cmd/compile/internal/syntax: expose additional information for gc

gc needs access to line offsets for Nodes. It also needs access to the
end line offset for function bodies so it knows what line number to
use for things like implicit returns and defer executions.

Lastly, include an extra bool to distinguish between simple and full
slice expressions. This is redundant in valid parse trees, but needed
by gc for producing complete warnings in invalid inputs.

Change-Id: I64baf334a35c72336d26fa6755c67eb9d6f4e93c
Reviewed-on: https://go-review.googlesource.com/27196
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/cmd/compile/internal/syntax/nodes.go b/src/cmd/compile/internal/syntax/nodes.go
index 4e264c1e829e1ac734c7a08d0212f70218da681c..e56b1235fe075a7e4197b1b26e425e58ecd1f83d 100644 (file)
--- a/src/cmd/compile/internal/syntax/nodes.go
+++ b/src/cmd/compile/internal/syntax/nodes.go
@@ -8,6 +8,7 @@ package syntax
 // Nodes
 
 type Node interface {
+       Line() uint32
        aNode()
 }
 
@@ -19,6 +20,10 @@ type node struct {
 
 func (*node) aNode() {}
 
+func (n *node) Line() uint32 {
+       return n.line
+}
+
 func (n *node) init(p *parser) {
        n.pos = uint32(p.pos)
        n.line = uint32(p.line)
@@ -80,11 +85,12 @@ type (
        }
 
        FuncDecl struct {
-               Attr map[string]bool // go:attr map
-               Recv *Field          // nil means regular function
-               Name *Name
-               Type *FuncType
-               Body []Stmt // nil means no body (forward declaration)
+               Attr    map[string]bool // go:attr map
+               Recv    *Field          // nil means regular function
+               Name    *Name
+               Type    *FuncType
+               Body    []Stmt // nil means no body (forward declaration)
+               EndLine uint32 // TODO(mdempsky): Cleaner solution.
                decl
        }
 )
@@ -136,8 +142,9 @@ type (
 
        // func Type { Body }
        FuncLit struct {
-               Type *FuncType
-               Body []Stmt
+               Type    *FuncType
+               Body    []Stmt
+               EndLine uint32 // TODO(mdempsky): Cleaner solution.
                expr
        }
 
@@ -165,6 +172,11 @@ type (
        SliceExpr struct {
                X     Expr
                Index [3]Expr
+               // Full indicates whether this is a simple or full slice expression.
+               // In a valid AST, this is equivalent to Index[2] != nil.
+               // TODO(mdempsky): This is only needed to report the "3-index
+               // slice of string" error when Index[2] is missing.
+               Full bool
                expr
        }
 

diff --git a/src/cmd/compile/internal/syntax/parser.go b/src/cmd/compile/internal/syntax/parser.go
index f267d4b2c9577dafb086b2e737bc680dbc50e92b..40253224f0892ba92e2a65caeedb3d202a579124 100644 (file)
--- a/src/cmd/compile/internal/syntax/parser.go
+++ b/src/cmd/compile/internal/syntax/parser.go
@@ -422,6 +422,8 @@ func (p *parser) funcDecl() *FuncDecl {
        f.Type = p.funcType()
        f.Body = p.funcBody()
 
+       f.EndLine = uint32(p.line)
+
        // TODO(gri) deal with function properties
        // if noescape && body != nil {
        //      p.error("can only use //go:noescape with external func implementations")
@@ -624,6 +626,7 @@ func (p *parser) operand(keep_parens bool) Expr {
                        f.init(p)
                        f.Type = t
                        f.Body = p.funcBody()
+                       f.EndLine = uint32(p.line)
                        p.xnest--
                        p.fnest--
                        return f
@@ -739,6 +742,7 @@ loop:
                                t.Index[1] = p.expr()
                        }
                        if p.got(_Colon) {
+                               t.Full = true
                                // x[i:j:...]
                                if t.Index[1] == nil {
                                        p.error("middle index required in 3-index slice")