Fix crash if a submodule overrides one of its own macros, and add support for

submodule macro overriding within the same top-level module (necessary for the
testcase to be remotely reasonable). Incidentally reduces the number of libc++
testsuite regressions with modules enabled from 7 to 6.

llvm-svn: 203063

clang/lib/Serialization/ASTReader.cpp

@@ -1679,8 +1679,9 @@ void ASTReader::removeOverriddenMacros(IdentifierInfo *II,
     HiddenNames &Hidden = HiddenNamesMap[Owner];
     HiddenMacrosMap::iterator HI = Hidden.HiddenMacros.find(II);
     if (HI != Hidden.HiddenMacros.end()) {
-      removeOverriddenMacros(II, Ambig, HI->second->getOverriddenSubmodules());
+      auto SubOverrides = HI->second->getOverriddenSubmodules();
       Hidden.HiddenMacros.erase(HI);
+      removeOverriddenMacros(II, Ambig, SubOverrides);
     }
 
     // If this macro is already in our list of conflicts, remove it from there.

clang/lib/Serialization/ASTWriter.cpp

@@ -3021,9 +3021,19 @@ class ASTIdentifierTableTrait {
       // We can't do that currently, because a #include of a different submodule
       // of the same module just leaks through macros instead of providing new
       // DefMacroDirectives for them.
-      if (DefMacroDirective *DefMD = dyn_cast<DefMacroDirective>(MD))
-        if (SubmoduleID SourceID = DefMD->getInfo()->getOwningModuleID())
+      if (DefMacroDirective *DefMD = dyn_cast<DefMacroDirective>(MD)) {
+        // Figure out which submodule the macro was originally defined within.
+        SubmoduleID SourceID = DefMD->getInfo()->getOwningModuleID();
+        if (!SourceID) {
+          SourceLocation DefLoc = DefMD->getInfo()->getDefinitionLoc();
+          if (DefLoc == MD->getLocation())
+            SourceID = ThisModID;
+          else
+            SourceID = Writer.inferSubmoduleIDFromLocation(DefLoc);
+        }
+        if (SourceID != OrigModID)
           Overridden.push_back(SourceID);
+      }
 
       // We are looking for a definition in a different submodule than the one
       // that we started with. If a submodule has re-definitions of the same

clang/test/Modules/Inputs/macros_top.h

@@ -20,3 +20,5 @@
 #define TOP_OTHER_REDEF2 2
 
 #define TOP_OTHER_DEF_RIGHT_UNDEF void
+
+#define TOP_REDEF_IN_SUBMODULES 0

clang/test/Modules/Inputs/macros_top_b.h

@@ -0,0 +1,5 @@
+#include "macros_top.h"
+#undef TOP_REDEF_IN_SUBMODULES
+#define TOP_REDEF_IN_SUBMODULES 1
+#undef TOP_REDEF_IN_SUBMODULES
+#define TOP_REDEF_IN_SUBMODULES 2

clang/test/Modules/Inputs/macros_top_c.h

@@ -0,0 +1,2 @@
+#include "macros_top_b.h"
+#undef TOP_REDEF_IN_SUBMODULES

clang/test/Modules/Inputs/module.map

@@ -23,6 +23,8 @@ module module_private_left { header "module_private_left.h" }
 module module_private_right { header "module_private_right.h" }
 module macros_top { 
   header "macros_top.h" 
+  explicit module b { header "macros_top_b.h" }
+  explicit module c { header "macros_top_c.h" }
 }
 module macros_left { 
   header "macros_left.h" 

clang/test/Modules/macros2.c

@@ -75,3 +75,9 @@ int n1 = TOP_OTHER_REDEF1; // expected-warning{{ambiguous expansion of macro 'TO
 int n2 = TOP_OTHER_REDEF2; // ok
 
 int n3 = TOP_OTHER_DEF_RIGHT_UNDEF; // ok
+
+int top_redef_in_submodules = TOP_REDEF_IN_SUBMODULES;
+@import macros_top.c;
+void test2() {
+  int TOP_REDEF_IN_SUBMODULES = top_redef_in_submodules;
+}