[wasm] Add function pointer think tests

Author: turran

clang/test/CodeGenWebAssembly/function-pointer-arg.c

@@ -0,0 +1,25 @@
+// REQUIRES: webassembly-registered-target
+// RUN: %clang_cc1 -triple wasm32-unknown-unknown -emit-llvm -O1 -o - %s | FileCheck %s
+
+// Basic test of function pointer usage for wasm32
+
+#define FUNCTION_POINTER(f) ((FunctionPointer)(f))
+typedef int (*FunctionPointer)(int a, int b);
+
+int fp_as_arg(FunctionPointer fp, int a, int b) {
+  return fp(a, b);
+}
+
+int fp_less(int a) {
+  return a;
+}
+
+// CHECK-LABEL: @test
+// CHECK: call i32 @fp_as_arg(ptr noundef @__fp_less_iii, i32 noundef 10, i32 noundef 20)
+void test() {
+  return fp_as_arg(FUNCTION_POINTER(fp_less), 10, 20);
+}
+
+// CHECK: define internal i32 @__fp_less_iii(i32 %0, i32 %1)
+// CHECK: %2 = call i32 @fp_less(i32 %0)
+// CHECK: ret i32 %2