Add #pragma clang module build/endbuild pragmas for performing a module build

as part of a compilation.

This is intended for two purposes:

1) Writing self-contained test cases for modules: we can now write a single
source file test that builds some number of module files on the side and
imports them.

2) Debugging / test case reduction. A single-source testcase is much more
amenable to reduction, compared to a VFS tarball or .pcm files.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@305101 91177308-0d34-0410-b5e6-96231b3b80d8

Author: zygoloid

include/clang/Basic/DiagnosticLexKinds.td

@@ -527,6 +527,10 @@ def err_pp_module_end_without_module_begin : Error<
   "'#pragma clang module end'">;
 def note_pp_module_begin_here : Note<
   "entering module '%0' due to this pragma">;
+def err_pp_module_build_pth : Error<
+  "'#pragma clang module build' not supported in pretokenized header">;
+def err_pp_module_build_missing_end : Error<
+  "no matching '#pragma clang module endbuild' for this '#pragma clang module build'">;
 
 def err_defined_macro_name : Error<"'defined' cannot be used as a macro name">;
 def err_paste_at_start : Error<

include/clang/Frontend/ASTUnit.h

@@ -67,7 +67,7 @@ class FileSystem;
 
 /// \brief Utility class for loading a ASTContext from an AST file.
 ///
-class ASTUnit : public ModuleLoader {
+class ASTUnit {
 public:
   struct StandaloneFixIt {
     std::pair<unsigned, unsigned> RemoveRange;
@@ -119,10 +119,13 @@ class ASTUnit : public ModuleLoader {
   /// LoadFromCommandLine available.
   std::shared_ptr<CompilerInvocation> Invocation;
 
+  /// Fake module loader: the AST unit doesn't need to load any modules.
+  TrivialModuleLoader ModuleLoader;
+
   // OnlyLocalDecls - when true, walking this AST should only visit declarations
   // that come from the AST itself, not from included precompiled headers.
   // FIXME: This is temporary; eventually, CIndex will always do this.
-  bool                              OnlyLocalDecls;
+  bool OnlyLocalDecls;
 
   /// \brief Whether to capture any diagnostics produced.
   bool CaptureDiagnostics;
@@ -496,7 +499,7 @@ class ASTUnit : public ModuleLoader {
   };
   friend class ConcurrencyCheck;
 
-  ~ASTUnit() override;
+  ~ASTUnit();
 
   bool isMainFileAST() const { return MainFileIsAST; }
 
@@ -945,21 +948,6 @@ class ASTUnit : public ModuleLoader {
   ///
   /// \returns True if an error occurred, false otherwise.
   bool serialize(raw_ostream &OS);
-
-  ModuleLoadResult loadModule(SourceLocation ImportLoc, ModuleIdPath Path,
-                              Module::NameVisibilityKind Visibility,
-                              bool IsInclusionDirective) override {
-    // ASTUnit doesn't know how to load modules (not that this matters).
-    return ModuleLoadResult();
-  }
-
-  void makeModuleVisible(Module *Mod, Module::NameVisibilityKind Visibility,
-                         SourceLocation ImportLoc) override {}
-
-  GlobalModuleIndex *loadGlobalModuleIndex(SourceLocation TriggerLoc) override
-    { return nullptr; }
-  bool lookupMissingImports(StringRef Name, SourceLocation TriggerLoc) override
-    { return 0; }
 };
 
 } // namespace clang

include/clang/Frontend/CompilerInstance.h

@@ -136,6 +136,10 @@ class CompilerInstance : public ModuleLoader {
   /// along with the module map
   llvm::DenseMap<const IdentifierInfo *, Module *> KnownModules;
 
+  /// \brief The set of top-level modules that has already been built on the
+  /// fly as part of this overall compilation action.
+  std::map<std::string, std::string> BuiltModules;
+
   /// \brief The location of the module-import keyword for the last module
   /// import. 
   SourceLocation LastModuleImportLoc;
@@ -773,6 +777,9 @@ class CompilerInstance : public ModuleLoader {
                               Module::NameVisibilityKind Visibility,
                               bool IsInclusionDirective) override;
 
+  void loadModuleFromSource(SourceLocation ImportLoc, StringRef ModuleName,
+                            StringRef Source) override;
+
   void makeModuleVisible(Module *Mod, Module::NameVisibilityKind Visibility,
                          SourceLocation ImportLoc) override;
 

include/clang/Lex/ModuleLoader.h

@@ -109,6 +109,16 @@ class ModuleLoader {
                                       Module::NameVisibilityKind Visibility,
                                       bool IsInclusionDirective) = 0;
 
+  /// Attempt to load the given module from the specified source buffer. Does
+  /// not make any submodule visible; for that, use loadModule or
+  /// makeModuleVisible.
+  ///
+  /// \param Loc The location at which the module was loaded.
+  /// \param ModuleName The name of the module to build.
+  /// \param Source The source of the module: a (preprocessed) module map.
+  virtual void loadModuleFromSource(SourceLocation Loc, StringRef ModuleName,
+                                    StringRef Source) = 0;
+
   /// \brief Make the given module visible.
   virtual void makeModuleVisible(Module *Mod,
                                  Module::NameVisibilityKind Visibility,
@@ -136,6 +146,30 @@ class ModuleLoader {
 
   bool HadFatalFailure;
 };
+
+/// A module loader that doesn't know how to load modules.
+class TrivialModuleLoader : public ModuleLoader {
+public:
+  ModuleLoadResult loadModule(SourceLocation ImportLoc, ModuleIdPath Path,
+                              Module::NameVisibilityKind Visibility,
+                              bool IsInclusionDirective) override {
+    return ModuleLoadResult();
+  }
+
+  void loadModuleFromSource(SourceLocation ImportLoc, StringRef ModuleName,
+                            StringRef Source) override {}
+
+  void makeModuleVisible(Module *Mod, Module::NameVisibilityKind Visibility,
+                         SourceLocation ImportLoc) override {}
+
+  GlobalModuleIndex *loadGlobalModuleIndex(SourceLocation TriggerLoc) override {
+    return nullptr;
+  }
+  bool lookupMissingImports(StringRef Name,
+                            SourceLocation TriggerLoc) override {
+    return 0;
+  }
+};
 
 }
 

include/clang/Lex/Preprocessor.h

@@ -2028,6 +2028,7 @@ class Preprocessor {
   void HandlePragmaPushMacro(Token &Tok);
   void HandlePragmaPopMacro(Token &Tok);
   void HandlePragmaIncludeAlias(Token &Tok);
+  void HandlePragmaModuleBuild(Token &Tok);
   IdentifierInfo *ParsePragmaPushOrPopMacro(Token &Tok);
 
   // Return true and store the first token only if any CommentHandler

lib/Frontend/ASTUnit.cpp

@@ -716,7 +716,7 @@ std::unique_ptr<ASTUnit> ASTUnit::LoadFromASTFile(
 
   AST->PP = std::make_shared<Preprocessor>(
       AST->PPOpts, AST->getDiagnostics(), *AST->LangOpts,
-      AST->getSourceManager(), *AST->PCMCache, HeaderInfo, *AST,
+      AST->getSourceManager(), *AST->PCMCache, HeaderInfo, AST->ModuleLoader,
       /*IILookup=*/nullptr,
       /*OwnsHeaderSearch=*/false);
   Preprocessor &PP = *AST->PP;