mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-11-24 04:36:38 +00:00
1186 lines
29 KiB
Go
1186 lines
29 KiB
Go
|
// Copyright 2018 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 wasm
|
||
|
|
||
|
import (
|
||
|
"bytes"
|
||
|
"github.com/twitchyliquid64/golang-asm/obj"
|
||
|
"github.com/twitchyliquid64/golang-asm/objabi"
|
||
|
"github.com/twitchyliquid64/golang-asm/sys"
|
||
|
"encoding/binary"
|
||
|
"fmt"
|
||
|
"io"
|
||
|
"math"
|
||
|
)
|
||
|
|
||
|
var Register = map[string]int16{
|
||
|
"SP": REG_SP,
|
||
|
"CTXT": REG_CTXT,
|
||
|
"g": REG_g,
|
||
|
"RET0": REG_RET0,
|
||
|
"RET1": REG_RET1,
|
||
|
"RET2": REG_RET2,
|
||
|
"RET3": REG_RET3,
|
||
|
"PAUSE": REG_PAUSE,
|
||
|
|
||
|
"R0": REG_R0,
|
||
|
"R1": REG_R1,
|
||
|
"R2": REG_R2,
|
||
|
"R3": REG_R3,
|
||
|
"R4": REG_R4,
|
||
|
"R5": REG_R5,
|
||
|
"R6": REG_R6,
|
||
|
"R7": REG_R7,
|
||
|
"R8": REG_R8,
|
||
|
"R9": REG_R9,
|
||
|
"R10": REG_R10,
|
||
|
"R11": REG_R11,
|
||
|
"R12": REG_R12,
|
||
|
"R13": REG_R13,
|
||
|
"R14": REG_R14,
|
||
|
"R15": REG_R15,
|
||
|
|
||
|
"F0": REG_F0,
|
||
|
"F1": REG_F1,
|
||
|
"F2": REG_F2,
|
||
|
"F3": REG_F3,
|
||
|
"F4": REG_F4,
|
||
|
"F5": REG_F5,
|
||
|
"F6": REG_F6,
|
||
|
"F7": REG_F7,
|
||
|
"F8": REG_F8,
|
||
|
"F9": REG_F9,
|
||
|
"F10": REG_F10,
|
||
|
"F11": REG_F11,
|
||
|
"F12": REG_F12,
|
||
|
"F13": REG_F13,
|
||
|
"F14": REG_F14,
|
||
|
"F15": REG_F15,
|
||
|
|
||
|
"F16": REG_F16,
|
||
|
"F17": REG_F17,
|
||
|
"F18": REG_F18,
|
||
|
"F19": REG_F19,
|
||
|
"F20": REG_F20,
|
||
|
"F21": REG_F21,
|
||
|
"F22": REG_F22,
|
||
|
"F23": REG_F23,
|
||
|
"F24": REG_F24,
|
||
|
"F25": REG_F25,
|
||
|
"F26": REG_F26,
|
||
|
"F27": REG_F27,
|
||
|
"F28": REG_F28,
|
||
|
"F29": REG_F29,
|
||
|
"F30": REG_F30,
|
||
|
"F31": REG_F31,
|
||
|
|
||
|
"PC_B": REG_PC_B,
|
||
|
}
|
||
|
|
||
|
var registerNames []string
|
||
|
|
||
|
func init() {
|
||
|
obj.RegisterRegister(MINREG, MAXREG, rconv)
|
||
|
obj.RegisterOpcode(obj.ABaseWasm, Anames)
|
||
|
|
||
|
registerNames = make([]string, MAXREG-MINREG)
|
||
|
for name, reg := range Register {
|
||
|
registerNames[reg-MINREG] = name
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func rconv(r int) string {
|
||
|
return registerNames[r-MINREG]
|
||
|
}
|
||
|
|
||
|
var unaryDst = map[obj.As]bool{
|
||
|
ASet: true,
|
||
|
ATee: true,
|
||
|
ACall: true,
|
||
|
ACallIndirect: true,
|
||
|
ACallImport: true,
|
||
|
ABr: true,
|
||
|
ABrIf: true,
|
||
|
ABrTable: true,
|
||
|
AI32Store: true,
|
||
|
AI64Store: true,
|
||
|
AF32Store: true,
|
||
|
AF64Store: true,
|
||
|
AI32Store8: true,
|
||
|
AI32Store16: true,
|
||
|
AI64Store8: true,
|
||
|
AI64Store16: true,
|
||
|
AI64Store32: true,
|
||
|
ACALLNORESUME: true,
|
||
|
}
|
||
|
|
||
|
var Linkwasm = obj.LinkArch{
|
||
|
Arch: sys.ArchWasm,
|
||
|
Init: instinit,
|
||
|
Preprocess: preprocess,
|
||
|
Assemble: assemble,
|
||
|
UnaryDst: unaryDst,
|
||
|
}
|
||
|
|
||
|
var (
|
||
|
morestack *obj.LSym
|
||
|
morestackNoCtxt *obj.LSym
|
||
|
gcWriteBarrier *obj.LSym
|
||
|
sigpanic *obj.LSym
|
||
|
sigpanic0 *obj.LSym
|
||
|
deferreturn *obj.LSym
|
||
|
jmpdefer *obj.LSym
|
||
|
)
|
||
|
|
||
|
const (
|
||
|
/* mark flags */
|
||
|
WasmImport = 1 << 0
|
||
|
)
|
||
|
|
||
|
func instinit(ctxt *obj.Link) {
|
||
|
morestack = ctxt.Lookup("runtime.morestack")
|
||
|
morestackNoCtxt = ctxt.Lookup("runtime.morestack_noctxt")
|
||
|
gcWriteBarrier = ctxt.Lookup("runtime.gcWriteBarrier")
|
||
|
sigpanic = ctxt.LookupABI("runtime.sigpanic", obj.ABIInternal)
|
||
|
sigpanic0 = ctxt.LookupABI("runtime.sigpanic", 0) // sigpanic called from assembly, which has ABI0
|
||
|
deferreturn = ctxt.LookupABI("runtime.deferreturn", obj.ABIInternal)
|
||
|
// jmpdefer is defined in assembly as ABI0, but what we're
|
||
|
// looking for is the *call* to jmpdefer from the Go function
|
||
|
// deferreturn, so we're looking for the ABIInternal version
|
||
|
// of jmpdefer that's called by Go.
