[clang][IFS] Prevent Clang-IFS from Leaking symbols from inside a block.

Built libdispatch with clang interface stubs. Ran into some block
related issues. Basically VarDecl symbols can leak out because I wasn't
checking the case where a VarDecl is contained inside a BlockDecl
(versus a method or function).

This patch checks that a VarDecl is not a child decl of a BlockDecl.
This patch also does something very similar for c++ lambdas as well.

Differential Revision: https://reviews.llvm.org/D71301

clang/lib/Frontend/InterfaceStubFunctionsConsumer.cpp

@@ -53,6 +53,10 @@ class InterfaceStubFunctionsConsumer : public ASTConsumer {
         return true;
 
       if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
+        if (const auto *Parent = VD->getParentFunctionOrMethod())
+          if (isa<BlockDecl>(Parent) || isa<CXXMethodDecl>(Parent))
+            return true;
+
         if ((VD->getStorageClass() == StorageClass::SC_Extern) ||
             (VD->getStorageClass() == StorageClass::SC_Static &&
              VD->getParentFunctionOrMethod() == nullptr))

clang/test/InterfaceStubs/blocks.c

@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -emit-interface-stubs -fblocks -o - %s | FileCheck %s
+
+// CHECK: --- !experimental-ifs-v1
+// CHECK-NEXT: IfsVersion: 1.0
+// CHECK-NEXT: Triple:
+// CHECK-NEXT: ObjectFileFormat: ELF
+// CHECK-NEXT: Symbols:
+// CHECK-NEXT: ...
+static void (^f)(void*) = ^(void* data) { int i; };

clang/test/InterfaceStubs/lambda.cpp

@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -emit-interface-stubs -o - %s | FileCheck %s
+
+// CHECK: --- !experimental-ifs-v1
+// CHECK-NEXT: IfsVersion: 1.0
+// CHECK-NEXT: Triple:
+// CHECK-NEXT: ObjectFileFormat: ELF
+// CHECK-NEXT: Symbols:
+// CHECK-NEXT:   "f" : { Type: Object, Size: 1 }
+// CHECK-NEXT: ...
+auto f = [](void* data) { int i; };