llvm-project/clang/lib/CodeGen/CGDeclCXX.cpp

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//===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This contains code dealing with code generation of C++ declarations
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "CGCXXABI.h"
#include "CGObjCRuntime.h"
#include "CGOpenMPRuntime.h"
#include "TargetInfo.h"
#include "clang/Basic/CodeGenOptions.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/Support/Path.h"
using namespace clang;
using namespace CodeGen;
static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
ConstantAddress DeclPtr) {
assert(
(D.hasGlobalStorage() ||
(D.hasLocalStorage() && CGF.getContext().getLangOpts().OpenCLCPlusPlus)) &&
"VarDecl must have global or local (in the case of OpenCL) storage!");
assert(!D.getType()->isReferenceType() &&
"Should not call EmitDeclInit on a reference!");
QualType type = D.getType();
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
LValue lv = CGF.MakeAddrLValue(DeclPtr, type);
const Expr *Init = D.getInit();
switch (CGF.getEvaluationKind(type)) {
case TEK_Scalar: {
CodeGenModule &CGM = CGF.CGM;
if (lv.isObjCStrong())
CGM.getObjCRuntime().EmitObjCGlobalAssign(CGF, CGF.EmitScalarExpr(Init),
DeclPtr, D.getTLSKind());
else if (lv.isObjCWeak())
CGM.getObjCRuntime().EmitObjCWeakAssign(CGF, CGF.EmitScalarExpr(Init),
DeclPtr);
else
CGF.EmitScalarInit(Init, &D, lv, false);
return;
}
case TEK_Complex:
CGF.EmitComplexExprIntoLValue(Init, lv, /*isInit*/ true);
return;
case TEK_Aggregate:
CGF.EmitAggExpr(Init, AggValueSlot::forLValue(lv,AggValueSlot::IsDestructed,
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsNotAliased,
AggValueSlot::DoesNotOverlap));
return;
}
llvm_unreachable("bad evaluation kind");
}
/// Emit code to cause the destruction of the given variable with
/// static storage duration.
static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
ConstantAddress Addr) {
// Honor __attribute__((no_destroy)) and bail instead of attempting
// to emit a reference to a possibly nonexistent destructor, which
// in turn can cause a crash. This will result in a global constructor
// that isn't balanced out by a destructor call as intended by the
// attribute. This also checks for -fno-c++-static-destructors and
// bails even if the attribute is not present.
if (D.isNoDestroy(CGF.getContext()))
return;
CodeGenModule &CGM = CGF.CGM;
// FIXME: __attribute__((cleanup)) ?
QualType Type = D.getType();
QualType::DestructionKind DtorKind = Type.isDestructedType();
switch (DtorKind) {
case QualType::DK_none:
return;
case QualType::DK_cxx_destructor:
break;
case QualType::DK_objc_strong_lifetime:
case QualType::DK_objc_weak_lifetime:
case QualType::DK_nontrivial_c_struct:
// We don't care about releasing objects during process teardown.
assert(!D.getTLSKind() && "should have rejected this");
return;
}
llvm::FunctionCallee Func;
llvm::Constant *Argument;
2016-05-11 01:44:52 +08:00
// Special-case non-array C++ destructors, if they have the right signature.
// Under some ABIs, destructors return this instead of void, and cannot be
// passed directly to __cxa_atexit if the target does not allow this
// mismatch.
const CXXRecordDecl *Record = Type->getAsCXXRecordDecl();
bool CanRegisterDestructor =
Record && (!CGM.getCXXABI().HasThisReturn(
GlobalDecl(Record->getDestructor(), Dtor_Complete)) ||
CGM.getCXXABI().canCallMismatchedFunctionType());
// If __cxa_atexit is disabled via a flag, a different helper function is
// generated elsewhere which uses atexit instead, and it takes the destructor
// directly.
bool UsingExternalHelper = !CGM.getCodeGenOpts().CXAAtExit;
2016-05-11 01:44:52 +08:00
if (Record && (CanRegisterDestructor || UsingExternalHelper)) {
assert(!Record->hasTrivialDestructor());
CXXDestructorDecl *Dtor = Record->getDestructor();
Func = CGM.getAddrAndTypeOfCXXStructor(GlobalDecl(Dtor, Dtor_Complete));
if (CGF.getContext().getLangOpts().OpenCL) {
auto DestAS =
CGM.getTargetCodeGenInfo().getAddrSpaceOfCxaAtexitPtrParam();
auto DestTy = CGF.getTypes().ConvertType(Type)->getPointerTo(
CGM.getContext().getTargetAddressSpace(DestAS));
auto SrcAS = D.getType().getQualifiers().getAddressSpace();
if (DestAS == SrcAS)
Argument = llvm::ConstantExpr::getBitCast(Addr.getPointer(), DestTy);
else
// FIXME: On addr space mismatch we are passing NULL. The generation
// of the global destructor function should be adjusted accordingly.
