make/autoconf/flags-ldflags.m4

8209817: stack is executable when building with Clang on Linux
Reviewed-by: dholmes, martin, mikael, ihse
Contributed-by: Arthur Eubanks <aeubanks@google.com>

*** 72,85 ****
      fi
  
      # Add -z defs, to forbid undefined symbols in object files.
      BASIC_LDFLAGS="$BASIC_LDFLAGS -Wl,-z,defs"
  
!     BASIC_LDFLAGS_JVM_ONLY="-Wl,-z,noexecstack -Wl,-O1 -Wl,-z,relro"
  
-     BASIC_LDFLAGS_JDK_LIB_ONLY="-Wl,-z,noexecstack"
-     LIBJSIG_NOEXECSTACK_LDFLAGS="-Wl,-z,noexecstack"
  
    elif test "x$TOOLCHAIN_TYPE" = xclang; then
      BASIC_LDFLAGS_JVM_ONLY="-mno-omit-leaf-frame-pointer -mstack-alignment=16 \
          -fPIC"
  
--- 72,83 ----
      fi
  
      # Add -z defs, to forbid undefined symbols in object files.
      BASIC_LDFLAGS="$BASIC_LDFLAGS -Wl,-z,defs"
  
!     BASIC_LDFLAGS_JVM_ONLY="-Wl,-O1 -Wl,-z,relro"
  
  
    elif test "x$TOOLCHAIN_TYPE" = xclang; then
      BASIC_LDFLAGS_JVM_ONLY="-mno-omit-leaf-frame-pointer -mstack-alignment=16 \
          -fPIC"
  
*** 101,110 ****
--- 99,114 ----
      BASIC_LDFLAGS="-nologo -opt:ref"
      BASIC_LDFLAGS_JDK_ONLY="-incremental:no"
      BASIC_LDFLAGS_JVM_ONLY="-opt:icf,8 -subsystem:windows"
    fi
  
+   if test "x$TOOLCHAIN_TYPE" = xgcc || test "x$TOOLCHAIN_TYPE" = xclang; then
+     if test -n "$HAS_NOEXECSTACK"; then
+       BASIC_LDFLAGS="$BASIC_LDFLAGS -Wl,-z,noexecstack"
+     fi
+   fi
+ 
    # Setup OS-dependent LDFLAGS
    if test "x$TOOLCHAIN_TYPE" = xclang || test "x$TOOLCHAIN_TYPE" = xgcc; then
      if test "x$OPENJDK_TARGET_OS" = xmacosx; then
        # Assume clang or gcc.
        # FIXME: We should really generalize SET_SHARED_LIBRARY_ORIGIN instead.