Automerge: [Clang][AArch64] Add support for SHF_AARCH64_PURECODE ELF section flag (2/3) (#125688)

Il-Capitano · github-actions[bot] · commit 329d3da954f2 · 2025-03-10T09:44:34.000Z
Add support for the new SHF_AARCH64_PURECODE ELF section flag: ARM-software/abi-aa#304 The general implementation follows the existing one for ARM targets. Simlarly to ARM targets, generating object files with the `SHF_AARCH64_PURECODE` flag set is enabled by the `-mexecute-only`/`-mpure-code` driver flag. Related PRs: * LLVM: llvm/llvm-project#125687 * LLD: llvm/llvm-project#125689
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
@@ -4725,9 +4725,9 @@ def mno_long_calls : Flag<["-"], "mno-long-calls">, Group<m_Group>,
   HelpText<"Restore the default behaviour of not generating long calls">;
 } // let Flags = [TargetSpecific]
 def mexecute_only : Flag<["-"], "mexecute-only">, Group<m_arm_Features_Group>,
-  HelpText<"Disallow generation of data access to code sections (ARM only)">;
+  HelpText<"Disallow generation of data access to code sections (AArch64/ARM only)">;
 def mno_execute_only : Flag<["-"], "mno-execute-only">, Group<m_arm_Features_Group>,
-  HelpText<"Allow generation of data access to code sections (ARM only)">;
+  HelpText<"Allow generation of data access to code sections (AArch64/ARM only)">;
 let Flags = [TargetSpecific] in {
 def mtp_mode_EQ : Joined<["-"], "mtp=">, Group<m_arm_Features_Group>, Values<"soft,cp15,tpidrurw,tpidruro,tpidrprw,el0,el1,el2,el3,tpidr_el0,tpidr_el1,tpidr_el2,tpidr_el3,tpidrro_el0,auto">,
   HelpText<"Thread pointer access method. "
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
@@ -210,7 +210,9 @@ static void getAArch64MultilibFlags(const Driver &D,
                                           const llvm::opt::ArgList &Args,
                                           Multilib::flags_list &Result) {
   std::vector<StringRef> Features;
-  tools::aarch64::getAArch64TargetFeatures(D, Triple, Args, Features, false);
+  tools::aarch64::getAArch64TargetFeatures(D, Triple, Args, Features,
+                                           /*ForAS=*/false,
+                                           /*ForMultilib=*/true);
   const auto UnifiedFeatures = tools::unifyTargetFeatures(Features);
   llvm::DenseSet<StringRef> FeatureSet(UnifiedFeatures.begin(),
                                        UnifiedFeatures.end());
diff --git a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -196,7 +196,7 @@ void aarch64::getAArch64TargetFeatures(const Driver &D,
                                        const llvm::Triple &Triple,
                                        const ArgList &Args,
                                        std::vector<StringRef> &Features,
-                                       bool ForAS) {
+                                       bool ForAS, bool ForMultilib) {
   Arg *A;
   bool success = true;
   llvm::StringRef WaMArch;
@@ -332,6 +332,19 @@ void aarch64::getAArch64TargetFeatures(const Driver &D,
   } else if (Triple.isOSOpenBSD())
     Features.push_back("+strict-align");
 
+  // Generate execute-only output (no data access to code sections).
+  // This only makes sense for the compiler, not for the assembler.
+  // It's not needed for multilib selection and may hide an unused
+  // argument diagnostic if the code is always run.
+  if (!ForAS && !ForMultilib) {
+    if (Arg *A = Args.getLastArg(options::OPT_mexecute_only,
+                                 options::OPT_mno_execute_only)) {
+      if (A->getOption().matches(options::OPT_mexecute_only)) {
+        Features.push_back("+execute-only");
+      }
+    }
+  }
+
   if (Args.hasArg(options::OPT_ffixed_x1))
     Features.push_back("+reserve-x1");
 
diff --git a/clang/lib/Driver/ToolChains/Arch/AArch64.h b/clang/lib/Driver/ToolChains/Arch/AArch64.h
@@ -23,7 +23,7 @@ namespace aarch64 {
 void getAArch64TargetFeatures(const Driver &D, const llvm::Triple &Triple,
                               const llvm::opt::ArgList &Args,
                               std::vector<llvm::StringRef> &Features,
-                              bool ForAS);
+                              bool ForAS, bool ForMultilib = false);
 
