If a macro has been #undef'd in a precompiled header, we still need to

write out the macro history for that macro. Similarly, we need to cope
with reading a macro definition that has been #undef'd.

Take advantage of this new ability so that global code-completion
results can refer to #undef'd macros, rather than losing them
entirely. For multiply defined/#undef'd macros, we will still get the
wrong result, but it's better than getting no result.

llvm-svn: 165502

Author: DougGregor

clang/include/clang/Basic/IdentifierTable.h

@@ -147,6 +147,9 @@ class IdentifierInfo {
   bool hadMacroDefinition() const {
     return HadMacro;
   }
+  void setHadMacroDefinition(bool Val) {
+    HadMacro = Val;
+  }
 
   /// getTokenID - If this is a source-language token (e.g. 'for'), this API
   /// can be used to cause the lexer to map identifiers to source-language

clang/lib/Sema/SemaCodeComplete.cpp

@@ -2495,7 +2495,7 @@ CodeCompletionResult::CreateCodeCompletionString(ASTContext &Ctx,
   }
 
   if (Kind == RK_Macro) {
-    MacroInfo *MI = PP.getMacroInfo(Macro);
+    MacroInfo *MI = PP.getMacroInfoHistory(Macro);
     assert(MI && "Not a macro?");
 
     Result.AddTypedTextChunk(
@@ -2902,6 +2902,7 @@ CXCursorKind clang::getCursorKindForDecl(Decl *D) {
 }
 
 static void AddMacroResults(Preprocessor &PP, ResultBuilder &Results,
+                            bool IncludeUndefined,
                             bool TargetTypeIsPointer = false) {
   typedef CodeCompletionResult Result;
 
@@ -2910,11 +2911,8 @@ static void AddMacroResults(Preprocessor &PP, ResultBuilder &Results,
   for (Preprocessor::macro_iterator M = PP.macro_begin(), 
                                  MEnd = PP.macro_end();
        M != MEnd; ++M) {
-    // FIXME: Eventually, we'd want to be able to look back to the macro
-    // definition that was actually active at the point of code completion (even
-    // if that macro has since been #undef'd).
-    if (M->first->hasMacroDefinition())
-      Results.AddResult(Result(M->first, 
+    if (IncludeUndefined || M->first->hasMacroDefinition())
+      Results.AddResult(Result(M->first,
                              getMacroUsagePriority(M->first->getName(),
                                                    PP.getLangOpts(),
                                                    TargetTypeIsPointer)));
@@ -3213,7 +3211,7 @@ void Sema::CodeCompleteOrdinaryName(Scope *S,
   }
 
   if (CodeCompleter->includeMacros())
-    AddMacroResults(PP, Results);
+    AddMacroResults(PP, Results, false);
 
   HandleCodeCompleteResults(this, CodeCompleter, Results.getCompletionContext(),
                             Results.data(),Results.size());
@@ -3344,7 +3342,7 @@ void Sema::CodeCompleteExpression(Scope *S,
     AddPrettyFunctionResults(PP.getLangOpts(), Results);        
 
   if (CodeCompleter->includeMacros())
-    AddMacroResults(PP, Results, PreferredTypeIsPointer);
+    AddMacroResults(PP, Results, false, PreferredTypeIsPointer);
   HandleCodeCompleteResults(this, CodeCompleter, 
                 CodeCompletionContext(CodeCompletionContext::CCC_Expression, 
                                       Data.PreferredType),
@@ -3736,7 +3734,7 @@ void Sema::CodeCompleteCase(Scope *S) {
   //so only say we include macros if the code completer says we do
   enum CodeCompletionContext::Kind kind = CodeCompletionContext::CCC_Other;
   if (CodeCompleter->includeMacros()) {
-    AddMacroResults(PP, Results);
+    AddMacroResults(PP, Results, false);
     kind = CodeCompletionContext::CCC_OtherWithMacros;
   }
 
@@ -3959,7 +3957,7 @@ void Sema::CodeCompleteAfterIf(Scope *S) {
     AddPrettyFunctionResults(PP.getLangOpts(), Results);        
 
   if (CodeCompleter->includeMacros())
-    AddMacroResults(PP, Results);
+    AddMacroResults(PP, Results, false);
 
