cmd/compile: update comments only for Node types and some functions
Improve the comments in syntax.go on Node structs and constants. Also, updated a
few function header comments.
Change-Id: I3e6e4a3c5678fc0b4e18844507b3460303ce1240
Reviewed-on: https://go-review.googlesource.com/c/go/+/269538
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Trust: Dan Scales <danscales@google.com>
diff --git a/src/cmd/compile/internal/gc/closure.go b/src/cmd/compile/internal/gc/closure.go
index 902d2e3..bd350f6 100644
--- a/src/cmd/compile/internal/gc/closure.go
+++ b/src/cmd/compile/internal/gc/closure.go
@@ -71,6 +71,10 @@
return clo
}
+// typecheckclosure typechecks an OCLOSURE node. It also creates the named
+// function associated with the closure.
+// TODO: This creation of the named function should probably really be done in a
+// separate pass from type-checking.
func typecheckclosure(clo *Node, top int) {
xfunc := clo.Func.Closure
// Set current associated iota value, so iota can be used inside
diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go
index b8ca0d2..6e90eb4 100644
--- a/src/cmd/compile/internal/gc/dcl.go
+++ b/src/cmd/compile/internal/gc/dcl.go
@@ -257,6 +257,8 @@
// oldname returns the Node that declares symbol s in the current scope.
// If no such Node currently exists, an ONONAME Node is returned instead.
+// Automatically creates a new closure variable if the referenced symbol was
+// declared in a different (containing) function.
func oldname(s *types.Sym) *Node {
n := asNode(s.Def)
if n == nil {
diff --git a/src/cmd/compile/internal/gc/inl.go b/src/cmd/compile/internal/gc/inl.go
index 139572f..d49a094 100644
--- a/src/cmd/compile/internal/gc/inl.go
+++ b/src/cmd/compile/internal/gc/inl.go
@@ -94,10 +94,11 @@
typecheckslice(fn.Func.Inl.Body, ctxStmt)
Curfn = savefn
- // During typechecking, declarations are added to
- // Curfn.Func.Dcl. Move them to Inl.Dcl for consistency with
- // how local functions behave. (Append because typecheckinl
- // may be called multiple times.)
+ // During expandInline (which imports fn.Func.Inl.Body),
+ // declarations are added to fn.Func.Dcl by funcHdr(). Move them
+ // to fn.Func.Inl.Dcl for consistency with how local functions
+ // behave. (Append because typecheckinl may be called multiple
+ // times.)
fn.Func.Inl.Dcl = append(fn.Func.Inl.Dcl, fn.Func.Dcl...)
fn.Func.Dcl = nil
@@ -448,9 +449,9 @@
v.visitList(n.Ninit) || v.visitList(n.Nbody)
}
-// Inlcopy and inlcopylist recursively copy the body of a function.
-// Any name-like node of non-local class is marked for re-export by adding it to
-// the exportlist.
+// inlcopylist (together with inlcopy) recursively copies a list of nodes, except
+// that it keeps the same ONAME, OTYPE, and OLITERAL nodes. It is used for copying
+// the body and dcls of an inlineable function.
func inlcopylist(ll []*Node) []*Node {
s := make([]*Node, 0, len(ll))
for _, n := range ll {
@@ -889,10 +890,10 @@
var inlgen int
-// If n is a call, and fn is a function with an inlinable body,
-// return an OINLCALL.
-// On return ninit has the parameter assignments, the nbody is the
-// inlined function body and list, rlist contain the input, output
+// If n is a call node (OCALLFUNC or OCALLMETH), and fn is an ONAME node for a
+// function with an inlinable body, return an OINLCALL node that can replace n.
+// The returned node's Ninit has the parameter assignments, the Nbody is the
+// inlined function body, and (List, Rlist) contain the (input, output)
// parameters.
// The result of mkinlcall MUST be assigned back to n, e.g.
// n.Left = mkinlcall(n.Left, fn, isddd)
diff --git a/src/cmd/compile/internal/gc/syntax.go b/src/cmd/compile/internal/gc/syntax.go
index 649f7f4..4335833 100644
--- a/src/cmd/compile/internal/gc/syntax.go
+++ b/src/cmd/compile/internal/gc/syntax.go
@@ -344,14 +344,22 @@
// Name holds Node fields used only by named nodes (ONAME, OTYPE, OPACK, OLABEL, some OLITERAL).
type Name struct {
- Pack *Node // real package for import . names
- Pkg *types.Pkg // pkg for OPACK nodes
- Defn *Node // initializing assignment
- Curfn *Node // function for local variables
- Param *Param // additional fields for ONAME, OTYPE
- Decldepth int32 // declaration loop depth, increased for every loop or label
- Vargen int32 // unique name for ONAME within a function. Function outputs are numbered starting at one.
