requires a guard variable, which "
281              "the kernel does not support");
282
283  CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
284}
285
286void CodeGenFunction::EmitCXXGuardedInitBranch(llvm::Value *NeedsInit,
287                                               llvm::BasicBlock *InitBlock,
288                                               llvm::BasicBlock *NoInitBlock,
289                                               GuardKind Kind,
290                                               const VarDecl *D) {
291   (0) . __assert_fail ("(Kind == GuardKind..TlsGuard || D) && \"no guarded variable\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 291, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
292
293  // A guess at how many times we will enter the initialization of a
294  // variable, depending on the kind of variable.
295  static const uint64_t InitsPerTLSVar = 1024;
296  static const uint64_t InitsPerLocalVar = 1024 * 1024;
297
298  llvm::MDNode *Weights;
299  if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
300    // For non-local variables, don't apply any weighting for now. Due to our
301    // use of COMDATs, we expect there to be at most one initialization of the
302    // variable per DSO, but we have no way to know how many DSOs will try to
303    // initialize the variable.
304    Weights = nullptr;
305  } else {
306    uint64_t NumInits;
307    // FIXME: For the TLS case, collect and use profiling information to
308    // determine a more accurate brach weight.
309    if (Kind == GuardKind::TlsGuard || D->getTLSKind())
310      NumInits = InitsPerTLSVar;
311    else
312      NumInits = InitsPerLocalVar;
313
314    // The probability of us entering the initializer is
315    //   1 / (total number of times we attempt to initialize the variable).
316    llvm::MDBuilder MDHelper(CGM.getLLVMContext());
317    Weights = MDHelper.createBranchWeights(1, NumInits - 1);
318  }
319
320  Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
321}
322
323llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
324    llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
325    SourceLocation Loc, bool TLS) {
326  llvm::Function *Fn =
327    llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
328                           Name, &getModule());
329  if (!getLangOpts().AppleKext && !TLS) {
330    // Set the section if needed.
331    if (const char *Section = getTarget().getStaticInitSectionSpecifier())
332      Fn->setSection(Section);
333  }
334
335  SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
336
337  Fn->setCallingConv(getRuntimeCC());
338
339  if (!getLangOpts().Exceptions)
340    Fn->setDoesNotThrow();
341
342  if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
343      !isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
344    Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
345
346  if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
347      !isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
348    Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
349
350  if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
351      !isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
352    Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
353
354  if (getLangOpts().Sanitize.has(SanitizerKind::KernelHWAddress) &&
355      !isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
356    Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
357
358  if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
359      !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
360    Fn->addFnAttr(llvm::Attribute::SanitizeThread);
361
362  if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
363      !isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
364    Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
365
366  if (getLangOpts().Sanitize.has(SanitizerKind::KernelMemory) &&
367      !isInSanitizerBlacklist(SanitizerKind::KernelMemory, Fn, Loc))
368    Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
369
370  if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
371      !isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
372    Fn->addFnAttr(llvm::Attribute::SafeStack);
373
374  if (getLangOpts().Sanitize.has(SanitizerKind::ShadowCallStack) &&
375      !isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
376    Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
377
378  auto RASignKind = getCodeGenOpts().getSignReturnAddress();
379  if (RASignKind != CodeGenOptions::SignReturnAddressScope::None) {
380    Fn->addFnAttr("sign-return-address",
381                  RASignKind == CodeGenOptions::SignReturnAddressScope::All
382                      ? "all"
383                      : "non-leaf");
384    auto RASignKey = getCodeGenOpts().getSignReturnAddressKey();
385    Fn->addFnAttr("sign-return-address-key",
386                  RASignKey == CodeGenOptions::SignReturnAddressKeyValue::AKey
387                      ? "a_key"
388                      : "b_key");
389  }
390
391  if (getCodeGenOpts().BranchTargetEnforcement)
392    Fn->addFnAttr("branch-target-enforcement");
393
394  return Fn;
395}
396
397/// Create a global pointer to a function that will initialize a global
398/// variable.  The user has requested that this pointer be emitted in a specific
399/// section.
400void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
401                                          llvm::GlobalVariable *GV,
402                                          llvm::Function *InitFunc,
403                                          InitSegAttr *ISA) {
404  llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
405      TheModule, InitFunc->getType(), /*isConstant=*/true,
406      llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
407  PtrArray->setSection(ISA->getSection());
408  addUsedGlobal(PtrArray);
409
410  // If the GV is already in a comdat group, then we have to join it.
