diff options
Diffstat (limited to 'lib/CodeGen/CGBuiltin.cpp')
-rw-r--r-- | lib/CodeGen/CGBuiltin.cpp | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp index a655966d6e..20140034b8 100644 --- a/lib/CodeGen/CGBuiltin.cpp +++ b/lib/CodeGen/CGBuiltin.cpp @@ -20,6 +20,7 @@ #include "clang/Basic/TargetBuiltins.h" #include "clang/Basic/TargetInfo.h" #include "llvm/IR/DataLayout.h" +#include "llvm/IR/InlineAsm.h" // @LOCALMOD #include "llvm/IR/Intrinsics.h" using namespace clang; @@ -1034,7 +1035,29 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD, // any way to safely use it... but in practice, it mostly works // to use it with non-atomic loads and stores to get acquire/release // semantics. - Builder.CreateFence(llvm::SequentiallyConsistent); + // @LOCALMOD-START + // Targets can ask that ``__sync_synchronize()`` be surrounded with + // compiler fences. This should enforce ordering of more than just + // atomic memory accesses, though it won't guarantee that all + // accesses (e.g. those to non-escaping objects) won't be reordered. + llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false); + std::string AsmString; // Empty. + std::string Constraints("~{memory}"); + bool HasSideEffect = true; + if (getTargetHooks().addAsmMemoryAroundSyncSynchronize()) { + Builder.CreateCall( + llvm::InlineAsm::get(FTy, AsmString, Constraints, HasSideEffect))-> + addAttribute(llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind); + Builder.CreateFence(llvm::SequentiallyConsistent); + Builder.CreateCall( + llvm::InlineAsm::get(FTy, AsmString, Constraints, HasSideEffect))-> + addAttribute(llvm::AttributeSet::FunctionIndex, + llvm::Attribute::NoUnwind); + } else { + Builder.CreateFence(llvm::SequentiallyConsistent); + } + // @LOCALMOD-END return RValue::get(0); } |