From: Alexey Bataev <a.bataev@hotmail.com>
Date: Mon, 20 Aug 2018 16:00:22 +0000 (+0000)
Subject: [OPENMP][BLOCKS]Fix PR38923: reference to a global variable is captured
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5b14cddec6bdb8da8f375dfe0c0910ff970a0e05;p=clang

[OPENMP][BLOCKS]Fix PR38923: reference to a global variable is captured
by a block.

Added checks for capturing of the variable in the block when trying to
emit correct address for the variable with the reference type. This
extra check allows correctly identify the variables that are not
captured in the block context.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@340181 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 605c01d52b..b74937e9ca 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -2437,6 +2437,7 @@ LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
     // A DeclRefExpr for a reference initialized by a constant expression can
     // appear without being odr-used. Directly emit the constant initializer.
     const Expr *Init = VD->getAnyInitializer(VD);
+    const auto *BD = dyn_cast_or_null<BlockDecl>(CurCodeDecl);
     if (Init && !isa<ParmVarDecl>(VD) && VD->getType()->isReferenceType() &&
         VD->isUsableInConstantExpressions(getContext()) &&
         VD->checkInitIsICE() &&
@@ -2446,7 +2447,7 @@ LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
             (LocalDeclMap.count(VD->getCanonicalDecl()) ||
              CapturedStmtInfo->lookup(VD->getCanonicalDecl()))) ||
            LambdaCaptureFields.lookup(VD->getCanonicalDecl()) ||
-           isa<BlockDecl>(CurCodeDecl)))) {
+           (BD && BD->capturesVariable(VD))))) {
       llvm::Constant *Val =
         ConstantEmitter(*this).emitAbstract(E->getLocation(),
                                             *VD->evaluateValue(),
diff --git a/test/CodeGenCXX/block-byref.cpp b/test/CodeGenCXX/block-byref.cpp
new file mode 100644
index 0000000000..1cb86a5475
--- /dev/null
+++ b/test/CodeGenCXX/block-byref.cpp
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 %s -fblocks -triple x86_64-apple-darwin -std=c++11 -emit-llvm -o - | FileCheck %s
+// REQUIRES: x86-registered-target
+
+// CHECK: @b = global i32 0,
+
+// CHECK: define {{.*}}void @{{.*}}test{{.*}}_block_invoke(
+// CHECK: store i32 2, i32* @b,
+// CHECK: ret void
+
+int b;
+
+void test() {
+  int &a = b;
+  ^{ a = 2; };
+}