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llvm-mirror/test/CodeGen/WinEH/wineh-statenumbering.ll
David Majnemer 81eb2d6bae [WinEH] Optimize WinEH state stores
32-bit x86 Windows targets use a linked-list of nodes allocated on the
stack, referenced to via thread-local storage.  The personality routine
interprets one of the fields in the node as a 'state number' which
indicates where the personality routine should transfer control.

State transitions are possible only before call-sites which may throw
exceptions.  Our previous scheme had us update the state number before
all call-sites which may throw.

Instead, we can try to minimize the number of times we need to store by
reasoning about the nearest store which dominates the current call-site.
If the last store agrees with the current call-site, then we know that
the state-update is redundant and can be elided.

This is largely straightforward: an RPO walk of the blocks allows us to
correctly forward propagate the information when the function is a DAG.
Currently, loops are not handled optimally and may trigger superfluous
state stores.

Differential Revision: http://reviews.llvm.org/D16763

llvm-svn: 261122
2016-02-17 18:37:11 +00:00

220 lines
8.0 KiB
LLVM

; RUN: opt -mtriple=i686-pc-windows-msvc -S -x86-winehstate < %s | FileCheck %s
target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
target triple = "i686-pc-windows-msvc"
%rtti.TypeDescriptor2 = type { i8**, i8*, [3 x i8] }
%eh.CatchableType = type { i32, i8*, i32, i32, i32, i32, i8* }
%eh.CatchableTypeArray.1 = type { i32, [1 x %eh.CatchableType*] }
%eh.ThrowInfo = type { i32, i8*, i8*, i8* }
$"\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
@"_CT??_R0H@84" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 1, i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i8*), i32 0, i32 -1, i32 0, i32 4, i8* null }, section ".xdata", comdat
@_CTA1H = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.1 { i32 1, [1 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0H@84"] }, section ".xdata", comdat
@_TI1H = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 0, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.1* @_CTA1H to i8*) }, section ".xdata", comdat
define i32 @main() #0 personality i32 (...)* @__CxxFrameHandler3 {
entry:
%tmp = alloca i32, align 4
; CHECK: entry:
; CHECK: store i32 -1
; CHECK: call void @g(i32 3)
; CHECK-NEXT: call void @g(i32 4)
; CHECK-NEXT: call void @g(i32 5)
call void @g(i32 3)
call void @g(i32 4)
call void @g(i32 5)
store i32 0, i32* %tmp, align 4
%0 = bitcast i32* %tmp to i8*
; CHECK: store i32 0
; CHECK: invoke void @_CxxThrowException(
invoke void @_CxxThrowException(i8* %0, %eh.ThrowInfo* nonnull @_TI1H) #1
to label %unreachable.for.entry unwind label %catch.dispatch
catch.dispatch: ; preds = %entry
%cs1 = catchswitch within none [label %catch] unwind to caller
catch: ; preds = %catch.dispatch
%1 = catchpad within %cs1 [i8* null, i32 u0x40, i8* null]
; CHECK: catch:
; CHECK: store i32 2
; CHECK: invoke void @_CxxThrowException(
invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) [ "funclet"(token %1) ]
to label %unreachable unwind label %catch.dispatch.1
catch.dispatch.1: ; preds = %catch
%cs2 = catchswitch within %1 [label %catch.3] unwind to caller
catch.3: ; preds = %catch.dispatch.1
%2 = catchpad within %cs2 [i8* null, i32 u0x40, i8* null]
; CHECK: catch.3:
; CHECK: store i32 3
; CHECK: call void @g(i32 1)
; CHECK-NEXT: call void @g(i32 2)
; CHECK-NEXT: call void @g(i32 3)
call void @g(i32 1)
call void @g(i32 2)
call void @g(i32 3)
catchret from %2 to label %try.cont
try.cont: ; preds = %catch.3
; CHECK: try.cont:
; CHECK: store i32 1
; CHECK: call void @g(i32 2)
; CHECK-NEXT: call void @g(i32 3)
; CHECK-NEXT: call void @g(i32 4)
