ld/x86: Add -z report-relative-reloc

Linker generated relative relocations don't have symbol info:

[hjl@gnu-cfl-2 tmpdir]$ readelf -rW dump

Relocation section '.rela.dyn' at offset 0x180 contains 2 entries:
 Offset     Info    Type                Sym. Value  Symbol's Name + Addend
00002f70  00000008 R_X86_64_RELATIVE                 1000
00002f68  00000025 R_X86_64_IRELATIVE                1007
[hjl@gnu-cfl-2 tmpdir]$

Add -z report-relative-reloc to x86 ELF linker to report dynamic relative
relocations:

[hjl@gnu-cfl-2 tmpdir]$ ../ld-new -pie -melf32_x86_64 -z report-relative-reloc -o dump report-reloc-1.o
dump: R_X86_64_IRELATIVE (offset: 0x00002f68, info: 0x00000025, addend: 0x00001007) against 'ifunc' for section '.data.rel.ro.local' in report-reloc-1.o
dump: R_X86_64_RELATIVE (offset: 0x00002f70, info: 0x00000008, addend: 0x00001000) against '_start' for section '.data.rel.ro.local' in report-reloc-1.o
[hjl@gnu-cfl-2 tmpdir]$

It can be used to map relative relocations to corresponding symbols.

bfd/

	* elf-linker-x86.h (elf_linker_x86_params): Add
	report_relative_reloc.
	* elf32-i386.c (elf_i386_relocate_section): Call
	_bfd_x86_elf_link_report_relative_reloc to report relative
	relocations for -z report-relative-reloc.
	(elf_i386_finish_dynamic_symbol): Likewse.
	* elf64-x86-64.c (elf_x86_64_relocate_section): Likewse.
	(elf_x86_64_finish_dynamic_symbol): Likewse.
	* elfxx-x86.c (_bfd_x86_elf_link_report_relative_reloc): New
	function.
	* elfxx-x86.h (_bfd_x86_elf_link_report_relative_reloc): New
	prototype.

ld/

	* NEWS: Mention -z report-relative-reloc.
	* ld.texi: Document -z report-relative-reloc.
	* emulparams/elf32_x86_64.sh: Source x86-report-relative.sh.
	* emulparams/elf_i386.sh: Likewse.
	* emulparams/elf_x86_64.sh: Likewse.
	* emulparams/x86-report-relative.sh: New file.
	* testsuite/ld-i386/report-reloc-1.d: Likewse.
	* testsuite/ld-i386/report-reloc-1.l: Likewse.
	* testsuite/ld-i386/report-reloc-1.s: Likewse.
	* testsuite/ld-x86-64/report-reloc-1-x32.d: Likewse.
	* testsuite/ld-x86-64/report-reloc-1.d: Likewse.
	* testsuite/ld-x86-64/report-reloc-1.l: Likewse.
	* testsuite/ld-x86-64/report-reloc-1.s: Likewse.
	* testsuite/ld-i386/i386.exp: Run report-reloc-1.
	* testsuite/ld-x86-64/x86-64.exp: Run report-reloc-1 and
	report-reloc-1-x32.

16 files changed, 101 insertions, 0 deletions

diff --git a/ld/ChangeLog b/ld/ChangeLog
index c412eb64c67..6e534148907 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,22 @@
+2021-01-15  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* NEWS: Mention -z report-relative-reloc.
+	* ld.texi: Document -z report-relative-reloc.
+	* emulparams/elf32_x86_64.sh: Source x86-report-relative.sh.
+	* emulparams/elf_i386.sh: Likewse.
+	* emulparams/elf_x86_64.sh: Likewse.
+	* emulparams/x86-report-relative.sh: New file.
+	* testsuite/ld-i386/report-reloc-1.d: Likewse.
+	* testsuite/ld-i386/report-reloc-1.l: Likewse.
+	* testsuite/ld-i386/report-reloc-1.s: Likewse.
+	* testsuite/ld-x86-64/report-reloc-1-x32.d: Likewse.
+	* testsuite/ld-x86-64/report-reloc-1.d: Likewse.
+	* testsuite/ld-x86-64/report-reloc-1.l: Likewse.
+	* testsuite/ld-x86-64/report-reloc-1.s: Likewse.
+	* testsuite/ld-i386/i386.exp: Run report-reloc-1.
+	* testsuite/ld-x86-64/x86-64.exp: Run report-reloc-1 and
+	report-reloc-1-x32.
+
 2021-01-16  Alan Modra  <amodra@gmail.com>
 
