CodeGen: Cast temporary variable to proper address space
In C++ all variables are in default address space. Previously change has been
made to cast automatic variables to default address space. However that is
not sufficient since all temporary variables need to be casted to default
address space.
This patch casts all temporary variables to default address space except those
for passing indirect arguments since they are only used for load/store.
This patch only affects target having non-zero alloca address space.
Differential Revision: https://reviews.llvm.org/D33706
llvm-svn: 305711
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index c65dc18..0e5ccc0 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -3813,7 +3813,8 @@
assert(NumIRArgs == 1);
if (RV.isScalar() || RV.isComplex()) {
// Make a temporary alloca to pass the argument.
- Address Addr = CreateMemTemp(I->Ty, ArgInfo.getIndirectAlign());
+ Address Addr = CreateMemTemp(I->Ty, ArgInfo.getIndirectAlign(),
+ "indirect-arg-temp", false);
IRCallArgs[FirstIRArg] = Addr.getPointer();
LValue argLV = MakeAddrLValue(Addr, I->Ty);
@@ -3842,7 +3843,8 @@
< Align.getQuantity()) ||
(ArgInfo.getIndirectByVal() && (RVAddrSpace != ArgAddrSpace))) {
// Create an aligned temporary, and copy to it.
- Address AI = CreateMemTemp(I->Ty, ArgInfo.getIndirectAlign());
+ Address AI = CreateMemTemp(I->Ty, ArgInfo.getIndirectAlign(),
+ "byval-temp", false);
IRCallArgs[FirstIRArg] = AI.getPointer();
EmitAggregateCopy(AI, Addr, I->Ty, RV.isVolatileQualified());
} else {
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 87bfa50..ccd3b8d 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -954,6 +954,7 @@
CodeGenFunction::AutoVarEmission
CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
QualType Ty = D.getType();
+ assert(Ty.getAddressSpace() == LangAS::Default);
AutoVarEmission emission(D);
@@ -1046,8 +1047,7 @@
// Create the alloca. Note that we set the name separately from
// building the instruction so that it's there even in no-asserts
// builds.
- address = CreateTempAlloca(allocaTy, allocaAlignment);
- address.getPointer()->setName(D.getName());
+ address = CreateTempAlloca(allocaTy, allocaAlignment, D.getName());
// Don't emit lifetime markers for MSVC catch parameters. The lifetime of
// the catch parameter starts in the catchpad instruction, and we can't
@@ -1107,27 +1107,9 @@
llvm::Type *llvmTy = ConvertTypeForMem(elementType);
// Allocate memory for the array.
- llvm::AllocaInst *vla = Builder.CreateAlloca(llvmTy, elementCount, "vla");
- vla->setAlignment(alignment.getQuantity());
-
- address = Address(vla, alignment);
+ address = CreateTempAlloca(llvmTy, alignment, "vla", elementCount);
}
- // Alloca always returns a pointer in alloca address space, which may
- // be different from the type defined by the language. For example,
- // in C++ the auto variables are in the default address space. Therefore
- // cast alloca to the expected address space when necessary.
- auto T = D.getType();
- assert(T.getAddressSpace() == LangAS::Default);
- if (getASTAllocaAddressSpace() != LangAS::Default) {
- auto *Addr = getTargetHooks().performAddrSpaceCast(
- *this, address.getPointer(), getASTAllocaAddressSpace(),
- T.getAddressSpace(),
- address.getElementType()->getPointerTo(
- getContext().getTargetAddressSpace(T.getAddressSpace())),
- /*non-null*/ true);
- address = Address(Addr, address.getAlignment());
- }
setAddrOfLocalVar(&D, address);
emission.Addr = address;
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 7359006..2ee1c96 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -61,18 +61,36 @@
/// CreateTempAlloca - This creates a alloca and inserts it into the entry
/// block.
Address CodeGenFunction::CreateTempAlloca(llvm::Type *Ty, CharUnits Align,
- const Twine &Name) {
- auto Alloca = CreateTempAlloca(Ty, Name);
+ const Twine &Name,
+ llvm::Value *ArraySize,
+ bool CastToDefaultAddrSpace) {
+ auto Alloca = CreateTempAlloca(Ty, Name, ArraySize);
Alloca->setAlignment(Align.getQuantity());
- return Address(Alloca, Align);
+ llvm::Value *V = Alloca;
+ // Alloca always returns a pointer in alloca address space, which may
+ // be different from the type defined by the language. For example,
+ // in C++ the auto variables are in the default address space. Therefore
+ // cast alloca to the default address space when necessary.
+ if (CastToDefaultAddrSpace && getASTAllocaAddressSpace() != LangAS::Default) {
+ auto DestAddrSpace = getContext().getTargetAddressSpace(LangAS::Default);
+ V = getTargetHooks().performAddrSpaceCast(
+ *this, V, getASTAllocaAddressSpace(), LangAS::Default,
+ Ty->getPointerTo(DestAddrSpace), /*non-null*/ true);
+ }
+
+ return Address(V, Align);
}
-/// CreateTempAlloca - This creates a alloca and inserts it into the entry
-/// block.
