TrueCloudLab/neoneo-go
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compiler: count local variables on the go

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Create local variables as they are needed and remove `INITSLOT`
if there were no locals. This helps to eliminate a whole class
of bugs when calculated and real amount mismatched.
This commit is contained in:
Evgeniy Stratonikov 2021-04-28 16:10:44 +03:00
parent bfa2bafb04
commit b693d54282
9 changed files with 181 additions and 230 deletions
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132
pkg/compiler/codegen.go
View file

@ -40,6 +40,9 @@ type codegen struct {
// A mapping of lambda functions into their scope.
lambda map[string]*funcScope
// reverseOffsetMap maps function offsets to a local variable count.
reverseOffsetMap map[int]nameWithLocals
// Current funcScope being converted.
scope *funcScope
@ -124,6 +127,11 @@ type labelWithStackSize struct {
sz int
}
type nameWithLocals struct {
name string
count int
}
type varType int
const (
@ -333,24 +341,30 @@ func (c *codegen) clearSlots(n int) {
}
}
func (c *codegen) convertInitFuncs(f *ast.File, pkg *types.Package, seenBefore bool) bool {
// convertInitFuncs converts `init()` functions in file f and returns
// number of locals in last processed definition as well as maximum locals number encountered.
func (c *codegen) convertInitFuncs(f *ast.File, pkg *types.Package, lastCount int) (int, int) {
maxCount := -1
ast.Inspect(f, func(node ast.Node) bool {
switch n := node.(type) {
case *ast.FuncDecl:
if isInitFunc(n) {
if seenBefore {
cnt, _ := c.countLocals(n)
c.clearSlots(cnt)
seenBefore = true
if lastCount != -1 {
c.clearSlots(lastCount)
}
f := c.convertFuncDecl(f, n, pkg)
lastCount = f.vars.localsCnt
if lastCount > maxCount {
maxCount = lastCount
}
c.convertFuncDecl(f, n, pkg)
}
case *ast.GenDecl:
return false
}
return true
})
return seenBefore
return lastCount, maxCount
}
func isDeployFunc(decl *ast.FuncDecl) bool {
@ -363,19 +377,22 @@ func isDeployFunc(decl *ast.FuncDecl) bool {
return ok && typ.Name == "bool"
}
func (c *codegen) convertDeployFuncs() {
seenBefore := false
func (c *codegen) convertDeployFuncs() int {
maxCount, lastCount := 0, -1
c.ForEachFile(func(f *ast.File, pkg *types.Package) {
ast.Inspect(f, func(node ast.Node) bool {
switch n := node.(type) {
case *ast.FuncDecl:
if isDeployFunc(n) {
if seenBefore {
cnt, _ := c.countLocals(n)
c.clearSlots(cnt)
if lastCount != -1 {
c.clearSlots(lastCount)
}
f := c.convertFuncDecl(f, n, pkg)
lastCount = f.vars.localsCnt
if lastCount > maxCount {
maxCount = lastCount
}
c.convertFuncDecl(f, n, pkg)
seenBefore = true
}
case *ast.GenDecl:
return false
@ -383,9 +400,10 @@ func (c *codegen) convertDeployFuncs() {
return true
})
})
return maxCount
}
func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl, pkg *types.Package) {
func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl, pkg *types.Package) *funcScope {
var (
f *funcScope
ok, isLambda bool
@ -399,7 +417,7 @@ func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl, pkg *types.
if ok {
// If this function is a syscall or builtin we will not convert it to bytecode.
if isSyscall(f) || isCustomBuiltin(f) {
return
return f
}
c.setLabel(f.label)
} else if f, ok = c.lambda[c.getIdentName("", decl.Name.Name)]; ok {
@ -417,17 +435,11 @@ func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl, pkg *types.
// All globals copied into the scope of the function need to be added
// to the stack size of the function.
if !isInit && !isDeploy {
sizeLoc := c.countLocalsWithDefer(f)
if sizeLoc > 255 {
c.prog.Err = errors.New("maximum of 255 local variables is allowed")
}
sizeArg := f.countArgs()
if sizeArg > 255 {
c.prog.Err = errors.New("maximum of 255 local variables is allowed")
}
if sizeLoc != 0 || sizeArg != 0 {
emit.Instruction(c.prog.BinWriter, opcode.INITSLOT, []byte{byte(sizeLoc), byte(sizeArg)})
}
emit.Instruction(c.prog.BinWriter, opcode.INITSLOT, []byte{byte(0), byte(sizeArg)})
}
f.vars.newScope()
@ -478,6 +490,14 @@ func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl, pkg *types.
