cmd/asm: require -p flag

CL 391014 requires the compiler to be invoked with the -p flag, to
specify the package path. Later, CL 394217 makes the compiler to
produce an unlinkable object file, so "go tool compile x.go" can
still be used on the command line. This CL does the same for the
assembler, requiring -p, otherwise generating an unlinkable object.

No special case for the main package, as the main package cannot
be only assembly code, and there is no way to tell if it is the
main package from an assembly file.

Now we guarantee that we always have an expanded package path in
the object file. A later CL will delete the name expansion code
in the linker.

Change-Id: I8c10661aaea2ff794614924ead958d80e7e2487d
Reviewed-on: https://go-review.googlesource.com/c/go/+/404298
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/src/cmd/internal/goobj/objfile.go b/src/cmd/internal/goobj/objfile.go
index 665fa41475..34c5bb97f8 100644
--- a/src/cmd/internal/goobj/objfile.go
+++ b/src/cmd/internal/goobj/objfile.go
@@ -281,10 +281,10 @@ const SymSize = stringRefSize + 2 + 1 + 1 + 1 + 4 + 4
 const SymABIstatic = ^uint16(0)
 
 const (
-	ObjFlagShared            = 1 << iota // this object is built with -shared
-	ObjFlagNeedNameExpansion             // the linker needs to expand `"".` to package path in symbol names
-	ObjFlagFromAssembly                  // object is from asm src, not go
-	ObjFlagUnlinkable                    // unlinkable package (linker will emit an error)
+	ObjFlagShared       = 1 << iota // this object is built with -shared
+	_                               // was ObjFlagNeedNameExpansion
+	ObjFlagFromAssembly             // object is from asm src, not go
+	ObjFlagUnlinkable               // unlinkable package (linker will emit an error)
 )
 
 // Sym.Flag
@@ -873,6 +873,6 @@ func (r *Reader) Flags() uint32 {
 }
 
 func (r *Reader) Shared() bool            { return r.Flags()&ObjFlagShared != 0 }
-func (r *Reader) NeedNameExpansion() bool { return r.Flags()&ObjFlagNeedNameExpansion != 0 }
+func (r *Reader) NeedNameExpansion() bool { return false } // TODO: delete
 func (r *Reader) FromAssembly() bool      { return r.Flags()&ObjFlagFromAssembly != 0 }
 func (r *Reader) Unlinkable() bool        { return r.Flags()&ObjFlagUnlinkable != 0 }