[Driver] Default Android toolchains to noexecstack.

[danalbert]

Summary

Android does not support executable stacks.

[pirama]

include/clang/Driver/ToolChain.h

415

typo: toolchain

include/clang/Driver/ToolChain.h

public:
   virtual bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const;
 
   /// Test whether this toolchain defaults to PIC.
   virtual bool isPICDefault() const = 0;
 
   /// Test whether this toolchain defaults to PIE.
   virtual bool isPIEDefault() const = 0;
 
+  /// Test whether this toolchaind defaults to non-executable stacks.
+  virtual bool isNoExecStackDefault() const;
+
   /// Tests whether this toolchain forces its default for PIC, PIE or
   /// non-PIC.  If this returns true, any PIC related flags should be ignored
   /// and instead the results of \c isPICDefault() and \c isPIEDefault() are
   /// used exclusively.
   virtual bool isPICDefaultForced() const = 0;
 
   /// SupportsProfiling - Does this tool chain support -pg.
   virtual bool SupportsProfiling() const { return true; }

lib/Driver/ToolChain.cpp

return Args.hasFlag(options::OPT_fintegrated_as,
                       options::OPT_fno_integrated_as,
                       IsIntegratedAssemblerDefault());
 }
 
 bool ToolChain::useRelaxRelocations() const {
   return ENABLE_X86_RELAX_RELOCATIONS;
 }
 
+bool ToolChain::isNoExecStackDefault() const {
+    return false;
+}
+
 const SanitizerArgs& ToolChain::getSanitizerArgs() const {
   if (!SanitizerArguments.get())
     SanitizerArguments.reset(new SanitizerArgs(*this, Args));
   return *SanitizerArguments.get();
 }
 
 const XRayArgs& ToolChain::getXRayArgs() const {
   if (!XRayArguments.get())

lib/Driver/ToolChains/Clang.cpp

static void CollectArgsForIntegratedAssembler(Compilation &C,
   // When passing -I arguments to the assembler we sometimes need to
   // unconditionally take the next argument.  For example, when parsing
   // '-Wa,-I -Wa,foo' we need to accept the -Wa,foo arg after seeing the
   // -Wa,-I arg and when parsing '-Wa,-I,foo' we need to accept the 'foo'
   // arg after parsing the '-I' arg.
   bool TakeNextArg = false;
 
   bool UseRelaxRelocations = C.getDefaultToolChain().useRelaxRelocations();
+  bool UseNoExecStack = C.getDefaultToolChain().isNoExecStackDefault();
   const char *MipsTargetFeature = nullptr;
   for (const Arg *A :
        Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler)) {
     A->claim();
 
     for (StringRef Value : A->getValues()) {
       if (TakeNextArg) {
         CmdArgs.push_back(Value.data());
for (StringRef Value : A->getValues()) {
 
       if (Value == "-force_cpusubtype_ALL") {
         // Do nothing, this is the default and we don't support anything else.
       } else if (Value == "-L") {
         CmdArgs.push_back("-msave-temp-labels");
       } else if (Value == "--fatal-warnings") {
         CmdArgs.push_back("-massembler-fatal-warnings");
       } else if (Value == "--noexecstack") {
-        CmdArgs.push_back("-mnoexecstack");
+        UseNoExecStack = true;
       } else if (Value.startswith("-compress-debug-sections") ||
                  Value.startswith("--compress-debug-sections") ||
                  Value == "-nocompress-debug-sections" ||
                  Value == "--nocompress-debug-sections") {
         CmdArgs.push_back(Value.data());
       } else if (Value == "-mrelax-relocations=yes" ||
                  Value == "--mrelax-relocations=yes") {
         UseRelaxRelocations = true;
for (StringRef Value : A->getValues()) {
       } else {
         D.Diag(diag::err_drv_unsupported_option_argument)
             << A->getOption().getName() << Value;
       }
     }
   }
   if (UseRelaxRelocations)
     CmdArgs.push_back("--mrelax-relocations");
+  if (UseNoExecStack)
+    CmdArgs.push_back("-mnoexecstack");
   if (MipsTargetFeature != nullptr) {
     CmdArgs.push_back("-target-feature");
     CmdArgs.push_back(MipsTargetFeature);
   }
 
