From 954ec09aed4f2be04bb5f4e10dbb4ea8bd19ef9a Mon Sep 17 00:00:00 2001 From: Jennifer Yu Date: Thu, 30 May 2019 01:05:46 +0000 Subject: clang support gnu asm goto. Syntax: asm [volatile] goto ( AssemblerTemplate : : InputOperands : Clobbers : GotoLabels) https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html New llvm IR is "callbr" for inline asm goto instead "call" for inline asm For: asm goto("testl %0, %0; jne %l1;" :: "r"(cond)::label_true, loop); IR: callbr void asm sideeffect "testl $0, $0; jne ${1:l};", "r,X,X,~{dirflag},~{fpsr},~{flags}"(i32 %0, i8* blockaddress(@foo, %label_true), i8* blockaddress(@foo, %loop)) #1 to label %asm.fallthrough [label %label_true, label %loop], !srcloc !3 asm.fallthrough: Compiler need to generate: 1> a dummy constarint 'X' for each label. 2> an unique fallthrough label for each asm goto stmt " asm.fallthrough%number". Diagnostic 1> duplicate asm operand name are used in output, input and label. 2> goto out of scope. llvm-svn: 362045 --- clang/lib/CodeGen/CGStmt.cpp | 126 ++++++++++++++++++++++++++++--------------- 1 file changed, 82 insertions(+), 44 deletions(-) (limited to 'clang/lib/CodeGen') diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp index c617b198d76..5c24db70925 100644 --- a/clang/lib/CodeGen/CGStmt.cpp +++ b/clang/lib/CodeGen/CGStmt.cpp @@ -1896,6 +1896,55 @@ static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str, return llvm::MDNode::get(CGF.getLLVMContext(), Locs); } +static void UpdateAsmCallInst(llvm::CallBase &Result, bool HasSideEffect, + bool ReadOnly, bool ReadNone, const AsmStmt &S, + const std::vector &ResultRegTypes, + CodeGenFunction &CGF, + std::vector &RegResults) { + Result.addAttribute(llvm::AttributeList::FunctionIndex, + llvm::Attribute::NoUnwind); + // Attach readnone and readonly attributes. + if (!HasSideEffect) { + if (ReadNone) + Result.addAttribute(llvm::AttributeList::FunctionIndex, + llvm::Attribute::ReadNone); + else if (ReadOnly) + Result.addAttribute(llvm::AttributeList::FunctionIndex, + llvm::Attribute::ReadOnly); + } + + // Slap the source location of the inline asm into a !srcloc metadata on the + // call. + if (const auto *gccAsmStmt = dyn_cast(&S)) + Result.setMetadata("srcloc", + getAsmSrcLocInfo(gccAsmStmt->getAsmString(), CGF)); + else { + // At least put the line number on MS inline asm blobs. + llvm::Constant *Loc = llvm::ConstantInt::get(CGF.Int32Ty, + S.getAsmLoc().getRawEncoding()); + Result.setMetadata("srcloc", + llvm::MDNode::get(CGF.getLLVMContext(), + llvm::ConstantAsMetadata::get(Loc))); + } + + if (CGF.getLangOpts().assumeFunctionsAreConvergent()) + // Conservatively, mark all inline asm blocks in CUDA or OpenCL as + // convergent (meaning, they may call an intrinsically convergent op, such + // as bar.sync, and so can't have certain optimizations applied around + // them). + Result.addAttribute(llvm::AttributeList::FunctionIndex, + llvm::Attribute::Convergent); + // Extract all of the register value results from the asm. + if (ResultRegTypes.size() == 1) { + RegResults.push_back(&Result); + } else { + for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) { + llvm::Value *Tmp = CGF.Builder.CreateExtractValue(&Result, i, "asmresult"); + RegResults.push_back(Tmp); + } + } +} + void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { // Assemble the final asm string. std::string AsmString = S.generateAsmString(getContext()); @@ -2138,6 +2187,29 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { } Constraints += InOutConstraints; + // Labels + SmallVector Transfer; + llvm::BasicBlock *Fallthrough = nullptr; + bool IsGCCAsmGoto = false; + if (const auto *GS = dyn_cast(&S)) { + IsGCCAsmGoto = GS->isAsmGoto(); + if (IsGCCAsmGoto) { + for (auto *E : GS->labels()) { + JumpDest Dest = getJumpDestForLabel(E->getLabel()); + Transfer.push_back(Dest.getBlock()); + llvm::BlockAddress *BA = + llvm::BlockAddress::get(CurFn, Dest.getBlock()); + Args.push_back(BA); + ArgTypes.push_back(BA->getType()); + if (!Constraints.empty()) + Constraints += ','; + Constraints += 'X'; + } + StringRef Name = "asm.fallthrough"; + Fallthrough = createBasicBlock(Name); + } + } + // Clobbers for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) { StringRef Clobber = S.getClobber(i); @@ -2180,52 +2252,18 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { llvm::InlineAsm *IA = llvm::InlineAsm::get(FTy, AsmString, Constraints, HasSideEffect, /* IsAlignStack */ false, AsmDialect); - llvm::CallInst *Result = - Builder.CreateCall(IA, Args, getBundlesForFunclet(IA)); - Result->addAttribute(llvm::AttributeList::FunctionIndex, - llvm::Attribute::NoUnwind); - - // Attach readnone and readonly attributes. - if (!HasSideEffect) { - if (ReadNone) - Result->addAttribute(llvm::AttributeList::FunctionIndex, - llvm::Attribute::ReadNone); - else if (ReadOnly) - Result->addAttribute(llvm::AttributeList::FunctionIndex, - llvm::Attribute::ReadOnly); - } - - // Slap the source location of the inline asm into a !srcloc metadata on the - // call. - if (const GCCAsmStmt *gccAsmStmt = dyn_cast(&S)) { - Result->setMetadata("srcloc", getAsmSrcLocInfo(gccAsmStmt->getAsmString(), - *this)); - } else { - // At least put the line number on MS inline asm blobs. - auto Loc = llvm::ConstantInt::get(Int32Ty, S.getAsmLoc().getRawEncoding()); - Result->setMetadata("srcloc", - llvm::MDNode::get(getLLVMContext(), - llvm::ConstantAsMetadata::get(Loc))); - } - - if (getLangOpts().assumeFunctionsAreConvergent()) { - // Conservatively, mark all inline asm blocks in CUDA or OpenCL as - // convergent (meaning, they may call an intrinsically convergent op, such - // as bar.sync, and so can't have certain optimizations applied around - // them). - Result->addAttribute(llvm::AttributeList::FunctionIndex, - llvm::Attribute::Convergent); - } - - // Extract all of the register value results from the asm. std::vector RegResults; - if (ResultRegTypes.size() == 1) { - RegResults.push_back(Result); + if (IsGCCAsmGoto) { + llvm::CallBrInst *Result = + Builder.CreateCallBr(IA, Fallthrough, Transfer, Args); + UpdateAsmCallInst(cast(*Result), HasSideEffect, ReadOnly, + ReadNone, S, ResultRegTypes, *this, RegResults); + EmitBlock(Fallthrough); } else { - for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) { - llvm::Value *Tmp = Builder.CreateExtractValue(Result, i, "asmresult"); - RegResults.push_back(Tmp); - } + llvm::CallInst *Result = + Builder.CreateCall(IA, Args, getBundlesForFunclet(IA)); + UpdateAsmCallInst(cast(*Result), HasSideEffect, ReadOnly, + ReadNone, S, ResultRegTypes, *this, RegResults); } assert(RegResults.size() == ResultRegTypes.size()); -- cgit v1.2.3