+/// CreateTempAlloca - This creates an alloca and inserts it into the entry
+/// block if \p ArraySize is nullptr, otherwise inserts it at the current
+/// insertion point of the builder.
llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
- const Twine &Name) {
+ const Twine &Name,
+ llvm::Value *ArraySize) {
+ if (ArraySize)
+ return Builder.CreateAlloca(Ty, ArraySize, Name);
return new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(),
- nullptr, Name, AllocaInsertPt);
+ ArraySize, Name, AllocaInsertPt);
}
/// CreateDefaultAlignTempAlloca - This creates an alloca with the
@@ -99,14 +117,18 @@
return CreateTempAlloca(ConvertType(Ty), Align, Name);
}
-Address CodeGenFunction::CreateMemTemp(QualType Ty, const Twine &Name) {
+Address CodeGenFunction::CreateMemTemp(QualType Ty, const Twine &Name,
+ bool CastToDefaultAddrSpace) {
// FIXME: Should we prefer the preferred type alignment here?
- return CreateMemTemp(Ty, getContext().getTypeAlignInChars(Ty), Name);
+ return CreateMemTemp(Ty, getContext().getTypeAlignInChars(Ty), Name,
+ CastToDefaultAddrSpace);
}
Address CodeGenFunction::CreateMemTemp(QualType Ty, CharUnits Align,
- const Twine &Name) {
- return CreateTempAlloca(ConvertTypeForMem(Ty), Align, Name);
+ const Twine &Name,
+ bool CastToDefaultAddrSpace) {
+ return CreateTempAlloca(ConvertTypeForMem(Ty), Align, Name, nullptr,
+ CastToDefaultAddrSpace);
}
/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 831eedf..11dce07 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -1916,13 +1916,36 @@
LValueBaseInfo *BaseInfo = nullptr);
LValue EmitLoadOfPointerLValue(Address Ptr, const PointerType *PtrTy);
- /// CreateTempAlloca - This creates a alloca and inserts it into the entry
- /// block. The caller is responsible for setting an appropriate alignment on
+ /// CreateTempAlloca - This creates an alloca and inserts it into the entry
+ /// block if \p ArraySize is nullptr, otherwise inserts it at the current
+ /// insertion point of the builder. The caller is responsible for setting an
+ /// appropriate alignment on
/// the alloca.
- llvm::AllocaInst *CreateTempAlloca(llvm::Type *Ty,
- const Twine &Name = "tmp");
+ ///
+ /// \p ArraySize is the number of array elements to be allocated if it
+ /// is not nullptr.
+ ///
+ /// LangAS::Default is the address space of pointers to local variables and
+ /// temporaries, as exposed in the source language. In certain
+ /// configurations, this is not the same as the alloca address space, and a
+ /// cast is needed to lift the pointer from the alloca AS into
+ /// LangAS::Default. This can happen when the target uses a restricted
+ /// address space for the stack but the source language requires
+ /// LangAS::Default to be a generic address space. The latter condition is
+ /// common for most programming languages; OpenCL is an exception in that
+ /// LangAS::Default is the private address space, which naturally maps
+ /// to the stack.
+ ///
+ /// Because the address of a temporary is often exposed to the program in
+ /// various ways, this function will perform the cast by default. The cast
+ /// may be avoided by passing false as \p CastToDefaultAddrSpace; this is
+ /// more efficient if the caller knows that the address will not be exposed.
+ llvm::AllocaInst *CreateTempAlloca(llvm::Type *Ty, const Twine &Name = "tmp",
+ llvm::Value *ArraySize = nullptr);
Address CreateTempAlloca(llvm::Type *Ty, CharUnits align,
- const Twine &Name = "tmp");
+ const Twine &Name = "tmp",
+ llvm::Value *ArraySize = nullptr,
+ bool CastToDefaultAddrSpace = true);
/// CreateDefaultAlignedTempAlloca - This creates an alloca with the
/// default ABI alignment of the given LLVM type.
@@ -1957,9 +1980,12 @@
Address CreateIRTemp(QualType T, const Twine &Name = "tmp");
/// CreateMemTemp - Create a temporary memory object of the given type, with
- /// appropriate alignment.
- Address CreateMemTemp(QualType T, const Twine &Name = "tmp");
- Address CreateMemTemp(QualType T, CharUnits Align, const Twine &Name = "tmp");
+ /// appropriate alignment. Cast it to the default address space if
+ /// \p CastToDefaultAddrSpace is true.
+ Address CreateMemTemp(QualType T, const Twine &Name = "tmp",
+ bool CastToDefaultAddrSpace = true);
+ Address CreateMemTemp(QualType T, CharUnits Align, const Twine &Name = "tmp",
+ bool CastToDefaultAddrSpace = true);
/// CreateAggTemp - Create a temporary memory object for the given
/// aggregate type.