PCH + module: make sure we write out macros associated with builtin identifiers.

When we import a module that defines a builtin identifier from prefix header and
precompile the prefix header, the macro information related to the identifier
is lost.

If we don't precompile the prefix header, the source file can still see the
macro information. The reason is that we write out the identifier in the pch
but not the macro information since the macro is not defined locally.

This is related to r251565. In that commit, if we read a builtin identifier from
a module that wasn't "interesting" to that module, we will still write it out to
a PCH that imports that module.

The fix is to write exported module macros for PCH as well.

rdar://24666630

Differential Revision: http://reviews.llvm.org/D20383

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@271310 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index 7540bc03d155d3beb11623c6d2018302abd6005d..0c9264f403242eeb83d1f3ab7beeb02ebd453feb 100644 (file)
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -2187,30 +2187,29 @@ void ASTWriter::WritePreprocessor(const Preprocessor &PP, bool IsModule) {
 
     // Write out any exported module macros.
     bool EmittedModuleMacros = false;
-    if (IsModule) {
-      auto Leafs = PP.getLeafModuleMacros(Name);
-      SmallVector<ModuleMacro*, 8> Worklist(Leafs.begin(), Leafs.end());
-      llvm::DenseMap<ModuleMacro*, unsigned> Visits;
-      while (!Worklist.empty()) {
-        auto *Macro = Worklist.pop_back_val();
-
-        // Emit a record indicating this submodule exports this macro.
-        ModuleMacroRecord.push_back(
-            getSubmoduleID(Macro->getOwningModule()));
-        ModuleMacroRecord.push_back(getMacroRef(Macro->getMacroInfo(), Name));
-        for (auto *M : Macro->overrides())
-          ModuleMacroRecord.push_back(getSubmoduleID(M->getOwningModule()));
-
-        Stream.EmitRecord(PP_MODULE_MACRO, ModuleMacroRecord);
-        ModuleMacroRecord.clear();
-
-        // Enqueue overridden macros once we've visited all their ancestors.
-        for (auto *M : Macro->overrides())
-          if (++Visits[M] == M->getNumOverridingMacros())
-            Worklist.push_back(M);
-
-        EmittedModuleMacros = true;
-      }
+    // We write out exported module macros for PCH as well.
+    auto Leafs = PP.getLeafModuleMacros(Name);
+    SmallVector<ModuleMacro*, 8> Worklist(Leafs.begin(), Leafs.end());
+    llvm::DenseMap<ModuleMacro*, unsigned> Visits;
+    while (!Worklist.empty()) {
+      auto *Macro = Worklist.pop_back_val();
+
+      // Emit a record indicating this submodule exports this macro.
+      ModuleMacroRecord.push_back(
+          getSubmoduleID(Macro->getOwningModule()));
+      ModuleMacroRecord.push_back(getMacroRef(Macro->getMacroInfo(), Name));
+      for (auto *M : Macro->overrides())
+        ModuleMacroRecord.push_back(getSubmoduleID(M->getOwningModule()));
+
+      Stream.EmitRecord(PP_MODULE_MACRO, ModuleMacroRecord);
+      ModuleMacroRecord.clear();
+
+      // Enqueue overridden macros once we've visited all their ancestors.
+      for (auto *M : Macro->overrides())
+        if (++Visits[M] == M->getNumOverridingMacros())
+          Worklist.push_back(M);
+
+      EmittedModuleMacros = true;
     }
 
     if (Record.empty() && !EmittedModuleMacros)

diff --git a/test/Modules/Inputs/MacroFabs1.h b/test/Modules/Inputs/MacroFabs1.h
new file mode 100644 (file)
index 0000000..a78c553
--- /dev/null
+++ b/test/Modules/Inputs/MacroFabs1.h
@@ -0,0 +1,6 @@
+
+#undef fabs
+#define fabs(x) (x)
+
+#undef my_fabs
+#define my_fabs(x) (x)

diff --git a/test/Modules/Inputs/module.map b/test/Modules/Inputs/module.map
index 4db1cca925c03fdf9cfb50454bc49f367e38fa4e..6846690c849868f42c6096589f5b4a695812a7be 100644 (file)
--- a/test/Modules/Inputs/module.map
+++ b/test/Modules/Inputs/module.map
@@ -414,3 +414,7 @@ module MethodPoolString2 {
 }
 
 module Empty {}
+
+module MacroFabs1 {
+  header "MacroFabs1.h"
+}

diff --git a/test/Modules/Inputs/pch-import-module-with-macro.pch b/test/Modules/Inputs/pch-import-module-with-macro.pch
new file mode 100644 (file)
index 0000000..c06d772
--- /dev/null
+++ b/test/Modules/Inputs/pch-import-module-with-macro.pch
@@ -0,0 +1,3 @@
+
+@import MacroFabs1;
+

diff --git a/test/Modules/pch-module-macro.m b/test/Modules/pch-module-macro.m
new file mode 100644 (file)
index 0000000..cc9f687
--- /dev/null
+++ b/test/Modules/pch-module-macro.m
@@ -0,0 +1,9 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -emit-pch -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -o %t.pch -I %S/Inputs -x objective-c-header %S/Inputs/pch-import-module-with-macro.pch
+// RUN: %clang_cc1 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -fsyntax-only -I %S/Inputs -include-pch %t.pch %s -verify
+// expected-no-diagnostics
+
+int test(int x) {
+  return my_fabs(x) + fabs(x);
+}
+