Index: llvm/trunk/include/llvm/CodeGen/CommandFlags.h =================================================================== --- llvm/trunk/include/llvm/CodeGen/CommandFlags.h +++ llvm/trunk/include/llvm/CodeGen/CommandFlags.h @@ -16,6 +16,7 @@ #ifndef LLVM_CODEGEN_COMMANDFLAGS_H #define LLVM_CODEGEN_COMMANDFLAGS_H +#include "llvm/ADT/StringExtras.h" #include "llvm/IR/Module.h" #include "llvm/MC/MCTargetOptionsCommandFlags.h" #include "llvm//MC/SubtargetFeature.h" @@ -247,7 +248,6 @@ Options.FloatABIType = FloatABIForCalls; Options.NoZerosInBSS = DontPlaceZerosInBSS; Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt; - Options.DisableTailCalls = DisableTailCalls; Options.StackAlignmentOverride = OverrideStackAlignment; Options.TrapFuncName = TrapFuncName; Options.PositionIndependentExecutable = EnablePIE; @@ -315,6 +315,11 @@ "no-frame-pointer-elim", DisableFPElim ? "true" : "false"); + if (DisableTailCalls.getNumOccurrences() > 0) + NewAttrs = NewAttrs.addAttribute(Ctx, AttributeSet::FunctionIndex, + "disable-tail-calls", + toStringRef(DisableTailCalls)); + // Let NewAttrs override Attrs. NewAttrs = Attrs.addAttributes(Ctx, AttributeSet::FunctionIndex, NewAttrs); F.setAttributes(NewAttrs); Index: llvm/trunk/include/llvm/Target/TargetOptions.h =================================================================== --- llvm/trunk/include/llvm/Target/TargetOptions.h +++ llvm/trunk/include/llvm/Target/TargetOptions.h @@ -67,7 +67,7 @@ HonorSignDependentRoundingFPMathOption(false), NoZerosInBSS(false), GuaranteedTailCallOpt(false), - DisableTailCalls(false), StackAlignmentOverride(0), + StackAlignmentOverride(0), EnableFastISel(false), PositionIndependentExecutable(false), UseInitArray(false), DisableIntegratedAS(false), CompressDebugSections(false), FunctionSections(false), @@ -137,10 +137,6 @@ /// as their parent function, etc.), using an alternate ABI if necessary. unsigned GuaranteedTailCallOpt : 1; - /// DisableTailCalls - This flag controls whether we will use tail calls. - /// Disabling them may be useful to maintain a correct call stack. - unsigned DisableTailCalls : 1; - /// StackAlignmentOverride - Override default stack alignment for target. unsigned StackAlignmentOverride; @@ -236,7 +232,6 @@ ARE_EQUAL(HonorSignDependentRoundingFPMathOption) && ARE_EQUAL(NoZerosInBSS) && ARE_EQUAL(GuaranteedTailCallOpt) && - ARE_EQUAL(DisableTailCalls) && ARE_EQUAL(StackAlignmentOverride) && ARE_EQUAL(EnableFastISel) && ARE_EQUAL(PositionIndependentExecutable) && Index: llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp =================================================================== --- llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp +++ llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp @@ -1483,9 +1483,10 @@ bool isStructRet = (Outs.empty()) ? false : Outs[0].Flags.isSRet(); bool isThisReturn = false; bool isSibCall = false; + auto Attr = MF.getFunction()->getFnAttribute("disable-tail-calls"); // Disable tail calls if they're not supported. - if (!Subtarget->supportsTailCall() || MF.getTarget().Options.DisableTailCalls) + if (!Subtarget->supportsTailCall() || Attr.getValueAsString() == "true") isTailCall = false; if (isTailCall) { @@ -2375,7 +2376,9 @@ if (!Subtarget->supportsTailCall()) return false; - if (!CI->isTailCall() || getTargetMachine().Options.DisableTailCalls) + auto Attr = + CI->getParent()->getParent()->getFnAttribute("disable-tail-calls"); + if (!CI->isTailCall() || Attr.getValueAsString() == "true") return false; return !Subtarget->isThumb1Only(); Index: llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp =================================================================== --- llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp +++ llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp @@ -397,7 +397,9 @@ bool HexagonTargetLowering::mayBeEmittedAsTailCall(CallInst *CI) const { // If either no tail call or told not to tail call at all, don't. - if (!CI->isTailCall() || HTM.Options.DisableTailCalls) + auto Attr = + CI->getParent()->getParent()->getFnAttribute("disable-tail-calls"); + if (!CI->isTailCall() || Attr.getValueAsString() == "true") return false; return true; @@ -486,7 +488,8 @@ else CCInfo.AnalyzeCallOperands(Outs, CC_Hexagon); - if (DAG.getTarget().Options.DisableTailCalls) + auto Attr = MF.getFunction()->getFnAttribute("disable-tail-calls"); + if (Attr.getValueAsString() == "true") isTailCall = false; if (isTailCall) { Index: llvm/trunk/lib/Target/TargetMachine.cpp =================================================================== --- llvm/trunk/lib/Target/TargetMachine.cpp +++ llvm/trunk/lib/Target/TargetMachine.cpp @@ -70,7 +70,6 @@ RESET_OPTION(UnsafeFPMath, "unsafe-fp-math"); RESET_OPTION(NoInfsFPMath, "no-infs-fp-math"); RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math"); - RESET_OPTION(DisableTailCalls, "disable-tail-calls"); } /// getRelocationModel - Returns the code generation relocation model. The Index: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp =================================================================== --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp @@ -2233,7 +2233,9 @@ } bool X86TargetLowering::mayBeEmittedAsTailCall(CallInst *CI) const { - if (!CI->isTailCall() || getTargetMachine().Options.DisableTailCalls) + auto Attr = + CI->getParent()->getParent()->getFnAttribute("disable-tail-calls"); + if (!CI->isTailCall() || Attr.getValueAsString() == "true") return false; CallSite CS(CI); @@ -2762,8 +2764,9 @@ StructReturnType SR = callIsStructReturn(Outs); bool IsSibcall = false; X86MachineFunctionInfo *X86Info = MF.getInfo(); + auto Attr = MF.getFunction()->getFnAttribute("disable-tail-calls"); - if (MF.getTarget().Options.DisableTailCalls) + if (Attr.getValueAsString() == "true") isTailCall = false; if (Subtarget->isPICStyleGOT() && Index: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp =================================================================== --- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp +++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp @@ -94,7 +94,6 @@ SizeLevel = 0; LibraryInfo = nullptr; Inliner = nullptr; - DisableTailCalls = false; DisableUnitAtATime = false; DisableUnrollLoops = false; BBVectorize = RunBBVectorization; @@ -238,8 +237,7 @@ MPM.add(createInstructionCombiningPass()); // Combine silly seq's addExtensionsToPM(EP_Peephole, MPM); - if (!DisableTailCalls) - MPM.add(createTailCallEliminationPass()); // Eliminate tail calls + MPM.add(createTailCallEliminationPass()); // Eliminate tail calls MPM.add(createCFGSimplificationPass()); // Merge & remove BBs MPM.add(createReassociatePass()); // Reassociate expressions // Rotate Loop - disable header duplication at -Oz Index: llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp =================================================================== --- llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp +++ llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp @@ -158,6 +158,9 @@ if (skipOptnoneFunction(F)) return false; + if (F.getFnAttribute("disable-tail-calls").getValueAsString() == "true") + return false; + bool AllCallsAreTailCalls = false; bool Modified = markTails(F, AllCallsAreTailCalls); if (AllCallsAreTailCalls) Index: llvm/trunk/test/CodeGen/ARM/disable-tail-calls.ll =================================================================== --- llvm/trunk/test/CodeGen/ARM/disable-tail-calls.ll +++ llvm/trunk/test/CodeGen/ARM/disable-tail-calls.ll @@ -0,0 +1,40 @@ +; RUN: llc < %s -march arm | FileCheck %s --check-prefix=NO-OPTION +; RUN: llc < %s -march arm -disable-tail-calls | FileCheck %s --check-prefix=DISABLE-TRUE +; RUN: llc < %s -march arm -disable-tail-calls=false | FileCheck %s --check-prefix=DISABLE-FALSE + +; Check that command line option "-disable-tail-calls" overrides function +; attribute "disable-tail-calls". + +; NO-OPTION-LABEL: {{\_?}}func_attr +; NO-OPTION: bl {{\_?}}callee + +; DISABLE-FALSE-LABEL: {{\_?}}func_attr +; DISABLE-FALSE: b {{\_?}}callee + +; DISABLE-TRUE-LABEL: {{\_?}}func_attr +; DISABLE-TRUE: bl {{\_?}}callee + +define i32 @func_attr(i32 %a) #0 { +entry: + %call = tail call i32 @callee(i32 %a) + ret i32 %call +} + +; NO-OPTION-LABEL: {{\_?}}func_noattr +; NO-OPTION: b {{\_?}}callee + +; DISABLE-FALSE-LABEL: {{\_?}}func_noattr +; DISABLE-FALSE: b {{\_?}}callee + +; DISABLE-TRUE-LABEL: {{\_?}}func_noattr +; DISABLE-TRUE: bl {{\_?}}callee + +define i32 @func_noattr(i32 %a) { +entry: + %call = tail call i32 @callee(i32 %a) + ret i32 %call +} + +declare i32 @callee(i32) + +attributes #0 = { "disable-tail-calls"="true" } Index: llvm/trunk/test/CodeGen/X86/disable-tail-calls.ll =================================================================== --- llvm/trunk/test/CodeGen/X86/disable-tail-calls.ll +++ llvm/trunk/test/CodeGen/X86/disable-tail-calls.ll @@ -0,0 +1,40 @@ +; RUN: llc < %s -march x86-64 | FileCheck %s --check-prefix=NO-OPTION +; RUN: llc < %s -march x86-64 -disable-tail-calls | FileCheck %s --check-prefix=DISABLE-TRUE +; RUN: llc < %s -march x86-64 -disable-tail-calls=false | FileCheck %s --check-prefix=DISABLE-FALSE + +; Check that command line option "-disable-tail-calls" overrides function +; attribute "disable-tail-calls". + +; NO-OPTION-LABEL: {{\_?}}func_attr +; NO-OPTION: callq {{\_?}}callee + +; DISABLE-FALSE-LABEL: {{\_?}}func_attr +; DISABLE-FALSE: jmp {{\_?}}callee + +; DISABLE-TRUE-LABEL: {{\_?}}func_attr +; DISABLE-TRUE: callq {{\_?}}callee + +define i32 @func_attr(i32 %a) #0 { +entry: + %call = tail call i32 @callee(i32 %a) + ret i32 %call +} + +; NO-OPTION-LABEL: {{\_?}}func_noattr +; NO-OPTION: jmp {{\_?}}callee + +; DISABLE-FALSE-LABEL: {{\_?}}func_noattr +; DISABLE-FALSE: jmp {{\_?}}callee + +; DISABLE-TRUE-LABEL: {{\_?}}func_noattr +; DISABLE-TRUE: callq {{\_?}}callee + +define i32 @func_noattr(i32 %a) { +entry: + %call = tail call i32 @callee(i32 %a) + ret i32 %call +} + +declare i32 @callee(i32) + +attributes #0 = { "disable-tail-calls"="true" }