- flags bitset16
+ Pack *Node // real package for import . names
+ Pkg *types.Pkg // pkg for OPACK nodes
+ // For a local variable (not param) or extern, the initializing assignment (OAS or OAS2).
+ // For a closure var, the ONAME node of the outer captured variable
+ Defn *Node
+ // The ODCLFUNC node (for a static function/method or a closure) in which
+ // local variable or param is declared.
+ Curfn *Node
+ Param *Param // additional fields for ONAME, OTYPE
+ Decldepth int32 // declaration loop depth, increased for every loop or label
+ // Unique number for ONAME nodes within a function. Function outputs
+ // (results) are numbered starting at one, followed by function inputs
+ // (parameters), and then local variables. Vargen is used to distinguish
+ // local variables/params with the same name.
+ Vargen int32
+ flags bitset16
}
const (
@@ -608,10 +616,16 @@
// Func holds Node fields used only with function-like nodes.
type Func struct {
Shortname *types.Sym
- Enter Nodes // for example, allocate and initialize memory for escaping parameters
- Exit Nodes
- Cvars Nodes // closure params
- Dcl []*Node // autodcl for this func/closure
+ // Extra entry code for the function. For example, allocate and initialize
+ // memory for escaping parameters. However, just for OCLOSURE, Enter is a
+ // list of ONAME nodes of captured variables
+ Enter Nodes
+ Exit Nodes
+ // ONAME nodes for closure params, each should have closurevar set
+ Cvars Nodes
+ // ONAME nodes for all params/locals for this func/closure, does NOT
+ // include closurevars until transformclosure runs.
+ Dcl []*Node
// Parents records the parent scope of each scope within a
// function. The root scope (0) has no parent, so the i'th
@@ -630,7 +644,7 @@
DebugInfo *ssa.FuncDebug
Ntype *Node // signature
Top int // top context (ctxCallee, etc)
- Closure *Node // OCLOSURE <-> ODCLFUNC
+ Closure *Node // OCLOSURE <-> ODCLFUNC (see header comment above)
Nname *Node // The ONAME node associated with an ODCLFUNC (both have same Type)
lsym *obj.LSym
@@ -680,6 +694,8 @@
funcWrapper // is method wrapper
funcNeedctxt // function uses context register (has closure variables)
funcReflectMethod // function calls reflect.Type.Method or MethodByName
+ // true if closure inside a function; false if a simple function or a
+ // closure in a global variable initialization
funcIsHiddenClosure
funcHasDefer // contains a defer statement
funcNilCheckDisabled // disable nil checks when compiling this function
@@ -731,8 +747,10 @@
OXXX Op = iota
// names
- ONAME // var or func name
- ONONAME // unnamed arg or return value: f(int, string) (int, error) { etc }
+ ONAME // var or func name
+ // Unnamed arg or return value: f(int, string) (int, error) { etc }
+ // Also used for a qualified package identifier that hasn't been resolved yet.
+ ONONAME
OTYPE // type name
OPACK // import
OLITERAL // literal
@@ -752,14 +770,18 @@
OSTR2BYTES // Type(Left) (Type is []byte, Left is a string)
OSTR2BYTESTMP // Type(Left) (Type is []byte, Left is a string, ephemeral)
OSTR2RUNES // Type(Left) (Type is []rune, Left is a string)
- OAS // Left = Right or (if Colas=true) Left := Right
- OAS2 // List = Rlist (x, y, z = a, b, c)
- OAS2DOTTYPE // List = Right (x, ok = I.(int))
- OAS2FUNC // List = Right (x, y = f())
- OAS2MAPR // List = Right (x, ok = m["foo"])
- OAS2RECV // List = Right (x, ok = <-c)
- OASOP // Left Etype= Right (x += y)
- OCALL // Left(List) (function call, method call or type conversion)
+ // Left = Right or (if Colas=true) Left := Right
+ // If Colas, then Ninit includes a DCL node for Left.
+ OAS
+ // List = Rlist (x, y, z = a, b, c) or (if Colas=true) List := Rlist
+ // If Colas, then Ninit includes DCL nodes for List
+ OAS2
+ OAS2DOTTYPE // List = Right (x, ok = I.(int))
+ OAS2FUNC // List = Right (x, y = f())
+ OAS2MAPR // List = Right (x, ok = m["foo"])
+ OAS2RECV // List = Right (x, ok = <-c)
+ OASOP // Left Etype= Right (x += y)
+ OCALL // Left(List) (function call, method call or type conversion)
// OCALLFUNC, OCALLMETH, and OCALLINTER have the same structure.
// Prior to walk, they are: Left(List), where List is all regular arguments.