|
||
|
jmpdefer = ctxt.LookupABI(`"".jmpdefer`, obj.ABIInternal)
|
||
|
}
|
||
|
|
||
|
func preprocess(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
|
||
|
appendp := func(p *obj.Prog, as obj.As, args ...obj.Addr) *obj.Prog {
|
||
|
if p.As != obj.ANOP {
|
||
|
p2 := obj.Appendp(p, newprog)
|
||
|
p2.Pc = p.Pc
|
||
|
p = p2
|
||
|
}
|
||
|
p.As = as
|
||
|
switch len(args) {
|
||
|
case 0:
|
||
|
p.From = obj.Addr{}
|
||
|
p.To = obj.Addr{}
|
||
|
case 1:
|
||
|
if unaryDst[as] {
|
||
|
p.From = obj.Addr{}
|
||
|
p.To = args[0]
|
||
|
} else {
|
||
|
p.From = args[0]
|
||
|
p.To = obj.Addr{}
|
||
|
}
|
||
|
case 2:
|
||
|
p.From = args[0]
|
||
|
p.To = args[1]
|
||
|
default:
|
||
|
panic("bad args")
|
||
|
}
|
||
|
return p
|
||
|
}
|
||
|
|
||
|
framesize := s.Func.Text.To.Offset
|
||
|
if framesize < 0 {
|
||
|
panic("bad framesize")
|
||
|
}
|
||
|
s.Func.Args = s.Func.Text.To.Val.(int32)
|
||
|
s.Func.Locals = int32(framesize)
|
||
|
|
||
|
if s.Func.Text.From.Sym.Wrapper() {
|
||
|
// if g._panic != nil && g._panic.argp == FP {
|
||
|
// g._panic.argp = bottom-of-frame
|
||
|
// }
|
||
|
//
|
||
|
// MOVD g_panic(g), R0
|
||
|
// Get R0
|
||
|
// I64Eqz
|
||
|
// Not
|
||
|
// If
|
||
|
// Get SP
|
||
|
// I64ExtendI32U
|
||
|
// I64Const $framesize+8
|
||
|
// I64Add
|
||
|
// I64Load panic_argp(R0)
|
||
|
// I64Eq
|
||
|
// If
|
||
|
// MOVD SP, panic_argp(R0)
|
||
|
// End
|
||
|
// End
|
||
|
|
||
|
gpanic := obj.Addr{
|
||
|
Type: obj.TYPE_MEM,
|
||
|
Reg: REGG,
|
||
|
Offset: 4 * 8, // g_panic
|
||
|
}
|
||
|
|
||
|
panicargp := obj.Addr{
|
||
|
Type: obj.TYPE_MEM,
|
||
|
Reg: REG_R0,
|
||
|
Offset: 0, // panic.argp
|
||
|
}
|
||
|
|
||
|
p := s.Func.Text
|
||
|
p = appendp(p, AMOVD, gpanic, regAddr(REG_R0))
|
||
|
|
||
|
p = appendp(p, AGet, regAddr(REG_R0))
|
||
|
p = appendp(p, AI64Eqz)
|
||
|
p = appendp(p, ANot)
|
||
|
p = appendp(p, AIf)
|
||
|
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, AI64ExtendI32U)
|
||
|
p = appendp(p, AI64Const, constAddr(framesize+8))
|
||
|
p = appendp(p, AI64Add)
|
||
|
p = appendp(p, AI64Load, panicargp)
|
||
|
|
||
|
p = appendp(p, AI64Eq)
|
||
|
p = appendp(p, AIf)
|
||
|
p = appendp(p, AMOVD, regAddr(REG_SP), panicargp)
|
||
|
p = appendp(p, AEnd)
|
||
|
|
||
|
p = appendp(p, AEnd)
|
||
|
}
|
||
|
|
||
|
if framesize > 0 {
|
||
|
p := s.Func.Text
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, AI32Const, constAddr(framesize))
|
||
|
p = appendp(p, AI32Sub)
|
||
|
p = appendp(p, ASet, regAddr(REG_SP))
|
||
|
p.Spadj = int32(framesize)
|
||
|
}
|
||
|
|
||
|
// Introduce resume points for CALL instructions
|
||
|
// and collect other explicit resume points.
|
||
|
numResumePoints := 0
|
||
|
explicitBlockDepth := 0
|
||
|
pc := int64(0) // pc is only incremented when necessary, this avoids bloat of the BrTable instruction
|
||
|
var tableIdxs []uint64
|
||
|
tablePC := int64(0)
|
||
|
base := ctxt.PosTable.Pos(s.Func.Text.Pos).Base()
|
||
|
for p := s.Func.Text; p != nil; p = p.Link {
|
||
|
prevBase := base
|
||
|
base = ctxt.PosTable.Pos(p.Pos).Base()
|
||
|
switch p.As {
|
||
|
case ABlock, ALoop, AIf:
|
||
|
explicitBlockDepth++
|
||
|
|
||
|
case AEnd:
|
||
|
if explicitBlockDepth == 0 {
|
||
|
panic("End without block")
|
||
|
}
|
||
|
explicitBlockDepth--
|
||
|
|
||
|
case ARESUMEPOINT:
|
||
|
if explicitBlockDepth != 0 {
|
||
|
panic("RESUME can only be used on toplevel")
|
||
|
}
|
||
|
p.As = AEnd
|
||
|
for tablePC <= pc {
|
||
|
tableIdxs = append(tableIdxs, uint64(numResumePoints))
|
||
|
tablePC++
|
||
|
}
|
||
|
numResumePoints++
|
||
|
pc++
|
||
|
|
||
|
case obj.ACALL:
|
||
|
if explicitBlockDepth != 0 {
|
||
|
panic("CALL can only be used on toplevel, try CALLNORESUME instead")
|
||
|
}
|
||
|
appendp(p, ARESUMEPOINT)
|
||
|
}
|
||
|
|
||
|
p.Pc = pc
|
||
|
|
||
|
// Increase pc whenever some pc-value table needs a new entry. Don't increase it
|
||
|
// more often to avoid bloat of the BrTable instruction.
|
||
|
// The "base != prevBase" condition detects inlined instructions. They are an
|
||
|
// implicit call, so entering and leaving this section affects the stack trace.
|
||
|
if p.As == ACALLNORESUME || p.As == obj.ANOP || p.As == ANop || p.Spadj != 0 || base != prevBase {
|
||
|
pc++
|
||
|
if p.To.Sym == sigpanic {
|
||
|
// The panic stack trace expects the PC at the call of sigpanic,
|
||
|
// not the next one. However, runtime.Caller subtracts 1 from the
|
||
|
// PC. To make both PC and PC-1 work (have the same line number),
|
||
|
// we advance the PC by 2 at sigpanic.
