Revert r248959, "[WinEH] Emit int3 after noreturn calls on Win64"

It broke; LLVM :: CodeGen__Generic__2009-11-16-BadKillsCrash.ll

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249032 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Target/TargetOptions.h b/include/llvm/Target/TargetOptions.h
index e931ec875c0111ebdb9575ff1d98df834d904bfe..bd696f399d54358e69b9fa9130de5cd8a51e3a64 100644 (file)
--- a/include/llvm/Target/TargetOptions.h
+++ b/include/llvm/Target/TargetOptions.h
@@ -71,7 +71,7 @@ namespace llvm {
           EnableFastISel(false), PositionIndependentExecutable(false),
           UseInitArray(false), DisableIntegratedAS(false),
           CompressDebugSections(false), FunctionSections(false),
-          DataSections(false), UniqueSectionNames(true),
+          DataSections(false), UniqueSectionNames(true), TrapUnreachable(false),
           EmulatedTLS(false), FloatABIType(FloatABI::Default),
           AllowFPOpFusion(FPOpFusion::Standard), Reciprocals(TargetRecip()),
           JTType(JumpTable::Single),
@@ -169,6 +169,9 @@ namespace llvm {
 
     unsigned UniqueSectionNames : 1;
 
+    /// Emit target-specific trap instruction for 'unreachable' IR instructions.
+    unsigned TrapUnreachable : 1;
+
     /// EmulatedTLS - This flag enables emulated TLS model, using emutls
     /// function in the runtime library..
     unsigned EmulatedTLS : 1;
@@ -231,6 +234,7 @@ inline bool operator==(const TargetOptions &LHS,
     ARE_EQUAL(EnableFastISel) &&
     ARE_EQUAL(PositionIndependentExecutable) &&
     ARE_EQUAL(UseInitArray) &&
+    ARE_EQUAL(TrapUnreachable) &&
     ARE_EQUAL(EmulatedTLS) &&
     ARE_EQUAL(FloatABIType) &&
     ARE_EQUAL(AllowFPOpFusion) &&

diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index f97edb4ef0904a2939cba7754ca924df68087e98..13b097cfc6065e5329a458225dce007ee182eda6 100644 (file)
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -1569,8 +1569,10 @@ bool FastISel::selectOperator(const User *I, unsigned Opcode) {
   }
 
   case Instruction::Unreachable:
-    // Nothing to emit.
-    return true;
+    if (TM.Options.TrapUnreachable)
+      return fastEmit_(MVT::Other, MVT::Other, ISD::TRAP) != 0;
+    else
+      return true;
 
   case Instruction::Alloca:
     // FunctionLowering has the static-sized case covered.

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index a48de572113750efe9a1c2804b4f92236064b2df..72af2760bb7dfb4c5915230d40e082cb6bc3aedb 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2205,7 +2205,10 @@ void SelectionDAGBuilder::visitIndirectBr(const IndirectBrInst &I) {
                           getValue(I.getAddress())));
 }
 
-void SelectionDAGBuilder::visitUnreachable(const UnreachableInst &I) {}
+void SelectionDAGBuilder::visitUnreachable(const UnreachableInst &I) {
+  if (DAG.getTarget().Options.TrapUnreachable)
+    DAG.setRoot(DAG.getNode(ISD::TRAP, getCurSDLoc(), MVT::Other, DAG.getRoot()));
+}
 
 void SelectionDAGBuilder::visitFSub(const User &I) {
   // -0.0 - X --> fneg

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 6d8aa4a10d36779c94f2b7e45757a9fe36383043..71ff9be6cdadf3b5215139c591f2844099ec5c64 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2945,20 +2945,6 @@ static SDValue getMOVL(SelectionDAG &DAG, SDLoc dl, EVT VT, SDValue V1,
   return DAG.getVectorShuffle(VT, dl, V1, V2, &Mask[0]);
 }
 
-/// Check if the fall through instruction after a call site is unreachable.
-/// FIXME: This will fail if there are interesting non-code generating IR
-/// instructions between the call and the unreachable (lifetime.end). In
-/// practice, this should be rare because optimizations like to delete non-call
-/// code before unreachable.
-static bool isCallFollowedByUnreachable(ImmutableCallSite CS) {
-  const Instruction *NextInst;
-  if (auto *II = dyn_cast<InvokeInst>(CS.getInstruction()))
-    NextInst = II->getNormalDest()->getFirstNonPHIOrDbg();
-  else
-    NextInst = CS.getInstruction()->getNextNode();
-  return isa<UnreachableInst>(NextInst);
-}
-
 SDValue
 X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
                              SmallVectorImpl<SDValue> &InVals) const {
@@ -3464,15 +3450,6 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
     InFlag = Chain.getValue(1);
   }
 
