Use function attribute "trap-func-name" and remove TargetOptions::TrapFuncName.

This commit changes normal isel and fast isel to read the user-defined trap
function name from function attribute "trap-func-name" attached to llvm.trap or
llvm.debugtrap instead of from TargetOptions::TrapFuncName. This is needed to
use clang's command line option "-ftrap-function" for LTO and enable changing
the trap function name on a per-call-site basis.

Out-of-tree projects currently using TargetOptions::TrapFuncName to specify the
trap function name should attach attribute "trap-func-name" to the call sites
of llvm.trap and llvm.debugtrap instead.

rdar://problem/21225723

Differential Revision: http://reviews.llvm.org/D10832


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241305 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/CommandFlags.h

@@ -17,6 +17,8 @@
 #define LLVM_CODEGEN_COMMANDFLAGS_H
 
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/Module.h"
 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
 #include "llvm//MC/SubtargetFeature.h"
@@ -249,7 +251,6 @@ static inline TargetOptions InitTargetOptionsFromCodeGenFlags() {
   Options.NoZerosInBSS = DontPlaceZerosInBSS;
   Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt;
   Options.StackAlignmentOverride = OverrideStackAlignment;
-  Options.TrapFuncName = TrapFuncName;
   Options.PositionIndependentExecutable = EnablePIE;
   Options.UseInitArray = !UseCtors;
   Options.DataSections = DataSections;
@@ -320,6 +321,16 @@ static inline void setFunctionAttributes(StringRef CPU, StringRef Features,
                                        "disable-tail-calls",
                                        toStringRef(DisableTailCalls));
 
+    if (TrapFuncName.getNumOccurrences() > 0)
+      for (auto &B : F)
+        for (auto &I : B)
+          if (auto *Call = dyn_cast<CallInst>(&I))
+            if (const auto *F = Call->getCalledFunction())
+              if (F->getIntrinsicID() == Intrinsic::debugtrap ||
+                  F->getIntrinsicID() == Intrinsic::trap)
+                Call->addAttribute(llvm::AttributeSet::FunctionIndex,
+                                   "trap-func-name", TrapFuncName);
+
     // Let NewAttrs override Attrs.
     NewAttrs = Attrs.addAttributes(Ctx, AttributeSet::FunctionIndex, NewAttrs);
     F.setAttributes(NewAttrs);

include/llvm/Target/TargetOptions.h

@@ -72,7 +72,7 @@ namespace llvm {
           UseInitArray(false), DisableIntegratedAS(false),
           CompressDebugSections(false), FunctionSections(false),
           DataSections(false), UniqueSectionNames(true), TrapUnreachable(false),
-          TrapFuncName(), FloatABIType(FloatABI::Default),
+          FloatABIType(FloatABI::Default),
           AllowFPOpFusion(FPOpFusion::Standard), Reciprocals(TargetRecip()),
           JTType(JumpTable::Single),
           ThreadModel(ThreadModel::POSIX) {}
@@ -172,12 +172,6 @@ namespace llvm {
     /// Emit target-specific trap instruction for 'unreachable' IR instructions.
     unsigned TrapUnreachable : 1;
 
-    /// getTrapFunctionName - If this returns a non-empty string, this means
-    /// isel should lower Intrinsic::trap to a call to the specified function
-    /// name instead of an ISD::TRAP node.
-    std::string TrapFuncName;
-    StringRef getTrapFunctionName() const;
-
     /// FloatABIType - This setting is set by -float-abi=xxx option is specfied
     /// on the command line. This setting may either be Default, Soft, or Hard.
     /// Default selects the target's default behavior. Soft selects the ABI for
@@ -237,7 +231,6 @@ inline bool operator==(const TargetOptions &LHS,
     ARE_EQUAL(PositionIndependentExecutable) &&
     ARE_EQUAL(UseInitArray) &&
     ARE_EQUAL(TrapUnreachable) &&
-    ARE_EQUAL(TrapFuncName) &&
     ARE_EQUAL(FloatABIType) &&
     ARE_EQUAL(AllowFPOpFusion) &&
     ARE_EQUAL(Reciprocals) &&

lib/CodeGen/SelectionDAG/FastISel.cpp

@@ -1350,7 +1350,7 @@ bool FastISel::selectInstruction(const Instruction *I) {
 
     // Don't handle Intrinsic::trap if a trap funciton is specified.
     if (F && F->getIntrinsicID() == Intrinsic::trap &&
-        !TM.Options.getTrapFunctionName().empty())
+        Call->hasFnAttr("trap-func-name"))
       return false;
   }
 

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -4780,7 +4780,10 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
 
   case Intrinsic::debugtrap:
   case Intrinsic::trap: {
-    StringRef TrapFuncName = TM.Options.getTrapFunctionName();
+    StringRef TrapFuncName =
+        I.getAttributes()
+            .getAttribute(AttributeSet::FunctionIndex, "trap-func-name")
+            .getValueAsString();
     if (TrapFuncName.empty()) {
       ISD::NodeType Op = (Intrinsic == Intrinsic::trap) ?
         ISD::TRAP : ISD::DEBUGTRAP;

lib/CodeGen/TargetOptionsImpl.cpp

@@ -47,10 +47,3 @@ bool TargetOptions::LessPreciseFPMAD() const {
 bool TargetOptions::HonorSignDependentRoundingFPMath() const {
   return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;
 }
-
-/// getTrapFunctionName - If this returns a non-empty string, this means isel
-/// should lower Intrinsic::trap to a call to the specified function name
-/// instead of an ISD::TRAP node.
-StringRef TargetOptions::getTrapFunctionName() const {
-  return TrapFuncName;
-}

test/CodeGen/ARM/fnattr-trap.ll

@@ -0,0 +1,40 @@
+; RUN: llc < %s -march arm | FileCheck %s -check-prefix=NOOPTION
+; RUN: llc < %s -march arm -trap-func=trap_llc | FileCheck %s -check-prefix=TRAP
+
+; NOOPTION-LABEL: {{\_?}}foo0:
+; NOOPTION: trap{{$}}
+
+; TRAP-LABEL: {{\_?}}foo0:
+; TRAP: bl {{\_?}}trap_llc
+
+define void @foo0() {
+  call void @llvm.trap()
+  unreachable
+}
+
+; NOOPTION-LABEL: {{\_?}}foo1:
+; NOOPTION: bl {{\_?}}trap_func_attr0
+
+; TRAP-LABEL: {{\_?}}foo1:
+; TRAP: bl {{\_?}}trap_llc
+
+define void @foo1() {
+  call void @llvm.trap() #0
+  unreachable
+}
+
+; NOOPTION-LABEL: {{\_?}}foo2:
+; NOOPTION: bl {{\_?}}trap_func_attr1
+
+; TRAP-LABEL: {{\_?}}foo2:
+; TRAP: bl {{\_?}}trap_llc
+
+define void @foo2() {
+  call void @llvm.trap() #1
+  unreachable
+}
+
+declare void @llvm.trap() nounwind
+
+attributes #0 = { "trap-func-name"="trap_func_attr0" }
+attributes #1 = { "trap-func-name"="trap_func_attr1" }