#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Operator.h"
-#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
-using namespace llvm::PatternMatch;
#define DEBUG_TYPE "local"
return NumDeadInst;
}
-unsigned llvm::changeToUnreachable(Instruction *I) {
+unsigned llvm::changeToUnreachable(Instruction *I, bool UseLLVMTrap) {
BasicBlock *BB = I->getParent();
// Loop over all of the successors, removing BB's entry from any PHI
// nodes.
- for (BasicBlock *Succ : successors(BB))
- Succ->removePredecessor(BB);
-
+ for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
+ (*SI)->removePredecessor(BB);
+
+ // Insert a call to llvm.trap right before this. This turns the undefined
+ // behavior into a hard fail instead of falling through into random code.
+ if (UseLLVMTrap) {
+ Function *TrapFn =
+ Intrinsic::getDeclaration(BB->getParent()->getParent(), Intrinsic::trap);
+ CallInst *CallTrap = CallInst::Create(TrapFn, "", I);
+ CallTrap->setDebugLoc(I->getDebugLoc());
+ }
new UnreachableInst(I->getContext(), I);
// All instructions after this are dead.
// Do a quick scan of the basic block, turning any obviously unreachable
// instructions into LLVM unreachable insts. The instruction combining pass
// canonicalizes unreachable insts into stores to null or undef.
- for (Instruction &I : *BB) {
+ for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E;++BBI){
// Assumptions that are known to be false are equivalent to unreachable.
// Also, if the condition is undefined, then we make the choice most
// beneficial to the optimizer, and choose that to also be unreachable.
- if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I)) {
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BBI)) {
if (II->getIntrinsicID() == Intrinsic::assume) {
- if (match(II->getArgOperand(0), m_CombineOr(m_Zero(), m_Undef()))) {
- changeToUnreachable(II);
+ bool MakeUnreachable = false;
+ if (isa<UndefValue>(II->getArgOperand(0)))
+ MakeUnreachable = true;
+ else if (ConstantInt *Cond =
+ dyn_cast<ConstantInt>(II->getArgOperand(0)))
+ MakeUnreachable = Cond->isZero();
+
+ if (MakeUnreachable) {
+ // Don't insert a call to llvm.trap right before the unreachable.
+ changeToUnreachable(&*BBI, false);
Changed = true;
break;
}
// Note: unlike in llvm.assume, it is not "obviously profitable" for
// guards to treat `undef` as `false` since a guard on `undef` can
// still be useful for widening.
- if (match(II->getArgOperand(0), m_Zero()))
- if (!isa<UnreachableInst>(II->getNextNode())) {
- changeToUnreachable(II->getNextNode());
+ if (auto *CI = dyn_cast<ConstantInt>(II->getArgOperand(0)))
+ if (CI->isZero() && !isa<UnreachableInst>(II->getNextNode())) {
+ changeToUnreachable(II->getNextNode(), /*UseLLVMTrap=*/ false);
Changed = true;
break;
}
}
}
- if (auto *CI = dyn_cast<CallInst>(&I)) {
+ if (CallInst *CI = dyn_cast<CallInst>(BBI)) {
Value *Callee = CI->getCalledValue();
if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
- changeToUnreachable(CI);
+ changeToUnreachable(CI, /*UseLLVMTrap=*/false);
Changed = true;
break;
}
// If we found a call to a no-return function, insert an unreachable
// instruction after it. Make sure there isn't *already* one there
// though.
- if (!isa<UnreachableInst>(CI->getNextNode())) {
- changeToUnreachable(CI->getNextNode());
+ ++BBI;
+ if (!isa<UnreachableInst>(BBI)) {
+ // Don't insert a call to llvm.trap right before the unreachable.
+ changeToUnreachable(&*BBI, false);
Changed = true;
}
break;
// Store to undef and store to null are undefined and used to signal that
// they should be changed to unreachable by passes that can't modify the
// CFG.
- if (auto *SI = dyn_cast<StoreInst>(&I)) {
+ if (StoreInst *SI = dyn_cast<StoreInst>(BBI)) {
// Don't touch volatile stores.
if (SI->isVolatile()) continue;
if (isa<UndefValue>(Ptr) ||
(isa<ConstantPointerNull>(Ptr) &&
SI->getPointerAddressSpace() == 0)) {
- changeToUnreachable(SI);
+ changeToUnreachable(SI, true);
Changed = true;
break;
}
// Turn invokes that call 'nounwind' functions into ordinary calls.
Value *Callee = II->getCalledValue();
if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
- changeToUnreachable(II);
+ changeToUnreachable(II, true);
Changed = true;
} else if (II->doesNotThrow() && canSimplifyInvokeNoUnwind(&F)) {
if (II->use_empty() && II->onlyReadsMemory()) {
}
Changed |= ConstantFoldTerminator(BB, true);
- for (BasicBlock *Succ : successors(BB))
- if (Reachable.insert(Succ).second)
- Worklist.push_back(Succ);
+ for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
+ if (Reachable.insert(*SI).second)
+ Worklist.push_back(*SI);
} while (!Worklist.empty());
return Changed;
}
--- /dev/null
+; RUN: opt -S -simplifycfg < %s | FileCheck %s
+; Radar 9342286
+; Assign DebugLoc to trap instruction.
+define void @foo() nounwind ssp !dbg !0 {
+; CHECK: call void @llvm.trap(), !dbg
+ store i32 42, i32* null, !dbg !5
+ ret void, !dbg !7
+}
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!10}
+
+!0 = distinct !DISubprogram(name: "foo", line: 3, isLocal: false, isDefinition: true, virtualIndex: 6, isOptimized: false, unit: !2, file: !8, scope: !1, type: !3)
+!1 = !DIFile(filename: "foo.c", directory: "/private/tmp")
+!2 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "Apple clang version 3.0 (tags/Apple/clang-206.1) (based on LLVM 3.0svn)", isOptimized: true, emissionKind: FullDebug, file: !8, enums: !{}, retainedTypes: !{})
+!3 = !DISubroutineType(types: !4)
+!4 = !{null}
+!5 = !DILocation(line: 4, column: 2, scope: !6)
+!6 = distinct !DILexicalBlock(line: 3, column: 12, file: !8, scope: !0)
+!7 = !DILocation(line: 5, column: 1, scope: !6)
+!8 = !DIFile(filename: "foo.c", directory: "/private/tmp")
+!10 = !{i32 1, !"Debug Info Version", i32 3}
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