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[SjLj] Insert UnregisterFn before musttail call 

When inserting UnregisterFn, if there is a musttail call, we must insert before the call so that we don't break the musttail call contract.

Reviewed By: wenlei

Differential Revision: https://reviews.llvm.org/D104807
This commit is contained in:
Xun Li 2021-06-23 15:33:55 -07:00
parent f8c84da23b
commit f09ec01f1f
2 changed files with 37 additions and 2 deletions
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8
llvm/lib/CodeGen/SjLjEHPrepare.cpp
View File

@ -472,8 +472,12 @@ bool SjLjEHPrepare::setupEntryBlockAndCallSites(Function &F) {
// Finally, for any returns from this function, if this function contains an
// invoke, add a call to unregister the function context.
for (ReturnInst *Return : Returns)
CallInst::Create(UnregisterFn, FuncCtx, "", Return);
for (ReturnInst *Return : Returns) {
Instruction *InsertPoint = Return;
if (CallInst *CI = Return->getParent()->getTerminatingMustTailCall())
InsertPoint = CI;
CallInst::Create(UnregisterFn, FuncCtx, "", InsertPoint);
}
return true;
}

31
llvm/test/CodeGen/X86/sjlj-eh-musttail.ll Normal file
View File

@ -0,0 +1,31 @@
; FIXME: Fix machine verifier issues and remove -verify-machineinstrs=0. PR39439.
; RUN: llc -mtriple i386-windows-gnu -exception-model sjlj -filetype asm -o - %s -verify-machineinstrs=0 | FileCheck %s
declare void @_Z20function_that_throwsv()
declare i32 @__gxx_personality_sj0(...)
declare i8* @__cxa_begin_catch(i8*)
declare void @__cxa_end_catch()
declare void @_callee();
define void @_Z8functionv() personality i8* bitcast (i32 (...)* @__gxx_personality_sj0 to i8*) {
entry:
invoke void @_Z20function_that_throwsv()
to label %try.cont unwind label %lpad
lpad:
%0 = landingpad { i8*, i32 }
catch i8* null
%1 = extractvalue { i8*, i32 } %0, 0
%2 = tail call i8* @__cxa_begin_catch(i8* %1)
tail call void @__cxa_end_catch()
br label %try.cont
try.cont:
musttail call void @_callee();
ret void
}
; CHECK-LABEL: __Z8functionv:
; CHECK: calll __Unwind_SjLj_Unregister
; CHECK-NOT: {{.*}}:
; CHECK: jmp __callee