[PATCH] D144082: [llvm][AArch64] Fix BTI after returns_twice when call has no attributes

[David Spickett via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG93164dba086d: [llvm][AArch64] Fix BTI after returns_twice when call has no attributes (authored by DavidSpickett).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D144082/new/

https://reviews.llvm.org/D144082

Files:
  llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
  llvm/lib/Target/AArch64/GISel/AArch64CallLowering.cpp
  llvm/test/CodeGen/AArch64/setjmp-bti.ll


Index: llvm/test/CodeGen/AArch64/setjmp-bti.ll
===================================================================
--- llvm/test/CodeGen/AArch64/setjmp-bti.ll
+++ llvm/test/CodeGen/AArch64/setjmp-bti.ll
@@ -18,8 +18,9 @@
 ;
 ; void bbb(void) {
 ;   setjmp(0);
+;   setjmp(0); // With the attributes removed.
 ;   int (*fnptr)(ptr) = setjmp;
-;   fnptr(0);
+;   fnptr(0); // With attributes added.
 ;   notsetjmp();
 ; }
 
@@ -27,6 +28,8 @@
 ; BTI-LABEL: bbb:
 ; BTI:       bl setjmp
 ; BTI-NEXT:  hint #36
+; BTI:       bl setjmp
+; BTI-NEXT:  hint #36
 ; BTI:       blr x{{[0-9]+}}
 ; BTI-NEXT:  hint #36
 ; BTI:       bl notsetjmp
@@ -35,6 +38,8 @@
 ; BTISLS-LABEL: bbb:
 ; BTISLS:       bl setjmp
 ; BTISLS-NEXT:  hint #36
+; BTISLS:       bl setjmp
+; BTISLS-NEXT:  hint #36
 ; BTISLS:       bl __llvm_slsblr_thunk_x{{[0-9]+}}
 ; BTISLS-NEXT:  hint #36
 ; BTISLS:       bl notsetjmp
@@ -43,16 +48,22 @@
 ; NOBTI-LABEL: bbb:
 ; NOBTI:     bl setjmp
 ; NOBTI-NOT: hint #36
+; NOBTI:     bl setjmp
+; NOBTI-NOT: hint #36
 ; NOBTI:     blr x{{[0-9]+}}
 ; NOBTI-NOT: hint #36
 ; NOBTI:     bl notsetjmp
 ; NOBTI-NOT: hint #36
 entry:
   %fnptr = alloca ptr, align 8
+  ; The frontend may apply attributes to the call, but it doesn't have to. We
+  ; should be looking at the call base, which looks past that to the called function.
   %call = call i32 @setjmp(ptr noundef null) #0
+  %call1 = call i32 @setjmp(ptr noundef null)
   store ptr @setjmp, ptr %fnptr, align 8
   %0 = load ptr, ptr %fnptr, align 8
-  %call1 = call i32 %0(ptr noundef null) #0
+  ; Clang does not attach the attribute here but if it did, it should work.
+  %call2 = call i32 %0(ptr noundef null) #0
   call void @notsetjmp()
   ret void
 }
Index: llvm/lib/Target/AArch64/GISel/AArch64CallLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/GISel/AArch64CallLowering.cpp
+++ llvm/lib/Target/AArch64/GISel/AArch64CallLowering.cpp
@@ -1266,8 +1266,7 @@
     Opc = AArch64::BLR_RVMARKER;
   // A call to a returns twice function like setjmp must be followed by a bti
   // instruction.
-  else if (Info.CB &&
-           Info.CB->getAttributes().hasFnAttr(Attribute::ReturnsTwice) &&
+  else if (Info.CB && Info.CB->hasFnAttr(Attribute::ReturnsTwice) &&
            !Subtarget.noBTIAtReturnTwice() &&
            MF.getInfo<AArch64FunctionInfo>()->branchTargetEnforcement())
     Opc = AArch64::BLR_BTI;
Index: llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -7173,7 +7173,7 @@
   bool IsSibCall = false;
   bool GuardWithBTI = false;
 
-  if (CLI.CB && CLI.CB->getAttributes().hasFnAttr(Attribute::ReturnsTwice) &&
+  if (CLI.CB && CLI.CB->hasFnAttr(Attribute::ReturnsTwice) &&
       !Subtarget->noBTIAtReturnTwice()) {
     GuardWithBTI = FuncInfo->branchTargetEnforcement();
   }


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