|
||
|
pc++
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
tableIdxs = append(tableIdxs, uint64(numResumePoints))
|
||
|
s.Size = pc + 1
|
||
|
|
||
|
if !s.Func.Text.From.Sym.NoSplit() {
|
||
|
p := s.Func.Text
|
||
|
|
||
|
if framesize <= objabi.StackSmall {
|
||
|
// small stack: SP <= stackguard
|
||
|
// Get SP
|
||
|
// Get g
|
||
|
// I32WrapI64
|
||
|
// I32Load $stackguard0
|
||
|
// I32GtU
|
||
|
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, AGet, regAddr(REGG))
|
||
|
p = appendp(p, AI32WrapI64)
|
||
|
p = appendp(p, AI32Load, constAddr(2*int64(ctxt.Arch.PtrSize))) // G.stackguard0
|
||
|
p = appendp(p, AI32LeU)
|
||
|
} else {
|
||
|
// large stack: SP-framesize <= stackguard-StackSmall
|
||
|
// SP <= stackguard+(framesize-StackSmall)
|
||
|
// Get SP
|
||
|
// Get g
|
||
|
// I32WrapI64
|
||
|
// I32Load $stackguard0
|
||
|
// I32Const $(framesize-StackSmall)
|
||
|
// I32Add
|
||
|
// I32GtU
|
||
|
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, AGet, regAddr(REGG))
|
||
|
p = appendp(p, AI32WrapI64)
|
||
|
p = appendp(p, AI32Load, constAddr(2*int64(ctxt.Arch.PtrSize))) // G.stackguard0
|
||
|
p = appendp(p, AI32Const, constAddr(int64(framesize)-objabi.StackSmall))
|
||
|
p = appendp(p, AI32Add)
|
||
|
p = appendp(p, AI32LeU)
|
||
|
}
|
||
|
// TODO(neelance): handle wraparound case
|
||
|
|
||
|
p = appendp(p, AIf)
|
||
|
p = appendp(p, obj.ACALL, constAddr(0))
|
||
|
if s.Func.Text.From.Sym.NeedCtxt() {
|
||
|
p.To = obj.Addr{Type: obj.TYPE_MEM, Name: obj.NAME_EXTERN, Sym: morestack}
|
||
|
} else {
|
||
|
p.To = obj.Addr{Type: obj.TYPE_MEM, Name: obj.NAME_EXTERN, Sym: morestackNoCtxt}
|
||
|
}
|
||
|
p = appendp(p, AEnd)
|
||
|
}
|
||
|
|
||
|
// record the branches targeting the entry loop and the unwind exit,
|
||
|
// their targets with be filled in later
|
||
|
var entryPointLoopBranches []*obj.Prog
|
||
|
var unwindExitBranches []*obj.Prog
|
||
|
currentDepth := 0
|
||
|
for p := s.Func.Text; p != nil; p = p.Link {
|
||
|
switch p.As {
|
||
|
case ABlock, ALoop, AIf:
|
||
|
currentDepth++
|
||
|
case AEnd:
|
||
|
currentDepth--
|
||
|
}
|
||
|
|
||
|
switch p.As {
|
||
|
case obj.AJMP:
|
||
|
jmp := *p
|
||
|
p.As = obj.ANOP
|
||
|
|
||
|
if jmp.To.Type == obj.TYPE_BRANCH {
|
||
|
// jump to basic block
|
||
|
p = appendp(p, AI32Const, constAddr(jmp.To.Val.(*obj.Prog).Pc))
|
||
|
p = appendp(p, ASet, regAddr(REG_PC_B)) // write next basic block to PC_B
|
||
|
p = appendp(p, ABr) // jump to beginning of entryPointLoop
|
||
|
entryPointLoopBranches = append(entryPointLoopBranches, p)
|
||
|
break
|
||
|
}
|
||
|
|
||
|
// low-level WebAssembly call to function
|
||
|
switch jmp.To.Type {
|
||
|
case obj.TYPE_MEM:
|
||
|
if !notUsePC_B[jmp.To.Sym.Name] {
|
||
|
// Set PC_B parameter to function entry.
|
||
|
p = appendp(p, AI32Const, constAddr(0))
|
||
|
}
|
||
|
p = appendp(p, ACall, jmp.To)
|
||
|
|
||
|
case obj.TYPE_NONE:
|
||
|
// (target PC is on stack)
|
||
|
p = appendp(p, AI32WrapI64)
|
||
|
p = appendp(p, AI32Const, constAddr(16)) // only needs PC_F bits (16-31), PC_B bits (0-15) are zero
|
||
|
p = appendp(p, AI32ShrU)
|
||
|
|
||
|
// Set PC_B parameter to function entry.
|
||
|
// We need to push this before pushing the target PC_F,
|
||
|
// so temporarily pop PC_F, using our REG_PC_B as a
|
||
|
// scratch register, and push it back after pushing 0.
|
||
|
p = appendp(p, ASet, regAddr(REG_PC_B))
|
||
|
p = appendp(p, AI32Const, constAddr(0))
|
||
|
p = appendp(p, AGet, regAddr(REG_PC_B))
|
||
|
|
||
|
p = appendp(p, ACallIndirect)
|
||
|
|
||
|
default:
|
||
|
panic("bad target for JMP")
|
||
|
}
|
||
|
|
||
|
p = appendp(p, AReturn)
|
||
|
|
||
|
case obj.ACALL, ACALLNORESUME:
|
||
|
call := *p
|
||
|
p.As = obj.ANOP
|
||
|
|
||
|
pcAfterCall := call.Link.Pc
|
||
|
if call.To.Sym == sigpanic {
|
||
|
pcAfterCall-- // sigpanic expects to be called without advancing the pc
|
||
|
}
|
||
|
|
||
|
// jmpdefer manipulates the return address on the stack so deferreturn gets called repeatedly.
|
||
|
// Model this in WebAssembly with a loop.
|
||
|
if call.To.Sym == deferreturn {
|
||
|
p = appendp(p, ALoop)
|
||
|
}
|
||
|
|
||
|
// SP -= 8
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, AI32Const, constAddr(8))
|
||
|
p = appendp(p, AI32Sub)
|
||
|
p = appendp(p, ASet, regAddr(REG_SP))
|
||
|
|
||
|
// write return address to Go stack
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, AI64Const, obj.Addr{
|
||
|
Type: obj.TYPE_ADDR,
|
||
|
Name: obj.NAME_EXTERN,
|
||
|
Sym: s, // PC_F
|
||
|
Offset: pcAfterCall, // PC_B
|
||
|
})
|
||
|
p = appendp(p, AI64Store, constAddr(0))
|
||
|
|
||
|
// low-level WebAssembly call to function
|
||
|
switch call.To.Type {
|
||
|
case obj.TYPE_MEM:
|
||
|
if !notUsePC_B[call.To.Sym.Name] {
|
||
|
// Set PC_B parameter to function entry.
