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compiler: allow to use local variables in init()

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Because body of multiple `init()` functions constitute single
method in contract, we initialize slot with maximum amount of
locals encounterered in any of `init()` functions and clear them
before emitting body of each instance of `init()`.
This commit is contained in:
Evgenii Stratonikov 2020-10-06 18:25:40 +03:00
parent 2d9ef9219a
commit 6701e8cda0
4 changed files with 58 additions and 27 deletions
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30
pkg/compiler/analysis.go
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@ -37,20 +37,24 @@ func (c *codegen) getIdentName(pkg string, name string) string {
}
// traverseGlobals visits and initializes global variables.
// and returns number of variables initialized and
// true if any init functions were encountered.
func (c *codegen) traverseGlobals() (int, bool) {
// and returns number of variables initialized.
// Second return value is -1 if no `init()` functions were encountered
// and number of maximum amount of locals in any of init functions otherwise.
func (c *codegen) traverseGlobals() (int, int) {
var hasDefer bool
var n int
var hasInit bool
initLocals := -1
c.ForEachFile(func(f *ast.File, _ *types.Package) {
n += countGlobals(f)
if !hasInit || !hasDefer {
if initLocals == -1 || !hasDefer {
ast.Inspect(f, func(node ast.Node) bool {
switch n := node.(type) {
case *ast.FuncDecl:
if isInitFunc(n) {
hasInit = true
c, _ := countLocals(n)
if c > initLocals {
initLocals = c
}
}
return !hasDefer
case *ast.DeferStmt:
@ -64,14 +68,18 @@ func (c *codegen) traverseGlobals() (int, bool) {
if hasDefer {
n++
}
if n != 0 || hasInit {
if n != 0 || initLocals > -1 {
if n > 255 {
c.prog.BinWriter.Err = errors.New("too many global variables")
return 0, hasInit
return 0, initLocals
}
if n != 0 {
emit.Instruction(c.prog.BinWriter, opcode.INITSSLOT, []byte{byte(n)})
}
if initLocals > 0 {
emit.Instruction(c.prog.BinWriter, opcode.INITSLOT, []byte{byte(initLocals), 0})
}
seenBefore := false
c.ForEachPackage(func(pkg *loader.PackageInfo) {
if n > 0 {
for _, f := range pkg.Files {
@ -79,10 +87,10 @@ func (c *codegen) traverseGlobals() (int, bool) {
c.convertGlobals(f, pkg.Pkg)
}
}
if hasInit {
if initLocals > -1 {
for _, f := range pkg.Files {
c.fillImportMap(f, pkg.Pkg)
c.convertInitFuncs(f, pkg.Pkg)
seenBefore = c.convertInitFuncs(f, pkg.Pkg, seenBefore) || seenBefore
}
}
// because we reuse `convertFuncDecl` for init funcs,
@ -96,7 +104,7 @@ func (c *codegen) traverseGlobals() (int, bool) {
c.globals["<exception>"] = c.exceptionIndex
}
}
return n, hasInit
return n, initLocals
}
// countGlobals counts the global variables in the program to add