compiler: add func tests

This is basically just a golden test for the "switch" style of func
lowering. The next commit will make changes to this lowering, which will
be visible in the test output.

compiler/compiler_test.go

@@ -62,6 +62,7 @@ func TestCompiler(t *testing.T) {
 		"string.go",
 		"float.go",
 		"interface.go",
+		"func.go",
 	}
 
 	for _, testCase := range tests {

compiler/testdata/func.go

@@ -0,0 +1,12 @@
+package main
+
+func foo(callback func(int)) {
+	callback(3)
+}
+
+func bar() {
+	foo(someFunc)
+}
+
+func someFunc(int) {
+}

compiler/testdata/func.ll

@@ -0,0 +1,49 @@
+; ModuleID = 'func.go'
+source_filename = "func.go"
+target datalayout = "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-f64:32:64-f80:32-n8:16:32-S128"
+target triple = "i686--linux"
+
+%runtime.typecodeID = type { %runtime.typecodeID*, i32, %runtime.interfaceMethodInfo* }
+%runtime.interfaceMethodInfo = type { i8*, i32 }
+%runtime.funcValueWithSignature = type { i32, %runtime.typecodeID* }
+
+@"reflect/types.type:func:{basic:int}{}" = linkonce_odr constant %runtime.typecodeID zeroinitializer
+@"main.someFunc$withSignature" = linkonce_odr constant %runtime.funcValueWithSignature { i32 ptrtoint (void (i32, i8*, i8*)* @main.someFunc to i32), %runtime.typecodeID* @"reflect/types.type:func:{basic:int}{}" }
+
+declare noalias nonnull i8* @runtime.alloc(i32, i8*, i8*)
+
+define hidden void @main.init(i8* %context, i8* %parentHandle) unnamed_addr {
+entry:
+  ret void
+}
+
+define hidden void @main.foo(i8* %callback.context, i32 %callback.funcptr, i8* %context, i8* %parentHandle) unnamed_addr {
+entry:
+  %0 = call i32 @runtime.getFuncPtr(i8* %callback.context, i32 %callback.funcptr, %runtime.typecodeID* nonnull @"reflect/types.type:func:{basic:int}{}", i8* undef, i8* null)
+  %1 = icmp eq i32 %0, 0
+  br i1 %1, label %fpcall.throw, label %fpcall.next
+
+fpcall.throw:                                     ; preds = %entry
+  call void @runtime.nilPanic(i8* undef, i8* null)
+  unreachable
+
+fpcall.next:                                      ; preds = %entry
+  %2 = inttoptr i32 %0 to void (i32, i8*, i8*)*
+  call void %2(i32 3, i8* %callback.context, i8* undef)
+  ret void
+}
+
+declare i32 @runtime.getFuncPtr(i8*, i32, %runtime.typecodeID* dereferenceable_or_null(12), i8*, i8*)
+
+declare void @runtime.nilPanic(i8*, i8*)
+
+define hidden void @main.bar(i8* %context, i8* %parentHandle) unnamed_addr {
+entry:
+  call void @main.foo(i8* undef, i32 ptrtoint (%runtime.funcValueWithSignature* @"main.someFunc$withSignature" to i32), i8* undef, i8* undef)
+  ret void
+}
+
+define hidden void @main.someFunc(i32 %arg0, i8* %context, i8* %parentHandle) unnamed_addr {
+entry:
+  ret void
+}