|
||
|
p = appendp(p, AI32Const, constAddr(0))
|
||
|
}
|
||
|
p = appendp(p, ACall, call.To)
|
||
|
|
||
|
case obj.TYPE_NONE:
|
||
|
// (target PC is on stack)
|
||
|
p = appendp(p, AI32WrapI64)
|
||
|
p = appendp(p, AI32Const, constAddr(16)) // only needs PC_F bits (16-31), PC_B bits (0-15) are zero
|
||
|
p = appendp(p, AI32ShrU)
|
||
|
|
||
|
// Set PC_B parameter to function entry.
|
||
|
// We need to push this before pushing the target PC_F,
|
||
|
// so temporarily pop PC_F, using our PC_B as a
|
||
|
// scratch register, and push it back after pushing 0.
|
||
|
p = appendp(p, ASet, regAddr(REG_PC_B))
|
||
|
p = appendp(p, AI32Const, constAddr(0))
|
||
|
p = appendp(p, AGet, regAddr(REG_PC_B))
|
||
|
|
||
|
p = appendp(p, ACallIndirect)
|
||
|
|
||
|
default:
|
||
|
panic("bad target for CALL")
|
||
|
}
|
||
|
|
||
|
// gcWriteBarrier has no return value, it never unwinds the stack
|
||
|
if call.To.Sym == gcWriteBarrier {
|
||
|
break
|
||
|
}
|
||
|
|
||
|
// jmpdefer removes the frame of deferreturn from the Go stack.
|
||
|
// However, its WebAssembly function still returns normally,
|
||
|
// so we need to return from deferreturn without removing its
|
||
|
// stack frame (no RET), because the frame is already gone.
|
||
|
if call.To.Sym == jmpdefer {
|
||
|
p = appendp(p, AReturn)
|
||
|
break
|
||
|
}
|
||
|
|
||
|
// return value of call is on the top of the stack, indicating whether to unwind the WebAssembly stack
|
||
|
if call.As == ACALLNORESUME && call.To.Sym != sigpanic && call.To.Sym != sigpanic0 { // sigpanic unwinds the stack, but it never resumes
|
||
|
// trying to unwind WebAssembly stack but call has no resume point, terminate with error
|
||
|
p = appendp(p, AIf)
|
||
|
p = appendp(p, obj.AUNDEF)
|
||
|
p = appendp(p, AEnd)
|
||
|
} else {
|
||
|
// unwinding WebAssembly stack to switch goroutine, return 1
|
||
|
p = appendp(p, ABrIf)
|
||
|
unwindExitBranches = append(unwindExitBranches, p)
|
||
|
}
|
||
|
|
||
|
// jump to before the call if jmpdefer has reset the return address to the call's PC
|
||
|
if call.To.Sym == deferreturn {
|
||
|
// get PC_B from -8(SP)
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, AI32Const, constAddr(8))
|
||
|
p = appendp(p, AI32Sub)
|
||
|
p = appendp(p, AI32Load16U, constAddr(0))
|
||
|
p = appendp(p, ATee, regAddr(REG_PC_B))
|
||
|
|
||
|
p = appendp(p, AI32Const, constAddr(call.Pc))
|
||
|
p = appendp(p, AI32Eq)
|
||
|
p = appendp(p, ABrIf, constAddr(0))
|
||
|
p = appendp(p, AEnd) // end of Loop
|
||
|
}
|
||
|
|
||
|
case obj.ARET, ARETUNWIND:
|
||
|
ret := *p
|
||
|
p.As = obj.ANOP
|
||
|
|
||
|
if framesize > 0 {
|
||
|
// SP += framesize
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, AI32Const, constAddr(framesize))
|
||
|
p = appendp(p, AI32Add)
|
||
|
p = appendp(p, ASet, regAddr(REG_SP))
|
||
|
// TODO(neelance): This should theoretically set Spadj, but it only works without.
|
||
|
// p.Spadj = int32(-framesize)
|
||
|
}
|
||
|
|
||
|
if ret.To.Type == obj.TYPE_MEM {
|
||
|
// Set PC_B parameter to function entry.
|
||
|
p = appendp(p, AI32Const, constAddr(0))
|
||
|
|
||
|
// low-level WebAssembly call to function
|
||
|
p = appendp(p, ACall, ret.To)
|
||
|
p = appendp(p, AReturn)
|
||
|
break
|
||
|
}
|
||
|
|
||
|
// SP += 8
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, AI32Const, constAddr(8))
|
||
|
p = appendp(p, AI32Add)
|
||
|
p = appendp(p, ASet, regAddr(REG_SP))
|
||
|
|
||
|
if ret.As == ARETUNWIND {
|
||
|
// function needs to unwind the WebAssembly stack, return 1
|
||
|
p = appendp(p, AI32Const, constAddr(1))
|
||
|
p = appendp(p, AReturn)
|
||
|
break
|
||
|
}
|
||
|
|
||
|
// not unwinding the WebAssembly stack, return 0
|
||
|
p = appendp(p, AI32Const, constAddr(0))
|
||
|
p = appendp(p, AReturn)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
for p := s.Func.Text; p != nil; p = p.Link {
|
||
|
switch p.From.Name {
|
||
|
case obj.NAME_AUTO:
|
||
|
p.From.Offset += int64(framesize)
|
||
|
case obj.NAME_PARAM:
|
||
|
p.From.Reg = REG_SP
|
||
|
p.From.Offset += int64(framesize) + 8 // parameters are after the frame and the 8-byte return address
|
||
|
}
|
||
|
|
||
|
switch p.To.Name {
|
||
|
case obj.NAME_AUTO:
|
||
|
p.To.Offset += int64(framesize)
|
||
|
case obj.NAME_PARAM:
|
||
|
p.To.Reg = REG_SP
|
||
|
