[Driver][Android] Remove unneeded isNoExecStackDefault

ld.lld used by Android ignores .note.GNU-stack and defaults to noexecstack,
so the `-z noexecstack` linker option is unneeded.

The `--noexecstack` assembler option is unneeded because AsmPrinter.cpp
prints `.section .note.GNU-stack,"",@progbits` (when `llvm.init.trampoline` is unused),
so the assembler won't synthesize an executable .note.GNU-stack.

Reviewed By: danalbert

Differential Revision: https://reviews.llvm.org/D113840

clang/include/clang/Driver/ToolChain.h

@@ -487,9 +487,6 @@ public:
   /// Test whether this toolchain defaults to PIE.
   virtual bool isPIEDefault(const llvm::opt::ArgList &Args) 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(const

clang/lib/Driver/ToolChain.cpp

@@ -110,10 +110,6 @@ bool ToolChain::useRelaxRelocations() const {
   return ENABLE_X86_RELAX_RELOCATIONS;
 }
 
-bool ToolChain::isNoExecStackDefault() const {
-    return false;
-}
-
 SanitizerArgs
 ToolChain::getSanitizerArgs(const llvm::opt::ArgList &JobArgs) const {
   SanitizerArgs SanArgs(*this, JobArgs, !SanitizerArgsChecked);

clang/lib/Driver/ToolChains/Clang.cpp

@@ -2439,7 +2439,7 @@ static void CollectArgsForIntegratedAssembler(Compilation &C,
   bool TakeNextArg = false;
 
   bool UseRelaxRelocations = C.getDefaultToolChain().useRelaxRelocations();
-  bool UseNoExecStack = C.getDefaultToolChain().isNoExecStackDefault();
+  bool UseNoExecStack = false;
   const char *MipsTargetFeature = nullptr;
   StringRef ImplicitIt;
   for (const Arg *A :

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -429,11 +429,6 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("text");
   }
 
-  if (ToolChain.isNoExecStackDefault()) {
-    CmdArgs.push_back("-z");
-    CmdArgs.push_back("noexecstack");
-  }
-
   if (Args.hasArg(options::OPT_rdynamic))
     CmdArgs.push_back("-export-dynamic");
 
@@ -707,10 +702,6 @@ void tools::gnutools::Assembler::ConstructJob(Compilation &C,
     }
   }
 
-  if (getToolChain().isNoExecStackDefault()) {
-      CmdArgs.push_back("--noexecstack");
-  }
-
   switch (getToolChain().getArch()) {
   default:
     break;

clang/lib/Driver/ToolChains/Linux.cpp

@@ -680,10 +680,6 @@ bool Linux::IsAArch64OutlineAtomicsDefault(const ArgList &Args) const {
   return true;
 }
 
-bool Linux::isNoExecStackDefault() const {
-    return getTriple().isAndroid();
-}
-
 bool Linux::IsMathErrnoDefault() const {
   if (getTriple().isAndroid())
     return false;

clang/lib/Driver/ToolChains/Linux.h

@@ -44,7 +44,6 @@ public:
   bool
   IsAArch64OutlineAtomicsDefault(const llvm::opt::ArgList &Args) const override;
   bool isPIEDefault(const llvm::opt::ArgList &Args) const override;
-  bool isNoExecStackDefault() const override;
   bool IsMathErrnoDefault() const override;
   SanitizerMask getSupportedSanitizers() const override;
   void addProfileRTLibs(const llvm::opt::ArgList &Args,

clang/test/Driver/integrated-as.c

@@ -14,8 +14,3 @@
 // NOFIAS: -cc1
 // NOFIAS: "-fno-verbose-asm"
 // 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"

clang/test/Driver/linux-as.c

@@ -108,12 +108,12 @@
 // 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)?}}" "--noexecstack" "-EL" "-mfloat-abi=soft"
+// CHECK-ARM-ANDROID: as{{(.exe)?}}" "-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)?}}" "--noexecstack" "-EL" "-mfloat-abi=softfp" "-march=armv7-a"
+// CHECK-ARM-ANDROID-SOFTFP: as{{(.exe)?}}" "-EL" "-mfloat-abi=softfp" "-march=armv7-a"
 //
 // RUN: %clang -target arm-linux-eabi -mhard-float -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \

clang/test/Driver/linux-ld.c

@@ -989,15 +989,6 @@
 // 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 \
 // RUN:     --target=armv7-linux-android21 \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-WARN-SHARED-TEXTREL %s