[Modules] Add a command line option for loading the clang builtins modulemap file.

[eladcohen]

Summary

-fbuiltin-module-map loads the clang builtins modulemap file.
(This is equivalent to -fmodule-map-file=<resource dir>/include/module.modulemap)

It can be used for enabling clang's 'modules' feature for the clang intrinsics headers files.

[eladcohen]

Thanks for the review! committed r285548.

docs/Modules.rst

 
 Modules maintain references to each of the headers that were part of the module build. If any of those headers changes, or if any of the modules on which a module depends change, then the module will be (automatically) recompiled. The process should never require any user intervention.
 
 Command-line parameters
 -----------------------
 ``-fmodules``
   Enable the modules feature.
 
+``-fbuiltin-module-map``
+  Load the Clang builtins module map file. (Equivalent to ``-fmodule-map-file=<resource dir>/include/module.modulemap``)
+
 ``-fimplicit-module-maps``
   Enable implicit search for module map files named ``module.modulemap`` and similar. This option is implied by ``-fmodules``. If this is disabled with ``-fno-implicit-module-maps``, module map files will only be loaded if they are explicitly specified via ``-fmodule-map-file`` or transitively used by another module map file.
 
 ``-fmodules-cache-path=<directory>``
   Specify the path to the modules cache. If not provided, Clang will select a system-appropriate default.
 
 ``-fno-autolink``
   Disable automatic linking against the libraries associated with imported modules.

include/clang/Driver/Options.td

def fno_profile_use : Flag<["-"], "fno-profile-use">,
     Alias<fno_profile_instr_use>;
 
 def fblocks : Flag<["-"], "fblocks">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Enable the 'blocks' language feature">;
 def fbootclasspath_EQ : Joined<["-"], "fbootclasspath=">, Group<f_Group>;
 def fborland_extensions : Flag<["-"], "fborland-extensions">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Accept non-standard constructs supported by the Borland compiler">;
 def fbuiltin : Flag<["-"], "fbuiltin">, Group<f_Group>;
+def fbuiltin_module_map : Flag <["-"], "fbuiltin-module-map">, Group<f_Group>,
+  Flags<[DriverOption]>, HelpText<"Load the clang builtins module map file.">;
 def fcaret_diagnostics : Flag<["-"], "fcaret-diagnostics">, Group<f_Group>;
 def fclasspath_EQ : Joined<["-"], "fclasspath=">, Group<f_Group>;
 def fcolor_diagnostics : Flag<["-"], "fcolor-diagnostics">, Group<f_Group>,
   Flags<[CoreOption, CC1Option]>, HelpText<"Use colors in diagnostics">;
 def fdiagnostics_color : Flag<["-"], "fdiagnostics-color">, Group<f_Group>,
   Flags<[CoreOption, DriverOption]>;
 def fdiagnostics_color_EQ : Joined<["-"], "fdiagnostics-color=">, Group<f_Group>;
 def fansi_escape_codes : Flag<["-"], "fansi-escape-codes">, Group<f_Group>,

lib/Driver/Tools.cpp

   // -fmodule-name specifies the module that is currently being built (or
   // used for header checking by -fmodule-maps).
   Args.AddLastArg(CmdArgs, options::OPT_fmodule_name_EQ);
 
   // -fmodule-map-file can be used to specify files containing module
   // definitions.
   Args.AddAllArgs(CmdArgs, options::OPT_fmodule_map_file);
 
+  // -fbuiltin-module-map can be used to load the clang
+  // builtin headers modulemap file.
+  if (Args.hasArg(options::OPT_fbuiltin_module_map)) {
+    SmallString<128> BuiltinModuleMap(getToolChain().getDriver().ResourceDir);
+    llvm::sys::path::append(BuiltinModuleMap, "include");
+    llvm::sys::path::append(BuiltinModuleMap, "module.modulemap");
+    if (llvm::sys::fs::exists(BuiltinModuleMap)) {
+      CmdArgs.push_back(Args.MakeArgString("-fmodule-map-file=" +
+                                           BuiltinModuleMap));
+    }
+  }
+
   // -fmodule-file can be used to specify files containing precompiled modules.
   if (HaveAnyModules)
     Args.AddAllArgs(CmdArgs, options::OPT_fmodule_file);
   else
     Args.ClaimAllArgs(options::OPT_fmodule_file);
 
   // When building modules and generating crashdumps, we need to dump a module
   // dependency VFS alongside the output.

