Introduce a new libclang parsing flag,

CXTranslationUnit_NestedMacroInstantiations, which indicates whether
we want to see "nested" macro instantiations (e.g., those that occur
inside other macro instantiations) within the detailed preprocessing
record. Many clients (e.g., those that only care about visible tokens)
don't care about this information, and in code that uses preprocessor
metaprogramming, this information can have a very high cost.

Addresses <rdar://problem/9389320>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@130990 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 2 deletions

diff --git a/lib/Lex/PreprocessingRecord.cpp b/lib/Lex/PreprocessingRecord.cpp
index 9555611dc5..0c8d948ce0 100644
--- a/lib/Lex/PreprocessingRecord.cpp
+++ b/lib/Lex/PreprocessingRecord.cpp
@@ -45,8 +45,9 @@ void PreprocessingRecord::MaybeLoadPreallocatedEntities() const {
   ExternalSource->ReadPreprocessedEntities();
 }
 
-PreprocessingRecord::PreprocessingRecord()
-  : ExternalSource(0), NumPreallocatedEntities(0), 
+PreprocessingRecord::PreprocessingRecord(bool IncludeNestedMacroInstantiations)
+  : IncludeNestedMacroInstantiations(IncludeNestedMacroInstantiations),
+    ExternalSource(0), NumPreallocatedEntities(0), 
     LoadedPreallocatedEntities(false)
 {
 }
@@ -120,6 +121,9 @@ MacroDefinition *PreprocessingRecord::findMacroDefinition(const MacroInfo *MI) {
 }
 
 void PreprocessingRecord::MacroExpands(const Token &Id, const MacroInfo* MI) {
+  if (!IncludeNestedMacroInstantiations && Id.getLocation().isMacroID())
+    return;
+
   if (MacroDefinition *Def = findMacroDefinition(MI))
     PreprocessedEntities.push_back(
                        new (*this) MacroInstantiation(Id.getIdentifierInfo(),