neo-go/pkg/compiler/inline.go
Roman Khimov efb814a97e
Merge pull request #1995 from nspcc-dev/compiler-verify-notify
compiler: disallow `runtime.Notify` in `Verify` function
2021-06-06 11:34:42 +03:00

177 lines
4.7 KiB
Go

package compiler
import (
"fmt"
"go/ast"
"go/constant"
"go/types"
"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
"github.com/nspcc-dev/neo-go/pkg/vm/emit"
"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
)
// inlineCall inlines call of n for function represented by f.
// Call `f(a,b)` for definition `func f(x,y int)` is translated to block:
// {
// x := a
// y := b
// <inline body of f directly>
// }
func (c *codegen) inlineCall(f *funcScope, n *ast.CallExpr) {
labelSz := len(c.labelList)
offSz := len(c.inlineLabelOffsets)
c.inlineLabelOffsets = append(c.inlineLabelOffsets, labelSz)
defer func() {
c.inlineLabelOffsets = c.inlineLabelOffsets[:offSz]
c.labelList = c.labelList[:labelSz]
}()
pkg := c.buildInfo.program.Package(f.pkg.Path())
sig := c.typeOf(n.Fun).(*types.Signature)
c.processNotify(f, n.Args)
// When inlined call is used during global initialization
// there is no func scope, thus this if.
if c.scope == nil {
c.scope = &funcScope{}
c.scope.vars.newScope()
defer func() {
if cnt := c.scope.vars.localsCnt; cnt > c.globalInlineCount {
c.globalInlineCount = cnt
}
c.scope = nil
}()
}
// Arguments need to be walked with the current scope,
// while stored in the new.
oldScope := c.scope.vars.locals
c.scope.vars.newScope()
newScope := make([]map[string]varInfo, len(c.scope.vars.locals))
copy(newScope, c.scope.vars.locals)
defer c.scope.vars.dropScope()
hasVarArgs := !n.Ellipsis.IsValid()
needPack := sig.Variadic() && hasVarArgs
for i := range n.Args {
c.scope.vars.locals = oldScope
// true if normal arg or var arg is `slice...`
needStore := i < sig.Params().Len()-1 || !sig.Variadic() || !hasVarArgs
if !needStore {
break
}
name := sig.Params().At(i).Name()
if !c.hasCalls(n.Args[i]) {
// If argument contains no calls, we save context and traverse the expression
// when argument is emitted.
c.scope.vars.locals = newScope
c.scope.vars.addAlias(name, -1, unspecifiedVarIndex, &varContext{
importMap: c.importMap,
expr: n.Args[i],
scope: oldScope,
})
continue
}
ast.Walk(c, n.Args[i])
c.scope.vars.locals = newScope
c.scope.newLocal(name)
c.emitStoreVar("", name)
}
if needPack {
// traverse variadic args and pack them
// if they are provided directly i.e. without `...`
c.scope.vars.locals = oldScope
for i := sig.Params().Len() - 1; i < len(n.Args); i++ {
ast.Walk(c, n.Args[i])
}
c.scope.vars.locals = newScope
c.packVarArgs(n, sig)
name := sig.Params().At(sig.Params().Len() - 1).Name()
c.scope.newLocal(name)
c.emitStoreVar("", name)
}
c.pkgInfoInline = append(c.pkgInfoInline, pkg)
oldMap := c.importMap
c.fillImportMap(f.file, pkg.Pkg)
ast.Inspect(f.decl, c.scope.analyzeVoidCalls)
ast.Walk(c, f.decl.Body)
if c.scope.voidCalls[n] {
for i := 0; i < f.decl.Type.Results.NumFields(); i++ {
emit.Opcodes(c.prog.BinWriter, opcode.DROP)
}
}
c.importMap = oldMap
c.pkgInfoInline = c.pkgInfoInline[:len(c.pkgInfoInline)-1]
}
func (c *codegen) processNotify(f *funcScope, args []ast.Expr) {
if f != nil && f.pkg.Path() == interopPrefix+"/runtime" {
if f.name != "Notify" && f.name != "Log" {
return
}
if c.scope != nil && c.isVerifyFunc(c.scope.decl) &&
c.scope.pkg == c.mainPkg.Pkg && !c.buildInfo.options.NoEventsCheck {
c.prog.Err = fmt.Errorf("runtime.%s is not allowed in `Verify`", f.name)
return
}
if f.name == "Log" {
return
}
// Sometimes event name is stored in a var.
// Skip in this case.
tv := c.typeAndValueOf(args[0])
if tv.Value == nil {
return
}
params := make([]string, 0, len(args[1:]))
for _, p := range args[1:] {
st, _ := c.scAndVMTypeFromExpr(p)
params = append(params, st.String())
}
name := constant.StringVal(tv.Value)
if len(name) > runtime.MaxEventNameLen {
c.prog.Err = fmt.Errorf("event name '%s' should be less than %d",
name, runtime.MaxEventNameLen)
return
}
c.emittedEvents[name] = append(c.emittedEvents[name], params)
}
}
// hasCalls returns true if expression contains any calls.
// We uses this as a rough heuristic to determine if expression calculation
// has any side-effects.
func (c *codegen) hasCalls(expr ast.Expr) bool {
var has bool
ast.Inspect(expr, func(n ast.Node) bool {
ce, ok := n.(*ast.CallExpr)
if !has && ok {
isFunc := true
fun, ok := ce.Fun.(*ast.Ident)
if ok {
_, isFunc = c.getFuncFromIdent(fun)
} else {
var sel *ast.SelectorExpr
sel, ok = ce.Fun.(*ast.SelectorExpr)
if ok {
name, _ := c.getFuncNameFromSelector(sel)
_, isFunc = c.funcs[name]
fun = sel.Sel
}
}
has = isFunc || fun.Obj != nil && (fun.Obj.Kind == ast.Var || fun.Obj.Kind == ast.Fun)
}
return !has
})
return has
}