From 0bd1a2289d0e37ec5015ce3c05a5873c3a6da3e5 Mon Sep 17 00:00:00 2001 From: "Paul E. Murphy" Date: Tue, 12 Mar 2024 15:00:08 -0500 Subject: [release-branch.go1.21] cmd/internal/obj/ppc64: don't modify runtime.elf_* symbols The runtime.elf_* symbols are assembly functions which are used to support the gcc/llvm -Os option when used with cgo. When compiling Go for shared code, we attempt to strip out the TOC regenation code added by the go assembler for these symbols. This causes the symbol to no longer appear as an assembly function which causes problems later on when handling other implicit symbols. Avoid adding a TOC regeneration prologue to these functions to avoid this issue. Fixes #66411 Change-Id: Icbf8e4438d177082a57bb228e39b232e7a0d7ada Reviewed-on: https://go-review.googlesource.com/c/go/+/571835 Reviewed-by: Than McIntosh Run-TryBot: Paul Murphy Reviewed-by: Cherry Mui LUCI-TryBot-Result: Go LUCI Reviewed-by: Lynn Boger TryBot-Result: Gopher Robot Reviewed-on: https://go-review.googlesource.com/c/go/+/572876 --- .../go/testdata/script/test_ppc64_linker_funcs.txt | 4 ++++ src/cmd/internal/obj/ppc64/obj9.go | 19 ++++++++++++++++++- src/cmd/link/internal/ppc64/asm.go | 17 +---------------- 3 files changed, 23 insertions(+), 17 deletions(-) diff --git a/src/cmd/go/testdata/script/test_ppc64_linker_funcs.txt b/src/cmd/go/testdata/script/test_ppc64_linker_funcs.txt index 735b5dcc7f..d789f89f4e 100644 --- a/src/cmd/go/testdata/script/test_ppc64_linker_funcs.txt +++ b/src/cmd/go/testdata/script/test_ppc64_linker_funcs.txt @@ -14,6 +14,10 @@ go build -ldflags='-linkmode=internal' exec ./abitest stdout success +go build -buildmode=pie -o abitest.pie -ldflags='-linkmode=internal' +exec ./abitest.pie +stdout success + -- go.mod -- module abitest diff --git a/src/cmd/internal/obj/ppc64/obj9.go b/src/cmd/internal/obj/ppc64/obj9.go index 02831b890a..57660ce2ce 100644 --- a/src/cmd/internal/obj/ppc64/obj9.go +++ b/src/cmd/internal/obj/ppc64/obj9.go @@ -36,8 +36,25 @@ import ( "cmd/internal/sys" "internal/abi" "log" + "strings" ) +// Is this a symbol which should never have a TOC prologue generated? +// These are special functions which should not have a TOC regeneration +// prologue. +func isNOTOCfunc(name string) bool { + switch { + case name == "runtime.duffzero": + return true + case name == "runtime.duffcopy": + return true + case strings.HasPrefix(name, "runtime.elf_"): + return true + default: + return false + } +} + func progedit(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) { p.From.Class = 0 p.To.Class = 0 @@ -643,7 +660,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) { q = p - if NeedTOCpointer(c.ctxt) && c.cursym.Name != "runtime.duffzero" && c.cursym.Name != "runtime.duffcopy" { + if NeedTOCpointer(c.ctxt) && !isNOTOCfunc(c.cursym.Name) { // When compiling Go into PIC, without PCrel support, all functions must start // with instructions to load the TOC pointer into r2: // diff --git a/src/cmd/link/internal/ppc64/asm.go b/src/cmd/link/internal/ppc64/asm.go index d537bc533c..3def3e6919 100644 --- a/src/cmd/link/internal/ppc64/asm.go +++ b/src/cmd/link/internal/ppc64/asm.go @@ -475,24 +475,9 @@ func rewriteABIFuncReloc(ctxt *ld.Link, ldr *loader.Loader, tname string, r load r.SetAdd(int64((n - minReg) * offMul)) firstUse = !ldr.AttrReachable(ts) if firstUse { - ldr.SetAttrReachable(ts, true) // This function only becomes reachable now. It has been dropped from // the text section (it was unreachable until now), it needs included. - // - // Similarly, TOC regeneration should not happen for these functions, - // remove it from this save/restore function. - if ldr.AttrShared(ts) { - sb := ldr.MakeSymbolUpdater(ts) - sb.SetData(sb.Data()[8:]) - sb.SetSize(sb.Size() - 8) - relocs := sb.Relocs() - // Only one PCREL reloc to .TOC. should be present. - if relocs.Count() != 1 { - log.Fatalf("Unexpected number of relocs in %s\n", ldr.SymName(ts)) - } - sb.ResetRelocs() - - } + ldr.SetAttrReachable(ts, true) } return ts, firstUse } -- cgit v1.2.3-54-g00ecf