}
c.lambda = make(map[string]*funcScope)
}
if !isInit && !isDeploy {
c.reverseOffsetMap[int(f.rng.Start)] = nameWithLocals{
name: f.name,
count: f.vars.localsCnt,
}
}
return f
}
func (c *codegen) Visit(node ast.Node) ast.Visitor {
@ -1961,17 +1981,16 @@ func (c *codegen) compile(info *buildInfo, pkg *loader.PackageInfo) error {
// Bring all imported functions into scope.
c.ForEachFile(c.resolveFuncDecls)
n, initLocals, deployLocals := c.traverseGlobals()
hasInit := initLocals > -1
if n > 0 || hasInit {
c.initEndOffset = c.prog.Len()
emit.Opcodes(c.prog.BinWriter, opcode.RET)
}
hasDeploy := c.traverseGlobals()
hasDeploy := deployLocals > -1
if hasDeploy {
emit.Instruction(c.prog.BinWriter, opcode.INITSLOT, []byte{byte(deployLocals), 2})
c.convertDeployFuncs()
deployOffset := c.prog.Len()
emit.Instruction(c.prog.BinWriter, opcode.INITSLOT, []byte{0, 2})
locCount := c.convertDeployFuncs()
c.reverseOffsetMap[deployOffset] = nameWithLocals{
name: "_deploy",
count: locCount,
}
c.deployEndOffset = c.prog.Len()
emit.Opcodes(c.prog.BinWriter, opcode.RET)
}
@ -2008,16 +2027,17 @@ func (c *codegen) compile(info *buildInfo, pkg *loader.PackageInfo) error {
func newCodegen(info *buildInfo, pkg *loader.PackageInfo) *codegen {
return &codegen{
buildInfo: info,
prog: io.NewBufBinWriter(),
l: []int{},
funcs: map[string]*funcScope{},
lambda: map[string]*funcScope{},
globals: map[string]int{},
labels: map[labelWithType]uint16{},
typeInfo: &pkg.Info,
constMap: map[string]types.TypeAndValue{},
docIndex: map[string]int{},
buildInfo: info,
prog: io.NewBufBinWriter(),
l: []int{},
funcs: map[string]*funcScope{},
lambda: map[string]*funcScope{},
reverseOffsetMap: map[int]nameWithLocals{},
globals: map[string]int{},
labels: map[labelWithType]uint16{},
typeInfo: &pkg.Info,
constMap: map[string]types.TypeAndValue{},
docIndex: map[string]int{},
initEndOffset: -1,
deployEndOffset: -1,
@ -2087,6 +2107,18 @@ func (c *codegen) writeJumps(b []byte) ([]byte, error) {
if op != opcode.PUSHA && math.MinInt8 <= offset && offset <= math.MaxInt8 {
offsets = append(offsets, ctx.IP())
}
case opcode.INITSLOT:
nextIP := ctx.NextIP()
info := c.reverseOffsetMap[ctx.IP()]
if argCount := b[nextIP-1]; info.count == 0 && argCount == 0 {
offsets = append(offsets, ctx.IP())
continue
}
if info.count > 255 {
return nil, fmt.Errorf("func '%s' has %d local variables (maximum is 255)", info.name, info.count)
}
b[nextIP-2] = byte(info.count)
}
}
@ -2139,6 +2171,7 @@ func (c *codegen) replaceLabelWithOffset(ip int, arg []byte) (int, error) {
}
// longToShortRemoveCount is a difference between short and long instruction sizes in bytes.
// By pure coincidence, this is also the size of `INITSLOT` instruction.
const longToShortRemoveCount = 3
// shortenJumps returns converts b to a program where all long JMP*/CALL* specified by absolute offsets,
@ -2196,13 +2229,22 @@ func shortenJumps(b []byte, offsets []int) []byte {
// 2. Convert instructions.
copyOffset := 0
l := len(offsets)
b[offsets[0]] = byte(toShortForm(opcode.Opcode(b[offsets[0]])))
if op := opcode.Opcode(b[offsets[0]]); op != opcode.INITSLOT {
b[offsets[0]] = byte(toShortForm(op))
}
for i := 0; i < l; i++ {
start := offsets[i] + 2
if b[offsets[i]] == byte(opcode.INITSLOT) {
start = offsets[i]
}
end := len(b)
if i != l-1 {
end = offsets[i+1] + 2
b[offsets[i+1]] = byte(toShortForm(opcode.Opcode(b[offsets[i+1]])))
end = offsets[i+1]
if op := opcode.Opcode(b[offsets[i+1]]); op != opcode.INITSLOT {
end += 2
b[offsets[i+1]] = byte(toShortForm(op))
}
}
copy(b[start-copyOffset:], b[start+3:end])
copyOffset += longToShortRemoveCount