transform: optimize reflect.Type Implements() method

This commit adds a new transform that converts reflect Implements()
calls to runtime.interfaceImplements. At the moment, the Implements()
method is not yet implemented (how ironic) but if the value passed to
Implements is known at compile time the method call can be optimized to
runtime.interfaceImplements to make it a regular interface assert.

This commit is the last change necessary to add basic support for the
encoding/json package. The json package is certainly not yet fully
supported, but some trivial objects can be converted to JSON.

1 files changed, 35 insertions, 0 deletions

diff --git a/transform/testdata/reflect-implements.out.ll b/transform/testdata/reflect-implements.out.ll
new file mode 100644
index 000000000..03d977699
--- /dev/null
+++ b/transform/testdata/reflect-implements.out.ll
@@ -0,0 +1,35 @@
+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 }
+
+@"reflect/types.type:named:error" = linkonce_odr constant %runtime.typecodeID { %runtime.typecodeID* @"reflect/types.type:interface:{Error:func:{}{basic:string}}", i32 0, %runtime.interfaceMethodInfo* null }
+@"reflect/types.type:interface:{Error:func:{}{basic:string}}" = linkonce_odr constant %runtime.typecodeID { %runtime.typecodeID* bitcast ([1 x i8*]* @"reflect/types.interface:interface{Error() string}$interface" to %runtime.typecodeID*), i32 0, %runtime.interfaceMethodInfo* null }
+@"func Error() string" = external constant i8
+@"reflect/types.interface:interface{Error() string}$interface" = linkonce_odr constant [1 x i8*] [i8* @"func Error() string"]
+@"func Align() int" = external constant i8
+@"func Implements(reflect.Type) bool" = external constant i8
+@"reflect.Type$interface" = linkonce_odr constant [2 x i8*] [i8* @"func Align() int", i8* @"func Implements(reflect.Type) bool"]
+@"reflect/types.type:named:reflect.rawType" = linkonce_odr constant %runtime.typecodeID { %runtime.typecodeID* @"reflect/types.type:basic:uintptr", i32 0, %runtime.interfaceMethodInfo* getelementptr inbounds ([20 x %runtime.interfaceMethodInfo], [20 x %runtime.interfaceMethodInfo]* @"reflect.rawType$methodset", i32 0, i32 0) }
+@"reflect.rawType$methodset" = linkonce_odr constant [20 x %runtime.interfaceMethodInfo] zeroinitializer
+@"reflect/types.type:basic:uintptr" = linkonce_odr constant %runtime.typecodeID zeroinitializer
+
+declare i1 @runtime.interfaceImplements(i32, i8**, i8*, i8*)
+
+declare i32 @runtime.interfaceMethod(i32, i8**, i8*, i8*, i8*)
+
+define i1 @main.isError(i32 %typ.typecode, i8* %typ.value, i8* %context, i8* %parentHandle) {
+entry:
+  %0 = ptrtoint i8* %typ.value to i32
+  %1 = call i1 @runtime.interfaceImplements(i32 %0, i8** getelementptr inbounds ([1 x i8*], [1 x i8*]* @"reflect/types.interface:interface{Error() string}$interface", i32 0, i32 0), i8* undef, i8* undef)
+  ret i1 %1
+}
+
+define i1 @main.isUnknown(i32 %typ.typecode, i8* %typ.value, i32 %itf.typecode, i8* %itf.value, i8* %context, i8* %parentHandle) {
+entry:
+  %invoke.func = call i32 @runtime.interfaceMethod(i32 %typ.typecode, i8** getelementptr inbounds ([2 x i8*], [2 x i8*]* @"reflect.Type$interface", i32 0, i32 0), i8* nonnull @"func Implements(reflect.Type) bool", i8* undef, i8* null)
+  %invoke.func.cast = inttoptr i32 %invoke.func to i1 (i8*, i32, i8*, i8*, i8*)*
+  %result = call i1 %invoke.func.cast(i8* %typ.value, i32 %itf.typecode, i8* %itf.value, i8* undef, i8* undef)
+  ret i1 %result
+}