[WinEH] Make llvm.x86.seh.restoreframe work for stack realignment prologues

The incoming EBP value points to the end of a local stack allocation, so
we can use that to restore ESI, the base pointer. Once we do that, we
can use local stack allocations. If we know we need stack realignment,
spill the original frame pointer in the prologue and reload it after
restoring ESI.

llvm-svn: 241648

1 files changed, 99 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/seh-stack-realign-win32.ll b/llvm/test/CodeGen/X86/seh-stack-realign-win32.ll
new file mode 100644
index 00000000000..f3ab71803ca
--- /dev/null
+++ b/llvm/test/CodeGen/X86/seh-stack-realign-win32.ll
@@ -0,0 +1,99 @@
+; RUN: llc -mtriple=i686-windows-msvc < %s | FileCheck %s
+
+; 32-bit catch-all has to use a filter function because that's how it saves the
+; exception code.
+
+@str = linkonce_odr unnamed_addr constant [27 x i8] c"GetExceptionCode(): 0x%lx\0A\00", align 1
+
+declare i32 @_except_handler3(...)
+declare void @crash()
+declare i32 @printf(i8* nocapture readonly, ...) nounwind
+declare i32 @llvm.eh.typeid.for(i8*)
+declare i8* @llvm.frameaddress(i32)
+declare i8* @llvm.localrecover(i8*, i8*, i32)
+declare void @llvm.localescape(...)
+declare i8* @llvm.x86.seh.recoverfp(i8*, i8*)
+
+define i32 @main() personality i8* bitcast (i32 (...)* @_except_handler3 to i8*) {
+entry:
+  ; The EH code allocation is overaligned, triggering realignment.
+  %__exceptioncode = alloca i32, align 8
+  call void (...) @llvm.localescape(i32* %__exceptioncode)
+  invoke void @crash() #5
+          to label %__try.cont unwind label %lpad
+
+lpad:                                             ; preds = %entry
+  %0 = landingpad { i8*, i32 }
+          catch i8* bitcast (i32 ()* @"filt$main" to i8*)
+  %1 = extractvalue { i8*, i32 } %0, 1
+  %2 = call i32 @llvm.eh.typeid.for(i8* bitcast (i32 ()* @"filt$main" to i8*)) #4
+  %matches = icmp eq i32 %1, %2
+  br i1 %matches, label %__except, label %eh.resume
+
+__except:                                         ; preds = %lpad
+  %3 = load i32, i32* %__exceptioncode, align 4
+  %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([27 x i8], [27 x i8]* @str, i32 0, i32 0), i32 %3) #4
+  br label %__try.cont
+
+__try.cont:                                       ; preds = %entry, %__except
+  ret i32 0
+
+eh.resume:                                        ; preds = %lpad
+  resume { i8*, i32 } %0
+}
+
+define internal i32 @"filt$main"() {
+entry:
+  %ebp = tail call i8* @llvm.frameaddress(i32 1)
+  %parentfp = tail call i8* @llvm.x86.seh.recoverfp(i8* bitcast (i32 ()* @main to i8*), i8* %ebp)
+  %code.i8 = tail call i8* @llvm.localrecover(i8* bitcast (i32 ()* @main to i8*), i8* %parentfp, i32 0)
+  %__exceptioncode = bitcast i8* %code.i8 to i32*
+  %info.addr = getelementptr inbounds i8, i8* %ebp, i32 -20
+  %0 = bitcast i8* %info.addr to i32***
+  %1 = load i32**, i32*** %0, align 4
+  %2 = load i32*, i32** %1, align 4
+  %3 = load i32, i32* %2, align 4
+  store i32 %3, i32* %__exceptioncode, align 4
+  ret i32 1
+}
+
+; Check that we can get the exception code from eax to the printf.
+
+; CHECK-LABEL: _main:
+; CHECK: Lmain$frame_escape_0 = [[code_offs:[-0-9]+]]
+; CHECK: Lmain$frame_escape_1 = [[reg_offs:[-0-9]+]]
+; CHECK: movl %esp, [[reg_offs]](%esi)
+; CHECK: movl $L__ehtable$main,
+;       EH state 0
+; CHECK: movl $0, 40(%esi)
+; CHECK: calll _crash
+; CHECK: retl
+; CHECK: # Block address taken
+;       stackrestore
+; CHECK: movl -24(%ebp), %esp
+; CHECK: movl $Lmain$parent_frame_offset, %eax
+; CHECK: negl %eax
+; CHECK: leal -24(%ebp,%eax), %esi
+; CHECK: movl 12(%esi), %ebp    # 4-byte Reload
+;       EH state -1
+; CHECK: movl [[code_offs]](%esi), %[[code:[a-z]+]]
+; CHECK: movl $-1, 40(%esi)
+; CHECK-DAG: movl %[[code]], 4(%esp)
+; CHECK-DAG: movl $_str, (%esp)
+; CHECK: calll _printf
+
+; CHECK: .section .xdata,"dr"
+; CHECK: Lmain$parent_frame_offset = Lmain$frame_escape_1
+; CHECK: L__ehtable$main
+; CHECK-NEXT: .long -1
+; CHECK-NEXT: .long _filt$main
+; CHECK-NEXT: .long Ltmp{{[0-9]+}}
+
+; CHECK-LABEL: _filt$main:
+; CHECK: pushl %ebp
+; CHECK: movl %esp, %ebp
+; CHECK: movl (%ebp), %[[oldebp:[a-z]+]]
+; CHECK: movl -20(%[[oldebp]]), %[[ehinfo:[a-z]+]]
+; CHECK: movl (%[[ehinfo]]), %[[ehrec:[a-z]+]]
+; CHECK: movl (%[[ehrec]]), %[[ehcode:[a-z]+]]
+; CHECK: movl %[[ehcode]], {{.*}}(%{{.*}})