[Modules] Add platform feature to requires clause

[bruno]

Summary

Allows module map writers to add build requirements based on platform/os. Useful when target features and language dialects aren't enough to conditionalize building a module. Among other things, it also makes it more convenient for modules with the same name but different set of submodules to be described in the same module map.

rdar://problem/43909745

[aprantl]

docs/Modules.rst

470 ↗

(On Diff #164802)

Does this work with platforms+environment combinations, such as the ios simulator on Darwin?

[bruno]

Addressed Adrian's review. Added support to consider the environment and well the combination platform-environment. @aprantl also handled multiple variants of simulator combinations.

[aprantl]

docs/Modules.rst

470 ↗

(On Diff #164802)

Is iossimulator a thing? The triple is called x86_64-apple-ios-11.2.3-simulator and the SDK calls itself iphonesimulator, so I wonder if this shouldn't be called ios-simulator or iphonesimulator instead.

[aprantl]

lib/Basic/Module.cpp

101 ↗

(On Diff #165612)

Ah.. it looks like you are fully aware of this :-)

[rsmith]

docs/Modules.rst

476–477 ↗

(On Diff #165612)

What is the reason to allow these to be combined into a single feature name rather than treating them as two distinct features? (Eg, requires linux, gnueabi rather than requires linux-gnueabi)?

[bruno]

docs/Modules.rst

476–477 ↗

(On Diff #165612)

No specific reason other than the convenience of writing triple like requirements. But thinking more about it, it might make more sense to have it decoupled and written as a combination to avoid confusion. Will update the patch to reflect that.

[bruno]

Update patch after review.

[rsmith]

lib/Basic/Module.cpp

81 ↗

(On Diff #165861)

Comment is out of date.

cfe/trunk/docs/Modules.rst

*requires-declaration*:
     ``requires`` *feature-list*
 
   *feature-list*:
     *feature* (',' *feature*)*
 
   *feature*:
     ``!``:sub:`opt` *identifier*
 
-The requirements clause allows specific modules or submodules to specify that they are only accessible with certain language dialects or on certain platforms. The feature list is a set of identifiers, defined below. If any of the features is not available in a given translation unit, that translation unit shall not import the module. When building a module for use by a compilation, submodules requiring unavailable features are ignored. The optional ``!`` indicates that a feature is incompatible with the module.
+The requirements clause allows specific modules or submodules to specify that they are only accessible with certain language dialects, platforms, environments and target specific features. The feature list is a set of identifiers, defined below. If any of the features is not available in a given translation unit, that translation unit shall not import the module. When building a module for use by a compilation, submodules requiring unavailable features are ignored. The optional ``!`` indicates that a feature is incompatible with the module.
 
 The following features are defined:
 
 altivec
   The target supports AltiVec.
 
 blocks
   The "blocks" language feature is available.
opencl
   OpenCL is available
 
 tls
   Thread local storage is available.
 
 *target feature*
   A specific target feature (e.g., ``sse4``, ``avx``, ``neon``) is available.
 
+*platform/os*
+  A os/platform variant (e.g. ``freebsd``, ``win32``, ``windows``, ``linux``, ``ios``, ``macos``, ``iossimulator``) is available.
+
+*environment*
+  A environment variant (e.g. ``gnu``, ``gnueabi``, ``android``, ``msvc``) is available.
 
 **Example:** The ``std`` module can be extended to also include C++ and C++11 headers using a *requires-declaration*:
 
 .. parsed-literal::
 
  module std {
     // C standard library...
 

cfe/trunk/lib/Basic/Module.cpp

 
 Module::~Module() {
   for (submodule_iterator I = submodule_begin(), IEnd = submodule_end();
        I != IEnd; ++I) {
     delete *I;
   }
 }
 