test/Driver/modules.m

 // MODULES_PREBUILT_PATH: "-fprebuilt-module-path=foo"
 // MODULES_PREBUILT_PATH: "-fprebuilt-module-path=bar"
 
 // RUN: %clang -fmodules -fmodule-map-file=foo.map -fmodule-map-file=bar.map -### %s 2>&1 | FileCheck -check-prefix=CHECK-MODULE-MAP-FILES %s
 // CHECK-MODULE-MAP-FILES: "-fmodules"
 // CHECK-MODULE-MAP-FILES: "-fmodule-map-file=foo.map"
 // CHECK-MODULE-MAP-FILES: "-fmodule-map-file=bar.map"
 
+// RUN: %clang -fmodules -fbuiltin-module-map -### %s 2>&1 | FileCheck -check-prefix=CHECK-BUILTIN-MODULE-MAP %s
+// CHECK-BUILTIN-MODULE-MAP: "-fmodules"
+// CHECK-BUILTIN-MODULE-MAP: "-fmodule-map-file={{.*}}include{{/|\\\\}}module.modulemap"
+
 // RUN: %clang -fmodules -fmodule-file=foo.pcm -fmodule-file=bar.pcm -### %s 2>&1 | FileCheck -check-prefix=CHECK-MODULE-FILES %s
 // CHECK-MODULE-FILES: "-fmodules"
 // CHECK-MODULE-FILES: "-fmodule-file=foo.pcm"
 // CHECK-MODULE-FILES: "-fmodule-file=bar.pcm"
 
 // RUN: %clang -fno-modules -fmodule-file=foo.pcm -fmodule-file=bar.pcm -### %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MODULE-FILES %s
 // CHECK-NO-MODULE-FILES-NOT: "-fmodules"
 // CHECK-NO-MODULE-FILES-NOT: "-fmodule-file=foo.pcm"
 // CHECK-NO-MODULE-FILES-NOT: "-fmodule-file=bar.pcm"

test/Modules/compiler_builtins.m

 // RUN: rm -rf %t
 // RUN: %clang_cc1 -fsyntax-only -fmodules -fimplicit-module-maps -fmodules-cache-path=%t %s -I%S/Inputs/System/usr/include -verify
 // RUN: %clang_cc1 -fsyntax-only -std=c99 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t %s -I%S/Inputs/System/usr/include -verify
+// RUN: %clang_cc1 -fsyntax-only -fmodules -fmodule-map-file=%resource_dir/module.modulemap -fmodules-cache-path=%t %s -I%S/Inputs/System/usr/include -verify
 // expected-no-diagnostics
 
 #ifdef __SSE__
 @import _Builtin_intrinsics.intel.sse;
 #endif
 
 #ifdef __AVX2__
 @import _Builtin_intrinsics.intel.avx2;
 #endif

test/Modules/compiler_builtins_x86.c

 // RUN: rm -rf %t
 // RUN: %clang_cc1 -triple i686-unknown-unknown -fsyntax-only -fmodules -fimplicit-module-maps -fmodules-cache-path=%t %s -verify -ffreestanding
+// RUN: %clang_cc1 -triple i686-unknown-unknown -fsyntax-only -fmodules -fmodule-map-file=%resource_dir/module.modulemap -fmodules-cache-path=%t %s -verify -ffreestanding
 // expected-no-diagnostics
 
 #include<x86intrin.h>
 

test/lit.cfg

 config.substitutions.append( ('%clang_cl', ' ' + config.clang +
                               ' --driver-mode=cl '))
 config.substitutions.append( ('%clangxx', ' ' + config.clang +
                               ' --driver-mode=g++ '))
 config.substitutions.append( ('%clang', ' ' + config.clang + ' ') )
 config.substitutions.append( ('%test_debuginfo', ' ' + config.llvm_src_root + '/utils/test_debuginfo.pl ') )
 config.substitutions.append( ('%itanium_abi_triple', makeItaniumABITriple(config.target_triple)) )
 config.substitutions.append( ('%ms_abi_triple', makeMSABITriple(config.target_triple)) )
+config.substitutions.append( ('%resource_dir', getClangBuiltinIncludeDir(config.clang)) )
 
 # The host triple might not be set, at least if we're compiling clang from
 # an already installed llvm.
 if config.host_triple and config.host_triple != '@LLVM_HOST_TRIPLE@':
     config.substitutions.append( ('%target_itanium_abi_host_triple', '--target=%s' % makeItaniumABITriple(config.host_triple)) )
 else:
     config.substitutions.append( ('%target_itanium_abi_host_triple', '') )