[Modules] Don't eagerly load and associate all the module header files.

In a module-enabled Cocoa PCH file, we spend a lot of time stat'ing the headers
in order to associate the FileEntries with their modules and support implicit
module import.

Use a more lazy scheme by enhancing HeaderInfoTable to store extra info about
the module that a header belongs to, and associate it with its module only when
there is a request for loading the header info for a particular file.

Part of rdar://13391765

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176976 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 25 insertions, 6 deletions

diff --git a/lib/Lex/HeaderSearch.cpp b/lib/Lex/HeaderSearch.cpp
index d4d14e8745..9e4b68232a 100644
--- a/lib/Lex/HeaderSearch.cpp
+++ b/lib/Lex/HeaderSearch.cpp
@@ -47,7 +47,7 @@ HeaderSearch::HeaderSearch(IntrusiveRefCntPtr<HeaderSearchOptions> HSOpts,
                            const LangOptions &LangOpts, 
                            const TargetInfo *Target)
   : HSOpts(HSOpts), FileMgr(FM), FrameworkMap(64),
-    ModMap(FileMgr, *Diags.getClient(), LangOpts, Target)
+    ModMap(FileMgr, *Diags.getClient(), LangOpts, Target, *this)
 {
   AngledDirIdx = 0;
   SystemDirIdx = 0;
@@ -806,6 +806,7 @@ static void mergeHeaderFileInfo(HeaderFileInfo &HFI,
                                 const HeaderFileInfo &OtherHFI) {
   HFI.isImport |= OtherHFI.isImport;
   HFI.isPragmaOnce |= OtherHFI.isPragmaOnce;
+  HFI.isModuleHeader |= OtherHFI.isModuleHeader;
   HFI.NumIncludes += OtherHFI.NumIncludes;
   
   if (!HFI.ControllingMacro && !HFI.ControllingMacroID) {
@@ -851,6 +852,14 @@ bool HeaderSearch::isFileMultipleIncludeGuarded(const FileEntry *File) {
       HFI.ControllingMacro || HFI.ControllingMacroID;
 }
 
+void HeaderSearch::MarkFileModuleHeader(const FileEntry *FE) {
+  if (FE->getUID() >= FileInfo.size())
+    FileInfo.resize(FE->getUID()+1);
+
+  HeaderFileInfo &HFI = FileInfo[FE->getUID()];
+  HFI.isModuleHeader = true;
+}
+
 void HeaderSearch::setHeaderFileInfoForUID(HeaderFileInfo HFI, unsigned UID) {
   if (UID >= FileInfo.size())
     FileInfo.resize(UID+1);
@@ -948,7 +957,12 @@ bool HeaderSearch::hasModuleMap(StringRef FileName,
   } while (true);
 }
 
-Module *HeaderSearch::findModuleForHeader(const FileEntry *File) {
+Module *HeaderSearch::findModuleForHeader(const FileEntry *File) const {
+  if (ExternalSource) {
+    // Make sure the external source has handled header info about this file,
+    // which includes whether the file is part of a module.
+    (void)getFileInfo(File);
+  }
   if (Module *Mod = ModMap.findModuleForHeader(File))
     return Mod;
   
diff --git a/lib/Lex/ModuleMap.cpp b/lib/Lex/ModuleMap.cpp
index f9b4e2c947..71a98e2152 100644
--- a/lib/Lex/ModuleMap.cpp
+++ b/lib/Lex/ModuleMap.cpp
@@ -18,6 +18,7 @@
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/TargetOptions.h"
+#include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/LexDiagnostic.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Lex/LiteralSupport.h"
@@ -76,8 +77,10 @@ ModuleMap::resolveExport(Module *Mod,
 }
 
 ModuleMap::ModuleMap(FileManager &FileMgr, const DiagnosticConsumer &DC,
-                     const LangOptions &LangOpts, const TargetInfo *Target)
-  : LangOpts(LangOpts), Target(Target), BuiltinIncludeDir(0)
+                     const LangOptions &LangOpts, const TargetInfo *Target,
+                     HeaderSearch &HeaderInfo)
+  : LangOpts(LangOpts), Target(Target), HeaderInfo(HeaderInfo),
+    BuiltinIncludeDir(0)
 {
   IntrusiveRefCntPtr<DiagnosticIDs> DiagIDs(new DiagnosticIDs);
   Diags = IntrusiveRefCntPtr<DiagnosticsEngine>(
@@ -553,10 +556,12 @@ void ModuleMap::setUmbrellaDir(Module *Mod, const DirectoryEntry *UmbrellaDir) {
 
 void ModuleMap::addHeader(Module *Mod, const FileEntry *Header,
                           bool Excluded) {
-  if (Excluded)
+  if (Excluded) {
     Mod->ExcludedHeaders.push_back(Header);
-  else
+  } else {
     Mod->Headers.push_back(Header);
+    HeaderInfo.MarkFileModuleHeader(Header);
+  }
   Headers[Header] = KnownHeader(Mod, Excluded);
 }