   // forward -fembed-bitcode to assmebler
   if (C.getDriver().embedBitcodeEnabled() ||
       C.getDriver().embedBitcodeMarkerOnly())

lib/Driver/ToolChains/Gnu.cpp

if (IsPIE)
     CmdArgs.push_back("-pie");
 
   if (IsStaticPIE) {
     CmdArgs.push_back("-static");
     CmdArgs.push_back("-pie");
     CmdArgs.push_back("--no-dynamic-linker");
   }
 
+  if (ToolChain.isNoExecStackDefault()) {
+    CmdArgs.push_back("-z");
+    CmdArgs.push_back("noexecstack");
+  }
+
   if (Args.hasArg(options::OPT_rdynamic))
     CmdArgs.push_back("-export-dynamic");
 
   if (Args.hasArg(options::OPT_s))
     CmdArgs.push_back("-s");
 
   if (Triple.isARM() || Triple.isThumb() || Triple.isAArch64()) {
     bool IsBigEndian = isArmBigEndian(Triple, Args);
if (A->getOption().getID() == options::OPT_gz) {
             Args.MakeArgString("-compress-debug-sections=" + Twine(Value)));
       } else {
         D.Diag(diag::err_drv_unsupported_option_argument)
             << A->getOption().getName() << Value;
       }
     }
   }
 
+  if (getToolChain().isNoExecStackDefault()) {
+      CmdArgs.push_back("--noexecstack");
+  }
+
   switch (getToolChain().getArch()) {
   default:
     break;
   // Add --32/--64 to make sure we get the format we want.
   // This is incomplete
   case llvm::Triple::x86:
     CmdArgs.push_back("--32");
     break;

lib/Driver/ToolChains/Linux.h

void addLibStdCxxIncludePaths(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
   void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                           llvm::opt::ArgStringList &CC1Args) const override;
   void AddIAMCUIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                            llvm::opt::ArgStringList &CC1Args) const override;
   CXXStdlibType GetDefaultCXXStdlibType() const override;
   bool isPIEDefault() const override;
+  bool isNoExecStackDefault() const override;
   bool IsMathErrnoDefault() const override;
   SanitizerMask getSupportedSanitizers() const override;
   void addProfileRTLibs(const llvm::opt::ArgList &Args,
                         llvm::opt::ArgStringList &CmdArgs) const override;
   virtual std::string computeSysRoot() const;
 
   virtual std::string getDynamicLinker(const llvm::opt::ArgList &Args) const;
 

lib/Driver/ToolChains/Linux.cpp

void Linux::AddIAMCUIncludeArgs(const ArgList &DriverArgs,
   }
 }
 
 bool Linux::isPIEDefault() const {
   return (getTriple().isAndroid() && !getTriple().isAndroidVersionLT(16)) ||
           getTriple().isMusl() || getSanitizerArgs().requiresPIE();
 }
 
+bool Linux::isNoExecStackDefault() const {
+    return getTriple().isAndroid();
+}
+
 bool Linux::IsMathErrnoDefault() const {
   if (getTriple().isAndroid())
     return false;
   return Generic_ELF::IsMathErrnoDefault();
 }
 
 SanitizerMask Linux::getSupportedSanitizers() const {
   const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;

test/Driver/integrated-as.c

 // RUN: %clang -### -c -save-temps -integrated-as %s 2>&1 | FileCheck %s
 
 // CHECK: cc1as
 // CHECK: -mrelax-all
 
 // RUN: %clang -### -fintegrated-as -c -save-temps %s 2>&1 | FileCheck %s -check-prefix FIAS
 