Argument = llvm::ConstantPointerNull::get(DestTy);
} else {
Argument = llvm::ConstantExpr::getBitCast(
Addr.getPointer(), CGF.getTypes().ConvertType(Type)->getPointerTo());
}
// Otherwise, the standard logic requires a helper function.
} else {
Func = CodeGenFunction(CGM)
.generateDestroyHelper(Addr, Type, CGF.getDestroyer(DtorKind),
CGF.needsEHCleanup(DtorKind), &D);
Argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
}
CGM.getCXXABI().registerGlobalDtor(CGF, D, Func, Argument);
}
/// Emit code to cause the variable at the given address to be considered as
/// constant from this point onwards.
static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
llvm::Constant *Addr) {
return CGF.EmitInvariantStart(
Addr, CGF.getContext().getTypeSizeInChars(D.getType()));
}
void CodeGenFunction::EmitInvariantStart(llvm::Constant *Addr, CharUnits Size) {
// Do not emit the intrinsic if we're not optimizing.
if (!CGM.getCodeGenOpts().OptimizationLevel)
return;
// Grab the llvm.invariant.start intrinsic.
llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
// Overloaded address space type.
llvm::Type *ObjectPtr[1] = {Int8PtrTy};
llvm::Function *InvariantStart = CGM.getIntrinsic(InvStartID, ObjectPtr);
// Emit a call with the size in bytes of the object.
uint64_t Width = Size.getQuantity();
llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(Int64Ty, Width),
llvm::ConstantExpr::getBitCast(Addr, Int8PtrTy)};
Builder.CreateCall(InvariantStart, Args);
}
void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
llvm::Constant *DeclPtr,
bool PerformInit) {
const Expr *Init = D.getInit();
QualType T = D.getType();
// The address space of a static local variable (DeclPtr) may be different
// from the address space of the "this" argument of the constructor. In that
// case, we need an addrspacecast before calling the constructor.
//
// struct StructWithCtor {
// __device__ StructWithCtor() {...}
// };
// __device__ void foo() {
// __shared__ StructWithCtor s;
// ...
// }
//
// For example, in the above CUDA code, the static local variable s has a
// "shared" address space qualifier, but the constructor of StructWithCtor
// expects "this" in the "generic" address space.
unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(T);
unsigned ActualAddrSpace = DeclPtr->getType()->getPointerAddressSpace();
if (ActualAddrSpace != ExpectedAddrSpace) {
llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(T);
llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
DeclPtr = llvm::ConstantExpr::getAddrSpaceCast(DeclPtr, PTy);
}
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
ConstantAddress DeclAddr(DeclPtr, getContext().getDeclAlign(&D));
if (!T->isReferenceType()) {
if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
D.hasAttr<OMPThreadPrivateDeclAttr>()) {
(void)CGM.getOpenMPRuntime().emitThreadPrivateVarDefinition(
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
&D, DeclAddr, D.getAttr<OMPThreadPrivateDeclAttr>()->getLocation(),
PerformInit, this);
}
if (PerformInit)
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
EmitDeclInit(*this, D, DeclAddr);
if (CGM.isTypeConstant(D.getType(), true))
EmitDeclInvariant(*this, D, DeclPtr);
else
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
EmitDeclDestroy(*this, D, DeclAddr);
return;
}
assert(PerformInit && "cannot have constant initializer which needs "
"destruction for reference");
RValue RV = EmitReferenceBindingToExpr(Init);
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
EmitStoreOfScalar(RV.getScalarVal(), DeclAddr, false, T);
}
/// Create a stub function, suitable for being passed to atexit,
/// which passes the given address to the given destructor function.
