[PR41157][OpenCL] Prevent implicit init of local addr space var in C+…

…+ mode.

Prevent adding initializers implicitly to variables declared in
local address space. This happens when they get converted into
global variables and therefore theoretically have to be default
initialized in C++.

Differential Revision: https://reviews.llvm.org/D59646

llvm-svn: 357684

clang/lib/Sema/SemaDecl.cpp

@@ -11682,7 +11682,11 @@ void Sema::ActOnUninitializedDecl(Decl *RealDecl) {
           setFunctionHasBranchProtectedScope();
       }
     }
-
+    // In OpenCL, we can't initialize objects in the __local address space,
+    // even implicitly, so don't synthesize an implicit initializer.
+    if (getLangOpts().OpenCL &&
+        Var->getType().getAddressSpace() == LangAS::opencl_local)
+      return;
     // C++03 [dcl.init]p9:
     //   If no initializer is specified for an object, and the
     //   object is of (possibly cv-qualified) non-POD class type (or

clang/test/CodeGenOpenCLCXX/addrspace-of-this.cl

@@ -150,15 +150,13 @@ __kernel void test__global() {
 TEST(__local)
 
 // COMMON-LABEL: _Z11test__localv
-// EXPL: @__cxa_guard_acquire
 
-// Test the address space of 'this' when invoking a constructor for an object in non-default address space
-// EXPL: call void @_ZNU3AS41CC1Ev(%class.C addrspace(4)* addrspacecast (%class.C addrspace(3)* @_ZZ11test__localvE1c to %class.C addrspace(4)*))
+// Test that we don't initialize an object in local address space.
+// EXPL-NOT: call void @_ZNU3AS41CC1Ev(%class.C addrspace(4)* addrspacecast (%class.C addrspace(3)* @_ZZ11test__localvE1c to %class.C addrspace(4)*))
 
 // Test the address space of 'this' when invoking a method.
 // COMMON: %call = call i32 @_ZNU3AS41C3getEv(%class.C addrspace(4)* addrspacecast (%class.C addrspace(3)* @_ZZ11test__localvE1c to %class.C addrspace(4)*))
 
-
 // Test the address space of 'this' when invoking copy-constructor.
 // COMMON: [[C1GEN:%[0-9]+]] = addrspacecast %class.C* %c1 to %class.C addrspace(4)*
 // EXPL: call void @_ZNU3AS41CC1ERU3AS4KS_(%class.C addrspace(4)* [[C1GEN]], %class.C addrspace(4)* dereferenceable(4) addrspacecast (%class.C addrspace(3)* @_ZZ11test__localvE1c to %class.C addrspace(4)*))

clang/test/CodeGenOpenCLCXX/local_addrspace_init.cl

@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 %s -triple spir -cl-std=c++ -emit-llvm -O0 -o - | FileCheck %s
+
+// Test that we don't initialize local address space objects.
+//CHECK: @_ZZ4testvE1i = internal addrspace(3) global i32 undef
+//CHECK: @_ZZ4testvE2ii = internal addrspace(3) global %class.C undef
+class C {
+  int i;
+};
+
+kernel void test() {
+  __local int i;
+  __local C ii;
+  // FIXME: In OpenCL C we don't accept initializers for local
+  // address space variables. User defined initialization could
+  // make sense, but would it mean that all work items need to
+  // execute it? Potentially disallowing any initialization would
+  // make things easier and assingments can be used to set specific
+  // values. This rules should make it consistent with OpenCL C.
+  //__local C c();
+}