[PATCH] D132725: [llvm][CodeGen] Skip WinCFGuard on non-Windows targets

[Alvin Wong via Phabricator via llvm-commits]

alvinhochun created this revision.
alvinhochun added reviewers: rnk, ajpaverd, mstorsjo, aaron.ballman.
Herald added a subscriber: hiraditya.
Herald added a project: All.
alvinhochun requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

This fixes a crash when passing -cfguard to the clang frontend while not
targeting Windows. Control Flow Guard is only supported on Windows.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D132725

Files:
  llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
  llvm/test/CodeGen/WinCFGuard/cfguard-unsupported.ll


Index: llvm/test/CodeGen/WinCFGuard/cfguard-unsupported.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/WinCFGuard/cfguard-unsupported.ll
@@ -0,0 +1,51 @@
+; RUN: llc < %s -mtriple=x86_64-linux-gnu
+; Control Flow Guard is currently only available on Windows
+; This test checks that the cfguard attribute does not crash on non-Windows
+; target.
+
+; This file was generated from the following source, using this command line:
+; clang -target x86_64-linux-gnu cfguard-unsupported.c -S -emit-llvm -o cfguard-unsupported.ll -O -Xclang -cfguard
+;-------------------------------------------------------------------------------
+; extern void address_taken(void);
+;
+; void (*get_ptr(void))(void) {
+;     return &address_taken;
+; }
+;
+; void call_ptr(void (*p)(void)) {
+;     p();
+; }
+;-------------------------------------------------------------------------------
+
+; ModuleID = 'cfguard-unsupported.c'
+source_filename = "cfguard-unsupported.c"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone willreturn uwtable
+define dso_local nonnull ptr @get_ptr() local_unnamed_addr #0 {
+  ret ptr @address_taken
+}
+
+declare void @address_taken() #1
+
+; Function Attrs: nounwind uwtable
+define dso_local void @call_ptr(ptr nocapture noundef readonly %0) local_unnamed_addr #2 {
+  tail call void %0() #3
+  ret void
+}
+
+attributes #0 = { mustprogress nofree norecurse nosync nounwind readnone willreturn uwtable "frame-pointer"="none" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #1 = { "frame-pointer"="none" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #2 = { nounwind uwtable "frame-pointer"="none" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #3 = { nounwind }
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4}
+!llvm.ident = !{!5}
+
+!0 = !{i32 2, !"cfguard", i32 2}
+!1 = !{i32 1, !"wchar_size", i32 4}
+!2 = !{i32 8, !"PIC Level", i32 2}
+!3 = !{i32 7, !"PIE Level", i32 2}
+!4 = !{i32 7, !"uwtable", i32 2}
+!5 = !{!"clang version 16.0.0"}
Index: llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -585,7 +585,8 @@
                           DWARFGroupDescription);
 
   // Emit tables for any value of cfguard flag (i.e. cfguard=1 or cfguard=2).
-  if (mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("cfguard")))
+  if (Target.isOSWindows() &&
+      mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("cfguard")))
     Handlers.emplace_back(std::make_unique<WinCFGuard>(this), CFGuardName,
                           CFGuardDescription, DWARFGroupName,
                           DWARFGroupDescription);


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D132725.455839.patch
Type: text/x-patch
Size: 3337 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220826/e754a6a3/attachment.bin>