+static bool isPlatformEnvironment(const TargetInfo &Target, StringRef Feature) {
+  StringRef Platform = Target.getPlatformName();
+  StringRef Env = Target.getTriple().getEnvironmentName();
+
+  // Attempt to match platform and environment.
+  if (Platform == Feature || Target.getTriple().getOSName() == Feature ||
+      Env == Feature)
+    return true;
+
+  auto CmpPlatformEnv = [](StringRef LHS, StringRef RHS) {
+    auto Pos = LHS.find("-");
+    if (Pos == StringRef::npos)
+      return false;
+    SmallString<128> NewLHS = LHS.slice(0, Pos);
+    NewLHS += LHS.slice(Pos+1, LHS.size());
+    return NewLHS == RHS;
+  };
+
+  SmallString<128> PlatformEnv = Target.getTriple().getOSAndEnvironmentName();
+  // Darwin has different but equivalent variants for simulators, example:
+  //   1. x86_64-apple-ios-simulator
+  //   2. x86_64-apple-iossimulator
+  // where both are valid examples of the same platform+environment but in the
+  // variant (2) the simulator is hardcoded as part of the platform name. Both
+  // forms above should match for "iossimulator" requirement.
+  if (Target.getTriple().isOSDarwin() && PlatformEnv.endswith("simulator"))
+    return PlatformEnv == Feature || CmpPlatformEnv(PlatformEnv, Feature);
+
+  return PlatformEnv == Feature;
+}
+
 /// Determine whether a translation unit built using the current
 /// language options has the given feature.
 static bool hasFeature(StringRef Feature, const LangOptions &LangOpts,
                        const TargetInfo &Target) {
   bool HasFeature = llvm::StringSwitch<bool>(Feature)
                         .Case("altivec", LangOpts.AltiVec)
                         .Case("blocks", LangOpts.Blocks)
                         .Case("coroutines", LangOpts.CoroutinesTS)
                         .Case("cplusplus", LangOpts.CPlusPlus)
                         .Case("cplusplus11", LangOpts.CPlusPlus11)
                         .Case("cplusplus14", LangOpts.CPlusPlus14)
                         .Case("cplusplus17", LangOpts.CPlusPlus17)
                         .Case("c99", LangOpts.C99)
                         .Case("c11", LangOpts.C11)
                         .Case("c17", LangOpts.C17)
                         .Case("freestanding", LangOpts.Freestanding)
                         .Case("gnuinlineasm", LangOpts.GNUAsm)
                         .Case("objc", LangOpts.ObjC1)
                         .Case("objc_arc", LangOpts.ObjCAutoRefCount)
                         .Case("opencl", LangOpts.OpenCL)
                         .Case("tls", Target.isTLSSupported())
                         .Case("zvector", LangOpts.ZVector)
-                        .Default(Target.hasFeature(Feature));
+                        .Default(Target.hasFeature(Feature) ||
+                                 isPlatformEnvironment(Target, Feature));
   if (!HasFeature)
     HasFeature = std::find(LangOpts.ModuleFeatures.begin(),
                            LangOpts.ModuleFeatures.end(),
                            Feature) != LangOpts.ModuleFeatures.end();
   return HasFeature;
 }
 
