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author | Reid Kleckner <reid@kleckner.net> | 2014-05-16 20:39:27 +0000 |
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committer | Reid Kleckner <reid@kleckner.net> | 2014-05-16 20:39:27 +0000 |
commit | 1ce308866915c9eab78486066d28d2107b7fede2 (patch) | |
tree | 9de4e45b4a8b60edb08ccdb8d31577d12b38c2e9 /lib/Transforms/Utils | |
parent | dedd6203ad632d99de7648c43e482af8476ba6ed (diff) | |
download | llvm-1ce308866915c9eab78486066d28d2107b7fede2.tar.gz llvm-1ce308866915c9eab78486066d28d2107b7fede2.tar.bz2 llvm-1ce308866915c9eab78486066d28d2107b7fede2.tar.xz |
Add comdat key field to llvm.global_ctors and llvm.global_dtors
This allows us to put dynamic initializers for weak data into the same
comdat group as the data being initialized. This is necessary for MSVC
ABI compatibility. Once we have comdats for guard variables, we can use
the combination to help GlobalOpt fire more often for weak data with
guarded initialization on other platforms.
Reviewers: nlewycky
Differential Revision: http://reviews.llvm.org/D3499
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209015 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Utils')
-rw-r--r-- | lib/Transforms/Utils/CtorUtils.cpp | 26 | ||||
-rw-r--r-- | lib/Transforms/Utils/ModuleUtils.cpp | 29 |
2 files changed, 35 insertions, 20 deletions
diff --git a/lib/Transforms/Utils/CtorUtils.cpp b/lib/Transforms/Utils/CtorUtils.cpp index 7cf793f626..a3594248de 100644 --- a/lib/Transforms/Utils/CtorUtils.cpp +++ b/lib/Transforms/Utils/CtorUtils.cpp @@ -29,26 +29,28 @@ namespace { void installGlobalCtors(GlobalVariable *GCL, const std::vector<Function *> &Ctors) { // If we made a change, reassemble the initializer list. - Constant *CSVals[2]; - CSVals[0] = ConstantInt::get(Type::getInt32Ty(GCL->getContext()), 65535); - CSVals[1] = nullptr; + Constant *CSVals[3]; StructType *StructTy = cast<StructType>(GCL->getType()->getElementType()->getArrayElementType()); // Create the new init list. std::vector<Constant *> CAList; - for (unsigned i = 0, e = Ctors.size(); i != e; ++i) { - if (Ctors[i]) { - CSVals[1] = Ctors[i]; + for (Function *F : Ctors) { + Type *Int32Ty = Type::getInt32Ty(GCL->getContext()); + if (F) { + CSVals[0] = ConstantInt::get(Int32Ty, 65535); + CSVals[1] = F; } else { - Type *FTy = FunctionType::get(Type::getVoidTy(GCL->getContext()), false); - PointerType *PFTy = PointerType::getUnqual(FTy); - CSVals[1] = Constant::getNullValue(PFTy); - CSVals[0] = - ConstantInt::get(Type::getInt32Ty(GCL->getContext()), 0x7fffffff); + CSVals[0] = ConstantInt::get(Int32Ty, 0x7fffffff); + CSVals[1] = Constant::getNullValue(StructTy->getElementType(1)); } - CAList.push_back(ConstantStruct::get(StructTy, CSVals)); + // FIXME: Only allow the 3-field form in LLVM 4.0. + size_t NumElts = StructTy->getNumElements(); + if (NumElts > 2) + CSVals[2] = Constant::getNullValue(StructTy->getElementType(2)); + CAList.push_back( + ConstantStruct::get(StructTy, makeArrayRef(CSVals, NumElts))); } // Create the array initializer. diff --git a/lib/Transforms/Utils/ModuleUtils.cpp b/lib/Transforms/Utils/ModuleUtils.cpp index ff6e6f9c60..d9dbbca1c3 100644 --- a/lib/Transforms/Utils/ModuleUtils.cpp +++ b/lib/Transforms/Utils/ModuleUtils.cpp @@ -24,16 +24,16 @@ static void appendToGlobalArray(const char *Array, Module &M, Function *F, int Priority) { IRBuilder<> IRB(M.getContext()); FunctionType *FnTy = FunctionType::get(IRB.getVoidTy(), false); - StructType *Ty = StructType::get( - IRB.getInt32Ty(), PointerType::getUnqual(FnTy), NULL); - - Constant *RuntimeCtorInit = ConstantStruct::get( - Ty, IRB.getInt32(Priority), F, NULL); // Get the current set of static global constructors and add the new ctor // to the list. SmallVector<Constant *, 16> CurrentCtors; - if (GlobalVariable * GVCtor = M.getNamedGlobal(Array)) { + StructType *EltTy; + if (GlobalVariable *GVCtor = M.getNamedGlobal(Array)) { + // If there is a global_ctors array, use the existing struct type, which can + // have 2 or 3 fields. + ArrayType *ATy = cast<ArrayType>(GVCtor->getType()->getElementType()); + EltTy = cast<StructType>(ATy->getElementType()); if (Constant *Init = GVCtor->getInitializer()) { unsigned n = Init->getNumOperands(); CurrentCtors.reserve(n + 1); @@ -41,13 +41,26 @@ static void appendToGlobalArray(const char *Array, CurrentCtors.push_back(cast<Constant>(Init->getOperand(i))); } GVCtor->eraseFromParent(); + } else { + // Use a simple two-field struct if there isn't one already. + EltTy = StructType::get(IRB.getInt32Ty(), PointerType::getUnqual(FnTy), + nullptr); } + // Build a 2 or 3 field global_ctor entry. We don't take a comdat key. + Constant *CSVals[3]; + CSVals[0] = IRB.getInt32(Priority); + CSVals[1] = F; + // FIXME: Drop support for the two element form in LLVM 4.0. + if (EltTy->getNumElements() >= 3) + CSVals[2] = llvm::Constant::getNullValue(IRB.getInt8PtrTy()); + Constant *RuntimeCtorInit = + ConstantStruct::get(EltTy, makeArrayRef(CSVals, EltTy->getNumElements())); + CurrentCtors.push_back(RuntimeCtorInit); // Create a new initializer. - ArrayType *AT = ArrayType::get(RuntimeCtorInit->getType(), - CurrentCtors.size()); + ArrayType *AT = ArrayType::get(EltTy, CurrentCtors.size()); Constant *NewInit = ConstantArray::get(AT, CurrentCtors); // Create the new global variable and replace all uses of |