 // FIAS: cc1as
 
 // RUN: %clang -target none -### -fno-integrated-as -S %s 2>&1 \
 // RUN:     | FileCheck %s -check-prefix NOFIAS
 
 // NOFIAS-NOT: cc1as
 // NOFIAS: -cc1
 // NOFIAS: -no-integrated-as
+
+// RUN: %clang -target arm-linux-androideabi -### \
+// RUN:   -integrated-as -c %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM-ANDROID %s
+// CHECK-ARM-ANDROID: "-mnoexecstack"

test/Driver/linux-as.c

 // RUN: %clang -target arm-linux -mfloat-abi=hard -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-MFLOAT-ABI %s
 // CHECK-ARM-MFLOAT-ABI: as{{(.exe)?}}" "-EL" "-mfloat-abi=hard"
 //
 // RUN: %clang -target arm-linux-androideabi -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-ANDROID %s
-// CHECK-ARM-ANDROID: as{{(.exe)?}}" "-EL" "-mfloat-abi=soft"
+// CHECK-ARM-ANDROID: as{{(.exe)?}}" "--noexecstack" "-EL" "-mfloat-abi=soft"
 //
 // RUN: %clang -target arm-linux-androideabi -march=armv7-a -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-ANDROID-SOFTFP %s
-// CHECK-ARM-ANDROID-SOFTFP: as{{(.exe)?}}" "-EL" "-mfloat-abi=softfp" "-march=armv7-a"
+// CHECK-ARM-ANDROID-SOFTFP: as{{(.exe)?}}" "--noexecstack" "-EL" "-mfloat-abi=softfp" "-march=armv7-a"
 //
 // RUN: %clang -target arm-linux-eabi -mhard-float -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-HARDFP %s
 // CHECK-ARM-HARDFP: as{{(.exe)?}}" "-EL" "-mfloat-abi=hard"
 //
 // RUN: %clang -target aarch64-linux-gnu -mcpu=cortex-a53 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \

test/Driver/linux-ld.c

 // CHECK-ANDROID-HASH-STYLE-L: "{{.*}}ld{{(.exe)?}}"
 // CHECK-ANDROID-HASH-STYLE-L: "--hash-style=both"
 //
 // RUN: %clang %s -### -o %t.o 2>&1 \
 // RUN:     --target=armv7-linux-android23 \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-HASH-STYLE-M %s
 // CHECK-ANDROID-HASH-STYLE-M: "{{.*}}ld{{(.exe)?}}"
 // CHECK-ANDROID-HASH-STYLE-M: "--hash-style=gnu"
+
+// RUN: %clang %s -### -o %t.o 2>&1 \
+// RUN:     --target=armv7-linux-android21 \
+// RUN:   | FileCheck --check-prefix=CHECK-ANDROID-NOEXECSTACK %s
+// CHECK-ANDROID-NOEXECSTACK: "{{.*}}ld{{(.exe)?}}"
+// CHECK-ANDROID-NOEXECSTACK: "-z" "noexecstack"
+// CHECK-ANDROID-NOEXECSTACK-NOT: "-z" "execstack"
+// CHECK-ANDROID-NOEXECSTACK-NOT: "-z,execstack"
+// CHECK-ANDROID-NOEXECSTACK-NOT: "-zexecstack"
 //
 // RUN: %clang %s -### -o %t.o 2>&1 --target=mips64-linux-gnuabin32 \
 // RUN:   | FileCheck --check-prefix=CHECK-MIPS64EL-GNUABIN32 %s
 // CHECK-MIPS64EL-GNUABIN32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-MIPS64EL-GNUABIN32: "-m" "elf32btsmipn32"
 // CHECK-MIPS64EL-GNUABIN32: "-dynamic-linker" "{{.*}}/lib{{(32)?}}/ld.so.1"
 // CHECK-MIPS64EL-GNUABIN32-NOT: "--hash-style={{gnu|both}}"
 //