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| author | Cherry Mui <cherryyz@google.com> | 2021-10-01 12:21:36 -0400 |
|---|---|---|
| committer | Cherry Mui <cherryyz@google.com> | 2021-10-04 22:46:23 +0000 |
| commit | 17674e2f174280c38ea7ae8297571c09b6eb076b (patch) | |
| tree | 6a9ca87bfe8d5da20eaad3b7357e7cfbdb060543 /src/cmd/internal | |
| parent | c2483a5c034152fcdfbb2e6dbcf48b0103d8db6a (diff) | |
| download | go-17674e2f174280c38ea7ae8297571c09b6eb076b.tar.gz go-17674e2f174280c38ea7ae8297571c09b6eb076b.zip | |
cmd/internal/obj, cmd/link: move symbol alignment logic to object file writer
Change-Id: I827a9702dfa01b712b88331668434f8db94df249
Reviewed-on: https://go-review.googlesource.com/c/go/+/353569
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Diffstat (limited to 'src/cmd/internal')
| -rw-r--r-- | src/cmd/internal/obj/objfile.go | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go index 4fd2119b96..b6b922e02b 100644 --- a/src/cmd/internal/obj/objfile.go +++ b/src/cmd/internal/obj/objfile.go @@ -332,14 +332,27 @@ func (w *writer) Sym(s *LSym) { if fn := s.Func(); fn != nil { align = uint32(fn.Align) } - if s.ContentAddressable() { - // We generally assume data symbols are natually aligned, - // except for strings. If we dedup a string symbol and a - // non-string symbol with the same content, we should keep + if s.ContentAddressable() && s.Size != 0 { + // We generally assume data symbols are natually aligned + // (e.g. integer constants), except for strings and a few + // compiler-emitted funcdata. If we dedup a string symbol and + // a non-string symbol with the same content, we should keep // the largest alignment. // TODO: maybe the compiler could set the alignment for all // data symbols more carefully. - if s.Size != 0 && !strings.HasPrefix(s.Name, "go.string.") { + switch { + case strings.HasPrefix(s.Name, "go.string."), + strings.HasPrefix(name, "type..namedata."), + strings.HasPrefix(name, "type..importpath."), + strings.HasSuffix(name, ".opendefer"), + strings.HasSuffix(name, ".arginfo0"), + strings.HasSuffix(name, ".arginfo1"): + // These are just bytes, or varints. + align = 1 + case strings.HasPrefix(name, "gclocals·"): + // It has 32-bit fields. + align = 4 + default: switch { case w.ctxt.Arch.PtrSize == 8 && s.Size%8 == 0: align = 8 @@ -347,8 +360,9 @@ func (w *writer) Sym(s *LSym) { align = 4 case s.Size%2 == 0: align = 2 + default: + align = 1 } - // don't bother setting align to 1. } } if s.Size > cutoff { |