llvm::Function *CodeGenFunction::createAtExitStub(const VarDecl &VD,
llvm::FunctionCallee dtor,
llvm::Constant *addr) {
// Get the destructor function type, void(*)(void).
llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
SmallString<256> FnName;
{
llvm::raw_svector_ostream Out(FnName);
CGM.getCXXABI().getMangleContext().mangleDynamicAtExitDestructor(&VD, Out);
}
const CGFunctionInfo &FI = CGM.getTypes().arrangeNullaryFunction();
llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
ty, FnName.str(), FI, VD.getLocation());
CodeGenFunction CGF(CGM);
CGF.StartFunction(GlobalDecl(&VD, DynamicInitKind::AtExit),
CGM.getContext().VoidTy, fn, FI, FunctionArgList());
llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
// Make sure the call and the callee agree on calling convention.
if (llvm::Function *dtorFn =
dyn_cast<llvm::Function>(dtor.getCallee()->stripPointerCasts()))
call->setCallingConv(dtorFn->getCallingConv());
CGF.FinishFunction();
return fn;
}
/// Register a global destructor using the C atexit runtime function.
void CodeGenFunction::registerGlobalDtorWithAtExit(const VarDecl &VD,
llvm::FunctionCallee dtor,
llvm::Constant *addr) {
// Create a function which calls the destructor.
llvm::Constant *dtorStub = createAtExitStub(VD, dtor, addr);
registerGlobalDtorWithAtExit(dtorStub);
}
void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
// extern "C" int atexit(void (*f)(void));
llvm::FunctionType *atexitTy =
llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
llvm::FunctionCallee atexit =
CGM.CreateRuntimeFunction(atexitTy, "atexit", llvm::AttributeList(),
/*Local=*/true);
if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit.getCallee()))
atexitFn->setDoesNotThrow();
EmitNounwindRuntimeCall(atexit, dtorStub);
}
void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
llvm::GlobalVariable *DeclPtr,
bool PerformInit) {
// If we've been asked to forbid guard variables, emit an error now.
// This diagnostic is hard-coded for Darwin's use case; we can find
// better phrasing if someone else needs it.
if (CGM.getCodeGenOpts().ForbidGuardVariables)
CGM.Error(D.getLocation(),
"this initialization requires a guard variable, which "
"the kernel does not support");
CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
}
void CodeGenFunction::EmitCXXGuardedInitBranch(llvm::Value *NeedsInit,
llvm::BasicBlock *InitBlock,
llvm::BasicBlock *NoInitBlock,
GuardKind Kind,
const VarDecl *D) {
assert((Kind == GuardKind::TlsGuard || D) && "no guarded variable");
// A guess at how many times we will enter the initialization of a
// variable, depending on the kind of variable.
static const uint64_t InitsPerTLSVar = 1024;
static const uint64_t InitsPerLocalVar = 1024 * 1024;
llvm::MDNode *Weights;
if (Kind == GuardKind::VariableGuard && !D->isLocalVarDecl()) {
// For non-local variables, don't apply any weighting for now. Due to our
// use of COMDATs, we expect there to be at most one initialization of the
// variable per DSO, but we have no way to know how many DSOs will try to
// initialize the variable.
Weights = nullptr;
} else {
uint64_t NumInits;
// FIXME: For the TLS case, collect and use profiling information to
// determine a more accurate brach weight.
if (Kind == GuardKind::TlsGuard || D->getTLSKind())
NumInits = InitsPerTLSVar;
else
NumInits = InitsPerLocalVar;
// The probability of us entering the initializer is
// 1 / (total number of times we attempt to initialize the variable).
