[modules] Fix a rejects-valid resulting from emitting an inline function

recursively within the emission of another inline function. This ultimately
led to us emitting the same inline function definition twice, which we then
rejected because we believed we had a mangled name conflict.

llvm-svn: 215579

clang/lib/CodeGen/ModuleBuilder.cpp

@@ -117,10 +117,14 @@ namespace {
     }
 
     void EmitDeferredDecls() {
+      if (DeferredInlineMethodDefinitions.empty())
+        return;
+
       // Emit any deferred inline method definitions. Note that more deferred
       // methods may be added during this loop, since ASTConsumer callbacks
       // can be invoked if AST inspection results in declarations being added.
-      for (unsigned I = 0; I < DeferredInlineMethodDefinitions.size(); ++I)
+      HandlingTopLevelDeclRAII HandlingDecl(*this);
+      for (unsigned I = 0; I != DeferredInlineMethodDefinitions.size(); ++I)
         Builder->EmitTopLevelDecl(DeferredInlineMethodDefinitions[I]);
       DeferredInlineMethodDefinitions.clear();
     }

clang/test/Modules/Inputs/cxx-irgen-top.h

@@ -38,3 +38,14 @@ namespace OperatorDeleteLookup {
   template<typename T> struct B { void operator delete(void*); virtual ~B() {} typedef int t; };
   typedef B<int>::t b_int_instantated;
 }
+
+namespace EmitInlineMethods {
+  struct A {
+    void f() {}
+    void g();
+  };
+  struct B {
+    void f();
+    void g() {}
+  };
+}

clang/test/Modules/cxx-irgen.cpp

@@ -1,5 +1,6 @@
 // RUN: rm -rf %t
 // RUN: %clang_cc1 -fmodules -x objective-c++ -std=c++11 -fmodules-cache-path=%t -I %S/Inputs -triple %itanium_abi_triple -disable-llvm-optzns -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -fmodules -x objective-c++ -std=c++11 -fmodules-cache-path=%t -I %S/Inputs -triple %itanium_abi_triple -disable-llvm-optzns -emit-llvm -g -o - %s | FileCheck %s
 // FIXME: When we have a syntax for modules in C++, use that.
 
 @import cxx_irgen_top;
@@ -10,6 +11,22 @@ CtorInit<int> x;
 @import cxx_irgen_left;
 @import cxx_irgen_right;
 
+// Keep these two namespace definitions separate; merging them hides the bug.
+namespace EmitInlineMethods {
+  // CHECK-DAG: define linkonce_odr void @_ZN17EmitInlineMethods1C1fEPNS_1AE(
+  // CHECK-DAG: declare void @_ZN17EmitInlineMethods1A1gEv(
+  struct C {
+    __attribute__((used)) void f(A *p) { p->g(); }
+  };
+}
+namespace EmitInlineMethods {
+  // CHECK-DAG: define linkonce_odr void @_ZN17EmitInlineMethods1D1fEPNS_1BE(
+  // CHECK-DAG: define linkonce_odr void @_ZN17EmitInlineMethods1B1gEv(
+  struct D {
+    __attribute__((used)) void f(B *p) { p->g(); }
+  };
+}
+
 // CHECK-DAG: define available_externally hidden {{signext i32|i32}} @_ZN1SIiE1gEv({{.*}} #[[ALWAYS_INLINE:.*]] align
 int a = S<int>::g();