p.To.Offset += int64(framesize) + 8 // parameters are after the frame and the 8-byte return address
|
||
|
}
|
||
|
|
||
|
switch p.As {
|
||
|
case AGet:
|
||
|
if p.From.Type == obj.TYPE_ADDR {
|
||
|
get := *p
|
||
|
p.As = obj.ANOP
|
||
|
|
||
|
switch get.From.Name {
|
||
|
case obj.NAME_EXTERN:
|
||
|
p = appendp(p, AI64Const, get.From)
|
||
|
case obj.NAME_AUTO, obj.NAME_PARAM:
|
||
|
p = appendp(p, AGet, regAddr(get.From.Reg))
|
||
|
if get.From.Reg == REG_SP {
|
||
|
p = appendp(p, AI64ExtendI32U)
|
||
|
}
|
||
|
if get.From.Offset != 0 {
|
||
|
p = appendp(p, AI64Const, constAddr(get.From.Offset))
|
||
|
p = appendp(p, AI64Add)
|
||
|
}
|
||
|
default:
|
||
|
panic("bad Get: invalid name")
|
||
|
}
|
||
|
}
|
||
|
|
||
|
case AI32Load, AI64Load, AF32Load, AF64Load, AI32Load8S, AI32Load8U, AI32Load16S, AI32Load16U, AI64Load8S, AI64Load8U, AI64Load16S, AI64Load16U, AI64Load32S, AI64Load32U:
|
||
|
if p.From.Type == obj.TYPE_MEM {
|
||
|
as := p.As
|
||
|
from := p.From
|
||
|
|
||
|
p.As = AGet
|
||
|
p.From = regAddr(from.Reg)
|
||
|
|
||
|
if from.Reg != REG_SP {
|
||
|
p = appendp(p, AI32WrapI64)
|
||
|
}
|
||
|
|
||
|
p = appendp(p, as, constAddr(from.Offset))
|
||
|
}
|
||
|
|
||
|
case AMOVB, AMOVH, AMOVW, AMOVD:
|
||
|
mov := *p
|
||
|
p.As = obj.ANOP
|
||
|
|
||
|
var loadAs obj.As
|
||
|
var storeAs obj.As
|
||
|
switch mov.As {
|
||
|
case AMOVB:
|
||
|
loadAs = AI64Load8U
|
||
|
storeAs = AI64Store8
|
||
|
case AMOVH:
|
||
|
loadAs = AI64Load16U
|
||
|
storeAs = AI64Store16
|
||
|
case AMOVW:
|
||
|
loadAs = AI64Load32U
|
||
|
storeAs = AI64Store32
|
||
|
case AMOVD:
|
||
|
loadAs = AI64Load
|
||
|
storeAs = AI64Store
|
||
|
}
|
||
|
|
||
|
appendValue := func() {
|
||
|
switch mov.From.Type {
|
||
|
case obj.TYPE_CONST:
|
||
|
p = appendp(p, AI64Const, constAddr(mov.From.Offset))
|
||
|
|
||
|
case obj.TYPE_ADDR:
|
||
|
switch mov.From.Name {
|
||
|
case obj.NAME_NONE, obj.NAME_PARAM, obj.NAME_AUTO:
|
||
|
p = appendp(p, AGet, regAddr(mov.From.Reg))
|
||
|
if mov.From.Reg == REG_SP {
|
||
|
p = appendp(p, AI64ExtendI32U)
|
||
|
}
|
||
|
p = appendp(p, AI64Const, constAddr(mov.From.Offset))
|
||
|
p = appendp(p, AI64Add)
|
||
|
case obj.NAME_EXTERN:
|
||
|
p = appendp(p, AI64Const, mov.From)
|
||
|
default:
|
||
|
panic("bad name for MOV")
|
||
|
}
|
||
|
|
||
|
case obj.TYPE_REG:
|
||
|
p = appendp(p, AGet, mov.From)
|
||
|
if mov.From.Reg == REG_SP {
|
||
|
p = appendp(p, AI64ExtendI32U)
|
||
|
}
|
||
|
|
||
|
case obj.TYPE_MEM:
|
||
|
p = appendp(p, AGet, regAddr(mov.From.Reg))
|
||
|
if mov.From.Reg != REG_SP {
|
||
|
p = appendp(p, AI32WrapI64)
|
||
|
}
|
||
|
p = appendp(p, loadAs, constAddr(mov.From.Offset))
|
||
|
|
||
|
default:
|
||
|
panic("bad MOV type")
|
||
|
}
|
||
|
}
|
||
|
|
||
|
switch mov.To.Type {
|
||
|
case obj.TYPE_REG:
|
||
|
appendValue()
|
||
|
if mov.To.Reg == REG_SP {
|
||
|
p = appendp(p, AI32WrapI64)
|
||
|
}
|
||
|
p = appendp(p, ASet, mov.To)
|
||
|
|
||
|
case obj.TYPE_MEM:
|
||
|
switch mov.To.Name {
|
||
|
case obj.NAME_NONE, obj.NAME_PARAM:
|
||
|
p = appendp(p, AGet, regAddr(mov.To.Reg))
|
||
|
if mov.To.Reg != REG_SP {
|
||
|
p = appendp(p, AI32WrapI64)
|
||
|
}
|
||
|
case obj.NAME_EXTERN:
|
||
|
p = appendp(p, AI32Const, obj.Addr{Type: obj.TYPE_ADDR, Name: obj.NAME_EXTERN, Sym: mov.To.Sym})
|
||
|
default:
|
||
|
panic("bad MOV name")
|
||
|
}
|
||
|
appendValue()
|
||
|
p = appendp(p, storeAs, constAddr(mov.To.Offset))
|
||
|
|
||
|
default:
|
||
|
panic("bad MOV type")
|
||
|
}
|
||
|
|
||
|
case ACallImport:
|
||
|
p.As = obj.ANOP
|
||
|
p = appendp(p, AGet, regAddr(REG_SP))
|
||
|
p = appendp(p, ACall, obj.Addr{Type: obj.TYPE_MEM, Name: obj.NAME_EXTERN, Sym: s})
|
||
|
p.Mark = WasmImport
|
||
|
}
|
||
|
}
|
||
|
|
||
|
{
|
||
|
p := s.Func.Text
|
||
|
if len(unwindExitBranches) > 0 {
|
||
|
p = appendp(p, ABlock) // unwindExit, used to return 1 when unwinding the stack
|
||
|
for _, b := range unwindExitBranches {
|
||
|
b.To = obj.Addr{Type: obj.TYPE_BRANCH, Val: p}
|
||
|
}
|
||
|
}
|
||
|
if len(entryPointLoopBranches) > 0 {
|
||
|
p = appendp(p, ALoop) // entryPointLoop, used to jump between basic blocks
|
||
|
for _, b := range entryPointLoopBranches {
|
||
|
b.To = obj.Addr{Type: obj.TYPE_BRANCH, Val: p}
|
||
|
}
|
||
|
}
|
||
|
if numResumePoints > 0 {
|
||
|
// Add Block instructions for resume points and BrTable to jump to selected resume point.