llvm::MDBuilder MDHelper(CGM.getLLVMContext());
Weights = MDHelper.createBranchWeights(1, NumInits - 1);
}
Builder.CreateCondBr(NeedsInit, InitBlock, NoInitBlock, Weights);
}
SanitizerBlacklist: blacklist functions by their source location. This commit changes the way we blacklist functions in ASan, TSan, MSan and UBSan. We used to treat function as "blacklisted" and turned off instrumentation in it in two cases: 1) Function is explicitly blacklisted by its mangled name. This part is not changed. 2) Function is located in llvm::Module, whose identifier is contained in the list of blacklisted sources. This is completely wrong, as llvm::Module may not correspond to the actual source file function is defined in. Also, function can be defined in a header, in which case user had to blacklist the .cpp file this header was #include'd into, not the header itself. Such functions could cause other problems - for instance, if the header was included in multiple source files, compiled separately and linked into a single executable, we could end up with both instrumented and non-instrumented version of the same function participating in the same link. After this change we will make blacklisting decision based on the SourceLocation of a function definition. If a function is not explicitly defined in the source file, (for example, the function is compiler-generated and responsible for initialization/destruction of a global variable), then it will be blacklisted if the corresponding global variable is defined in blacklisted source file, and will be instrumented otherwise. After this commit, the active users of blacklist files may have to revisit them. This is a backwards-incompatible change, but I don't think it's possible or makes sense to support the old incorrect behavior. I plan to make similar change for blacklisting GlobalVariables (which is ASan-specific). llvm-svn: 219997
2014-10-17 08:20:19 +08:00
llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
llvm::FunctionType *FTy, const Twine &Name, const CGFunctionInfo &FI,
SourceLocation Loc, bool TLS) {
llvm::Function *Fn =
llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
Name, &getModule());
if (!getLangOpts().AppleKext && !TLS) {
// Set the section if needed.
if (const char *Section = getTarget().getStaticInitSectionSpecifier())
Fn->setSection(Section);
}
SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
Fn->setCallingConv(getRuntimeCC());
if (!getLangOpts().Exceptions)
Fn->setDoesNotThrow();
if (getLangOpts().Sanitize.has(SanitizerKind::Address) &&
!isInSanitizerBlacklist(SanitizerKind::Address, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
if (getLangOpts().Sanitize.has(SanitizerKind::KernelAddress) &&
!isInSanitizerBlacklist(SanitizerKind::KernelAddress, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::SanitizeAddress);
if (getLangOpts().Sanitize.has(SanitizerKind::HWAddress) &&
!isInSanitizerBlacklist(SanitizerKind::HWAddress, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
if (getLangOpts().Sanitize.has(SanitizerKind::KernelHWAddress) &&
!isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
if (getLangOpts().Sanitize.has(SanitizerKind::MemTag) &&
!isInSanitizerBlacklist(SanitizerKind::MemTag, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::SanitizeMemTag);
if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
!isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::SanitizeThread);
if (getLangOpts().Sanitize.has(SanitizerKind::Memory) &&
!isInSanitizerBlacklist(SanitizerKind::Memory, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
if (getLangOpts().Sanitize.has(SanitizerKind::KernelMemory) &&
!isInSanitizerBlacklist(SanitizerKind::KernelMemory, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::SanitizeMemory);
if (getLangOpts().Sanitize.has(SanitizerKind::SafeStack) &&
!isInSanitizerBlacklist(SanitizerKind::SafeStack, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::SafeStack);
if (getLangOpts().Sanitize.has(SanitizerKind::ShadowCallStack) &&
!isInSanitizerBlacklist(SanitizerKind::ShadowCallStack, Fn, Loc))
Fn->addFnAttr(llvm::Attribute::ShadowCallStack);
auto RASignKind = getCodeGenOpts().getSignReturnAddress();
if (RASignKind != CodeGenOptions::SignReturnAddressScope::None) {
Fn->addFnAttr("sign-return-address",
RASignKind == CodeGenOptions::SignReturnAddressScope::All
? "all"
: "non-leaf");
auto RASignKey = getCodeGenOpts().getSignReturnAddressKey();
Fn->addFnAttr("sign-return-address-key",
RASignKey == CodeGenOptions::SignReturnAddressKeyValue::AKey
? "a_key"
: "b_key");
}
if (getCodeGenOpts().BranchTargetEnforcement)
Fn->addFnAttr("branch-target-enforcement");
return Fn;
}
/// Create a global pointer to a function that will initialize a global
/// variable. The user has requested that this pointer be emitted in a specific
/// section.
void CodeGenModule::EmitPointerToInitFunc(const VarDecl *D,
llvm::GlobalVariable *GV,
llvm::Function *InitFunc,
InitSegAttr *ISA) {
llvm::GlobalVariable *PtrArray = new llvm::GlobalVariable(
TheModule, InitFunc->getType(), /*isConstant=*/true,
llvm::GlobalValue::PrivateLinkage, InitFunc, "__cxx_init_fn_ptr");
PtrArray->setSection(ISA->getSection());
addUsedGlobal(PtrArray);
// If the GV is already in a comdat group, then we have to join it.
