go/src/cmd/compile/internal/ssa/sizeof_test.go

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssa
import (
"reflect"
"testing"
"unsafe"
)
// Assert that the size of important structures do not change unexpectedly.
func TestSizeof(t *testing.T) {
const _64bit = unsafe.Sizeof(uintptr(0)) == 8
var tests = []struct {
val interface{} // type as a value
_32bit uintptr // size on 32bit platforms
_64bit uintptr // size on 64bit platforms
}{
cmd/compile: add wasm stack optimization Go's SSA instructions only operate on registers. For example, an add instruction would read two registers, do the addition and then write to a register. WebAssembly's instructions, on the other hand, operate on the stack. The add instruction first pops two values from the stack, does the addition, then pushes the result to the stack. To fulfill Go's semantics, one needs to map Go's single add instruction to 4 WebAssembly instructions: - Push the value of local variable A to the stack - Push the value of local variable B to the stack - Do addition - Write value from stack to local variable C Now consider that B was set to the constant 42 before the addition: - Push constant 42 to the stack - Write value from stack to local variable B This works, but is inefficient. Instead, the stack is used directly by inlining instructions if possible. With inlining it becomes: - Push the value of local variable A to the stack (add) - Push constant 42 to the stack (constant) - Do addition (add) - Write value from stack to local variable C (add) Note that the two SSA instructions can not be generated sequentially anymore, because their WebAssembly instructions are interleaved. Design doc: https://docs.google.com/document/d/131vjr4DH6JFnb-blm_uRdaC0_Nv3OUwjEY5qVCxCup4 Updates #18892 Change-Id: Ie35e1c0bebf4985fddda0d6330eb2066f9ad6dec Reviewed-on: https://go-review.googlesource.com/103535 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-03-09 00:14:58 +01:00
{Value{}, 72, 112},
cmd/compile: add SSA rules for s390x compare-and-branch instructions This commit adds SSA rules for the s390x combined compare-and-branch instructions. These have a shorter encoding than separate compare and branch instructions and they also don't clobber the condition code (a.k.a. flag register) reducing pressure on the flag allocator. I have deleted the 'loop_test.go' file and replaced it with a new codegen test which performs a wider range of checks. Object sizes from compilebench: name old object-bytes new object-bytes delta Template 562kB ± 0% 561kB ± 0% -0.28% (p=0.000 n=10+10) Unicode 217kB ± 0% 217kB ± 0% -0.17% (p=0.000 n=10+10) GoTypes 2.03MB ± 0% 2.02MB ± 0% -0.59% (p=0.000 n=10+10) Compiler 8.16MB ± 0% 8.11MB ± 0% -0.62% (p=0.000 n=10+10) SSA 27.4MB ± 0% 27.0MB ± 0% -1.45% (p=0.000 n=10+10) Flate 356kB ± 0% 356kB ± 0% -0.12% (p=0.000 n=10+10) GoParser 438kB ± 0% 436kB ± 0% -0.51% (p=0.000 n=10+10) Reflect 1.37MB ± 0% 1.37MB ± 0% -0.42% (p=0.000 n=10+10) Tar 485kB ± 0% 483kB ± 0% -0.39% (p=0.000 n=10+10) XML 630kB ± 0% 621kB ± 0% -1.45% (p=0.000 n=10+10) [Geo mean] 1.14MB 1.13MB -0.60% name old text-bytes new text-bytes delta HelloSize 763kB ± 0% 754kB ± 0% -1.30% (p=0.000 n=10+10) CmdGoSize 10.7MB ± 0% 10.6MB ± 0% -0.91% (p=0.000 n=10+10) [Geo mean] 2.86MB 2.82MB -1.10% Change-Id: Ibca55d9c0aa1254aee69433731ab5d26a43a7c18 Reviewed-on: https://go-review.googlesource.com/c/go/+/198037 Run-TryBot: Michael Munday <mike.munday@ibm.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
2019-09-17 07:29:31 -07:00
{Block{}, 164, 304},
{LocalSlot{}, 32, 48},
{valState{}, 28, 40},
}
for _, tt := range tests {
want := tt._32bit
if _64bit {
want = tt._64bit
}
got := reflect.TypeOf(tt.val).Size()
if want != got {
t.Errorf("unsafe.Sizeof(%T) = %d, want %d", tt.val, got, want)
}
}
}