 bool Module::isAvailable(const LangOptions &LangOpts, const TargetInfo &Target,

cfe/trunk/test/Modules/target-platform-features.m

+// Clear and create directories
+// RUN: rm -rf %t
+// RUN: mkdir %t
+// RUN: mkdir %t/cache
+// RUN: mkdir %t/InputsA
+
+// RUN: echo "module RequiresMacOS {"       >> %t/InputsA/module.map
+// RUN: echo "  requires macos"             >> %t/InputsA/module.map
+// RUN: echo "}"                            >> %t/InputsA/module.map
+// RUN: echo "module RequiresNotiOS {"      >> %t/InputsA/module.map
+// RUN: echo "  requires !ios"              >> %t/InputsA/module.map
+// RUN: echo "}"                            >> %t/InputsA/module.map
+// RUN: echo "module RequiresMain {"        >> %t/InputsA/module.map
+// RUN: echo "  module SubRequiresNotiOS {" >> %t/InputsA/module.map
+// RUN: echo "    requires !ios"            >> %t/InputsA/module.map
+// RUN: echo "  }"                          >> %t/InputsA/module.map
+// RUN: echo "}"                            >> %t/InputsA/module.map
+
+// RUN: %clang_cc1 -triple=x86_64-apple-macosx10.6 -DENABLE_DARWIN -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache -x objective-c -I%t/InputsA -verify %s 
+// expected-no-diagnostics
+
+// RUN: not %clang_cc1 -triple=arm64-apple-ios -DENABLE_DARWIN -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache -x objective-c -I%t/InputsA %s  2> %t/notios
+// RUN: FileCheck %s -check-prefix=CHECK-IOS < %t/notios
+#ifdef ENABLE_DARWIN
+// CHECK-IOS: module 'RequiresMacOS' requires feature 'macos'
+@import RequiresMacOS;
+// CHECK-IOS: module 'RequiresNotiOS' is incompatible with feature 'ios'
+@import RequiresNotiOS;
+// We should never get errors for submodules that don't match
+// CHECK-IOS-NOT: module 'RequiresMain'
+@import RequiresMain;
+#endif
+
+// RUN: mkdir %t/InputsB
+// RUN: echo "module RequiresiOSSim {"     >> %t/InputsB/module.map
+// RUN: echo "  requires iossimulator"      >> %t/InputsB/module.map
+// RUN: echo "}"                            >> %t/InputsB/module.map
+// RUN: %clang_cc1 -triple=x86_64-apple-iossimulator -DENABLE_IOSSIM -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache -x objective-c -I%t/InputsB %s  -verify
+// RUN: %clang_cc1 -triple=x86_64-apple-ios-simulator -DENABLE_IOSSIM -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache -x objective-c -I%t/InputsB %s  -verify
+
+#ifdef ENABLE_IOSSIM
+@import RequiresiOSSim;
+#endif
+
+// RUN: mkdir %t/InputsC
+// RUN: echo "module RequiresLinuxEABIA {"  >> %t/InputsC/module.map
+// RUN: echo "  requires linux, gnueabi"    >> %t/InputsC/module.map
+// RUN: echo "}"                            >> %t/InputsC/module.map
+// RUN: echo "module RequiresLinuxEABIB {"  >> %t/InputsC/module.map
+// RUN: echo "  requires gnueabi"           >> %t/InputsC/module.map
+// RUN: echo "}"                            >> %t/InputsC/module.map
+// RUN: echo "module RequiresLinuxEABIC {"  >> %t/InputsC/module.map
+// RUN: echo "  requires linux"             >> %t/InputsC/module.map
+// RUN: echo "}"                            >> %t/InputsC/module.map
+// RUN: %clang_cc1 -triple=armv8r-none-linux-gnueabi -DENABLE_LINUXEABI -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache -x objective-c -I%t/InputsC %s -verify
+
+#ifdef ENABLE_LINUXEABI
+@import RequiresLinuxEABIA;
+@import RequiresLinuxEABIB;
+@import RequiresLinuxEABIC;
+#endif
+
+// RUN: mkdir %t/InputsD
+// RUN: echo "module RequiresWinMSVCA {"  >> %t/InputsD/module.map
+// RUN: echo "  requires windows"         >> %t/InputsD/module.map
+// RUN: echo "}"                          >> %t/InputsD/module.map
+// RUN: echo "module RequiresWinMSVCB {"  >> %t/InputsD/module.map
+// RUN: echo "  requires windows, msvc"   >> %t/InputsD/module.map
+// RUN: echo "}"                          >> %t/InputsD/module.map
+// RUN: echo "module RequiresWinMSVCC {"  >> %t/InputsD/module.map
+// RUN: echo "  requires msvc"            >> %t/InputsD/module.map
+// RUN: echo "}"                          >> %t/InputsD/module.map
+// RUN: %clang_cc1 -triple=thumbv7-unknown-windows-msvc -DENABLE_WINMSVC -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache -x objective-c -I%t/InputsD %s  -verify
+
+#ifdef ENABLE_WINMSVC
+@import RequiresWinMSVCA;
+@import RequiresWinMSVCB;
+@import RequiresWinMSVCC;
+#endif