-  if (Subtarget->isTargetWin64() && CLI.CS) {
-    // Look for a call followed by unreachable. On Win64, we need to ensure that
-    // the call does not accidentally fall through to something that looks like
-    // an epilogue. We do this by inserting a DEBUGTRAP, which lowers to int3,
-    // which is what MSVC emits after noreturn calls.
-    if (isCallFollowedByUnreachable(*CLI.CS))
-      Chain = DAG.getNode(ISD::DEBUGTRAP, dl, MVT::Other, Chain);
-  }
-
   // Handle result values, copying them out of physregs into vregs that we
   // return.
   return LowerCallResult(Chain, InFlag, CallConv, isVarArg,

diff --git a/lib/Target/X86/X86TargetMachine.cpp b/lib/Target/X86/X86TargetMachine.cpp
index d318244e0f70710ac78b5e32b9eaad3adf36fd19..2e869eb7c3cd6eaf34b0d2b68d8cbae06f5ecab0 100644 (file)
--- a/lib/Target/X86/X86TargetMachine.cpp
+++ b/lib/Target/X86/X86TargetMachine.cpp
@@ -110,6 +110,13 @@ X86TargetMachine::X86TargetMachine(const Target &T, const Triple &TT,
                         OL),
       TLOF(createTLOF(getTargetTriple())),
       Subtarget(TT, CPU, FS, *this, Options.StackAlignmentOverride) {
+  // Windows stack unwinder gets confused when execution flow "falls through"
+  // after a call to 'noreturn' function.
+  // To prevent that, we emit a trap for 'unreachable' IR instructions.
+  // (which on X86, happens to be the 'ud2' instruction)
+  if (Subtarget.isTargetWin64())
+    this->Options.TrapUnreachable = true;
+
   // By default (and when -ffast-math is on), enable estimate codegen for
   // everything except scalar division. By default, use 1 refinement step for
   // all operations. Defaults may be overridden by using command-line options.

diff --git a/test/CodeGen/X86/br-fold.ll b/test/CodeGen/X86/br-fold.ll
index 9a7552ddad82a2c70abb1f10d5f72c5856b38038..fd1e73bde8cc5d457fbba5676958e52b3efb7c38 100644 (file)
--- a/test/CodeGen/X86/br-fold.ll
+++ b/test/CodeGen/X86/br-fold.ll
@@ -10,10 +10,10 @@
 ; X64_LINUX-NEXT: %bb8.i329
 
 ; X64_WINDOWS: orq %rax, %rcx
-; X64_WINDOWS-NEXT: %bb8.i329
+; X64_WINDOWS-NEXT: ud2
 
 ; X64_WINDOWS_GNU: orq %rax, %rcx
-; X64_WINDOWS_GNU-NEXT: %bb8.i329
+; X64_WINDOWS_GNU-NEXT: ud2
 
 @_ZN11xercesc_2_513SchemaSymbols21fgURI_SCHEMAFORSCHEMAE = external constant [33 x i16], align 32 ; <[33 x i16]*> [#uses=1]
 @_ZN11xercesc_2_56XMLUni16fgNotationStringE = external constant [9 x i16], align 16 ; <[9 x i16]*> [#uses=1]