if (llvm::Comdat *C = GV->getComdat())
PtrArray->setComdat(C);
}
void
CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
llvm::GlobalVariable *Addr,
bool PerformInit) {
// According to E.2.3.1 in CUDA-7.5 Programming guide: __device__,
// __constant__ and __shared__ variables defined in namespace scope,
// that are of class type, cannot have a non-empty constructor. All
// the checks have been done in Sema by now. Whatever initializers
// are allowed are empty and we just need to ignore them here.
if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
(D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
D->hasAttr<CUDASharedAttr>()))
return;
if (getLangOpts().OpenMP &&
getOpenMPRuntime().emitDeclareTargetVarDefinition(D, Addr, PerformInit))
return;
// Check if we've already initialized this decl.
auto I = DelayedCXXInitPosition.find(D);
if (I != DelayedCXXInitPosition.end() && I->second == ~0U)
return;
llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
SmallString<256> FnName;
{
llvm::raw_svector_ostream Out(FnName);
getCXXABI().getMangleContext().mangleDynamicInitializer(D, Out);
}
// Create a variable initialization function.
SanitizerBlacklist: blacklist functions by their source location. This commit changes the way we blacklist functions in ASan, TSan, MSan and UBSan. We used to treat function as "blacklisted" and turned off instrumentation in it in two cases: 1) Function is explicitly blacklisted by its mangled name. This part is not changed. 2) Function is located in llvm::Module, whose identifier is contained in the list of blacklisted sources. This is completely wrong, as llvm::Module may not correspond to the actual source file function is defined in. Also, function can be defined in a header, in which case user had to blacklist the .cpp file this header was #include'd into, not the header itself. Such functions could cause other problems - for instance, if the header was included in multiple source files, compiled separately and linked into a single executable, we could end up with both instrumented and non-instrumented version of the same function participating in the same link. After this change we will make blacklisting decision based on the SourceLocation of a function definition. If a function is not explicitly defined in the source file, (for example, the function is compiler-generated and responsible for initialization/destruction of a global variable), then it will be blacklisted if the corresponding global variable is defined in blacklisted source file, and will be instrumented otherwise. After this commit, the active users of blacklist files may have to revisit them. This is a backwards-incompatible change, but I don't think it's possible or makes sense to support the old incorrect behavior. I plan to make similar change for blacklisting GlobalVariables (which is ASan-specific). llvm-svn: 219997
2014-10-17 08:20:19 +08:00
llvm::Function *Fn =
CreateGlobalInitOrDestructFunction(FTy, FnName.str(),
getTypes().arrangeNullaryFunction(),
D->getLocation());
auto *ISA = D->getAttr<InitSegAttr>();
CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
PerformInit);
llvm::GlobalVariable *COMDATKey =
supportsCOMDAT() && D->isExternallyVisible() ? Addr : nullptr;
if (D->getTLSKind()) {
// FIXME: Should we support init_priority for thread_local?
// FIXME: We only need to register one __cxa_thread_atexit function for the
// entire TU.
CXXThreadLocalInits.push_back(Fn);
CXXThreadLocalInitVars.push_back(D);
} else if (PerformInit && ISA) {
EmitPointerToInitFunc(D, Addr, Fn, ISA);
} else if (auto *IPA = D->getAttr<InitPriorityAttr>()) {
OrderGlobalInits Key(IPA->getPriority(), PrioritizedCXXGlobalInits.size());
PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
} else if (isTemplateInstantiation(D->getTemplateSpecializationKind()) ||
getContext().GetGVALinkageForVariable(D) == GVA_DiscardableODR) {
// C++ [basic.start.init]p2:
// Definitions of explicitly specialized class template static data
// members have ordered initialization. Other class template static data
// members (i.e., implicitly or explicitly instantiated specializations)
// have unordered initialization.
//
// As a consequence, we can put them into their own llvm.global_ctors entry.
//
// If the global is externally visible, put the initializer into a COMDAT
// group with the global being initialized. On most platforms, this is a
// minor startup time optimization. In the MS C++ ABI, there are no guard
// variables, so this COMDAT key is required for correctness.