 std::string getAArch64TargetCPU(const llvm::opt::ArgList &Args,
                                 const llvm::Triple &Triple, llvm::opt::Arg *&A);
diff --git a/clang/test/CodeGen/aarch64-execute-only.c b/clang/test/CodeGen/aarch64-execute-only.c
@@ -0,0 +1,19 @@
+// RUN: %clang -target aarch64 -### %s 2>&1 | \
+// RUN:   FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY
+// RUN: %clang -target aarch64 -### -mexecute-only %s 2>&1 | \
+// RUN:   FileCheck %s -check-prefix CHECK-EXECUTE-ONLY
+// RUN: %clang -target aarch64 -### -mexecute-only -mno-execute-only %s 2>&1 | \
+// RUN:   FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY
+
+/// -mpure-code flag for GCC compatibility
+// RUN: %clang -target aarch64 -### %s 2>&1 | \
+// RUN:   FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY
+// RUN: %clang -target aarch64 -### -mpure-code %s 2>&1 | \
+// RUN:   FileCheck %s -check-prefix CHECK-EXECUTE-ONLY
+// RUN: %clang -target aarch64 -### -mpure-code -mno-pure-code %s 2>&1 | \
+// RUN:   FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY
+
+// CHECK-NO-EXECUTE-ONLY-NOT: "+execute-only"
+// CHECK-EXECUTE-ONLY: "+execute-only"
+
+void a() {}
diff --git a/clang/test/Driver/aarch64-execute-only.c b/clang/test/Driver/aarch64-execute-only.c
@@ -0,0 +1,9 @@
+// RUN: %clang --sysroot=%S/Inputs -c -fdriver-only -Werror --target=aarch64-unknown-linux-gnu \
+// RUN:     -mexecute-only %s 2>&1 | count 0
+
+// RUN: %clang -### --target=aarch64-unknown-linux-gnu -x assembler -mexecute-only %s -c -### 2>&1 | \
+// RUN:   FileCheck %s --check-prefix=CHECK-NO-EXECUTE-ONLY-ASM
+// RUN: %clang -### --multi-lib-config=%S/Inputs/multilib/empty.yaml --sysroot= \
+// RUN:     --target=aarch64-none-elf -x assembler -mexecute-only %s -c -### 2>&1 | \
+// RUN:   FileCheck %s --check-prefix=CHECK-NO-EXECUTE-ONLY-ASM
+// CHECK-NO-EXECUTE-ONLY-ASM: warning: argument unused during compilation: '-mexecute-only'
diff --git a/clang/test/Driver/fsanitize.c b/clang/test/Driver/fsanitize.c
@@ -1053,21 +1053,26 @@
 // RUN: not %clang --target=x86_64-sie-ps5 -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-TARGET
 // RUN: not %clang --target=x86_64-sie-ps5 -fsanitize=function -fsanitize=kcfi %s -### 2>&1 | FileCheck %s  --check-prefix=CHECK-UBSAN-KCFI-TARGET --check-prefix=CHECK-UBSAN-FUNCTION-TARGET
 // RUN: %clang --target=x86_64-sie-ps5 -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-UNDEFINED
-// CHECK-UBSAN-UNDEFINED: "-fsanitize={{((alignment|array-bounds|bool|builtin|enum|float-cast-overflow|integer-divide-by-zero|nonnull-attribute|null|pointer-overflow|return|returns-nonnull-attribute|shift-base|shift-exponent|signed-integer-overflow|unreachable|vla-bound),?){17}"}}
 
 // RUN: not %clang --target=armv6t2-eabi -mexecute-only -fsanitize=function %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-FUNCTION-MEXECUTE-ONLY
 // RUN: not %clang --target=armv6t2-eabi -mpure-code -fsanitize=function %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-FUNCTION-MPURE-CODE
 // RUN: not %clang --target=armv6t2-eabi -mexecute-only -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-MEXECUTE-ONLY
 // RUN: not %clang --target=armv6t2-eabi -mpure-code -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-MPURE-CODE
-// RUN: %clang --target=armv6t2-eabi -mexecute-only -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-UNDEFINED-VPTR
+// RUN: %clang --target=armv6t2-eabi -mexecute-only -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-UNDEFINED
+
+// RUN: not %clang --target=aarch64 -mexecute-only -fsanitize=function %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-FUNCTION-MEXECUTE-ONLY
+// RUN: not %clang --target=aarch64 -mpure-code -fsanitize=function %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-FUNCTION-MPURE-CODE
+// RUN: not %clang --target=aarch64 -mexecute-only -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-MEXECUTE-ONLY
+// RUN: not %clang --target=aarch64 -mpure-code -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-MPURE-CODE
+// RUN: %clang --target=aarch64 -mexecute-only -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-UNDEFINED
 
 // CHECK-UBSAN-KCFI-TARGET-DAG: error: unsupported option '-fsanitize=kcfi' for target 'x86_64-sie-ps5'
 // CHECK-UBSAN-KCFI-MEXECUTE-ONLY-DAG: error: invalid argument '-fsanitize=kcfi' not allowed with '-mexecute-only'
 // CHECK-UBSAN-KCFI-MPURE-CODE-DAG: error: invalid argument '-fsanitize=kcfi' not allowed with '-mpure-code'
 // CHECK-UBSAN-FUNCTION-TARGET-DAG: error: unsupported option '-fsanitize=function' for target 'x86_64-sie-ps5'
 // CHECK-UBSAN-FUNCTION-MEXECUTE-ONLY-DAG: error: invalid argument '-fsanitize=function' not allowed with '-mexecute-only'
 // CHECK-UBSAN-FUNCTION-MPURE-CODE-DAG: error: invalid argument '-fsanitize=function' not allowed with '-mpure-code'
-// CHECK-UBSAN-UNDEFINED-VPTR: "-fsanitize={{((alignment|array-bounds|bool|builtin|enum|float-cast-overflow|integer-divide-by-zero|nonnull-attribute|null|pointer-overflow|return|returns-nonnull-attribute|shift-base|shift-exponent|signed-integer-overflow|unreachable|vla-bound),?){17}"}}
+// CHECK-UBSAN-UNDEFINED: "-fsanitize={{((alignment|array-bounds|bool|builtin|enum|float-cast-overflow|integer-divide-by-zero|nonnull-attribute|null|pointer-overflow|return|returns-nonnull-attribute|shift-base|shift-exponent|signed-integer-overflow|unreachable|vla-bound),?){17}"}}
 
 // * Test BareMetal toolchain sanitizer support *
 
