[OpenCL] Set calling convention for -fdeclare-opencl-builtins

[svenvh]

Summary

IR produced using TableGen builtin function declarations
(fdeclare-opencl-builtins.cl) did not have the target's calling
convention applied to builtin calls.

Fix this, and update the codegen test to check that IR produced using
opencl-c.h and -fdeclare-opencl-builtins is identical with respect
to the builtin calls.

[Anastasia]

LGTM. Thanks!

clang/lib/Sema/SemaLookup.cpp

 ///        Only meaningful for generic types, otherwise equals 1.
 /// \param FunctionList (out) List of FunctionTypes.
 /// \param RetTypes (in) List of the possible return types.
 /// \param ArgTypes (in) List of the possible types for the arguments.
 static void GetOpenCLBuiltinFctOverloads(
     ASTContext &Context, unsigned GenTypeMaxCnt,
     std::vector<QualType> &FunctionList, SmallVector<QualType, 1> &RetTypes,
     SmallVector<SmallVector<QualType, 1>, 5> &ArgTypes) {
-  FunctionProtoType::ExtProtoInfo PI;
+  FunctionProtoType::ExtProtoInfo PI(
+      Context.getDefaultCallingConvention(false, false, true));
   PI.Variadic = false;
 
   // Create FunctionTypes for each (gen)type.
   for (unsigned IGenType = 0; IGenType < GenTypeMaxCnt; IGenType++) {
     SmallVector<QualType, 5> ArgList;
 
     for (unsigned A = 0; A < ArgTypes.size(); A++) {
       // Builtins such as "max" have an "sgentype" argument that represents

clang/test/CodeGenOpenCL/fdeclare-opencl-builtins.cl

+// RUN: %clang_cc1 -emit-llvm -o - -O0 -triple spir-unknown-unknown -cl-std=CL1.2 -finclude-default-header %s | FileCheck %s
 // RUN: %clang_cc1 -emit-llvm -o - -O0 -triple spir-unknown-unknown -cl-std=CL1.2 -fdeclare-opencl-builtins -finclude-default-header %s | FileCheck %s
 
 // Test that mix is correctly defined.
 // CHECK-LABEL: @test_float
-// CHECK: call <4 x float> @_Z3mixDv4_fS_f
+// CHECK: call spir_func <4 x float> @_Z3mixDv4_fS_f
 // CHECK: ret
 void test_float(float4 x, float a) {
   float4 ret = mix(x, x, a);
 }
 
 // Test that Attr.Const from OpenCLBuiltins.td is lowered to a readnone attribute.
 // CHECK-LABEL: @test_const_attr
-// CHECK: call i32 @_Z3maxii({{.*}}) [[ATTR_CONST:#[0-9]]]
+// CHECK: call spir_func i32 @_Z3maxii({{.*}}) [[ATTR_CONST:#[0-9]]]
 // CHECK: ret
 int test_const_attr(int a) {
   return max(a, 2);
 }
 
 // Test that Attr.Pure from OpenCLBuiltins.td is lowered to a readonly attribute.
 // CHECK-LABEL: @test_pure_attr
-// CHECK: call <4 x float> @_Z11read_imagef{{.*}} [[ATTR_PURE:#[0-9]]]
+// CHECK: call spir_func <4 x float> @_Z11read_imagef{{.*}} [[ATTR_PURE:#[0-9]]]
 // CHECK: ret
 kernel void test_pure_attr(read_only image1d_t img) {
   float4 resf = read_imagef(img, 42);
 }
 
 // Test that builtins with only one prototype are mangled.
 // CHECK-LABEL: @test_mangling
-// CHECK: call i32 @_Z12get_local_idj
+// CHECK: call spir_func i32 @_Z12get_local_idj
 kernel void test_mangling() {
   size_t lid = get_local_id(0);
 }
 
 // CHECK: attributes [[ATTR_CONST]] =
 // CHECK-SAME: readnone
 // CHECK: attributes [[ATTR_PURE]] =
 // CHECK-SAME: readonly