AddGlobalCtor(Fn, 65535, COMDATKey);
if (getTarget().getCXXABI().isMicrosoft() && COMDATKey) {
// In The MS C++, MS add template static data member in the linker
// drective.
addUsedGlobal(COMDATKey);
}
} else if (D->hasAttr<SelectAnyAttr>()) {
// SelectAny globals will be comdat-folded. Put the initializer into a
// COMDAT group associated with the global, so the initializers get folded
// too.
AddGlobalCtor(Fn, 65535, COMDATKey);
} else {
I = DelayedCXXInitPosition.find(D); // Re-do lookup in case of re-hash.
if (I == DelayedCXXInitPosition.end()) {
CXXGlobalInits.push_back(Fn);
} else if (I->second != ~0U) {
assert(I->second < CXXGlobalInits.size() &&
CXXGlobalInits[I->second] == nullptr);
CXXGlobalInits[I->second] = Fn;
}
}
// Remember that we already emitted the initializer for this global.
DelayedCXXInitPosition[D] = ~0U;
}
void CodeGenModule::EmitCXXThreadLocalInitFunc() {
getCXXABI().EmitThreadLocalInitFuncs(
*this, CXXThreadLocals, CXXThreadLocalInits, CXXThreadLocalInitVars);
CXXThreadLocalInits.clear();
CXXThreadLocalInitVars.clear();
CXXThreadLocals.clear();
}
void
CodeGenModule::EmitCXXGlobalInitFunc() {
while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
CXXGlobalInits.pop_back();
if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
return;
llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
// Create our global initialization function.
if (!PrioritizedCXXGlobalInits.empty()) {
SmallVector<llvm::Function *, 8> LocalCXXGlobalInits;
llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
PrioritizedCXXGlobalInits.end());
// Iterate over "chunks" of ctors with same priority and emit each chunk
// into separate function. Note - everything is sorted first by priority,
// second - by lex order, so we emit ctor functions in proper order.
for (SmallVectorImpl<GlobalInitData >::iterator
I = PrioritizedCXXGlobalInits.begin(),
E = PrioritizedCXXGlobalInits.end(); I != E; ) {
SmallVectorImpl<GlobalInitData >::iterator
PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
LocalCXXGlobalInits.clear();
unsigned Priority = I->first.priority;
// Compute the function suffix from priority. Prepend with zeroes to make
// sure the function names are also ordered as priorities.
std::string PrioritySuffix = llvm::utostr(Priority);
// Priority is always <= 65535 (enforced by sema).
PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
FTy, "_GLOBAL__I_" + PrioritySuffix, FI);
for (; I < PrioE; ++I)
LocalCXXGlobalInits.push_back(I->second);
CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
AddGlobalCtor(Fn, Priority);
}
PrioritizedCXXGlobalInits.clear();
}
// Include the filename in the symbol name. Including "sub_" matches gcc and
// makes sure these symbols appear lexicographically behind the symbols with
// priority emitted above.
SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
if (FileName.empty())
FileName = "<null>";
for (size_t i = 0; i < FileName.size(); ++i) {
// Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
// to be the set of C preprocessing numbers.
if (!isPreprocessingNumberBody(FileName[i]))
FileName[i] = '_';
}
llvm::Function *Fn = CreateGlobalInitOrDestructFunction(
FTy, llvm::Twine("_GLOBAL__sub_I_", FileName), FI);
CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, CXXGlobalInits);
AddGlobalCtor(Fn);
// In OpenCL global init functions must be converted to kernels in order to
// be able to launch them from the host.
// FIXME: Some more work might be needed to handle destructors correctly.
// Current initialization function makes use of function pointers callbacks.
// We can't support function pointers especially between host and device.
// However it seems global destruction has little meaning without any
// dynamic resource allocation on the device and program scope variables are
// destroyed by the runtime when program is released.
if (getLangOpts().OpenCL) {
GenOpenCLArgMetadata(Fn);
Fn->setCallingConv(llvm::CallingConv::SPIR_KERNEL);
}
CXXGlobalInits.clear();
}
void CodeGenModule::EmitCXXGlobalDtorFunc() {
if (CXXGlobalDtors.empty())
return;
llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
// Create our global destructor function.
const CGFunctionInfo &FI = getTypes().arrangeNullaryFunction();
llvm::Function *Fn =
CreateGlobalInitOrDestructFunction(FTy, "_GLOBAL__D_a", FI);
CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
AddGlobalDtor(Fn);
}
/// Emit the code necessary to initialize the given global variable.
