[Clang] Always set -z now linker option on Fuchsia

[phosek]

Summary

This should be the default on Fuchsia.

[leonardchan]

LGTM. But just to confirm, did you test this on CQ/bots by adding ["now", "-z"] as linker flags to the config("compiler") in Fuchsia + Zircon?

[phosek]

In D70576#1756049, @leonardchan wrote:

LGTM. But just to confirm, did you test this on CQ/bots by adding ["now", "-z"] as linker flags to the config("compiler") in Fuchsia + Zircon?

https://fuchsia-review.googlesource.com/c/fuchsia/+/342078

clang/lib/Driver/ToolChains/Fuchsia.cpp

void fuchsia::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   // Silence warning for "clang -g foo.o -o foo"
   Args.ClaimAllArgs(options::OPT_g_Group);
   // and "clang -emit-llvm foo.o -o foo"
   Args.ClaimAllArgs(options::OPT_emit_llvm);
   // and for "clang -w foo.o -o foo". Other warning options are already
   // handled somewhere else.
   Args.ClaimAllArgs(options::OPT_w);
 
+  CmdArgs.push_back("-z");
+  CmdArgs.push_back("now");
+
   const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
   if (llvm::sys::path::filename(Exec).equals_lower("ld.lld") ||
       llvm::sys::path::stem(Exec).equals_lower("ld.lld")) {
     CmdArgs.push_back("-z");
     CmdArgs.push_back("rodynamic");
     CmdArgs.push_back("-z");
     CmdArgs.push_back("separate-loadable-segments");
   }

clang/test/Driver/fuchsia.c

 // CHECK: "-munwind-tables"
 // CHECK: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
 // CHECK: "-isysroot" "[[SYSROOT:[^"]+]]"
 // CHECK: "-internal-externc-isystem" "[[SYSROOT]]{{/|\\\\}}include"
 // 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-loadable-segments"
+// CHECK: {{.*}}ld.lld{{.*}}" "-z" "now" "-z" "rodynamic" "-z" "separate-loadable-segments"
 // CHECK: "--sysroot=[[SYSROOT]]"
 // CHECK: "-pie"
 // CHECK: "--build-id"
 // CHECK: "--hash-style=gnu"
 // CHECK: "-dynamic-linker" "ld.so.1"
 // CHECK: Scrt1.o
 // CHECK-NOT: crti.o
 // CHECK-NOT: crtbegin.o

clang/test/Driver/fuchsia.cpp

 // CHECK-X86_64: "-triple" "x86_64-unknown-fuchsia"
 // CHECK-AARCH64: "-triple" "aarch64-unknown-fuchsia"
 // CHECK-RISCV64: "-triple" "riscv64-unknown-fuchsia"
 // CHECK-NOT: "-fno-use-init-array"
 // CHECK: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
 // CHECK: "-isysroot" "[[SYSROOT:[^"]+]]"
 // CHECK: "-internal-isystem" "{{.*[/\\]}}include{{/|\\\\}}c++{{/|\\\\}}v1"
 // CHECK: "-internal-externc-isystem" "[[SYSROOT]]{{/|\\\\}}include"
-// CHECK: {{.*}}ld.lld{{.*}}" "-z" "rodynamic"
+// CHECK: {{.*}}ld.lld{{.*}}" "-z" "now" "-z" "rodynamic" "-z" "separate-loadable-segments"
 // CHECK: "--sysroot=[[SYSROOT]]"
 // CHECK: "-pie"
 // CHECK: "--build-id"
 // CHECK: "-dynamic-linker" "ld.so.1"
 // CHECK: Scrt1.o
 // CHECK-NOT: crti.o
 // CHECK-NOT: crtbegin.o
 // CHECK: "-L[[SYSROOT]]{{/|\\\\}}lib"