[llvm] 20f7773 - [MC] [Win64EH] Fill in FuncletOrFuncEnd if missing
Martin Storsjö via llvm-commits
llvm-commits at lists.llvm.org
Sat Aug 29 05:16:33 PDT 2020
Author: Martin Storsjö
Date: 2020-08-29T15:15:22+03:00
New Revision: 20f7773bb4bb458c3f3b4e46d1601465e6479746
URL: https://github.com/llvm/llvm-project/commit/20f7773bb4bb458c3f3b4e46d1601465e6479746
DIFF: https://github.com/llvm/llvm-project/commit/20f7773bb4bb458c3f3b4e46d1601465e6479746.diff
LOG: [MC] [Win64EH] Fill in FuncletOrFuncEnd if missing
This can happen e.g. for code that declare .seh_proc/.seh_endproc
in assembly, or for code that use .seh_handlerdata (which triggers
the unwind info to be emitted before the end of the function).
The TextSection field must be made non-const to be able to use it
with Streamer.SwitchSection().
Differential Revision: https://reviews.llvm.org/D86528
Added:
Modified:
llvm/include/llvm/MC/MCWinEH.h
llvm/lib/MC/MCStreamer.cpp
llvm/lib/MC/MCWin64EH.cpp
llvm/test/MC/AArch64/seh.s
Removed:
################################################################################
diff --git a/llvm/include/llvm/MC/MCWinEH.h b/llvm/include/llvm/MC/MCWinEH.h
index baeafa3468e2..53cffccce8c1 100644
--- a/llvm/include/llvm/MC/MCWinEH.h
+++ b/llvm/include/llvm/MC/MCWinEH.h
@@ -36,7 +36,7 @@ struct FrameInfo {
const MCSymbol *Function = nullptr;
const MCSymbol *PrologEnd = nullptr;
const MCSymbol *Symbol = nullptr;
- const MCSection *TextSection = nullptr;
+ MCSection *TextSection = nullptr;
bool HandlesUnwind = false;
bool HandlesExceptions = false;
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index df08c343f69f..995828b57738 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -692,6 +692,8 @@ void MCStreamer::EmitWinCFIEndProc(SMLoc Loc) {
MCSymbol *Label = emitCFILabel();
CurFrame->End = Label;
+ if (!CurFrame->FuncletOrFuncEnd)
+ CurFrame->FuncletOrFuncEnd = CurFrame->End;
}
void MCStreamer::EmitWinCFIFuncletOrFuncEnd(SMLoc Loc) {
diff --git a/llvm/lib/MC/MCWin64EH.cpp b/llvm/lib/MC/MCWin64EH.cpp
index 76c82cd176a1..d81687295bd0 100644
--- a/llvm/lib/MC/MCWin64EH.cpp
+++ b/llvm/lib/MC/MCWin64EH.cpp
@@ -525,9 +525,7 @@ static void ARM64EmitUnwindInfo(MCStreamer &streamer, WinEH::FrameInfo *info) {
int64_t RawFuncLength;
if (!info->FuncletOrFuncEnd) {
- // FIXME: This is very wrong; we emit SEH data which covers zero bytes
- // of code. But otherwise test/MC/AArch64/seh.s crashes.
- RawFuncLength = 0;
+ report_fatal_error("FuncletOrFuncEnd not set");
} else {
// FIXME: GetAbsDifference tries to compute the length of the function
// immediately, before the whole file is emitted, but in general
@@ -702,6 +700,16 @@ void llvm::Win64EH::ARM64UnwindEmitter::Emit(MCStreamer &Streamer) const {
void llvm::Win64EH::ARM64UnwindEmitter::EmitUnwindInfo(
MCStreamer &Streamer, WinEH::FrameInfo *info) const {
+ // Called if there's an .seh_handlerdata directive before the end of the
+ // function. This forces writing the xdata record already here - and
+ // in this case, the function isn't actually ended already, but the xdata
+ // record needs to know the function length. In these cases, if the funclet
+ // end hasn't been marked yet, the xdata function length won't cover the
+ // whole function, only up to this point.
+ if (!info->FuncletOrFuncEnd) {
+ Streamer.SwitchSection(info->TextSection);
+ info->FuncletOrFuncEnd = Streamer.emitCFILabel();
+ }
// Switch sections (the static function above is meant to be called from
// here and from Emit().
MCSection *XData = Streamer.getAssociatedXDataSection(info->TextSection);
diff --git a/llvm/test/MC/AArch64/seh.s b/llvm/test/MC/AArch64/seh.s
index 878b7ad944cf..7fa9d5e0e151 100644
--- a/llvm/test/MC/AArch64/seh.s
+++ b/llvm/test/MC/AArch64/seh.s
@@ -46,6 +46,12 @@
// CHECK-NEXT: }
// CHECK-NEXT: ]
+// CHECK-NEXT: UnwindInformation [
+// CHECK-NEXT: RuntimeFunction {
+// CHECK-NEXT: Function: func
+// CHECK-NEXT: ExceptionRecord: .xdata
+// CHECK-NEXT: ExceptionData {
+// CHECK-NEXT: FunctionLength: 8
.text
.globl func
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