void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
const VarDecl *D,
llvm::GlobalVariable *Addr,
bool PerformInit) {
// Check if we need to emit debug info for variable initializer.
if (D->hasAttr<NoDebugAttr>())
DebugInfo = nullptr; // disable debug info indefinitely for this function
CurEHLocation = D->getBeginLoc();
StartFunction(GlobalDecl(D, DynamicInitKind::Initializer),
getContext().VoidTy, Fn, getTypes().arrangeNullaryFunction(),
FunctionArgList(), D->getLocation(),
D->getInit()->getExprLoc());
// Use guarded initialization if the global variable is weak. This
// occurs for, e.g., instantiated static data members and
// definitions explicitly marked weak.
//
// Also use guarded initialization for a variable with dynamic TLS and
// unordered initialization. (If the initialization is ordered, the ABI
// layer will guard the whole-TU initialization for us.)
if (Addr->hasWeakLinkage() || Addr->hasLinkOnceLinkage() ||
(D->getTLSKind() == VarDecl::TLS_Dynamic &&
isTemplateInstantiation(D->getTemplateSpecializationKind()))) {
EmitCXXGuardedInit(*D, Addr, PerformInit);
} else {
EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
}
FinishFunction();
}
void
CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
ArrayRef<llvm::Function *> Decls,
ConstantAddress Guard) {
{
auto NL = ApplyDebugLocation::CreateEmpty(*this);
StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
getTypes().arrangeNullaryFunction(), FunctionArgList());
// Emit an artificial location for this function.
auto AL = ApplyDebugLocation::CreateArtificial(*this);
llvm::BasicBlock *ExitBlock = nullptr;
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
if (Guard.isValid()) {
// If we have a guard variable, check whether we've already performed
// these initializations. This happens for TLS initialization functions.
llvm::Value *GuardVal = Builder.CreateLoad(Guard);
llvm::Value *Uninit = Builder.CreateIsNull(GuardVal,
"guard.uninitialized");
llvm::BasicBlock *InitBlock = createBasicBlock("init");
ExitBlock = createBasicBlock("exit");
EmitCXXGuardedInitBranch(Uninit, InitBlock, ExitBlock,
GuardKind::TlsGuard, nullptr);
EmitBlock(InitBlock);
// Mark as initialized before initializing anything else. If the
// initializers use previously-initialized thread_local vars, that's
// probably supposed to be OK, but the standard doesn't say.
Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(),1), Guard);
// The guard variable can't ever change again.
EmitInvariantStart(
Guard.getPointer(),
CharUnits::fromQuantity(
CGM.getDataLayout().getTypeAllocSize(GuardVal->getType())));
}
RunCleanupsScope Scope(*this);
// When building in Objective-C++ ARC mode, create an autorelease pool
// around the global initializers.
if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
llvm::Value *token = EmitObjCAutoreleasePoolPush();
EmitObjCAutoreleasePoolCleanup(token);
}
for (unsigned i = 0, e = Decls.size(); i != e; ++i)
if (Decls[i])
EmitRuntimeCall(Decls[i]);
Scope.ForceCleanup();
if (ExitBlock) {
Builder.CreateBr(ExitBlock);
EmitBlock(ExitBlock);
}
}
FinishFunction();
}
void CodeGenFunction::GenerateCXXGlobalDtorsFunc(
llvm::Function *Fn,
const std::vector<std::tuple<llvm::FunctionType *, llvm::WeakTrackingVH,
llvm::Constant *>> &DtorsAndObjects) {
{
auto NL = ApplyDebugLocation::CreateEmpty(*this);
StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
getTypes().arrangeNullaryFunction(), FunctionArgList());
// Emit an artificial location for this function.
auto AL = ApplyDebugLocation::CreateArtificial(*this);
// Emit the dtors, in reverse order from construction.
for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
llvm::FunctionType *CalleeTy;
llvm::Value *Callee;
llvm::Constant *Arg;
std::tie(CalleeTy, Callee, Arg) = DtorsAndObjects[e - i - 1];
llvm::CallInst *CI = Builder.CreateCall(CalleeTy, Callee, Arg);
// 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();
}
/// generateDestroyHelper - Generates a helper function which, when
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
/// invoked, destroys the given object. The address of the object
/// should be in global memory.
