[PATCH] D115140: [ARM][clang] Option b-key must not affect __ARM_FEATURE_PAC_DEFAULT

[Ties Stuij via Phabricator via cfe-commits]

stuij created this revision.
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When using -mbranch-protection=pac-ret+b-key, macro __ARM_FEATURE_PAC_DEFAULT
should still have the value corresponding to a-key, because b-key is only valid
for AArch64.

This patch is part of a series that adds support for the PACBTI-M extension of
the Armv8.1-M architecture, as detailed here:

https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension

The PACBTI-M specification can be found in the Armv8-M Architecture Reference
Manual:

https://developer.arm.com/documentation/ddi0553/latest

The following people contributed to this patch:

- Victor Campos


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D115140

Files:
  clang/lib/Basic/Targets/ARM.cpp
  clang/test/Preprocessor/arm-target-features.c


Index: clang/test/Preprocessor/arm-target-features.c
===================================================================
--- clang/test/Preprocessor/arm-target-features.c
+++ clang/test/Preprocessor/arm-target-features.c
@@ -881,20 +881,18 @@
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-NOBTI,CHECK-NOPAC %s
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=bti -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-BTI,CHECK-NOPAC %s
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=pac-ret -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC,CHECK-NOBTI %s
-// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=pac-ret+b-key -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC-BKEY,CHECK-NOBTI %s
+// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=pac-ret+b-key -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC,CHECK-NOBTI %s
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=pac-ret+leaf -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC-LEAF,CHECK-NOBTI %s
-// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=pac-ret+b-key+leaf -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC-BKEY-LEAF,CHECK-NOBTI %s
+// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=pac-ret+b-key+leaf -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC-LEAF,CHECK-NOBTI %s
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=bti+pac-ret -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC,CHECK-BTI %s
-// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=bti+pac-ret+b-key -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC-BKEY,CHECK-BTI %s
+// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=bti+pac-ret+b-key -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC,CHECK-BTI %s
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=bti+pac-ret+leaf -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC-LEAF,CHECK-BTI %s
-// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=bti+pac-ret+b-key+leaf -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC-BKEY-LEAF,CHECK-BTI %s
+// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -mbranch-protection=bti+pac-ret+b-key+leaf -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PAC-LEAF,CHECK-BTI %s
 // CHECK-NOBTI-NOT: #define __ARM_FEATURE_BTI_DEFAULT
 // CHECK-NOPAC-NOT: #define __ARM_FEATURE_PAC_DEFAULT
 // CHECK-BTI: #define __ARM_FEATURE_BTI_DEFAULT 1
 // CHECK-PAC: #define __ARM_FEATURE_PAC_DEFAULT 1
-// CHECK-PAC-BKEY: #define __ARM_FEATURE_PAC_DEFAULT 2
 // CHECK-PAC-LEAF: #define __ARM_FEATURE_PAC_DEFAULT 5
-// CHECK-PAC-BKEY-LEAF: #define __ARM_FEATURE_PAC_DEFAULT 6
 
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-NOBTI-EXT,CHECK-NOPAC-EXT %s
 // RUN: %clang -target arm-arm-none-eabi -march=armv7-m+pacbti -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-PACBTI-EXT %s
Index: clang/lib/Basic/Targets/ARM.cpp
===================================================================
--- clang/lib/Basic/Targets/ARM.cpp
+++ clang/lib/Basic/Targets/ARM.cpp
@@ -911,7 +911,7 @@
     Builder.defineMacro("__ARM_FEATURE_BTI_DEFAULT", "1");
 
   if (Opts.hasSignReturnAddress()) {
-    unsigned Value = Opts.isSignReturnAddressWithAKey() ? 1 : 2;
+    unsigned Value = 1;
     if (Opts.isSignReturnAddressScopeAll())
       Value |= 1 << 2;
     Builder.defineMacro("__ARM_FEATURE_PAC_DEFAULT", Twine(Value));


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