 	PR 26002
diff --git a/ld/NEWS b/ld/NEWS
index 9948c3b31c4..88bf533b4fb 100644
--- a/ld/NEWS
+++ b/ld/NEWS
@@ -1,5 +1,8 @@
 -*- text -*-
 
+* Add -z report-relative-reloc to x86 ELF linker to report dynamic
+  relative relocations.
+
 Changes in 2.36:
 
 * Add libdep plugin, for linking dependencies of static libraries that
diff --git a/ld/emulparams/elf32_x86_64.sh b/ld/emulparams/elf32_x86_64.sh
index 0d7c7145a60..ac0a7aa6dcf 100644
--- a/ld/emulparams/elf32_x86_64.sh
+++ b/ld/emulparams/elf32_x86_64.sh
@@ -4,6 +4,7 @@ source_sh ${srcdir}/emulparams/dynamic_undefined_weak.sh
 source_sh ${srcdir}/emulparams/reloc_overflow.sh
 source_sh ${srcdir}/emulparams/call_nop.sh
 source_sh ${srcdir}/emulparams/cet.sh
+source_sh ${srcdir}/emulparams/x86-report-relative.sh
 source_sh ${srcdir}/emulparams/x86-64-level.sh
 source_sh ${srcdir}/emulparams/static.sh
 SCRIPT_NAME=elf
diff --git a/ld/emulparams/elf_i386.sh b/ld/emulparams/elf_i386.sh
index 741633fa07a..98532e5edbc 100644
--- a/ld/emulparams/elf_i386.sh
+++ b/ld/emulparams/elf_i386.sh
@@ -3,6 +3,7 @@ source_sh ${srcdir}/emulparams/extern_protected_data.sh
 source_sh ${srcdir}/emulparams/dynamic_undefined_weak.sh
 source_sh ${srcdir}/emulparams/call_nop.sh
 source_sh ${srcdir}/emulparams/cet.sh
+source_sh ${srcdir}/emulparams/x86-report-relative.sh
 source_sh ${srcdir}/emulparams/x86-64-level.sh
 source_sh ${srcdir}/emulparams/static.sh
 SCRIPT_NAME=elf
diff --git a/ld/emulparams/elf_x86_64.sh b/ld/emulparams/elf_x86_64.sh
index 664ff189c04..6e31d2242cd 100644
--- a/ld/emulparams/elf_x86_64.sh
+++ b/ld/emulparams/elf_x86_64.sh
@@ -4,6 +4,7 @@ source_sh ${srcdir}/emulparams/dynamic_undefined_weak.sh
 source_sh ${srcdir}/emulparams/reloc_overflow.sh
 source_sh ${srcdir}/emulparams/call_nop.sh
 source_sh ${srcdir}/emulparams/cet.sh
+source_sh ${srcdir}/emulparams/x86-report-relative.sh
 source_sh ${srcdir}/emulparams/x86-64-level.sh
 source_sh ${srcdir}/emulparams/x86-64-lam.sh
 source_sh ${srcdir}/emulparams/static.sh
diff --git a/ld/emulparams/x86-report-relative.sh b/ld/emulparams/x86-report-relative.sh
new file mode 100644
index 00000000000..426bb8bd786
--- /dev/null
+++ b/ld/emulparams/x86-report-relative.sh
@@ -0,0 +1,11 @@
+PARSE_AND_LIST_OPTIONS_X86_REPORT_RELATIVE='
+  fprintf (file, _("\
+  -z report-relative-reloc    Report relative relocations\n"));
+'
+PARSE_AND_LIST_ARGS_CASE_Z_X86_REPORT_RELATIVE='
+      else if (strcmp (optarg, "report-relative-reloc") == 0)
+	params.report_relative_reloc = 1;
+'
+
+PARSE_AND_LIST_OPTIONS="$PARSE_AND_LIST_OPTIONS $PARSE_AND_LIST_OPTIONS_X86_REPORT_RELATIVE"
+PARSE_AND_LIST_ARGS_CASE_Z="$PARSE_AND_LIST_ARGS_CASE_Z $PARSE_AND_LIST_ARGS_CASE_Z_X86_REPORT_RELATIVE"
diff --git a/ld/ld.texi b/ld/ld.texi
index 7a602b9c6ab..0f34d1fbdf6 100644
--- a/ld/ld.texi
+++ b/ld/ld.texi
@@ -1426,6 +1426,10 @@ relocation, if supported.  Specifying @samp{common-page-size} smaller
 than the system page size will render this protection ineffective.
 Don't create an ELF @code{PT_GNU_RELRO} segment if @samp{norelro}.
 