call void @g(i32 2)
call void @g(i32 3)
call void @g(i32 4)
unreachable
unreachable: ; preds = %catch
unreachable
unreachable.for.entry: ; preds = %entry
unreachable
}
define i32 @nopads() #0 personality i32 (...)* @__CxxFrameHandler3 {
ret i32 0
}
; CHECK-LABEL: define i32 @nopads()
; CHECK-NEXT: ret i32 0
; CHECK-NOT: __ehhandler$nopads
; CHECK-LABEL: define void @PR25926()
define void @PR25926() personality i32 (...)* @__CxxFrameHandler3 {
entry:
; CHECK: entry:
; CHECK: store i32 -1
; CHECK: store i32 0
; CHECK: invoke void @_CxxThrowException(
invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null)
to label %unreachable unwind label %catch.dispatch
catch.dispatch: ; preds = %entry
%0 = catchswitch within none [label %catch] unwind to caller
catch: ; preds = %catch.dispatch
%1 = catchpad within %0 [i8* null, i32 64, i8* null]
; CHECK: catch:
; CHECK: store i32 3
; CHECK: invoke void @_CxxThrowException(
invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) [ "funclet"(token %1) ]
to label %unreachable1 unwind label %catch.dispatch1
catch.dispatch1: ; preds = %catch
%2 = catchswitch within %1 [label %catch2] unwind label %ehcleanup
catch2: ; preds = %catch.dispatch1
%3 = catchpad within %2 [i8* null, i32 64, i8* null]
catchret from %3 to label %try.cont
try.cont: ; preds = %catch2
; CHECK: try.cont:
; CHECK: store i32 1
; CHECK: call void @dtor()
; CHECK-NEXT: call void @dtor()
; CHECK-NEXT: call void @dtor()
call void @dtor() #3 [ "funclet"(token %1) ]
call void @dtor() #3 [ "funclet"(token %1) ]
call void @dtor() #3 [ "funclet"(token %1) ]
catchret from %1 to label %try.cont4
try.cont4: ; preds = %try.cont
ret void
ehcleanup: ; preds = %catch.dispatch1
%4 = cleanuppad within %1 []
; CHECK: ehcleanup:
; CHECK: call void @dtor()
call void @dtor() #3 [ "funclet"(token %4) ]
cleanupret from %4 unwind to caller
unreachable: ; preds = %entry
unreachable
unreachable1: ; preds = %catch
unreachable
}
; CHECK-LABEL: define void @required_state_store(
define void @required_state_store(i1 zeroext %cond) personality i32 (...)* @_except_handler3 {
entry:
%__exception_code = alloca i32, align 4
call void (...) @llvm.localescape(i32* nonnull %__exception_code)
; CHECK: store i32 -1
; CHECK: call void @g(i32 0)
call void @g(i32 0)
br i1 %cond, label %if.then, label %if.end
if.then: ; preds = %entry
; CHECK: store i32 0
; CHECK-NEXT: invoke void @g(i32 1)
invoke void @g(i32 1)
to label %if.end unwind label %catch.dispatch
catch.dispatch: ; preds = %if.then
%0 = catchswitch within none [label %__except.ret] unwind to caller
__except.ret: ; preds = %catch.dispatch
%1 = catchpad within %0 [i8* bitcast (i32 ()* @"\01?filt$0@0@required_state_store@@" to i8*)]
catchret from %1 to label %if.end
if.end: ; preds = %if.then, %__except.ret, %entry
; CHECK: store i32 -1
; CHECK-NEXT: call void @dtor()
call void @dtor()
ret void
}
define internal i32 @"\01?filt$0@0@required_state_store@@"() {
entry:
%0 = tail call i8* @llvm.frameaddress(i32 1)
%1 = tail call i8* @llvm.x86.seh.recoverfp(i8* bitcast (void (i1)* @required_state_store to i8*), i8* %0)
%2 = tail call i8* @llvm.localrecover(i8* bitcast (void (i1)* @required_state_store 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
}
declare void @g(i32) #0
declare void @dtor()
declare x86_stdcallcc void @_CxxThrowException(i8*, %eh.ThrowInfo*)
declare i32 @__CxxFrameHandler3(...)
declare i8* @llvm.frameaddress(i32)
declare i8* @llvm.x86.seh.recoverfp(i8*, i8*)
declare i8* @llvm.localrecover(i8*, i8*, i32)
declare void @llvm.localescape(...)
declare i32 @_except_handler3(...)
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" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { noreturn }
!llvm.ident = !{!0}
!0 = !{!"clang version 3.8.0 (trunk 245153) (llvm/trunk 245238)"}