|
||
|
for i := 0; i < numResumePoints+1; i++ {
|
||
|
p = appendp(p, ABlock)
|
||
|
}
|
||
|
p = appendp(p, AGet, regAddr(REG_PC_B)) // read next basic block from PC_B
|
||
|
p = appendp(p, ABrTable, obj.Addr{Val: tableIdxs})
|
||
|
p = appendp(p, AEnd) // end of Block
|
||
|
}
|
||
|
for p.Link != nil {
|
||
|
p = p.Link // function instructions
|
||
|
}
|
||
|
if len(entryPointLoopBranches) > 0 {
|
||
|
p = appendp(p, AEnd) // end of entryPointLoop
|
||
|
}
|
||
|
p = appendp(p, obj.AUNDEF)
|
||
|
if len(unwindExitBranches) > 0 {
|
||
|
p = appendp(p, AEnd) // end of unwindExit
|
||
|
p = appendp(p, AI32Const, constAddr(1))
|
||
|
}
|
||
|
}
|
||
|
|
||
|
currentDepth = 0
|
||
|
blockDepths := make(map[*obj.Prog]int)
|
||
|
for p := s.Func.Text; p != nil; p = p.Link {
|
||
|
switch p.As {
|
||
|
case ABlock, ALoop, AIf:
|
||
|
currentDepth++
|
||
|
blockDepths[p] = currentDepth
|
||
|
case AEnd:
|
||
|
currentDepth--
|
||
|
}
|
||
|
|
||
|
switch p.As {
|
||
|
case ABr, ABrIf:
|
||
|
if p.To.Type == obj.TYPE_BRANCH {
|
||
|
blockDepth, ok := blockDepths[p.To.Val.(*obj.Prog)]
|
||
|
if !ok {
|
||
|
panic("label not at block")
|
||
|
}
|
||
|
p.To = constAddr(int64(currentDepth - blockDepth))
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func constAddr(value int64) obj.Addr {
|
||
|
return obj.Addr{Type: obj.TYPE_CONST, Offset: value}
|
||
|
}
|
||
|
|
||
|
func regAddr(reg int16) obj.Addr {
|
||
|
return obj.Addr{Type: obj.TYPE_REG, Reg: reg}
|
||
|
}
|
||
|
|
||
|
// Most of the Go functions has a single parameter (PC_B) in
|
||
|
// Wasm ABI. This is a list of exceptions.
|
||
|
var notUsePC_B = map[string]bool{
|
||
|
"_rt0_wasm_js": true,
|
||
|
"wasm_export_run": true,
|
||
|
"wasm_export_resume": true,
|
||
|
"wasm_export_getsp": true,
|
||
|
"wasm_pc_f_loop": true,
|
||
|
"runtime.wasmMove": true,
|
||
|
"runtime.wasmZero": true,
|
||
|
"runtime.wasmDiv": true,
|
||
|
"runtime.wasmTruncS": true,
|
||
|
"runtime.wasmTruncU": true,
|
||
|
"runtime.gcWriteBarrier": true,
|
||
|
"cmpbody": true,
|
||
|
"memeqbody": true,
|
||
|
"memcmp": true,
|
||
|
"memchr": true,
|
||
|
}
|
||
|
|
||
|
func assemble(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
|
||
|
type regVar struct {
|
||
|
global bool
|
||
|
index uint64
|
||
|
}
|
||
|
|
||
|
type varDecl struct {
|
||
|
count uint64
|
||
|
typ valueType
|
||
|
}
|
||
|
|
||
|
hasLocalSP := false
|
||
|
regVars := [MAXREG - MINREG]*regVar{
|
||
|
REG_SP - MINREG: {true, 0},
|
||
|
REG_CTXT - MINREG: {true, 1},
|
||
|
REG_g - MINREG: {true, 2},
|
||
|
REG_RET0 - MINREG: {true, 3},
|
||
|
REG_RET1 - MINREG: {true, 4},
|
||
|
REG_RET2 - MINREG: {true, 5},
|
||
|
REG_RET3 - MINREG: {true, 6},
|
||
|
REG_PAUSE - MINREG: {true, 7},
|
||
|
}
|
||
|
var varDecls []*varDecl
|
||
|
useAssemblyRegMap := func() {
|
||
|
for i := int16(0); i < 16; i++ {
|
||
|
regVars[REG_R0+i-MINREG] = ®Var{false, uint64(i)}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Function starts with declaration of locals: numbers and types.
|
||
|
// Some functions use a special calling convention.
|
||
|
switch s.Name {
|
||
|
case "_rt0_wasm_js", "wasm_export_run", "wasm_export_resume", "wasm_export_getsp", "wasm_pc_f_loop",
|
||
|
"runtime.wasmMove", "runtime.wasmZero", "runtime.wasmDiv", "runtime.wasmTruncS", "runtime.wasmTruncU", "memeqbody":
|
||
|
varDecls = []*varDecl{}
|
||
|
useAssemblyRegMap()
|
||
|
case "memchr", "memcmp":
|
||
|
varDecls = []*varDecl{{count: 2, typ: i32}}
|
||
|
useAssemblyRegMap()
|
||
|
case "cmpbody":
|
||
|
varDecls = []*varDecl{{count: 2, typ: i64}}
|
||
|
useAssemblyRegMap()
|
||
|
case "runtime.gcWriteBarrier":
|
||
|
varDecls = []*varDecl{{count: 4, typ: i64}}
|
||
|
useAssemblyRegMap()
|
||
|
default:
|
||
|
// Normal calling convention: PC_B as WebAssembly parameter. First local variable is local SP cache.
|
||
|
regVars[REG_PC_B-MINREG] = ®Var{false, 0}
|
||
|
hasLocalSP = true
|
||
|
|
||
|
var regUsed [MAXREG - MINREG]bool
|
||
|
for p := s.Func.Text; p != nil; p = p.Link {
|
||
|
if p.From.Reg != 0 {
|
||
|
regUsed[p.From.Reg-MINREG] = true
|
||
|
}
|
||
|
if p.To.Reg != 0 {
|
||
|
regUsed[p.To.Reg-MINREG] = true
|
||
|
}
|
||
|
}
|
||
|
|
||
|
regs := []int16{REG_SP}
|
||
|
for reg := int16(REG_R0); reg <= REG_F31; reg++ {
|
||
|
if regUsed[reg-MINREG] {
|
||
|
regs = append(regs, reg)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
var lastDecl *varDecl
|
||
|
for i, reg := range regs {
|
||
|
t := regType(reg)
|
||
|
if lastDecl == nil || lastDecl.typ != t {
|
||
|
lastDecl = &varDecl{
|
||
|
count: 0,
|
||
|
typ: t,
|
||
|
}
|
||
|
varDecls = append(varDecls, lastDecl)
|
||
|
}
|
||
|
lastDecl.count++
|
||
|
if reg != REG_SP {
|
||
|
regVars[reg-MINREG] = ®Var{false, 1 + uint64(i)}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
w := new(bytes.Buffer)
|
||
|
|
||
|
writeUleb128(w, uint64(len(varDecls)))
|
||
|
for _, decl := range varDecls {
|
||
|
writeUleb128(w, decl.count)
|
||
|
w.WriteByte(byte(decl.typ))
|
||
|
}
|
||
|
|
||
|
if hasLocalSP {
|
||
|
// Copy SP from its global variable into a local variable. Accessing a local variable is more efficient.
