Add -linker (and -linker=) alias for -fuse-ld=

[filcab]

Summary

This implements one of the changes in the initial PS4 toolchain
definition.

http://reviews.llvm.org/D11279#inline-92724

[filcab]

Update to latest trunk. Ping.

[echristo]

include/clang/Driver/Options.td

1853–1854

Any reason to have both options?

[filcab]

Addressed Eric's comment.

[echristo]

One inline comment and then OK.

-eric

test/Driver/fuse-ld.c

27–33

Bet this doesn't work :)

[thakis]

include/clang/Driver/Options.td

1853

Any reason to have another alias for this at all? Does gcc understand this spelling? If not, could you limit this flag to PS4 targets? (I'm guessing you need it for PS4 targets for some reason.)

[pcc]

test/Driver/fuse-ld.c

32–33

Prefix mismatch here.

39–40

Same here.

[echristo]

include/clang/Driver/Options.td

1853

Any reason? (And I'm not sure how to limit it btw on target).

[filcab]

Addressed comments.

[kromanova]

include/clang/Driver/Options.td

1853–1854

We will remove -linker alias. We had to confirm with the interested parties that they are OK with this option being removed.

[filcab]

We don't need this anymore, since we're making some internal changes.
Thank you for the feedback!

include/clang/Driver/Options.td

1853

Same here, no idea how to limit the flag to a specific target.

1853–1854

I went and double-checked our docs. We should only need one.

test/Driver/fuse-ld.c

27–33

Derp. Sorry.

32–33

Ah yes. Thanks!

include/clang/Driver/Options.td

multiclass BooleanFFlag<string name> {
   def _f : Flag<["-"], "f"#name>;
   def _fno : Flag<["-"], "fno-"#name>;
 }
 
 defm : BooleanFFlag<"keep-inline-functions">, Group<clang_ignored_gcc_optimization_f_Group>;
 
 def fprofile_dir : Joined<["-"], "fprofile-dir=">, Group<clang_ignored_gcc_optimization_f_Group>;
 
-def fuse_ld_EQ : Joined<["-"], "fuse-ld=">, Group<f_Group>;
+def fuse_ld_EQ : Joined<["-"], "fuse-ld=">, HelpText<"Use linker <name>">, Group<f_Group>;
+def linker_EQ : Joined<["-"], "linker=">, Alias<fuse_ld_EQ>, MetaVarName<"<name>">;
 
 defm align_functions : BooleanFFlag<"align-functions">, Group<clang_ignored_gcc_optimization_f_Group>;
 def falign_functions_EQ : Joined<["-"], "falign-functions=">, Group<clang_ignored_gcc_optimization_f_Group>;
 defm align_labels : BooleanFFlag<"align-labels">, Group<clang_ignored_gcc_optimization_f_Group>;
 def falign_labels_EQ : Joined<["-"], "falign-labels=">, Group<clang_ignored_gcc_optimization_f_Group>;
 defm align_loops : BooleanFFlag<"align-loops">, Group<clang_ignored_gcc_optimization_f_Group>;
 def falign_loops_EQ : Joined<["-"], "falign-loops=">, Group<clang_ignored_gcc_optimization_f_Group>;
 defm align_jumps : BooleanFFlag<"align-jumps">, Group<clang_ignored_gcc_optimization_f_Group>;
 def falign_jumps_EQ : Joined<["-"], "falign-jumps=">, Group<clang_ignored_gcc_optimization_f_Group>;

test/Driver/fuse-ld.c

 
 // RUN: %clang %s -### -fuse-ld=plib \
 // RUN:     --sysroot=%S/Inputs/basic_freebsd_tree \
 // RUN:     -target x86_64-unknown-freebsd \
 // RUN:     -B%S/Inputs/basic_freebsd_tree/usr/bin 2>&1 \
 // RUN:   | FileCheck %s -check-prefix=CHECK-FREEBSD-PLIB
 // CHECK-FREEBSD-PLIB: error: invalid linker name
 
+// -linker= is an alias to fuse-ld. Don't need to retry all combinations
+// RUN: %clang %s -### -linker=gold \
+// RUN:     --sysroot=%S/Inputs/basic_freebsd_tree \
+// RUN:     -target x86_64-unknown-freebsd \
+// RUN:     -B%S/Inputs/basic_freebsd_tree/usr/bin 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-FREEBSD-LINKEREQ-GOLD
+// CHECK-FREEBSD-LINKEREQ-GOLD: Inputs/basic_freebsd_tree/usr/bin{{/|\\+}}ld.gold
 
 
 // RUN: %clang %s -### \
 // RUN:     -target arm-linux-androideabi \
 // RUN:     -B%S/Inputs/basic_android_tree/bin 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-ANDROID-ARM-LD
 // CHECK-ANDROID-ARM-LD: Inputs/basic_android_tree/bin{{/|\\+}}arm-linux-androideabi-ld
 
 // RUN: %clang %s -### -fuse-ld=bfd \
 // RUN:     -target arm-linux-androideabi \
 // RUN:     -B%S/Inputs/basic_android_tree/bin 2>&1 \
 // RUN:   | FileCheck %s -check-prefix=CHECK-ANDROID-ARM-BFD
 // CHECK-ANDROID-ARM-BFD: Inputs/basic_android_tree/bin{{/|\\+}}arm-linux-androideabi-ld.bfd
 
 // RUN: %clang %s -### -fuse-ld=gold \