Teach Preprocessor::macro_begin/macro_end to lazily load all macro

definitions from a precompiled header. This ensures that
code-completion with macro names behaves the same with or without
precompiled headers.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@92497 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 93 insertions, 7 deletions

diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
index d8fd791b19..4c6e5f44a0 100644
--- a/lib/Frontend/PCHReader.cpp
+++ b/lib/Frontend/PCHReader.cpp
@@ -1079,6 +1079,61 @@ void PCHReader::ReadMacroRecord(uint64_t Offset) {
   }
 }
 
+void PCHReader::ReadDefinedMacros() {
+  // If there was no preprocessor block, do nothing.
+  if (!MacroCursor.getBitStreamReader())
+    return;
+  
+  llvm::BitstreamCursor Cursor = MacroCursor;
+  if (Cursor.EnterSubBlock(pch::PREPROCESSOR_BLOCK_ID)) {
+    Error("malformed preprocessor block record in PCH file");
+    return;
+  }
+  
+  RecordData Record;
+  while (true) {
+    unsigned Code = Cursor.ReadCode();
+    if (Code == llvm::bitc::END_BLOCK) {
+      if (Cursor.ReadBlockEnd())
+        Error("error at end of preprocessor block in PCH file");
+      return;
+    }
+    
+    if (Code == llvm::bitc::ENTER_SUBBLOCK) {
+      // No known subblocks, always skip them.
+      Cursor.ReadSubBlockID();
+      if (Cursor.SkipBlock()) {
+        Error("malformed block record in PCH file");
+        return;
+      }
+      continue;
+    }
+    
+    if (Code == llvm::bitc::DEFINE_ABBREV) {
+      Cursor.ReadAbbrevRecord();
+      continue;
+    }
+    
+    // Read a record.
+    const char *BlobStart;
+    unsigned BlobLen;
+    Record.clear();
+    switch (Cursor.ReadRecord(Code, Record, &BlobStart, &BlobLen)) {
+    default:  // Default behavior: ignore.
+      break;
+        
+    case pch::PP_MACRO_OBJECT_LIKE:
+    case pch::PP_MACRO_FUNCTION_LIKE:
+        DecodeIdentifierInfo(Record[0]);
+      break;
+
+    case pch::PP_TOKEN:
+      // Ignore tokens.
+      break;
+    }
+  }
+}
+
 /// \brief If we are loading a relocatable PCH file, and the filename is
 /// not an absolute path, add the system root to the beginning of the file
 /// name.
@@ -1140,6 +1195,10 @@ PCHReader::ReadPCHBlock() {
         break;
 
       case pch::PREPROCESSOR_BLOCK_ID:
+        MacroCursor = Stream;
+        if (PP)
+          PP->setExternalSource(this);
+
         if (Stream.SkipBlock()) {
           Error("malformed block record in PCH file");
           return Failure;
@@ -1494,7 +1553,8 @@ void PCHReader::InitializeContext(ASTContext &Ctx) {
   assert(PP && "Forgot to set Preprocessor ?");
   PP->getIdentifierTable().setExternalIdentifierLookup(this);
   PP->getHeaderSearchInfo().SetExternalLookup(this);
-
+  PP->setExternalSource(this);
+  
   // Load the translation unit declaration
   ReadDeclRecord(DeclOffsets[0], 0);
 
diff --git a/lib/Frontend/PCHWriter.cpp b/lib/Frontend/PCHWriter.cpp
index 2875f0930c..39e5d6f46b 100644
--- a/lib/Frontend/PCHWriter.cpp
+++ b/lib/Frontend/PCHWriter.cpp
@@ -1148,7 +1148,6 @@ void PCHWriter::WritePreprocessor(const Preprocessor &PP) {
 
   // Loop over all the macro definitions that are live at the end of the file,
   // emitting each to the PP section.
-  // FIXME: Make sure that this sees macros defined in included PCH files.
   for (Preprocessor::macro_iterator I = PP.macro_begin(), E = PP.macro_end();
        I != E; ++I) {
     // FIXME: This emits macros in hash table order, we should do it in a stable
@@ -1160,7 +1159,6 @@ void PCHWriter::WritePreprocessor(const Preprocessor &PP) {
     if (MI->isBuiltinMacro())
       continue;
 