411  if (llvm::Comdat *C = GV->getComdat())
412    PtrArray->setComdat(C);
413}
414
415void
416CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
417                                            llvm::GlobalVariable *Addr,
418                                            bool PerformInit) {
419
420  // According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
421  // __constant__ and __shared__ variables defined in namespace scope,
422  // that are of class type, cannot have a non-empty constructor. All
423  // the checks have been done in Sema by now. Whatever initializers
424  // are allowed are empty and we just need to ignore them here.
425  if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
426      (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
427       D->hasAttr<CUDASharedAttr>()))
428    return;
429
430  if (getLangOpts().OpenMP &&
431      getOpenMPRuntime().emitDeclareTargetVarDefinition(D, Addr, PerformInit))
432    return;
433
434  // Check if we've already initialized this decl.
435  auto I = DelayedCXXInitPosition.find(D);
436  if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
437    return;
438
439  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
440  SmallString<256> FnName;
441  {
442    llvm::raw_svector_ostream Out(FnName);
443    getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
444  }
445
446  // Create a variable initialization function.
447  llvm::Function *Fn =
448      CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
449                                         getTypes().arrangeNullaryFunction(),
450                                         D->getLocation());
451
452  auto *ISA = D->getAttr<InitSegAttr>();
453  CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
454                                                          PerformInit);
455
456  llvm::GlobalVariable *COMDATKey =
457      supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
458
459  if (D->getTLSKind()) {
460    // FIXME: Should we support init_priority for thread_local?
461    // FIXME: We only need to register one __cxa_thread_atexit function for the
462    // entire TU.
463    CXXThreadLocalInits.push_back(Fn);
464    CXXThreadLocalInitVars.push_back(D);
465  } else if (PerformInit && ISA) {
466    EmitPointerToInitFunc(D, Addr, Fn, ISA);
467  } else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
468    OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
469    PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
470  } else if (isTemplateInstantiation(D->getTemplateSpecializationKind())) {
471    // C++ [basic.start.init]p2:
472    //   Definitions of explicitly specialized class template static data
473    //   members have ordered initialization. Other class template static data
474    //   members (i.e., implicitly or explicitly instantiated specializations)
475    //   have unordered initialization.
476    //
477    // As a consequence, we can put them into their own llvm.global_ctors entry.
478    //
479    // If the global is externally visible, put the initializer into a COMDAT
480    // group with the global being initialized.  On most platforms, this is a
481    // minor startup time optimization.  In the MS C++ ABI, there are no guard
482    // variables, so this COMDAT key is required for correctness.
483    AddGlobalCtor(Fn, 65535, COMDATKey);
484  } else if (D->hasAttr<SelectAnyAttr>()) {
485    // SelectAny globals will be comdat-folded. Put the initializer into a
486    // COMDAT group associated with the global, so the initializers get folded
487    // too.
488    AddGlobalCtor(Fn, 65535, COMDATKey);
489  } else {
490    I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
491    if (I == DelayedCXXInitPosition.end()) {
492      CXXGlobalInits.push_back(Fn);
493    } else if (I->second != ~0U) {
494      second < CXXGlobalInits.size() && CXXGlobalInits[I->second] == nullptr", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 495, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(I->second < CXXGlobalInits.size() &&
495second < CXXGlobalInits.size() && CXXGlobalInits[I->second] == nullptr", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/CGDeclCXX.cpp", 495, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">             CXXGlobalInits[I->second] == nullptr);
496      CXXGlobalInits[I->second] = Fn;
497    }
498  }
499
500  // Remember that we already emitted the initializer for this global.
501  DelayedCXXInitPosition[D] = ~0U;
502}
503
504void CodeGenModule::EmitCXXThreadLocalInitFunc() {
505  getCXXABI().EmitThreadLocalInitFuncs(
506      *this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
507
508  CXXThreadLocalInits.clear();
509  CXXThreadLocalInitVars.clear();
510  CXXThreadLocals.clear();
511}
512
513void
514CodeGenModule::EmitCXXGlobalInitFunc() {
515  while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
516    CXXGlobalInits.pop_back();
517
518  if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
519    return;
520
521  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
522  const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
523
524  // Create our global initialization function.
