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Don't remove a landing pad if the invoke requires a table entry.

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An invoke may require a table entry. For instance, when the function it calls
is expected to throw.
<rdar://problem/13360379>

llvm-svn: 176827
This commit is contained in:
Bill Wendling 2013-03-11 20:53:00 +00:00
parent 712c6f4f44
commit a225da9719
2 changed files with 94 additions and 3 deletions
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20
lib/Transforms/Utils/SimplifyCFG.cpp
View File

@ -2789,9 +2789,20 @@ bool SimplifyCFGOpt::SimplifyResume(ResumeInst *RI, IRBuilder<> &Builder) {
return false;
// Turn all invokes that unwind here into calls and delete the basic block.
bool InvokeRequiresTableEntry = false;
bool Changed = false;
for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;) {
InvokeInst *II = cast<InvokeInst>((*PI++)->getTerminator());
if (II->hasFnAttr(Attribute::UWTable)) {
// Don't remove an `invoke' instruction if the ABI requires an entry into
// the table.
InvokeRequiresTableEntry = true;
continue;
}
SmallVector<Value*, 8> Args(II->op_begin(), II->op_end() - 3);
// Insert a call instruction before the invoke.
CallInst *Call = CallInst::Create(II->getCalledValue(), Args, "", II);
Call->takeName(II);
@ -2811,11 +2822,14 @@ bool SimplifyCFGOpt::SimplifyResume(ResumeInst *RI, IRBuilder<> &Builder) {
// Finally, delete the invoke instruction!
II->eraseFromParent();
Changed = true;
}
// The landingpad is now unreachable. Zap it.
BB->eraseFromParent();
return true;
if (!InvokeRequiresTableEntry)
// The landingpad is now unreachable. Zap it.
BB->eraseFromParent();
return Changed;
}
bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI, IRBuilder<> &Builder) {

77
test/Transforms/SimplifyCFG/trivial-throw.ll Normal file
View File

@ -0,0 +1,77 @@
; RUN: opt -simplifycfg -S < %s | FileCheck %s
; <rdar://problem/13360379>
@_ZTVN10__cxxabiv117__class_type_infoE = external global i8*
@_ZTS13TestException = linkonce_odr constant [16 x i8] c"13TestException\00"
@_ZTI13TestException = linkonce_odr unnamed_addr constant { i8*, i8* } { i8* bitcast (i8** getelementptr inbounds (i8** @_ZTVN10__cxxabiv117__class_type_infoE, i64 2) to i8*), i8* getelementptr inbounds ([16 x i8]* @_ZTS13TestException, i32 0, i32 0) }
define void @throw(i32 %n) #0 {
entry:
%exception = call i8* @__cxa_allocate_exception(i64 1) #4
call void @__cxa_throw(i8* %exception, i8* bitcast ({ i8*, i8* }* @_ZTI13TestException to i8*), i8* null) #2
unreachable
}
define void @func() #0 {
entry:
; CHECK: func()
; CHECK: invoke void @throw
; CHECK-NOT: call void @throw
invoke void @throw(i32 42) #0
to label %exit unwind label %lpad
lpad:
%tmp0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
resume { i8*, i32 } %tmp0
exit:
invoke void @abort() #2
to label %invoke.cont unwind label %lpad1
invoke.cont:
unreachable
lpad1:
%tmp1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
catch i8* bitcast ({ i8*, i8* }* @_ZTI13TestException to i8*)
%tmp2 = extractvalue { i8*, i32 } %tmp1, 1
%tmp3 = call i32 @llvm.eh.typeid.for(i8* bitcast ({ i8*, i8* }* @_ZTI13TestException to i8*)) #4
%matches = icmp eq i32 %tmp2, %tmp3
br i1 %matches, label %catch, label %eh.resume
catch:
ret void
eh.resume:
resume { i8*, i32 } %tmp1
}
define linkonce_odr hidden void @__clang_call_terminate(i8*) #1 {
%2 = call i8* @__cxa_begin_catch(i8* %0) #4
call void @_ZSt9terminatev() #5
unreachable
}
declare void @abort() #2
declare i32 @llvm.eh.typeid.for(i8*) #3
declare void @__cxa_end_catch()
declare i8* @__cxa_allocate_exception(i64)
declare i32 @__gxx_personality_v0(...)
declare void @__cxa_throw(i8*, i8*, i8*)
declare i8* @__cxa_begin_catch(i8*)
declare void @_ZSt9terminatev()
attributes #0 = { ssp uwtable }
attributes #1 = { noinline noreturn nounwind }
attributes #2 = { noreturn }
attributes #3 = { nounwind readnone }
attributes #4 = { nounwind }
attributes #5 = { noreturn nounwind }