-    // FIXME: Remove this identifier reference?
     AddIdentifierRef(I->first, Record);
     MacroOffsets[I->first] = Stream.GetCurrentBitNo();
     Record.push_back(MI->getDefinitionLoc().getRawEncoding());
diff --git a/lib/Lex/PPLexerChange.cpp b/lib/Lex/PPLexerChange.cpp
index ce1b19ca7c..0b26ccbecb 100644
--- a/lib/Lex/PPLexerChange.cpp
+++ b/lib/Lex/PPLexerChange.cpp
@@ -249,7 +249,8 @@ bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) {
   // diagnostic is enabled, look for macros that have not been used.
   if (getDiagnostics().getDiagnosticLevel(diag::pp_macro_not_used) !=
         Diagnostic::Ignored) {
-    for (macro_iterator I = macro_begin(), E = macro_end(); I != E; ++I)
+    for (macro_iterator I = macro_begin(false), E = macro_end(false); 
+         I != E; ++I)
       if (!I->second->isUsed())
         Diag(I->second->getDefinitionLoc(), diag::pp_macro_not_used);
   }
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index 81966cb2b9..26bb3a90da 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -27,6 +27,7 @@
 
 #include "clang/Lex/Preprocessor.h"
 #include "MacroArgs.h"
+#include "clang/Lex/ExternalPreprocessorSource.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/MacroInfo.h"
 #include "clang/Lex/Pragma.h"
@@ -43,6 +44,7 @@
 using namespace clang;
 
 //===----------------------------------------------------------------------===//
+ExternalPreprocessorSource::~ExternalPreprocessorSource() { }
 
 Preprocessor::Preprocessor(Diagnostic &diags, const LangOptions &opts,
                            const TargetInfo &target, SourceManager &SM,
@@ -50,9 +52,9 @@ Preprocessor::Preprocessor(Diagnostic &diags, const LangOptions &opts,
                            IdentifierInfoLookup* IILookup,
                            bool OwnsHeaders)
   : Diags(&diags), Features(opts), Target(target),FileMgr(Headers.getFileMgr()),
-    SourceMgr(SM), HeaderInfo(Headers), Identifiers(opts, IILookup),
-    BuiltinInfo(Target), CodeCompletionFile(0), CurPPLexer(0), CurDirLookup(0),
-    Callbacks(0), MacroArgCache(0) {
+    SourceMgr(SM), HeaderInfo(Headers), ExternalSource(0),
+    Identifiers(opts, IILookup), BuiltinInfo(Target), CodeCompletionFile(0), 
+    CurPPLexer(0), CurDirLookup(0), Callbacks(0), MacroArgCache(0) {
   ScratchBuf = new ScratchBuffer(SourceMgr);
   CounterValue = 0; // __COUNTER__ starts at 0.
   OwnsHeaderSearch = OwnsHeaders;
@@ -77,6 +79,9 @@ Preprocessor::Preprocessor(Diagnostic &diags, const LangOptions &opts,
 
   CachedLexPos = 0;
 
+  // We haven't read anything from the external source.
+  ReadMacrosFromExternalSource = false;
+      
   // "Poison" __VA_ARGS__, which can only appear in the expansion of a macro.
   // This gets unpoisoned where it is allowed.
   (Ident__VA_ARGS__ = getIdentifierInfo("__VA_ARGS__"))->setIsPoisoned();
@@ -194,6 +199,28 @@ void Preprocessor::PrintStats() {
              << NumFastTokenPaste << " on the fast path.\n";
 }
 
+Preprocessor::macro_iterator 
+Preprocessor::macro_begin(bool IncludeExternalMacros) const { 
+  if (IncludeExternalMacros && ExternalSource && 
+      !ReadMacrosFromExternalSource) {
+    ReadMacrosFromExternalSource = true;
+    ExternalSource->ReadDefinedMacros();
+  }
+  
+  return Macros.begin(); 
+}
+
+Preprocessor::macro_iterator 
+Preprocessor::macro_end(bool IncludeExternalMacros) const { 
+  if (IncludeExternalMacros && ExternalSource && 
+      !ReadMacrosFromExternalSource) {
+    ReadMacrosFromExternalSource = true;
+    ExternalSource->ReadDefinedMacros();
+  }
+  
+  return Macros.end(); 
+}
+
 bool Preprocessor::SetCodeCompletionPoint(const FileEntry *File, 
                                           unsigned TruncateAtLine, 
                                           unsigned TruncateAtColumn) {