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| author | Cherry Zhang <cherryyz@google.com> | 2021-02-01 13:36:50 -0500 |
|---|---|---|
| committer | Cherry Zhang <cherryyz@google.com> | 2021-02-02 16:00:58 +0000 |
| commit | 98f8454a73b569d81d1c5e167d7b68f22e2e3fea (patch) | |
| tree | 30baeb9e90cbad80f4bf04b17843305227803603 /src | |
| parent | 1426a571b79bfcb3c0339e2fd96c893cd1549af6 (diff) | |
| download | go-98f8454a73b569d81d1c5e167d7b68f22e2e3fea.tar.gz go-98f8454a73b569d81d1c5e167d7b68f22e2e3fea.zip | |
cmd/link: don't decode type symbol in shared library in deadcode
In the linker's deadcode pass we decode type symbols for
interface satisfaction analysis. When linking against Go shared
libraries, the type symbol may come from a shared library, so it
doesn't have data in the current module being linked, so we cannot
decode it. We already have code to skip DYNIMPORT symbols. However,
this doesn't actually work, because at that point the type symbols'
names haven't been mangled, whereas they may be mangled in the
shared library. So the symbol definition (in shared library) and
reference (in current module) haven't been connected.
Skip decoding type symbols of type Sxxx (along with DYNIMPORT)
when linkShared.
Note: we cannot skip all type symbols, as we still need to mark
unexported methods defined in the current module.
Fixes #44031.
Change-Id: I833d19a060c94edbd6fc448172358f9a7d760657
Reviewed-on: https://go-review.googlesource.com/c/go/+/288496
Trust: Cherry Zhang <cherryyz@google.com>
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cmd/link/internal/ld/deadcode.go | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/src/cmd/link/internal/ld/deadcode.go b/src/cmd/link/internal/ld/deadcode.go index d8813fa9361..245076a83a5 100644 --- a/src/cmd/link/internal/ld/deadcode.go +++ b/src/cmd/link/internal/ld/deadcode.go @@ -165,13 +165,17 @@ func (d *deadcodePass) flood() { // R_USEIFACEMETHOD is a marker relocation that marks an interface // method as used. rs := r.Sym() - if d.ldr.SymType(rs) != sym.SDYNIMPORT { // don't decode DYNIMPORT symbol (we'll mark all exported methods anyway) - m := d.decodeIfaceMethod(d.ldr, d.ctxt.Arch, rs, r.Add()) - if d.ctxt.Debugvlog > 1 { - d.ctxt.Logf("reached iface method: %v\n", m) - } - d.ifaceMethod[m] = true + if d.ctxt.linkShared && (d.ldr.SymType(rs) == sym.SDYNIMPORT || d.ldr.SymType(rs) == sym.Sxxx) { + // Don't decode symbol from shared library (we'll mark all exported methods anyway). + // We check for both SDYNIMPORT and Sxxx because name-mangled symbols haven't + // been resolved at this point. + continue + } + m := d.decodeIfaceMethod(d.ldr, d.ctxt.Arch, rs, r.Add()) + if d.ctxt.Debugvlog > 1 { + d.ctxt.Logf("reached iface method: %v\n", m) } + d.ifaceMethod[m] = true continue } rs := r.Sym() |