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[SEH] Deal with users of the old lpad for SEH catch-all blocks

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The way we split SEH catch-all blocks can leave some dead EH values
behind at -O0. Try to remove them, and if we fail, replace them all with
undef.

Fixes a crash when removing the old unreachable landingpad which is
still used by extractvalue instructions in the catch-all block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235061 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Reid Kleckner 2015-04-16 00:02:04 +00:00
parent cbbeac14f0
commit f96076ed80
2 changed files with 68 additions and 0 deletions
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9
lib/CodeGen/WinEHPrepare.cpp
View File

@ -433,6 +433,10 @@ bool WinEHPrepare::prepareExceptionHandlers(
Invoke->setUnwindDest(NewLPadBB);
}
// If anyone is still using the old landingpad value, just give them undef
// instead. The eh pointer and selector values are not real.
LPad->replaceAllUsesWith(UndefValue::get(LPad->getType()));
// Replace the mapping of any nested landing pad that previously mapped
// to this landing pad with a referenced to the cloned version.
for (auto &LPadPair : NestedLPtoOriginalLP) {
@ -636,6 +640,11 @@ void WinEHPrepare::promoteLandingPadValues(LandingPadInst *LPad) {
PromoteMemToReg(EHAllocas, *DT);
EHAllocas.clear();
}
// After promotion, some extracts may be trivially dead. Remove them.
SmallVector<Value *, 4> Users(LPad->user_begin(), LPad->user_end());
for (auto *U : Users)
RecursivelyDeleteTriviallyDeadInstructions(U);
}
void WinEHPrepare::completeNestedLandingPad(Function *ParentFn,

59
test/CodeGen/WinEH/seh-catch-all.ll Normal file
View File

@ -0,0 +1,59 @@
; RUN: opt -S -winehprepare -sehprepare < %s | FileCheck %s
target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-windows-msvc"
@str.__except = internal unnamed_addr constant [9 x i8] c"__except\00", align 1
; Function Attrs: uwtable
declare i32 @puts(i8*)
define void @may_crash() {
entry:
store volatile i32 42, i32* null, align 4
ret void
}
declare i32 @__C_specific_handler(...)
; Function Attrs: nounwind readnone
declare i8* @llvm.frameaddress(i32)
; Function Attrs: uwtable
define void @seh_catch_all() {
entry:
%exn.slot = alloca i8*
%ehselector.slot = alloca i32
invoke void @may_crash()
to label %invoke.cont unwind label %lpad
invoke.cont: ; preds = %entry
br label %__try.cont
lpad: ; preds = %entry
%0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__C_specific_handler to i8*)
catch i8* null
%1 = extractvalue { i8*, i32 } %0, 0
store i8* %1, i8** %exn.slot
%2 = extractvalue { i8*, i32 } %0, 1
store i32 %2, i32* %ehselector.slot
br label %__except
__except: ; preds = %lpad
%call = call i32 @puts(i8* getelementptr inbounds ([9 x i8], [9 x i8]* @str.__except, i32 0, i32 0))
br label %__try.cont
__try.cont: ; preds = %__except, %invoke.cont
ret void
}
; CHECK-LABEL: define void @seh_catch_all()
; CHECK: landingpad
; CHECK-NEXT: catch i8* null
; CHECK-NEXT: call i8* (...)* @llvm.eh.actions(i32 1, i8* null, i32 -1, i8* blockaddress(@seh_catch_all, %catch.all))
; CHECK-NEXT: indirectbr
;
; CHECK: catch.all:
; CHECK-NOT: extractvalue
; CHECK: call i32 @puts