[Driver][Darwin] Emit an error when using -pg on OS without support for it.

[vsapsai]

Summary

Instead of letting a program fail at runtime, emit an error during
compilation.

rdar://problem/12206955

[steven_wu]

LGTM with a suggestion to make code cleaner.

clang/include/clang/Basic/DiagnosticDriverKinds.td

101 ↗

(On Diff #186089)

Might be cleaner if you use %select here.

[vsapsai]

• Use %select per Steven's recommendation.

cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td

 def err_drv_no_ast_support : Error<
   "'%0': unable to use AST files with this tool">;
 def err_drv_no_module_support : Error<
   "'%0': unable to use module files with this tool">;
 def err_drv_clang_unsupported : Error<
   "the clang compiler does not support '%0'">;
 def err_drv_clang_unsupported_opt_cxx_darwin_i386 : Error<
   "the clang compiler does not support '%0' for C++ on Darwin/i386">;
+def err_drv_clang_unsupported_opt_pg_darwin: Error<
+  "the clang compiler does not support -pg option on %select{Darwin|versions of OS X 10.9 and later}0">;
 def err_drv_clang_unsupported_opt_faltivec : Error<
   "the clang compiler does not support '%0', %1">;
 def err_drv_command_failed : Error<
   "%0 command failed with exit code %1 (use -v to see invocation)">;
 def err_drv_compilationdatabase : Error<
   "compilation database '%0' could not be opened: %1">;
 def err_drv_command_signalled : Error<
   "%0 command failed due to signal (use -v to see invocation)">;

cfe/trunk/lib/Driver/ToolChains/Darwin.cpp

if (Args.hasArg(options::OPT_bundle)) {
             CmdArgs.push_back("-lbundle1.o");
         } else {
           if (isMacosxVersionLT(10, 6))
             CmdArgs.push_back("-lbundle1.o");
         }
       }
     } else {
       if (Args.hasArg(options::OPT_pg) && SupportsProfiling()) {
+        if (isTargetMacOS() && isMacosxVersionLT(10, 9)) {
           if (Args.hasArg(options::OPT_static) ||
               Args.hasArg(options::OPT_object) ||
               Args.hasArg(options::OPT_preload)) {
             CmdArgs.push_back("-lgcrt0.o");
           } else {
             CmdArgs.push_back("-lgcrt1.o");
 
             // darwin_crt2 spec is empty.
           }
           // By default on OS X 10.8 and later, we don't link with a crt1.o
           // file and the linker knows to use _main as the entry point.  But,
           // when compiling with -pg, we need to link with the gcrt1.o file,
           // so pass the -no_new_main option to tell the linker to use the
           // "start" symbol as the entry point.
           if (isTargetMacOS() && !isMacosxVersionLT(10, 8))
             CmdArgs.push_back("-no_new_main");
         } else {
+          getDriver().Diag(diag::err_drv_clang_unsupported_opt_pg_darwin)
+              << isTargetMacOS();
+        }
+      } else {
         if (Args.hasArg(options::OPT_static) ||
             Args.hasArg(options::OPT_object) ||
             Args.hasArg(options::OPT_preload)) {
           CmdArgs.push_back("-lcrt0.o");
         } else {
           // Derived from darwin_crt1 spec.
           if (isTargetWatchOSBased()) {
             ; // watchOS does not need crt1.o.

cfe/trunk/test/Driver/darwin-ld.c

 // LINK_WATCHOS_KEXT: libclang_rt.cc_kext_watchos.a
 // LINK_WATCHOS_KEXT: libclang_rt.watchos.a
 
 // RUN: %clang -target i386-apple-darwin12 -pg -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=LINK_PG %s < %t.log
 // LINK_PG: -lgcrt1.o
 // LINK_PG: -no_new_main
 
+// RUN: %clang -target i386-apple-darwin13 -pg -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=LINK_PG_NO_SUPPORT_OSX %s < %t.log
+// LINK_PG_NO_SUPPORT_OSX: error: the clang compiler does not support -pg option on versions of OS X
+
+// RUN: %clang -target x86_64-apple-ios5.0 -pg -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=LINK_PG_NO_SUPPORT %s < %t.log
+// LINK_PG_NO_SUPPORT: error: the clang compiler does not support -pg option on Darwin
+
 // Check that clang links with libgcc_s.1 for iOS 4 and earlier, but not arm64.
 // RUN: %clang -target armv7-apple-ios4.0 -miphoneos-version-min=4.0 -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=LINK_IOS_LIBGCC_S %s < %t.log
 // LINK_IOS_LIBGCC_S: lgcc_s.1
 
 // RUN: %clang -target arm64-apple-ios4.0 -miphoneos-version-min=4.0 -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=LINK_NO_IOS_ARM64_LIBGCC_S %s < %t.log
 // LINK_NO_IOS_ARM64_LIBGCC_S-NOT: lgcc_s.1