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cmd/compile: give the closure generated for rangefunc bodies a name.

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The generated name has the form "#yield%d" for %d = 1, 2, 3, ...
This may help the debugger connect execution within a rangefunc
loop's body to the frame containing the rest of the source code.
(It may not actually be necessary; we need to confirm with Alessandro
Aarzilli or someone else on the Delve team.)

Change-Id: Iabbb2ea5604a4bc1558c160819ac80197e1f2242
Reviewed-on: https://go-review.googlesource.com/c/go/+/592175
Reviewed-by: Than McIntosh <thanm@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
This commit is contained in:
David Chase 2024-06-12 11:13:26 -04:00
parent a85b8810c4
commit f27a40ce5f
1 changed files with 32 additions and 12 deletions
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36
src/cmd/compile/internal/rangefunc/rewrite.go
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@ -568,9 +568,9 @@ type rewriter struct {
// Declared variables in generated code for outermost loop.
declStmt *syntax.DeclStmt
nextVar types2.Object
retVars []types2.Object
defers types2.Object
stateVarCount int // stateVars are referenced from their respective loops
bodyClosureCount int // to help the debugger, the closures generated for loop bodies get names
rangefuncBodyClosures map[*syntax.FuncLit]bool
}
@ -764,7 +764,7 @@ func (r *rewriter) editDefer(x *syntax.CallStmt) syntax.Stmt {
tv := syntax.TypeAndValue{Type: r.any.Type()}
tv.SetIsValue()
init.SetTypeInfo(tv)
r.defers = r.declVar("#defers", r.any.Type(), init)
r.defers = r.declOuterVar("#defers", r.any.Type(), init)
}
// Attach the token as an "extra" argument to the defer.
@ -1033,12 +1033,18 @@ func (r *rewriter) endLoop(loop *forLoop) {
base.Fatalf("invalid typecheck of range func")
}
// Give the closure generated for the body a name, to help the debugger connect it to its frame, if active.
r.bodyClosureCount++
clo := r.bodyFunc(nfor.Body.List, syntax.UnpackListExpr(rclause.Lhs), rclause.Def, ftyp, start, end)
cloDecl, cloVar := r.declSingleVar(fmt.Sprintf("#yield%d", r.bodyClosureCount), clo.GetTypeInfo().Type, clo)
setPos(cloDecl, start)
// Build X(bodyFunc)
call := &syntax.ExprStmt{
X: &syntax.CallExpr{
Fun: rclause.X,
ArgList: []syntax.Expr{
r.bodyFunc(nfor.Body.List, syntax.UnpackListExpr(rclause.Lhs), rclause.Def, ftyp, start, end),
r.useObj(cloVar),
},
},
}
@ -1073,7 +1079,7 @@ func (r *rewriter) endLoop(loop *forLoop) {
}
// iteratorFunc(bodyFunc)
block.List = append(block.List, call)
block.List = append(block.List, cloDecl, call)
if r.checkFuncMisuse() {
// iteratorFunc has exited, check for swallowed panic, and set body state to abi.RF_EXHAUSTED
@ -1092,7 +1098,6 @@ func (r *rewriter) endLoop(loop *forLoop) {
if len(r.forStack) == 1 { // ending an outermost loop
r.declStmt = nil
r.nextVar = nil
r.retVars = nil
r.defers = nil
}
@ -1348,7 +1353,7 @@ func (r *rewriter) callPanic(start syntax.Pos, arg syntax.Expr) syntax.Stmt {
// next returns a reference to the #next variable.
func (r *rewriter) next() *syntax.Name {
if r.nextVar == nil {
r.nextVar = r.declVar("#next", r.int.Type(), nil)
r.nextVar = r.declOuterVar("#next", r.int.Type(), nil)
}
return r.useObj(r.nextVar)
}
@ -1425,8 +1430,9 @@ func (r *rewriter) generateParamName(results []*syntax.Field, i int) {
r.info.Defs[n] = obj
}
// declVar declares a variable with a given name type and initializer value.
func (r *rewriter) declVar(name string, typ types2.Type, init syntax.Expr) *types2.Var {
// declOuterVar declares a variable with a given name, type, and initializer value,
// in the same scope as the outermost loop in a loop nest.
func (r *rewriter) declOuterVar(name string, typ types2.Type, init syntax.Expr) *types2.Var {
if r.declStmt == nil {
r.declStmt = &syntax.DeclStmt{}
}
@ -1440,6 +1446,20 @@ func (r *rewriter) declVar(name string, typ types2.Type, init syntax.Expr) *type
return obj
}
// declSingleVar declares a variable with a given name, type, and initializer value,
// and returns both the declaration and variable, so that the declaration can be placed
// in a specific scope.
func (r *rewriter) declSingleVar(name string, typ types2.Type, init syntax.Expr) (*syntax.DeclStmt, *types2.Var) {
stmt := &syntax.DeclStmt{}
obj, n := r.makeVarName(stmt.Pos(), name, typ)
stmt.DeclList = append(stmt.DeclList, &syntax.VarDecl{
NameList: []*syntax.Name{n},
// Note: Type is ignored
Values: init,
})
return stmt, obj
}
// runtimePkg is a fake runtime package that contains what we need to refer to in package runtime.
var runtimePkg = func() *types2.Package {
var nopos syntax.Pos