|
||
|
updateLocalSP(w)
|
||
|
}
|
||
|
|
||
|
for p := s.Func.Text; p != nil; p = p.Link {
|
||
|
switch p.As {
|
||
|
case AGet:
|
||
|
if p.From.Type != obj.TYPE_REG {
|
||
|
panic("bad Get: argument is not a register")
|
||
|
}
|
||
|
reg := p.From.Reg
|
||
|
v := regVars[reg-MINREG]
|
||
|
if v == nil {
|
||
|
panic("bad Get: invalid register")
|
||
|
}
|
||
|
if reg == REG_SP && hasLocalSP {
|
||
|
writeOpcode(w, ALocalGet)
|
||
|
writeUleb128(w, 1) // local SP
|
||
|
continue
|
||
|
}
|
||
|
if v.global {
|
||
|
writeOpcode(w, AGlobalGet)
|
||
|
} else {
|
||
|
writeOpcode(w, ALocalGet)
|
||
|
}
|
||
|
writeUleb128(w, v.index)
|
||
|
continue
|
||
|
|
||
|
case ASet:
|
||
|
if p.To.Type != obj.TYPE_REG {
|
||
|
panic("bad Set: argument is not a register")
|
||
|
}
|
||
|
reg := p.To.Reg
|
||
|
v := regVars[reg-MINREG]
|
||
|
if v == nil {
|
||
|
panic("bad Set: invalid register")
|
||
|
}
|
||
|
if reg == REG_SP && hasLocalSP {
|
||
|
writeOpcode(w, ALocalTee)
|
||
|
writeUleb128(w, 1) // local SP
|
||
|
}
|
||
|
if v.global {
|
||
|
writeOpcode(w, AGlobalSet)
|
||
|
} else {
|
||
|
if p.Link.As == AGet && p.Link.From.Reg == reg {
|
||
|
writeOpcode(w, ALocalTee)
|
||
|
p = p.Link
|
||
|
} else {
|
||
|
writeOpcode(w, ALocalSet)
|
||
|
}
|
||
|
}
|
||
|
writeUleb128(w, v.index)
|
||
|
continue
|
||
|
|
||
|
case ATee:
|
||
|
if p.To.Type != obj.TYPE_REG {
|
||
|
panic("bad Tee: argument is not a register")
|
||
|
}
|
||
|
reg := p.To.Reg
|
||
|
v := regVars[reg-MINREG]
|
||
|
if v == nil {
|
||
|
panic("bad Tee: invalid register")
|
||
|
}
|
||
|
writeOpcode(w, ALocalTee)
|
||
|
writeUleb128(w, v.index)
|
||
|
continue
|
||
|
|
||
|
case ANot:
|
||
|
writeOpcode(w, AI32Eqz)
|
||
|
continue
|
||
|
|
||
|
case obj.AUNDEF:
|
||
|
writeOpcode(w, AUnreachable)
|
||
|
continue
|
||
|
|
||
|
case obj.ANOP, obj.ATEXT, obj.AFUNCDATA, obj.APCDATA:
|
||
|
// ignore
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
writeOpcode(w, p.As)
|
||
|
|
||
|
switch p.As {
|
||
|
case ABlock, ALoop, AIf:
|
||
|
if p.From.Offset != 0 {
|
||
|
// block type, rarely used, e.g. for code compiled with emscripten
|
||
|
w.WriteByte(0x80 - byte(p.From.Offset))
|
||
|
continue
|
||
|
}
|
||
|
w.WriteByte(0x40)
|
||
|
|
||
|
case ABr, ABrIf:
|
||
|
if p.To.Type != obj.TYPE_CONST {
|
||
|
panic("bad Br/BrIf")
|
||
|
}
|
||
|
writeUleb128(w, uint64(p.To.Offset))
|
||
|
|
||
|
case ABrTable:
|
||
|
idxs := p.To.Val.([]uint64)
|
||
|
writeUleb128(w, uint64(len(idxs)-1))
|
||
|
for _, idx := range idxs {
|
||
|
writeUleb128(w, idx)
|
||
|
}
|
||
|
|
||
|
case ACall:
|
||
|
switch p.To.Type {
|
||
|
case obj.TYPE_CONST:
|
||
|
writeUleb128(w, uint64(p.To.Offset))
|
||
|
|
||
|
case obj.TYPE_MEM:
|
||
|
if p.To.Name != obj.NAME_EXTERN && p.To.Name != obj.NAME_STATIC {
|
||
|
fmt.Println(p.To)
|
||
|
panic("bad name for Call")
|
||
|
}
|
||
|
r := obj.Addrel(s)
|
||
|
r.Off = int32(w.Len())
|
||
|
r.Type = objabi.R_CALL
|
||
|
if p.Mark&WasmImport != 0 {
|
||
|
r.Type = objabi.R_WASMIMPORT
|
||
|
}
|
||
|
r.Sym = p.To.Sym
|
||
|
if hasLocalSP {
|
||
|
// The stack may have moved, which changes SP. Update the local SP variable.
|
||
|
updateLocalSP(w)
|
||
|
}
|
||
|
|
||
|
default:
|
||
|
panic("bad type for Call")
|
||
|
}
|
||
|
|
||
|
case ACallIndirect:
|
||
|
writeUleb128(w, uint64(p.To.Offset))
|
||
|
w.WriteByte(0x00) // reserved value
|
||
|
if hasLocalSP {
|
||
|
// The stack may have moved, which changes SP. Update the local SP variable.
