6436a4abd7
Switch gofrontend to using go.googlesource.com, and update to 81eb6a3f425b2158c67ee32c0cc973a72ce9d6be. There are various changes required to update to the go 1.5 runtime: typemap.go is changed to accommodate the change in representation for equal/hash algorithms, and the removal of the zero value/type. CMakeLists.txt is updated to add the build tree to the package search path, so internal packages, which are not installed, are found. various files changes due to removal of __go_new_nopointers; the same change as in D11863, but with NoUnwindAttribute added to the added runtime functions which are called with "callOnly". minor cleanups in ssa.go while investigating issues with unwinding/panic handling. Differential Revisision: http://reviews.llvm.org/D15188 llvm-svn: 263536
82 lines
2.1 KiB
Go
82 lines
2.1 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package reflect_test
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import (
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"fmt"
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"io"
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"os"
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"reflect"
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)
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func ExampleMakeFunc() {
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// swap is the implementation passed to MakeFunc.
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// It must work in terms of reflect.Values so that it is possible
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// to write code without knowing beforehand what the types
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// will be.
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swap := func(in []reflect.Value) []reflect.Value {
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return []reflect.Value{in[1], in[0]}
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}
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// makeSwap expects fptr to be a pointer to a nil function.
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// It sets that pointer to a new function created with MakeFunc.
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// When the function is invoked, reflect turns the arguments
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// into Values, calls swap, and then turns swap's result slice
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// into the values returned by the new function.
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makeSwap := func(fptr interface{}) {
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// fptr is a pointer to a function.
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// Obtain the function value itself (likely nil) as a reflect.Value
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// so that we can query its type and then set the value.
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fn := reflect.ValueOf(fptr).Elem()
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// Make a function of the right type.
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v := reflect.MakeFunc(fn.Type(), swap)
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// Assign it to the value fn represents.
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fn.Set(v)
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}
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// Make and call a swap function for ints.
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var intSwap func(int, int) (int, int)
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makeSwap(&intSwap)
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fmt.Println(intSwap(0, 1))
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// Make and call a swap function for float64s.
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var floatSwap func(float64, float64) (float64, float64)
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makeSwap(&floatSwap)
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fmt.Println(floatSwap(2.72, 3.14))
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// Output:
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// 1 0
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// 3.14 2.72
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}
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func ExampleStructTag() {
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type S struct {
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F string `species:"gopher" color:"blue"`
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}
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s := S{}
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st := reflect.TypeOf(s)
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field := st.Field(0)
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fmt.Println(field.Tag.Get("color"), field.Tag.Get("species"))
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// Output:
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// blue gopher
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}
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func ExampleTypeOf() {
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// As interface types are only used for static typing, a
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// common idiom to find the reflection Type for an interface
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// type Foo is to use a *Foo value.
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writerType := reflect.TypeOf((*io.Writer)(nil)).Elem()
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fileType := reflect.TypeOf((*os.File)(nil))
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fmt.Println(fileType.Implements(writerType))
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// Output:
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// true
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}
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