• Josh Bleecher Snyder's avatar
    cmd/internal/obj: fix LSym.Type during compilation, not linking · 18fb670e
    Josh Bleecher Snyder authored
    Prior to this CL, the compiler and assembler
    were sloppy about the LSym.Type for LSyms
    containing static data.
    
    The linker then fixed this up, converting
    Sxxx and SBSS to SDATA, and SNOPTRBSS to SNOPTRDATA
    if it noticed that the symbol had associated data.
    
    It is preferable to just get this right in cmd/compile
    and cmd/asm, because it removes an unnecessary traversal
    of the symbol table from the linker (see #14624).
    Do this by touching up the LSym.Type fixes in
    LSym.prepwrite and Link.Globl.
    
    I have confirmed by instrumenting the linker
    that the now-eliminated code paths were unreached.
    And an additional check in the object file writing code
    will help preserve that invariant.
    
    There was a case in the Windows linker,
    with internal linking and cgo,
    where we were generating SNOPTRBSS symbols with data.
    For now, convert those at the site at which they occur
    into SNOPTRDATA, just like they were.
    
    Does not pass toolstash-check,
    but does generate identical linked binaries.
    
    No compiler performance changes.
    
    Change-Id: I77b071ab103685ff8e042cee9abb864385488872
    Reviewed-on: https://go-review.googlesource.com/40864
    Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
    TryBot-Result: Gobot Gobot <gobot@golang.org>
    Reviewed-by: 's avatarAlex Brainman <alex.brainman@gmail.com>
    Reviewed-by: 's avatarMichael Hudson-Doyle <michael.hudson@canonical.com>
    18fb670e
file_test.go 14.7 KB