   HandleCodeCompleteResults(this, CodeCompleter, Results.getCompletionContext(),
                             Results.data(),Results.size());
@@ -4960,7 +4958,7 @@ void Sema::CodeCompleteObjCPassingType(Scope *S, ObjCDeclSpec &DS,
                      CodeCompleter->includeGlobals());
 
   if (CodeCompleter->includeMacros())
-    AddMacroResults(PP, Results);
+    AddMacroResults(PP, Results, false);
 
   HandleCodeCompleteResults(this, CodeCompleter,
                             CodeCompletionContext::CCC_Type,
@@ -5190,7 +5188,7 @@ void Sema::CodeCompleteObjCMessageReceiver(Scope *S) {
   Results.ExitScope();
 
   if (CodeCompleter->includeMacros())
-    AddMacroResults(PP, Results);
+    AddMacroResults(PP, Results, false);
   HandleCodeCompleteResults(this, CodeCompleter, Results.getCompletionContext(),
                             Results.data(), Results.size());
 
@@ -7190,7 +7188,7 @@ void Sema::CodeCompletePreprocessorExpression() {
                         CodeCompletionContext::CCC_PreprocessorExpression);
 
   if (!CodeCompleter || CodeCompleter->includeMacros())
-    AddMacroResults(PP, Results);
+    AddMacroResults(PP, Results, true);
 
     // defined (<macro>)
   Results.EnterNewScope();
@@ -7239,7 +7237,7 @@ void Sema::GatherGlobalCodeCompletions(CodeCompletionAllocator &Allocator,
   }
 
   if (!CodeCompleter || CodeCompleter->includeMacros())
-    AddMacroResults(PP, Builder);
+    AddMacroResults(PP, Builder, true);
 
   Results.clear();
   Results.insert(Results.end(), 

clang/lib/Serialization/ASTReader.cpp

@@ -1460,6 +1460,8 @@ void ASTReader::setIdentifierIsMacro(IdentifierInfo *II, ModuleFile &F,
   if (Visible) {
     // Note that this identifier has a macro definition.
     II->setHasMacroDefinition(true);
+  } else {
+    II->setHadMacroDefinition(true);
   }
 
   // Adjust the offset to a global offset.

clang/lib/Serialization/ASTWriter.cpp

@@ -1698,14 +1698,13 @@ void ASTWriter::WritePreprocessor(const Preprocessor &PP, bool IsModule) {
     IdentifierInfo *Name
       = const_cast<IdentifierInfo *>(DeserializedMacroNames[I]);
     if (Name->hadMacroDefinition() && MacroDefinitionsSeen.insert(Name))
-      MacrosToEmit.push_back(std::make_pair(Name, PP.getMacroInfo(Name)));
+      MacrosToEmit.push_back(std::make_pair(Name,
+                                            PP.getMacroInfoHistory(Name)));
   }
 
   for (unsigned I = 0, N = MacrosToEmit.size(); I != N; ++I) {
     const IdentifierInfo *Name = MacrosToEmit[I].first;
     MacroInfo *MI = MacrosToEmit[I].second;
-    if (!MI)
-      continue;
 
     // History of macro definitions for this identifier in chronological order.
     SmallVector<MacroInfo*, 8> MacroHistory;

clang/test/Index/complete-macros.c

@@ -1,8 +1,8 @@
 // Note: the run lines follow their respective tests, since line/column
 // matter in this test.
-
 #define FOO(Arg1,Arg2) foobar
 #define nil 0
+#undef FOO
 void f() {
 
 }
@@ -25,7 +25,8 @@ void test_variadic() {
 
 }
 
-// RUN: c-index-test -code-completion-at=%s:7:1 %s | FileCheck -check-prefix=CHECK-CC1 %s
+// RUN: c-index-test -code-completion-at=%s:7:1 %s | FileCheck -check-prefix=CHECK-CC0 %s
+// CHECK-CC0-NOT: FOO
 // RUN: env CINDEXTEST_EDITING=1 CINDEXTEST_COMPLETION_CACHING=1 c-index-test -code-completion-at=%s:7:1 %s | FileCheck -check-prefix=CHECK-CC1 %s
 // CHECK-CC1: macro definition:{TypedText FOO}{LeftParen (}{Placeholder Arg1}{Comma , }{Placeholder Arg2}{RightParen )}
 // RUN: c-index-test -code-completion-at=%s:13:13 %s | FileCheck -check-prefix=CHECK-CC2 %s