525  if (!PrioritizedCXXGlobalInits.empty()) {
526    SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
527    llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
528                         PrioritizedCXXGlobalInits.end());
529    // Iterate over "chunks" of ctors with same priority and emit each chunk
530    // into separate function. Note - everything is sorted first by priority,
531    // second - by lex order, so we emit ctor functions in proper order.
532    for (SmallVectorImpl<GlobalInitData >::iterator
533           I = PrioritizedCXXGlobalInits.begin(),
534           E = PrioritizedCXXGlobalInits.end(); I != E; ) {
535      SmallVectorImpl<GlobalInitData >::iterator
536        PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
537
538      LocalCXXGlobalInits.clear();
539      unsigned Priority = I->first.priority;
540      // Compute the function suffix from priority. Prepend with zeroes to make
541      // sure the function names are also ordered as priorities.
542      std::string PrioritySuffix = llvm::utostr(Priority);
543      // Priority is always <= 65535 (enforced by sema).
544      PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
545      llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
546          FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
547
548      for (; I < PrioE; ++I)
549        LocalCXXGlobalInits.push_back(I->second);
550
551      CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
552      AddGlobalCtor(Fn, Priority);
553    }
554    PrioritizedCXXGlobalInits.clear();
555  }
556
557  // Include the filename in the symbol name. Including "sub_" matches gcc and
558  // makes sure these symbols appear lexicographically behind the symbols with
559  // priority emitted above.
560  SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
561  if (FileName.empty())
562    FileName = "<null>";
563
564  for (size_t i = 0; i < FileName.size(); ++i) {
565    // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
566    // to be the set of C preprocessing numbers.
567    if (!isPreprocessingNumberBody(FileName[i]))
568      FileName[i] = '_';
569  }
570
571  llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
572      FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
573
574  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
575  AddGlobalCtor(Fn);
576
577  CXXGlobalInits.clear();
578}
579
580void CodeGenModule::EmitCXXGlobalDtorFunc() {
581  if (CXXGlobalDtors.empty())
582    return;
583
584  llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
585
586  // Create our global destructor function.
587  const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
588  llvm::Function *Fn =
589      CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
590
591  CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
592  AddGlobalDtor(Fn);
593}
594
595/// Emit the code necessary to initialize the given global variable.
596void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
597                                                       const VarDecl *D,
598                                                 llvm::GlobalVariable *Addr,
599                                                       bool PerformInit) {
600  // Check if we need to emit debug info for variable initializer.
601  if (D->hasAttr<NoDebugAttr>())
602    DebugInfo = nullptr; // disable debug info indefinitely for this function
603
604  CurEHLocation = D->getBeginLoc();
605
606  StartFunction(GlobalDecl(D), getContext().VoidTy, Fn,
607                getTypes().arrangeNullaryFunction(),
608                FunctionArgList(), D->getLocation(),
609                D->getInit()->getExprLoc());
610
611  // Use guarded initialization if the global variable is weak. This
612  // occurs for, e.g., instantiated static data members and
613  // definitions explicitly marked weak.
614  if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage()) {
615    EmitCXXGuardedInit(*D, Addr, PerformInit);
616  } else {
617    EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
618  }
619
620  FinishFunction();
621}
622
623void
624CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
625                                           ArrayRef<llvm::Function *> Decls,
626                                           ConstantAddress Guard) {
627  {
628    auto NL = ApplyDebugLocation::CreateEmpty(*this);
629    StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
630                  getTypes().arrangeNullaryFunction(), FunctionArgList());
631    // Emit an artificial location for this function.
632    auto AL = ApplyDebugLocation::CreateArtificial(*this);
633
634    llvm::BasicBlock *ExitBlock = nullptr;
635    if (Guard.isValid()) {
636      // If we have a guard variable, check whether we've already performed
637      // these initializations. This happens for TLS initialization functions.
638      llvm::Value *GuardVal = Builder.CreateLoad(Guard);
639      llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
640                                                 "guard.uninitialized");
641      llvm::BasicBlock *InitBlock = createBasicBlock("init");
642      ExitBlock = createBasicBlock("exit");
643      EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
644                               GuardKind::TlsGuard, nullptr);
645      EmitBlock(InitBlock);
646      // Mark as initialized before initializing anything else. If the
647      // initializers use previously-initialized thread_local vars, that's
648      // probably supposed to be OK, but the standard doesn't say.
649      Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
650
651      // The guard variable can't ever change again.