|
||
|
updateLocalSP(w)
|
||
|
}
|
||
|
|
||
|
case AI32Const, AI64Const:
|
||
|
if p.From.Name == obj.NAME_EXTERN {
|
||
|
r := obj.Addrel(s)
|
||
|
r.Off = int32(w.Len())
|
||
|
r.Type = objabi.R_ADDR
|
||
|
r.Sym = p.From.Sym
|
||
|
r.Add = p.From.Offset
|
||
|
break
|
||
|
}
|
||
|
writeSleb128(w, p.From.Offset)
|
||
|
|
||
|
case AF32Const:
|
||
|
b := make([]byte, 4)
|
||
|
binary.LittleEndian.PutUint32(b, math.Float32bits(float32(p.From.Val.(float64))))
|
||
|
w.Write(b)
|
||
|
|
||
|
case AF64Const:
|
||
|
b := make([]byte, 8)
|
||
|
binary.LittleEndian.PutUint64(b, math.Float64bits(p.From.Val.(float64)))
|
||
|
w.Write(b)
|
||
|
|
||
|
case AI32Load, AI64Load, AF32Load, AF64Load, AI32Load8S, AI32Load8U, AI32Load16S, AI32Load16U, AI64Load8S, AI64Load8U, AI64Load16S, AI64Load16U, AI64Load32S, AI64Load32U:
|
||
|
if p.From.Offset < 0 {
|
||
|
panic("negative offset for *Load")
|
||
|
}
|
||
|
if p.From.Type != obj.TYPE_CONST {
|
||
|
panic("bad type for *Load")
|
||
|
}
|
||
|
if p.From.Offset > math.MaxUint32 {
|
||
|
ctxt.Diag("bad offset in %v", p)
|
||
|
}
|
||
|
writeUleb128(w, align(p.As))
|
||
|
writeUleb128(w, uint64(p.From.Offset))
|
||
|
|
||
|
case AI32Store, AI64Store, AF32Store, AF64Store, AI32Store8, AI32Store16, AI64Store8, AI64Store16, AI64Store32:
|
||
|
if p.To.Offset < 0 {
|
||
|
panic("negative offset")
|
||
|
}
|
||
|
if p.From.Offset > math.MaxUint32 {
|
||
|
ctxt.Diag("bad offset in %v", p)
|
||
|
}
|
||
|
writeUleb128(w, align(p.As))
|
||
|
writeUleb128(w, uint64(p.To.Offset))
|
||
|
|
||
|
case ACurrentMemory, AGrowMemory:
|
||
|
w.WriteByte(0x00)
|
||
|
|
||
|
}
|
||
|
}
|
||
|
|
||
|
w.WriteByte(0x0b) // end
|
||
|
|
||
|
s.P = w.Bytes()
|
||
|
}
|
||
|
|
||
|
func updateLocalSP(w *bytes.Buffer) {
|
||
|
writeOpcode(w, AGlobalGet)
|
||
|
writeUleb128(w, 0) // global SP
|
||
|
writeOpcode(w, ALocalSet)
|
||
|
writeUleb128(w, 1) // local SP
|
||
|
}
|
||
|
|
||
|
func writeOpcode(w *bytes.Buffer, as obj.As) {
|
||
|
switch {
|
||
|
case as < AUnreachable:
|
||
|
panic(fmt.Sprintf("unexpected assembler op: %s", as))
|
||
|
case as < AEnd:
|
||
|
w.WriteByte(byte(as - AUnreachable + 0x00))
|
||
|
case as < ADrop:
|
||
|
w.WriteByte(byte(as - AEnd + 0x0B))
|
||
|
case as < ALocalGet:
|
||
|
w.WriteByte(byte(as - ADrop + 0x1A))
|
||
|
case as < AI32Load:
|
||
|
w.WriteByte(byte(as - ALocalGet + 0x20))
|
||
|
case as < AI32TruncSatF32S:
|
||
|
w.WriteByte(byte(as - AI32Load + 0x28))
|
||
|
case as < ALast:
|
||
|
w.WriteByte(0xFC)
|
||
|
w.WriteByte(byte(as - AI32TruncSatF32S + 0x00))
|
||
|
default:
|
||
|
panic(fmt.Sprintf("unexpected assembler op: %s", as))
|
||
|
}
|
||
|
}
|
||
|
|
||
|
type valueType byte
|
||
|
|
||
|
const (
|
||
|
i32 valueType = 0x7F
|
||
|
i64 valueType = 0x7E
|
||
|
f32 valueType = 0x7D
|
||
|
f64 valueType = 0x7C
|
||
|
)
|
||
|
|
||
|
func regType(reg int16) valueType {
|
||
|
switch {
|
||
|
case reg == REG_SP:
|
||
|
return i32
|
||
|
case reg >= REG_R0 && reg <= REG_R15:
|
||
|
return i64
|
||
|
case reg >= REG_F0 && reg <= REG_F15:
|
||
|
return f32
|
||
|
case reg >= REG_F16 && reg <= REG_F31:
|
||
|
return f64
|
||
|
default:
|
||
|
panic("invalid register")
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func align(as obj.As) uint64 {
|
||
|
switch as {
|
||
|
case AI32Load8S, AI32Load8U, AI64Load8S, AI64Load8U, AI32Store8, AI64Store8:
|
||
|
return 0
|
||
|
case AI32Load16S, AI32Load16U, AI64Load16S, AI64Load16U, AI32Store16, AI64Store16:
|
||
|
return 1
|
||
|
case AI32Load, AF32Load, AI64Load32S, AI64Load32U, AI32Store, AF32Store, AI64Store32:
|
||
|
return 2
|
||
|
case AI64Load, AF64Load, AI64Store, AF64Store:
|
||
|
return 3
|
||
|
default:
|
||
|
panic("align: bad op")
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func writeUleb128(w io.ByteWriter, v uint64) {
|
||
|
if v < 128 {
|
||
|
w.WriteByte(uint8(v))
|
||
|
return
|
||
|
}
|
||
|
more := true
|
||
|
for more {
|
||
|
c := uint8(v & 0x7f)
|
||
|
v >>= 7
|
||
|
more = v != 0
|
||
|
if more {
|
||
|
c |= 0x80
|
||
|
}
|
||
|
w.WriteByte(c)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func writeSleb128(w io.ByteWriter, v int64) {
|
||
|
more := true
|
||
|
for more {
|
||
|
c := uint8(v & 0x7f)
|
||
|
s := uint8(v & 0x40)
|
||
|
v >>= 7
|
||
|
more = !((v == 0 && s == 0) || (v == -1 && s != 0))
|
||
|
if more {
|
||
|
c |= 0x80
|
||
|
}
|
||
|
w.WriteByte(c)
|
||
|
}
|
||
|
}
|