llvm::Function *CodeGenFunction::generateDestroyHelper(
Compute and preserve alignment more faithfully in IR-generation. Introduce an Address type to bundle a pointer value with an alignment. Introduce APIs on CGBuilderTy to work with Address values. Change core APIs on CGF/CGM to traffic in Address where appropriate. Require alignments to be non-zero. Update a ton of code to compute and propagate alignment information. As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment helper function to CGF and made use of it in a number of places in the expression emitter. The end result is that we should now be significantly more correct when performing operations on objects that are locally known to be under-aligned. Since alignment is not reliably tracked in the type system, there are inherent limits to this, but at least we are no longer confused by standard operations like derived-to-base conversions and array-to-pointer decay. I've also fixed a large number of bugs where we were applying the complete-object alignment to a pointer instead of the non-virtual alignment, although most of these were hidden by the very conservative approach we took with member alignment. Also, because IRGen now reliably asserts on zero alignments, we should no longer be subject to an absurd but frustrating recurring bug where an incomplete type would report a zero alignment and then we'd naively do a alignmentAtOffset on it and emit code using an alignment equal to the largest power-of-two factor of the offset. We should also now be emitting much more aggressive alignment attributes in the presence of over-alignment. In particular, field access now uses alignmentAtOffset instead of min. Several times in this patch, I had to change the existing code-generation pattern in order to more effectively use the Address APIs. For the most part, this seems to be a strict improvement, like doing pointer arithmetic with GEPs instead of ptrtoint. That said, I've tried very hard to not change semantics, but it is likely that I've failed in a few places, for which I apologize. ABIArgInfo now always carries the assumed alignment of indirect and indirect byval arguments. In order to cut down on what was already a dauntingly large patch, I changed the code to never set align attributes in the IR on non-byval indirect arguments. That is, we still generate code which assumes that indirect arguments have the given alignment, but we don't express this information to the backend except where it's semantically required (i.e. on byvals). This is likely a minor regression for those targets that did provide this information, but it'll be trivial to add it back in a later patch. I partially punted on applying this work to CGBuiltin. Please do not add more uses of the CreateDefaultAligned{Load,Store} APIs; they will be going away eventually. llvm-svn: 246985
2015-09-08 16:05:57 +08:00
Address addr, QualType type, Destroyer *destroyer,
bool useEHCleanupForArray, const VarDecl *VD) {
FunctionArgList args;
ImplicitParamDecl Dst(getContext(), getContext().VoidPtrTy,
ImplicitParamDecl::Other);
args.push_back(&Dst);
const CGFunctionInfo &FI =
CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, args);
llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
SanitizerBlacklist: blacklist functions by their source location. This commit changes the way we blacklist functions in ASan, TSan, MSan and UBSan. We used to treat function as "blacklisted" and turned off instrumentation in it in two cases: 1) Function is explicitly blacklisted by its mangled name. This part is not changed. 2) Function is located in llvm::Module, whose identifier is contained in the list of blacklisted sources. This is completely wrong, as llvm::Module may not correspond to the actual source file function is defined in. Also, function can be defined in a header, in which case user had to blacklist the .cpp file this header was #include'd into, not the header itself. Such functions could cause other problems - for instance, if the header was included in multiple source files, compiled separately and linked into a single executable, we could end up with both instrumented and non-instrumented version of the same function participating in the same link. After this change we will make blacklisting decision based on the SourceLocation of a function definition. If a function is not explicitly defined in the source file, (for example, the function is compiler-generated and responsible for initialization/destruction of a global variable), then it will be blacklisted if the corresponding global variable is defined in blacklisted source file, and will be instrumented otherwise. After this commit, the active users of blacklist files may have to revisit them. This is a backwards-incompatible change, but I don't think it's possible or makes sense to support the old incorrect behavior. I plan to make similar change for blacklisting GlobalVariables (which is ASan-specific). llvm-svn: 219997
2014-10-17 08:20:19 +08:00
llvm::Function *fn = CGM.CreateGlobalInitOrDestructFunction(
FTy, "__cxx_global_array_dtor", FI, VD->getLocation());
CurEHLocation = VD->getBeginLoc();
StartFunction(VD, getContext().VoidTy, fn, FI, args);
emitDestroy(addr, type, destroyer, useEHCleanupForArray);
FinishFunction();
return fn;
}