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cmd/link: track content-hashed-ness for cloned symbols

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If a symbol is cloned to an external symbol in order to edit it
(e.g. to insert a trampoline), we need to keep track whether it is
a content hashed symbol, so we can set proper attributes in later
phases, in particular, for external linking.

This should fix the build failure on RISCV64, where there are a
lot more trampolines needed due to its small direct call range.
In theory, the same failure could occur on other platforms if a
call from a non-deduplicated closure needs a trampoline.

Fixes #79270.

Change-Id: I293194f4bf6bf152dc32e183ca32d92d62c0a4ef
Reviewed-on: https://go-review.googlesource.com/c/go/+/779402
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Cherry Mui 2026-05-18 17:42:04 -04:00
parent 99623c5a17
commit 003833a138
1 changed files with 26 additions and 16 deletions
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42
src/cmd/link/internal/loader/loader.go
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@ -92,6 +92,13 @@ type oReader struct {
// non-package symbols).
func (r *oReader) NAlldef() int { return r.ndef + r.nhashed64def + r.nhasheddef + r.NNonpkgdef() }
// whether the symbol at local index li is a content hashed symbol
func (r *oReader) IsContentHashed(li uint32) bool {
start := uint32(r.ndef + r.nhashed64def)
end := start + uint32(r.nhasheddef)
return start <= li && li < end
}
// objSym represents a symbol in an object file. It is a tuple of
// the object and the symbol's local index.
// For external symbols, objidx is the index of l.extReader (extObj),
@ -230,18 +237,19 @@ type Loader struct {
outer []Sym // indexed by global index
sub map[Sym]Sym
dynimplib map[Sym]string // stores Dynimplib symbol attribute
dynimpvers map[Sym]string // stores Dynimpvers symbol attribute
localentry map[Sym]uint8 // stores Localentry symbol attribute
extname map[Sym]string // stores Extname symbol attribute
elfType map[Sym]elf.SymType // stores elf type symbol property
elfSym map[Sym]int32 // stores elf sym symbol property
localElfSym map[Sym]int32 // stores "local" elf sym symbol property
symPkg map[Sym]string // stores package for symbol, or library for shlib-derived syms
plt map[Sym]int32 // stores dynimport for pe objects
got map[Sym]int32 // stores got for pe objects
dynid map[Sym]int32 // stores Dynid for symbol
weakBinding map[Sym]bool // stores whether a symbol has a weak binding
dynimplib map[Sym]string // stores Dynimplib symbol attribute
dynimpvers map[Sym]string // stores Dynimpvers symbol attribute
localentry map[Sym]uint8 // stores Localentry symbol attribute
extname map[Sym]string // stores Extname symbol attribute
elfType map[Sym]elf.SymType // stores elf type symbol property
elfSym map[Sym]int32 // stores elf sym symbol property
localElfSym map[Sym]int32 // stores "local" elf sym symbol property
symPkg map[Sym]string // stores package for symbol, or library for shlib-derived syms
plt map[Sym]int32 // stores dynimport for pe objects
got map[Sym]int32 // stores got for pe objects
dynid map[Sym]int32 // stores Dynid for symbol
weakBinding map[Sym]bool // stores whether a symbol has a weak binding
contentHashed map[Sym]bool // whether a symbol is a content hashed symbol, for external symbol only
relocVariant map[relocId]sym.RelocVariant // stores variant relocs
@ -331,6 +339,7 @@ func NewLoader(flags uint32, reporter *ErrorReporter) *Loader {
attrCgoExportDynamic: make(map[Sym]struct{}),
attrCgoExportStatic: make(map[Sym]struct{}),
deferReturnTramp: make(map[Sym]bool),
contentHashed: make(map[Sym]bool),
extStaticSyms: make(map[nameVer]Sym),
builtinSyms: make([]Sym, nbuiltin),
flags: flags,
@ -818,12 +827,10 @@ func (l *Loader) SymVersion(i Sym) int {
func (l *Loader) IsContentHashed(i Sym) bool {
if l.IsExternal(i) {
return false
return l.contentHashed[i]
}
r, li := l.toLocal(i)
start := uint32(r.ndef + r.nhashed64def)
end := start + uint32(r.nhasheddef)
return start <= li && li < end
return r.IsContentHashed(li)
}
func (l *Loader) IsFileLocal(i Sym) bool {
@ -2647,6 +2654,9 @@ func (l *Loader) cloneToExternal(symIdx Sym) *extSymPayload {
// Some attributes were encoded in the object file. Copy them over.
l.SetAttrDuplicateOK(symIdx, r.Sym(li).Dupok())
l.SetAttrShared(symIdx, r.Shared())
if r.IsContentHashed(li) {
l.contentHashed[symIdx] = true
}
return pp
}