diff --git a/test/CodeGen/X86/win-catchpad-rethrow.ll b/test/CodeGen/X86/win-catchpad-rethrow.ll
deleted file mode 100644 (file)
index 7585b07..0000000
--- a/test/CodeGen/X86/win-catchpad-rethrow.ll
+++ /dev/null
@@ -1,103 +0,0 @@
-; RUN: llc -mtriple=x86_64-pc-windows-msvc < %s | FileCheck %s
-
-; C++ EH rethrows are interesting, because they are calls to noreturn
-; functions. There *must* be some code after the call instruction that doesn't
-; look like an epilogue. We use int3 to be consistent with MSVC.
-
-; Based on this C++ source:
-; int main() {
-;   try {
-;     throw 42;
-;   } catch (int) {
-;     try {
-;       throw;
-;     } catch (int) {
-;     }
-;   }
-;   return 0;
-; }
-
-; ModuleID = 't.cpp'
-target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
-target triple = "x86_64-pc-windows-msvc"
-
-%rtti.TypeDescriptor2 = type { i8**, i8*, [3 x i8] }
-%eh.CatchableType = type { i32, i32, i32, i32, i32, i32, i32 }
-%eh.CatchableTypeArray.1 = type { i32, [1 x i32] }
-%eh.ThrowInfo = type { i32, i32, i32, i32 }
-
-$"\01??_R0H@8" = comdat any
-
-$"_CT??_R0H@84" = comdat any
-
-$_CTA1H = comdat any
-
-$_TI1H = comdat any
-
-@"\01??_7type_info@@6B@" = external constant i8*
-@"\01??_R0H@8" = linkonce_odr global %rtti.TypeDescriptor2 { i8** @"\01??_7type_info@@6B@", i8* null, [3 x i8] c".H\00" }, comdat
-@__ImageBase = external constant i8
-@"_CT??_R0H@84" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 1, i32 trunc (i64 sub nuw nsw (i64 ptrtoint (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i64), i64 ptrtoint (i8* @__ImageBase to i64)) to i32), i32 0, i32 -1, i32 0, i32 4, i32 0 }, section ".xdata", comdat
-@_CTA1H = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.1 { i32 1, [1 x i32] [i32 trunc (i64 sub nuw nsw (i64 ptrtoint (%eh.CatchableType* @"_CT??_R0H@84" to i64), i64 ptrtoint (i8* @__ImageBase to i64)) to i32)] }, section ".xdata", comdat
-@_TI1H = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 0, i32 0, i32 0, i32 trunc (i64 sub nuw nsw (i64 ptrtoint (%eh.CatchableTypeArray.1* @_CTA1H to i64), i64 ptrtoint (i8* @__ImageBase to i64)) to i32) }, section ".xdata", comdat
-
-define i32 @main() #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
-entry:
-  %tmp = alloca i32, align 4
-  store i32 42, i32* %tmp, align 4
-  %0 = bitcast i32* %tmp to i8*
-  invoke void @_CxxThrowException(i8* %0, %eh.ThrowInfo* nonnull @_TI1H) #1
-          to label %unreachable unwind label %catch.dispatch
-
-catch.dispatch:                                   ; preds = %entry
-  %1 = catchpad [%rtti.TypeDescriptor2* @"\01??_R0H@8", i32 0, i8* null]
-          to label %catch unwind label %catchendblock
-
-catch:                                            ; preds = %catch.dispatch
-  invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) #1
-          to label %unreachable unwind label %catch.dispatch.1
-
-catch.dispatch.1:                                 ; preds = %catch
-  %2 = catchpad [%rtti.TypeDescriptor2* @"\01??_R0H@8", i32 0, i8* null]
-          to label %catch.3 unwind label %catchendblock.2
-
-catch.3:                                          ; preds = %catch.dispatch.1
-  catchret %2 to label %try.cont
-
-try.cont:                                         ; preds = %catch.3
-  catchret %1 to label %try.cont.5
-
-try.cont.5:                                       ; preds = %try.cont
-  ret i32 0
-
-catchendblock.2:                                  ; preds = %catch.dispatch.1
-  catchendpad unwind label %catchendblock
-
-catchendblock:                                    ; preds = %catchendblock.2, %catch.dispatch
-  catchendpad unwind to caller
-
-unreachable:                                      ; preds = %catch, %entry
-  unreachable
-}
-
-declare void @_CxxThrowException(i8*, %eh.ThrowInfo*)
-
-declare i32 @__CxxFrameHandler3(...)
-
-attributes #0 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-features"="+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
-attributes #1 = { noreturn }
-
-; CHECK: main:
-; CHECK: .seh_proc main
-; CHECK: movl $42,
-; CHECK-DAG: leaq {{.*}}, %rcx
-; CHECK-DAG: leaq _TI1H(%rip), %rdx
-; CHECK: callq _CxxThrowException
-; CHECK-NEXT: int3
-
-; CHECK: "?catch$1@?0?main@4HA":
-; CHECK: .seh_proc "?catch$1@?0?main@4HA"
-; CHECK-DAG: xorl %ecx, %ecx
-; CHECK-DAG: xorl %edx, %edx
-; CHECK: callq _CxxThrowException
-; CHECK-NEXT: int3

diff --git a/test/CodeGen/X86/win64_call_epi.ll b/test/CodeGen/X86/win64_call_epi.ll
index d514032dcbf84bbc0d1dd564202fc174a1e15e90..096cbe41c5404431ac903bbbefb262e14f5fe5a6 100644 (file)
--- a/test/CodeGen/X86/win64_call_epi.ll
+++ b/test/CodeGen/X86/win64_call_epi.ll
@@ -24,9 +24,9 @@ catch:
 ; WIN64: nop
 ; WIN64: addq ${{[0-9]+}}, %rsp
 ; WIN64: retq
-; Check for 'int3' after noreturn call
+; Check for 'ud2' after noreturn call
 ; WIN64: callq _Unwind_Resume
-; WIN64-NEXT: int3
+; WIN64-NEXT: ud2
 ; WIN64: .seh_endproc