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llvm-mirror/test/CodeGen/X86/seh-except-restore.ll
Reid Kleckner 4849f968cb [SEH] Remove CATCHPAD SDNode and X86::EH_RESTORE MachineInstr
The CATCHPAD node mostly existed to be selected into the EH_RESTORE
instruction, which sets the frame back up when 32-bit Windows exceptions
return to the parent function. However, creating this MachineInstr early
increases the risk that other passes will come along and insert
instructions that use the stack before ESP and EBP are restored. That
happened in PR44697.

Instead of representing these in the instruction stream early, delay it
until PEI. Mark the blocks where this needs to happen as EHPads, but not
funclet entry blocks. Passes after PEI have to be careful not to hoist
instructions that can use stack across frame setup instructions, so this
should be relatively reliable.

Fixes PR44697

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D73752
2020-02-04 15:13:12 -08:00

70 lines
2.7 KiB
LLVM

; RUN: llc < %s | FileCheck %s
; In PR44697, the register allocator inserted loads into the __except block
; before the instructions that restore EBP and ESP back to what they should be.
; Make sure they are the first instructions in the __except block.
; ModuleID = 't.cpp'
source_filename = "t.cpp"
target datalayout = "e-m:x-p:32:32-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:32-n8:16:32-a:0:32-S32"
target triple = "i386-pc-windows-msvc19.24.28315"
declare i8* @llvm.frameaddress.p0i8(i32 immarg)
declare i8* @llvm.eh.recoverfp(i8*, i8*)
declare i8* @llvm.localrecover(i8*, i8*, i32 immarg)
declare dso_local i32 @_except_handler3(...)
declare void @llvm.localescape(...)
define dso_local zeroext i1 @invokewrapper(
void ()* nocapture %Fn,
i1 zeroext %DumpStackAndCleanup,
i32* nocapture dereferenceable(4) %RetCode)
personality i32 (...)* @_except_handler3 {
entry:
%__exception_code = alloca i32, align 4
call void (...) @llvm.localescape(i32* nonnull %__exception_code)
invoke void %Fn()
to label %return unwind label %catch.dispatch
catch.dispatch: ; preds = %entry
%0 = catchswitch within none [label %__except.ret] unwind to caller
__except.ret: ; preds = %catch.dispatch
%1 = catchpad within %0 [i8* bitcast (i32 ()* @filter to i8*)]
catchret from %1 to label %__except
__except: ; preds = %__except.ret
%2 = load i32, i32* %__exception_code, align 4
store i32 %2, i32* %RetCode, align 4
br label %return
return: ; preds = %entry, %__except
%retval.0 = phi i1 [ false, %__except ], [ true, %entry ]
ret i1 %retval.0
}
; CHECK-LABEL: _invokewrapper: # @invokewrapper
; CHECK: calll *8(%ebp)
; CHECK: LBB0_2: # %return
; CHECK: LBB0_1: # %__except.ret
; CHECK-NEXT: movl -24(%ebp), %esp
; CHECK-NEXT: addl $12, %ebp
; Function Attrs: nofree nounwind
define internal i32 @filter() {
entry:
%0 = tail call i8* @llvm.frameaddress.p0i8(i32 1)
%1 = tail call i8* @llvm.eh.recoverfp(i8* bitcast (i1 (void ()*, i1, i32*)* @invokewrapper to i8*), i8* %0)
%2 = tail call i8* @llvm.localrecover(i8* bitcast (i1 (void ()*, i1, i32*)* @invokewrapper to i8*), i8* %1, i32 0)
%__exception_code = bitcast i8* %2 to i32*
%3 = getelementptr inbounds i8, i8* %0, i32 -20
%4 = bitcast i8* %3 to { i32*, i8* }**
%5 = load { i32*, i8* }*, { i32*, i8* }** %4, align 4
%6 = getelementptr inbounds { i32*, i8* }, { i32*, i8* }* %5, i32 0, i32 0
%7 = load i32*, i32** %6, align 4
%8 = load i32, i32* %7, align 4
store i32 %8, i32* %__exception_code, align 4
ret i32 1
}