[PATCH] D147975: [StackProtector] don't check stack protector before calling nounwind functions
Nick Desaulniers via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Apr 11 15:10:14 PDT 2023
nickdesaulniers updated this revision to Diff 512599.
nickdesaulniers edited the summary of this revision.
nickdesaulniers added a comment.
- add note about Android
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D147975/new/
https://reviews.llvm.org/D147975
Files:
llvm/lib/CodeGen/StackProtector.cpp
llvm/test/CodeGen/X86/stack-protector-2.ll
llvm/test/CodeGen/X86/stack-protector-recursively.ll
Index: llvm/test/CodeGen/X86/stack-protector-recursively.ll
===================================================================
--- llvm/test/CodeGen/X86/stack-protector-recursively.ll
+++ llvm/test/CodeGen/X86/stack-protector-recursively.ll
@@ -12,15 +12,14 @@
; CHECK-NEXT: cmpq (%rsp), %rax
; CHECK-NEXT: jne .LBB0_2
; CHECK-NEXT: # %bb.1: # %SP_return
-; CHECK-NEXT: ud2
+; CHECK-NEXT: callq foo at PLT
; CHECK-NEXT: .LBB0_2: # %CallStackCheckFailBlk
; CHECK-NEXT: callq __stack_chk_fail
entry:
- tail call void @llvm.trap()
+ tail call void @foo() noreturn
unreachable
}
-declare void @llvm.trap() #1
+declare void @foo() noreturn
attributes #0 = { noreturn nounwind sspreq }
-attributes #1 = { noreturn nounwind }
Index: llvm/test/CodeGen/X86/stack-protector-2.ll
===================================================================
--- llvm/test/CodeGen/X86/stack-protector-2.ll
+++ llvm/test/CodeGen/X86/stack-protector-2.ll
@@ -1,4 +1,5 @@
-; RUN: llc -mtriple=x86_64-pc-linux-gnu -start-before=stack-protector -stop-after=stack-protector -o - < %s | FileCheck %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -start-before=stack-protector \
+; RUN: -stop-after=stack-protector -o - < %s | FileCheck %s
; Bugs 42238/43308: Test some additional situations not caught previously.
define void @store_captures() #0 {
@@ -219,5 +220,14 @@
ret i32 0
}
+declare void @callee() noreturn nounwind
+define void @caller() sspstrong {
+; Test that a stack protector is NOT inserted when we call nounwind functions.
+; CHECK-LABEL: @caller
+; CHECK-NEXT: call void @callee
+ call void @callee() noreturn nounwind
+ ret void
+}
+
attributes #0 = { sspstrong }
attributes #1 = { noreturn sspreq}
Index: llvm/lib/CodeGen/StackProtector.cpp
===================================================================
--- llvm/lib/CodeGen/StackProtector.cpp
+++ llvm/lib/CodeGen/StackProtector.cpp
@@ -482,18 +482,15 @@
if (&BB == FailBB)
continue;
Instruction *CheckLoc = dyn_cast<ReturnInst>(BB.getTerminator());
- if (!CheckLoc && !DisableCheckNoReturn) {
- for (auto &Inst : BB) {
- auto *CB = dyn_cast<CallBase>(&Inst);
- if (!CB)
- continue;
- if (!CB->doesNotReturn())
- continue;
- // Do stack check before non-return calls (e.g: __cxa_throw)
- CheckLoc = CB;
- break;
- }
- }
+ if (!CheckLoc && !DisableCheckNoReturn)
+ for (auto &Inst : BB)
+ if (auto *CB = dyn_cast<CallBase>(&Inst))
+ // Do stack check before noreturn calls that aren't nounwind (e.g:
+ // __cxa_throw).
+ if (CB->doesNotReturn() && !CB->doesNotThrow()) {
+ CheckLoc = CB;
+ break;
+ }
if (!CheckLoc)
continue;
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