[PATCH] D66712: [Driver] Enable ShadowCallStack, not SafeStack, by default on AArch64 Fuchsia

[Roland McGrath via Phabricator via cfe-commits]

mcgrathr created this revision.
Herald added subscribers: cfe-commits, cryptoad, kristof.beyls, javed.absar.
Herald added a project: clang.

On AArch64, Fuchsia fully supports both SafeStack and ShadowCallStack ABIs.
The latter is now preferred and will be the default.  It's possible to
enable both simultaneously, but ShadowCallStack is believed to have most
of the practical benefit of SafeStack with less cost.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D66712

Files:
  clang/lib/Driver/ToolChains/Fuchsia.cpp
  clang/test/Driver/fuchsia.c


Index: clang/test/Driver/fuchsia.c
===================================================================
--- clang/test/Driver/fuchsia.c
+++ clang/test/Driver/fuchsia.c
@@ -13,7 +13,8 @@
 // CHECK: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
 // CHECK: "-isysroot" "[[SYSROOT:[^"]+]]"
 // CHECK: "-internal-externc-isystem" "[[SYSROOT]]{{/|\\\\}}include"
-// CHECK: "-fsanitize=safe-stack"
+// CHECK-AARCH64: "-fsanitize=shadow-call-stack"
+// CHECK-X86_64: "-fsanitize=safe-stack"
 // CHECK: "-stack-protector" "2"
 // CHECK: "-fno-common"
 // CHECK: {{.*}}ld.lld{{.*}}" "-z" "rodynamic" "-z" "separate-code"
@@ -102,7 +103,7 @@
 // RUN:     -fuse-ld=lld \
 // RUN:     | FileCheck %s -check-prefix=CHECK-ASAN-AARCH64
 // CHECK-ASAN-AARCH64: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
-// CHECK-ASAN-AARCH64: "-fsanitize=address"
+// CHECK-ASAN-AARCH64: "-fsanitize=address,shadow-call-stack"
 // CHECK-ASAN-AARCH64: "-fsanitize-address-globals-dead-stripping"
 // CHECK-ASAN-AARCH64: "-dynamic-linker" "asan/ld.so.1"
 // CHECK-ASAN-AARCH64: "[[RESOURCE_DIR]]{{/|\\\\}}lib{{/|\\\\}}aarch64-fuchsia{{/|\\\\}}libclang_rt.asan.so"
@@ -134,7 +135,7 @@
 // RUN:     -fuse-ld=lld \
 // RUN:     | FileCheck %s -check-prefix=CHECK-FUZZER-AARCH64
 // CHECK-FUZZER-AARCH64: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
-// CHECK-FUZZER-AARCH64: "-fsanitize=fuzzer,fuzzer-no-link,safe-stack"
+// CHECK-FUZZER-AARCH64: "-fsanitize=fuzzer,fuzzer-no-link,shadow-call-stack"
 // CHECK-FUZZER-AARCH64: "[[RESOURCE_DIR]]{{/|\\\\}}lib{{/|\\\\}}aarch64-fuchsia{{/|\\\\}}libclang_rt.fuzzer.a"
 
 // RUN: %clang %s -### --target=x86_64-fuchsia \
@@ -153,7 +154,7 @@
 // RUN:     -fuse-ld=lld \
 // RUN:     | FileCheck %s -check-prefix=CHECK-SCUDO-AARCH64
 // CHECK-SCUDO-AARCH64: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
-// CHECK-SCUDO-AARCH64: "-fsanitize=safe-stack,scudo"
+// CHECK-SCUDO-AARCH64: "-fsanitize=shadow-call-stack,scudo"
 // CHECK-SCUDO-AARCH64: "-pie"
 // CHECK-SCUDO-AARCH64: "[[RESOURCE_DIR]]{{/|\\\\}}lib{{/|\\\\}}aarch64-fuchsia{{/|\\\\}}libclang_rt.scudo.so"
 
Index: clang/lib/Driver/ToolChains/Fuchsia.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Fuchsia.cpp
+++ clang/lib/Driver/ToolChains/Fuchsia.cpp
@@ -343,5 +343,10 @@
 }
 
 SanitizerMask Fuchsia::getDefaultSanitizers() const {
-  return SanitizerKind::SafeStack;
+  SanitizerMask Res;
+  if (getTriple().getArch() == llvm::Triple::aarch64)
+    Res |= SanitizerKind::ShadowCallStack;
+  else
+    Res |= SanitizerKind::SafeStack;
+  return Res;
 }


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