elf: Handle .gnu.debuglto_.debug_* sections

commit 994b25132814f4c2be93ce53a616a74139c4cf3c
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Sun Jan 17 20:01:16 2021 -0800

    ld/elf: Ignore section symbols when matching linkonce with comdat

ignored section symbols when comparing symbols in 2 sections.  Since all
references to debugging sections are done with section symbols, symbols
in debugging sections are ignored and we fail to match symbols in comdat
debugging sections.  Also .gnu.debuglto_.debug_* sections aren't treated
as debugging sections.

1. Treate .gnu.debuglto_.debug_ section as debugging section unless it
is marked with SHF_EXCLUDE.
2. Revert commit 994b2513281 in elf_create_symbuf.
3. Ignore section symbols only when matching non-debugging sections or
linkonce section with comdat section.

bfd/

	PR ld/27590
	* elf.c (_bfd_elf_make_section_from_shdr): Treate
	.gnu.debuglto_.debug_ section as debugging section unless it is
	marked with SHF_EXCLUDE.
	* elflink.c (elf_create_symbuf): Revert commit 994b2513281.
	(bfd_elf_match_symbols_in_sections): Ignore section symbols when
	matching non-debugging sections or linkonce section with comdat
	section.

ld/

	PR ld/27590
	* testsuite/ld-elf/pr27590.s: New file.
	* testsuite/ld-elf/pr27590a.d: Likewise.
	* testsuite/ld-elf/pr27590b.d: Likewise.
	* testsuite/ld-i386/i386.exp: Also run ld/27193 test with
	--reduce-memory-overheads.

5 files changed, 42 insertions, 2 deletions

diff --git a/ld/ChangeLog b/ld/ChangeLog
index d9b049f..30ac9b4 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,5 +1,14 @@
 2021-03-18  H.J. Lu  <hongjiu.lu@intel.com>
 
+	PR ld/27590
+	* testsuite/ld-elf/pr27590.s: New file.
+	* testsuite/ld-elf/pr27590a.d: Likewise.
+	* testsuite/ld-elf/pr27590b.d: Likewise.
+	* testsuite/ld-i386/i386.exp: Also run ld/27193 test with
+	--reduce-memory-overheads.
+
+2021-03-18  H.J. Lu  <hongjiu.lu@intel.com>
+
 	PR ld/27587
 	* testsuite/ld-x86-64/pr27587.err: New file.
 	* testsuite/ld-x86-64/pr27587a.obj.bz2: Likewise.
diff --git a/ld/testsuite/ld-elf/pr27590.s b/ld/testsuite/ld-elf/pr27590.s
new file mode 100644
index 0000000..f7340b4
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr27590.s
@@ -0,0 +1,6 @@
+	.section	.gnu.debuglto_.debug_macro,"",%progbits
+.Ldebug_macro0:
+	.dc.a	.Ldebug_macro2
+	.section	.gnu.debuglto_.debug_macro,"G",%progbits,wm4,comdat
+.Ldebug_macro2:
+	.long	0x4
diff --git a/ld/testsuite/ld-elf/pr27590a.d b/ld/testsuite/ld-elf/pr27590a.d
new file mode 100644
index 0000000..c24cd89
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr27590a.d
@@ -0,0 +1,10 @@
+#source: pr27590.s
+#ld: -r tmpdir/pr27590.o
+#readelf: -rW
+#xfail: [is_generic]
+
+Relocation section '\.rel.*\.gnu\.debuglto_\.debug_macro' at offset 0x[0-9a-z]+ contains 2 entries:
+[ \t]+Offset[ \t]+Info[ \t]+Type[ \t]+Sym.*
+[0-9a-f]+[ \t]+[0-9a-f]+[ \t]+R_.*[ \t]+[0]+[ \t]+\.gnu\.debuglto_\.debug_macro.*
+[0-9a-f]+[ \t]+[0-9a-f]+[ \t]+R_.*[ \t]+[0]+[ \t]+\.gnu\.debuglto_\.debug_macro.*
+#pass
diff --git a/ld/testsuite/ld-elf/pr27590b.d b/ld/testsuite/ld-elf/pr27590b.d
new file mode 100644
index 0000000..68b198b
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr27590b.d
@@ -0,0 +1,10 @@
+#source: pr27590.s
+#ld: -r tmpdir/pr27590.o --reduce-memory-overheads
+#readelf: -rW
+#xfail: [is_generic]
+
+Relocation section '\.rel.*\.gnu\.debuglto_\.debug_macro' at offset 0x[0-9a-z]+ contains 2 entries:
+[ \t]+Offset[ \t]+Info[ \t]+Type[ \t]+Sym.*
+[0-9a-f]+[ \t]+[0-9a-f]+[ \t]+R_.*[ \t]+[0]+[ \t]+\.gnu\.debuglto_\.debug_macro.*
+[0-9a-f]+[ \t]+[0-9a-f]+[ \t]+R_.*[ \t]+[0]+[ \t]+\.gnu\.debuglto_\.debug_macro.*
+#pass
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index d9075bf..6ad69a8 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -245,11 +245,16 @@ set i386tests {
      "-melf_i386 -shared -Bsymbolic -z notext" ""
      "--32 -mx86-used-note=yes"
      { pr19827a.S }  {{readelf {-rW} pr19827.rd}} "pr19827.so"}
-    {"Build pr27193.so"
+    {"Build pr27193a.so"
      "-melf_i386 -shared" ""
      "--32"
      { pr27193a.o.bz2 pr27193b.s }
-     {{objdump {-dw} pr27193.dd}} "pr27193.so"}
+     {{objdump {-dw} pr27193.dd}} "pr27193a.so"}
+    {"Build pr27193b.so"
+     "-melf_i386 -shared --reduce-memory-overheads" ""
+     "--32"
+     { pr27193a.o.bz2 pr27193b.s }
+     {{objdump {-dw} pr27193.dd}} "pr27193b.so"}
 }
 
 proc iamcu_tests {} {