[PATCH] D112431: [ARM][clang] Define feature test macro for the PACBTI-M extension

[Ties Stuij via Phabricator via cfe-commits]

stuij created this revision.
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If the extension string "+pacbti" was given in -march=... or -mcpu=... options the compiler shall define the following preprocessor macros:

  __ARM_FEATURE_PAUTH with value 1.
  __ARM_FEATURE_BTI with value 1.

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:

- Momchil Velikov
- Ties Stuij


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D112431

Files:
  clang/lib/Basic/Targets/ARM.cpp
  clang/lib/Basic/Targets/ARM.h
  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
@@ -896,6 +896,13 @@
 // 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
+// CHECK-NOBTI-EXT-NOT: #define __ARM_FEATURE_BTI 1
+// CHECK-NOPAC-EXT-NOT: #define __ARM_FEATURE_PAUTH 1
+// CHECK-PACBTI-EXT: #define __ARM_FEATURE_BTI 1
+// CHECK-PACBTI-EXT: #define __ARM_FEATURE_PAUTH 1
+
 // ================== Check BFloat16 Extensions.
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.6-a+bf16 -x c -E -dM %s -o - 2>&1 | FileCheck -check-prefix=CHECK-BFLOAT %s
 // CHECK-BFLOAT: #define __ARM_BF16_FORMAT_ALTERNATIVE 1
Index: clang/lib/Basic/Targets/ARM.h
===================================================================
--- clang/lib/Basic/Targets/ARM.h
+++ clang/lib/Basic/Targets/ARM.h
@@ -78,6 +78,8 @@
   unsigned Unaligned : 1;
   unsigned DotProd : 1;
   unsigned HasMatMul : 1;
+  unsigned HasPAC : 1;
+  unsigned HasBTI : 1;
 
   enum {
     LDREX_B = (1 << 0), /// byte (8-bit)
Index: clang/lib/Basic/Targets/ARM.cpp
===================================================================
--- clang/lib/Basic/Targets/ARM.cpp
+++ clang/lib/Basic/Targets/ARM.cpp
@@ -465,6 +465,8 @@
   HWDiv = 0;
   DotProd = 0;
   HasMatMul = 0;
+  HasPAC = 0;
+  HasBTI = 0;
   HasFloat16 = true;
   ARMCDECoprocMask = 0;
   HasBFloat16 = false;
@@ -544,6 +546,9 @@
       ARMCDECoprocMask |= (1U << Coproc);
     } else if (Feature == "+bf16") {
       HasBFloat16 = true;
+    } else if (Feature == "+pacbti") {
+      HasPAC = 1;
+      HasBTI = 1;
     }
   }
 
@@ -887,6 +892,11 @@
   if (HasMatMul)
     Builder.defineMacro("__ARM_FEATURE_MATMUL_INT8", "1");
 
+  if (HasPAC) {
+    Builder.defineMacro("__ARM_FEATURE_PAUTH", "1");
+    Builder.defineMacro("__ARM_FEATURE_BTI", "1");
+  }
+
   if (HasBFloat16) {
     Builder.defineMacro("__ARM_FEATURE_BF16", "1");
     Builder.defineMacro("__ARM_FEATURE_BF16_VECTOR_ARITHMETIC", "1");


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