Index: include/llvm/CodeGen/CommandFlags.h
===================================================================
--- include/llvm/CodeGen/CommandFlags.h
+++ 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"
@@ -239,7 +240,6 @@
Options.FloatABIType = FloatABIForCalls;
Options.NoZerosInBSS = DontPlaceZerosInBSS;
Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt;
- Options.DisableTailCalls = DisableTailCalls;
Options.StackAlignmentOverride = OverrideStackAlignment;
Options.TrapFuncName = TrapFuncName;
Options.PositionIndependentExecutable = EnablePIE;
@@ -307,6 +307,11 @@
"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: include/llvm/Target/TargetOptions.h
===================================================================
--- include/llvm/Target/TargetOptions.h
+++ include/llvm/Target/TargetOptions.h
@@ -66,7 +66,7 @@
HonorSignDependentRoundingFPMathOption(false),
NoZerosInBSS(false),
GuaranteedTailCallOpt(false),
- DisableTailCalls(false), StackAlignmentOverride(0),
+ StackAlignmentOverride(0),
EnableFastISel(false), PositionIndependentExecutable(false),
UseInitArray(false), DisableIntegratedAS(false),
CompressDebugSections(false), FunctionSections(false),
@@ -135,10 +135,6 @@
/// 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;
@@ -231,7 +227,6 @@
ARE_EQUAL(HonorSignDependentRoundingFPMathOption) &&
ARE_EQUAL(NoZerosInBSS) &&
ARE_EQUAL(GuaranteedTailCallOpt) &&
- ARE_EQUAL(DisableTailCalls) &&
ARE_EQUAL(StackAlignmentOverride) &&
ARE_EQUAL(EnableFastISel) &&
ARE_EQUAL(PositionIndependentExecutable) &&
Index: lib/Target/ARM/ARMISelLowering.cpp
===================================================================
--- lib/Target/ARM/ARMISelLowering.cpp
+++ lib/Target/ARM/ARMISelLowering.cpp
@@ -1480,9 +1480,10 @@
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) {
@@ -2372,7 +2373,9 @@
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: lib/Target/Hexagon/HexagonISelLowering.cpp
===================================================================
--- lib/Target/Hexagon/HexagonISelLowering.cpp
+++ 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: lib/Target/TargetMachine.cpp
===================================================================
--- lib/Target/TargetMachine.cpp
+++ 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: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -2247,7 +2247,9 @@
}
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);
@@ -2776,8 +2778,9 @@
StructReturnType SR = callIsStructReturn(Outs);
bool IsSibcall = false;
X86MachineFunctionInfo *X86Info = MF.getInfo<X86MachineFunctionInfo>();
+ auto Attr = MF.getFunction()->getFnAttribute("disable-tail-calls");
- if (MF.getTarget().Options.DisableTailCalls)
+ if (Attr.getValueAsString() == "true")
isTailCall = false;
bool IsMustTail = CLI.CS && CLI.CS->isMustTailCall();
Index: lib/Transforms/IPO/PassManagerBuilder.cpp
===================================================================
--- lib/Transforms/IPO/PassManagerBuilder.cpp
+++ 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: lib/Transforms/Scalar/TailRecursionElimination.cpp
===================================================================
--- lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ 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: test/CodeGen/ARM/disable-tail-calls.ll
===================================================================
--- /dev/null
+++ test/CodeGen/ARM/disable-tail-calls.ll
@@ -0,0 +1,19 @@
+; RUN: llc < %s -march arm | FileCheck %s --check-prefix=ENABLE-TAIL-CALLS
+; RUN: llc < %s -march arm -disable-tail-calls | FileCheck %s --check-prefix=DISABLE-TAIL-CALLS
+; RUN: llc < %s -march arm -disable-tail-calls=false | FileCheck %s --check-prefix=ENABLE-TAIL-CALLS
+
+; Check that command line option "-disable-tail-calls" overrides function
+; attribute "disable-tail-calls".
+
+; ENABLE-TAIL-CALLS: b {{\_?}}foo2
+; DISABLE-TAIL-CALLS: bl {{\_?}}foo2
+
+define i32 @foo1(i32 %a) #0 {
+entry:
+ %call = tail call i32 @foo2(i32 %a)
+ ret i32 %call
+}
+
+declare i32 @foo2(i32)
+
+attributes #0 = { "disable-tail-calls"="false" }