652      EmitInvariantStart(
653          Guard.getPointer(),
654          CharUnits::fromQuantity(
655              CGM.getDataLayout().getTypeAllocSize(GuardVal->getType())));
656    }
657
658    RunCleanupsScope Scope(*this);
659
660    // When building in Objective-C++ ARC mode, create an autorelease pool
661    // around the global initializers.
662    if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
663      llvm::Value *token = EmitObjCAutoreleasePoolPush();
664      EmitObjCAutoreleasePoolCleanup(token);
665    }
666
667    for (unsigned i = 0, e = Decls.size(); i != e; ++i)
668      if (Decls[i])
669        EmitRuntimeCall(Decls[i]);
670
671    Scope.ForceCleanup();
672
673    if (ExitBlock) {
674      Builder.CreateBr(ExitBlock);
675      EmitBlock(ExitBlock);
676    }
677  }
678
679  FinishFunction();
680}
681
682void CodeGenFunction::GenerateCXXGlobalDtorsFunc(
683    llvm::Function *Fn,
684    const std::vector<std::tuple<llvm::FunctionType *, llvm::WeakTrackingVH,
685                                 llvm::Constant *>> &DtorsAndObjects) {
686  {
687    auto NL = ApplyDebugLocation::CreateEmpty(*this);
688    StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
689                  getTypes().arrangeNullaryFunction(), FunctionArgList());
690    // Emit an artificial location for this function.
691    auto AL = ApplyDebugLocation::CreateArtificial(*this);
692
693    // Emit the dtors, in reverse order from construction.
694    for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
695      llvm::FunctionType *CalleeTy;
696      llvm::Value *Callee;
697      llvm::Constant *Arg;
698      std::tie(CalleeTy, Callee, Arg) = DtorsAndObjects[e - i - 1];
699      llvm::CallInst *CI = Builder.CreateCall(CalleeTy, Callee, Arg);
700      // Make sure the call and the callee agree on calling convention.
701      if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
702        CI->setCallingConv(F->getCallingConv());
703    }
704  }
705
706  FinishFunction();
707}
708
709/// generateDestroyHelper - Generates a helper function which, when
710/// invoked, destroys the given object.  The address of the object
711/// should be in global memory.
712llvm::Function *CodeGenFunction::generateDestroyHelper(
713    Address addr, QualType type, Destroyer *destroyer,
714    bool useEHCleanupForArray, const VarDecl *VD) {
715  FunctionArgList args;
716  ImplicitParamDecl Dst(getContext(), getContext().VoidPtrTy,
717                        ImplicitParamDecl::Other);
718  args.push_back(&Dst);
719
720  const CGFunctionInfo &FI =
721    CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, args);
722  llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
723  llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
724      FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
725
726  CurEHLocation = VD->getBeginLoc();
727
728  StartFunction(VD, getContext().VoidTy, fn, FI, args);
729
730  emitDestroy(addr, type, destroyer, useEHCleanupForArray);
731
732  FinishFunction();
733
734  return fn;
735}
736
clang::CodeGen::CodeGenFunction::EmitInvariantStart
clang::CodeGen::CodeGenFunction::EmitCXXGlobalVarDeclInit
clang::CodeGen::CodeGenFunction::createAtExitStub
clang::CodeGen::CodeGenFunction::registerGlobalDtorWithAtExit
clang::CodeGen::CodeGenFunction::registerGlobalDtorWithAtExit
clang::CodeGen::CodeGenFunction::EmitCXXGuardedInit
clang::CodeGen::CodeGenFunction::EmitCXXGuardedInitBranch
clang::CodeGen::CodeGenModule::CreateGlobalInitOrDestructFunction
clang::CodeGen::CodeGenModule::EmitPointerToInitFunc
clang::CodeGen::CodeGenModule::EmitCXXGlobalVarDeclInitFunc
clang::CodeGen::CodeGenModule::EmitCXXThreadLocalInitFunc
clang::CodeGen::CodeGenModule::EmitCXXGlobalInitFunc
clang::CodeGen::CodeGenModule::EmitCXXGlobalDtorFunc
clang::CodeGen::CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc
clang::CodeGen::CodeGenFunction::GenerateCXXGlobalInitFunc
clang::CodeGen::CodeGenFunction::GenerateCXXGlobalDtorsFunc
clang::CodeGen::CodeGenFunction::generateDestroyHelper
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