cmd/link: set alignment of compressed section based on arch

The ELF compression header(Chdr) has Addralign field that is set to the
alignment of the uncompressed section which makes section able to have
a different alignment than the decompressed section. However `file` and
other tools require both Chdr.Addralign and Addralign to be equal.

Ref https://sourceware.org/bugzilla/show_bug.cgi?id=23919
Related #42136

Fixes #51769

Change-Id: I3cf99dbd2359932576420a3c0d342c7e91b99227
Reviewed-on: https://go-review.googlesource.com/c/go/+/393916
Trust: mzh <mzh@golangcn.org>
Reviewed-by: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Fangrui Song <maskray@google.com>

diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go
index 289ebcb59580e66c8356ad34f8d19b784eb1c3d1..2e209d0c6b7dfa090103122cf205630ac6a047ab 100644 (file)
--- a/src/cmd/link/internal/ld/dwarf.go
+++ b/src/cmd/link/internal/ld/dwarf.go
@@ -2234,7 +2234,7 @@ func dwarfcompress(ctxt *Link) {
                                compressedSegName = ".zdebug_" + ldr.SymSect(s).Name[len(".debug_"):]
                        }
                        sect := addsection(ctxt.loader, ctxt.Arch, &Segdwarf, compressedSegName, 04)
-                       sect.Align = 1
+                       sect.Align = int32(ctxt.Arch.Alignment)
                        sect.Length = uint64(len(z.compressed))
                        sect.Compressed = true
                        newSym := ldr.MakeSymbolBuilder(compressedSegName)