PR24667: fix quadratic runtime if textually-included modular headers define large numbers of macros.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261705 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 3 deletions

diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index 1031cdac9f..d8e61713b3 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -507,9 +507,10 @@ class Preprocessor : public RefCountedBase<Preprocessor> {
   /// \brief Information about a submodule that we're currently building.
   struct BuildingSubmoduleInfo {
     BuildingSubmoduleInfo(Module *M, SourceLocation ImportLoc,
-                          SubmoduleState *OuterSubmoduleState)
-        : M(M), ImportLoc(ImportLoc), OuterSubmoduleState(OuterSubmoduleState) {
-    }
+                          SubmoduleState *OuterSubmoduleState,
+                          unsigned OuterPendingModuleMacroNames)
+        : M(M), ImportLoc(ImportLoc), OuterSubmoduleState(OuterSubmoduleState),
+          OuterPendingModuleMacroNames(OuterPendingModuleMacroNames) {}
 
     /// The module that we are building.
     Module *M;
@@ -517,6 +518,8 @@ class Preprocessor : public RefCountedBase<Preprocessor> {
     SourceLocation ImportLoc;
     /// The previous SubmoduleState.
     SubmoduleState *OuterSubmoduleState;
+    /// The number of pending module macro names when we started building this.
+    unsigned OuterPendingModuleMacroNames;
   };
   SmallVector<BuildingSubmoduleInfo, 8> BuildingSubmoduleStack;
 
@@ -541,6 +544,9 @@ class Preprocessor : public RefCountedBase<Preprocessor> {
   /// The set of known macros exported from modules.
   llvm::FoldingSet<ModuleMacro> ModuleMacros;
 
+  /// The names of potential module macros that we've not yet processed.
+  llvm::SmallVector<const IdentifierInfo*, 32> PendingModuleMacroNames;
+
   /// The list of module macros, for each identifier, that are not overridden by
   /// any other module macro.
   llvm::DenseMap<const IdentifierInfo *, llvm::TinyPtrVector<ModuleMacro*>>
@@ -1704,6 +1710,10 @@ private:
   void EnterSubmodule(Module *M, SourceLocation ImportLoc);
   void LeaveSubmodule();
 
+  /// Determine whether we need to create module macros for #defines in the
+  /// current context.
+  bool needModuleMacros() const;
+
   /// Update the set of active module macros and ambiguity flag for a module
   /// macro name.
   void updateModuleMacroInfo(const IdentifierInfo *II, ModuleMacroInfo &Info);