cmd/compile: refactor import statement parsing
Combine parser's import_stmt and import_here methods as a single new
importdcl method, and cleanup conditional logic slightly to make the
code easier to follow.
Also, eliminate importfile's unused line parameter, and get rid of all
of its duplicate type assertions.
Change-Id: Ic37ae8490afedc533f98ead9feef383e3599bc01
Reviewed-on: https://go-review.googlesource.com/19629
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/gc/go.go b/src/cmd/compile/internal/gc/go.go
index 8053aaf..ebc6a51 100644
--- a/src/cmd/compile/internal/gc/go.go
+++ b/src/cmd/compile/internal/gc/go.go
@@ -492,8 +492,6 @@
var Debug_checknil int
var Debug_typeassert int
-var importmyname *Sym // my name for package
-
var localpkg *Pkg // package being compiled
var importpkg *Pkg // package being imported
diff --git a/src/cmd/compile/internal/gc/lex.go b/src/cmd/compile/internal/gc/lex.go
index 8161cad..83f25a5 100644
--- a/src/cmd/compile/internal/gc/lex.go
+++ b/src/cmd/compile/internal/gc/lex.go
@@ -687,21 +687,21 @@
cannedimports("fake.o", "$$\n")
}
-// TODO(gri) line argument doesn't appear to be used
-func importfile(f *Val, line int) {
- if _, ok := f.U.(string); !ok {
+func importfile(f *Val) {
+ path_, ok := f.U.(string)
+ if !ok {
Yyerror("import statement not a string")
fakeimport()
return
}
- if len(f.U.(string)) == 0 {
+ if len(path_) == 0 {
Yyerror("import path is empty")
fakeimport()
return
}
- if isbadimport(f.U.(string)) {
+ if isbadimport(path_) {
fakeimport()
return
}
@@ -710,18 +710,16 @@
// but we reserve the import path "main" to identify
// the main package, just as we reserve the import
// path "math" to identify the standard math package.
- if f.U.(string) == "main" {
+ if path_ == "main" {
Yyerror("cannot import \"main\"")
errorexit()
}
- if myimportpath != "" && f.U.(string) == myimportpath {
- Yyerror("import %q while compiling that package (import cycle)", f.U.(string))
+ if myimportpath != "" && path_ == myimportpath {
+ Yyerror("import %q while compiling that package (import cycle)", path_)
errorexit()
}
- path_ := f.U.(string)
-
if mapped, ok := importMap[path_]; ok {
path_ = mapped
}
@@ -763,7 +761,7 @@
file, found := findpkg(path_)
if !found {
- Yyerror("can't find import: %q", f.U.(string))
+ Yyerror("can't find import: %q", path_)
errorexit()
}
@@ -788,7 +786,7 @@
var imp *obj.Biobuf
imp, err = obj.Bopenr(file)
if err != nil {
- Yyerror("can't open import: %q: %v", f.U.(string), err)
+ Yyerror("can't open import: %q: %v", path_, err)
errorexit()
}
@@ -878,7 +876,7 @@
incannedimport = 0
default:
- Yyerror("no import in %q", f.U.(string))
+ Yyerror("no import in %q", path_)
}
}
diff --git a/src/cmd/compile/internal/gc/parser.go b/src/cmd/compile/internal/gc/parser.go
index 7e521d1..6081383 100644
--- a/src/cmd/compile/internal/gc/parser.go
+++ b/src/cmd/compile/internal/gc/parser.go
@@ -323,108 +323,92 @@
p.want(LIMPORT)
if p.got('(') {
for p.tok != EOF && p.tok != ')' {
- p.import_stmt()
+ p.importdcl()
if !p.osemi(')') {
break
}
}
p.want(')')
} else {
- p.import_stmt()
- }
-}
-
-func (p *parser) import_stmt() {
- if trace && Debug['x'] != 0 {
- defer p.trace("import_stmt")()
- }
-
- line := int32(p.import_here())
- if p.tok == LPACKAGE {
- p.import_package()
- p.import_there()
-
- ipkg := importpkg
- my := importmyname
- importpkg = nil
- importmyname = nil
-
- if my == nil {
- my = Lookup(ipkg.Name)
- }
-
- pack := Nod(OPACK, nil, nil)
- pack.Sym = my
- pack.Name.Pkg = ipkg
- pack.Lineno = line
-
- if strings.HasPrefix(my.Name, ".") {
- importdot(ipkg, pack)
- return
- }
- if my.Name == "init" {
- lineno = line
- Yyerror("cannot import package as init - init must be a func")
- return
- }
- if my.Name == "_" {
- return
- }
- if my.Def != nil {
- lineno = line
- redeclare(my, "as imported package name")
- }
- my.Def = pack
- my.Lastlineno = line
- my.Block = 1 // at top level
-
- return
- }
-
- p.import_there()
- // When an invalid import path is passed to importfile,
- // it calls Yyerror and then sets up a fake import with
- // no package statement. This allows us to test more
- // than one invalid import statement in a single file.
- if nerrors == 0 {
- Fatalf("phase error in import")
+ p.importdcl()
}
}
// ImportSpec = [ "." | PackageName ] ImportPath .
// ImportPath = string_lit .
-//
-// import_here switches the underlying lexed source to the export data
-// of the imported package.
-func (p *parser) import_here() int {
+func (p *parser) importdcl() {
if trace && Debug['x'] != 0 {
- defer p.trace("import_here")()
+ defer p.trace("importdcl")()
}
- importmyname = nil
+ var my *Sym
switch p.tok {
case LNAME, '@', '?':
// import with given name
- importmyname = p.sym()
+ my = p.sym()
case '.':
// import into my name space
- importmyname = Lookup(".")
+ my = Lookup(".")
p.next()
}
- var path Val
- if p.tok == LLITERAL {
- path = p.val
- p.next()
- } else {
+ if p.tok != LLITERAL {
p.syntax_error("missing import path; require quoted string")
p.advance(';', ')')
+ return
}
- line := parserline()
- importfile(&path, line)
- return line
+ line := int32(parserline())
+ path := p.val
+ p.next()
+
+ importfile(&path)
+ if p.tok != LPACKAGE {
+ // When an invalid import path is passed to importfile,
+ // it calls Yyerror and then sets up a fake import with
+ // no package statement. This allows us to test more
+ // than one invalid import statement in a single file.
+ p.import_there()
+ if nerrors == 0 {
+ Fatalf("phase error in import")
+ }
+ return
+ }
+ p.import_package()
+ p.import_there()
+
+ ipkg := importpkg
+ importpkg = nil
+
+ if my == nil {
+ my = Lookup(ipkg.Name)
+ }
+
+ pack := Nod(OPACK, nil, nil)
+ pack.Sym = my
+ pack.Name.Pkg = ipkg
+ pack.Lineno = line
+
+ if strings.HasPrefix(my.Name, ".") {
+ importdot(ipkg, pack)
+ return
+ }
+ if my.Name == "init" {
+ lineno = line
+ Yyerror("cannot import package as init - init must be a func")
+ return
+ }
+ if my.Name == "_" {
+ return
+ }
+ if my.Def != nil {
+ lineno = line
+ redeclare(my, "as imported package name")
+ }
+ my.Def = pack
+ my.Lastlineno = line
+ my.Block = 1 // at top level
}
// import_package parses the header of an imported package as exported
