76 lines
3.3 KiB
Diff
76 lines
3.3 KiB
Diff
From 079dfdbb94013e05660e54e6c7c3654468bc4160 Mon Sep 17 00:00:00 2001
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From: Lynn Boger <laboger@linux.vnet.ibm.com>
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Date: Thu, 29 Apr 2021 16:07:25 -0500
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Subject: [PATCH] cmd/link/internal: fix use of DynlinkingGo with ppc64le
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trampolines
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When creating programs with large text sections on ppc64le,
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trampolines are needed for calls that are too far; however
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they are not created if the code is generated such that the TOC
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register r2 is initialized and maintained in the code because
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then the external linker can create the trampolines. Previously
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the function DynlinkingGo was used to determine this but in the
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case where plugins are used, this could return true even though
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r2 is not valid.
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To fix this problem I've added a new function r2Valid which returns
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true when the build options indicate that the r2 is
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initialized and maintained. Because of the ways that
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DynlinkingGo is used I wanted to maintain its previous
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behavior.
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Fixes #45850
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Change-Id: I6d902eba6ad41757aa6474948b79acdbd479cb38
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Reviewed-on: https://go-review.googlesource.com/c/go/+/315289
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Trust: Lynn Boger <laboger@linux.vnet.ibm.com>
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Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
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TryBot-Result: Go Bot <gobot@golang.org>
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---
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src/cmd/link/internal/ppc64/asm.go | 14 ++++++++++++--
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1 file changed, 12 insertions(+), 2 deletions(-)
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diff --git a/src/cmd/link/internal/ppc64/asm.go b/src/cmd/link/internal/ppc64/asm.go
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index 602f0b5299..539afac187 100644
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--- a/src/cmd/link/internal/ppc64/asm.go
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+++ b/src/cmd/link/internal/ppc64/asm.go
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@@ -642,6 +642,16 @@ func archrelocaddr(ldr *loader.Loader, target *ld.Target, syms *ld.ArchSyms, r l
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return int64(o2)<<32 | int64(o1)
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}
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+// Determine if the code was compiled so that the TOC register R2 is initialized and maintained
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+func r2Valid(ctxt *ld.Link) bool {
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+ switch ctxt.BuildMode {
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+ case ld.BuildModeCArchive, ld.BuildModeCShared, ld.BuildModePIE, ld.BuildModeShared, ld.BuildModePlugin:
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+ return true
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+ }
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+ // -linkshared option
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+ return ctxt.IsSharedGoLink()
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+}
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+
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// resolve direct jump relocation r in s, and add trampoline if necessary
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func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
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@@ -649,7 +659,7 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
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// For internal linking, trampolines are always created for long calls.
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// For external linking, the linker can insert a call stub to handle a long call, but depends on having the TOC address in
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// r2. For those build modes with external linking where the TOC address is not maintained in r2, trampolines must be created.
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- if ctxt.IsExternal() && (ctxt.DynlinkingGo() || ctxt.BuildMode == ld.BuildModeCArchive || ctxt.BuildMode == ld.BuildModeCShared || ctxt.BuildMode == ld.BuildModePIE) {
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+ if ctxt.IsExternal() && r2Valid(ctxt) {
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// No trampolines needed since r2 contains the TOC
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return
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}
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@@ -703,7 +713,7 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
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}
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}
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if ldr.SymType(tramp) == 0 {
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- if ctxt.DynlinkingGo() || ctxt.BuildMode == ld.BuildModeCArchive || ctxt.BuildMode == ld.BuildModeCShared || ctxt.BuildMode == ld.BuildModePIE {
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+ if r2Valid(ctxt) {
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// Should have returned for above cases
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ctxt.Errorf(s, "unexpected trampoline for shared or dynamic linking")
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} else {
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--
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2.30.2
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