+@item report-relative-reloc
+Report dynamic relative relocations generated by linker.  Supported for
+Linux/i386 and Linux/x86_64.
+
 @item separate-code
 @itemx noseparate-code
 Create separate code @code{PT_LOAD} segment header in the object.  This
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index 655f83df53a..f3e62a4151e 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -506,6 +506,7 @@ run_dump_test "pr18815"
 run_dump_test "pr19939a"
 run_dump_test "pr19939b"
 run_dump_test "tlsdesc2"
+run_dump_test "report-reloc-1"
 
 proc undefined_weak {cflags ldflags} {
     set testname "Undefined weak symbol"
diff --git a/ld/testsuite/ld-i386/report-reloc-1.d b/ld/testsuite/ld-i386/report-reloc-1.d
new file mode 100644
index 00000000000..51fbbd8d105
--- /dev/null
+++ b/ld/testsuite/ld-i386/report-reloc-1.d
@@ -0,0 +1,10 @@
+#source: report-reloc-1.s
+#as: --32
+#ld: -pie -melf_i386 -z report-relative-reloc
+#warning_output: report-reloc-1.l
+#readelf: -r --wide
+
+Relocation section '.rel.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
+ +Offset +Info +Type +Sym.* Value +Symbol's Name
+[0-9a-f]+ +[0-9a-f]+ +R_386_RELATIVE +
+[0-9a-f]+ +[0-9a-f]+ +R_386_IRELATIVE +
diff --git a/ld/testsuite/ld-i386/report-reloc-1.l b/ld/testsuite/ld-i386/report-reloc-1.l
new file mode 100644
index 00000000000..a0293bc4f96
--- /dev/null
+++ b/ld/testsuite/ld-i386/report-reloc-1.l
@@ -0,0 +1,2 @@
+tmpdir/dump: R_386_IRELATIVE \(offset: 0x0+2000, info: 0x0+2a\) against 'ifunc' for section '.data.rel.ro.local' in tmpdir/report-reloc-1.o
+tmpdir/dump: R_386_RELATIVE \(offset: 0x0+2004, info: 0x0+8\) against '_start' for section '.data.rel.ro.local' in tmpdir/report-reloc-1.o
diff --git a/ld/testsuite/ld-i386/report-reloc-1.s b/ld/testsuite/ld-i386/report-reloc-1.s
new file mode 100644
index 00000000000..689cb690a80
--- /dev/null
+++ b/ld/testsuite/ld-i386/report-reloc-1.s
@@ -0,0 +1,12 @@
+	.text
+	.globl _start
+	.type ifunc, @gnu_indirect_function
+_start:
+	lea	.Ljmp@GOTOFF(%ebx), %eax
+ifunc:
+	jmp	*(%eax)
+	.section	.data.rel.ro.local,"aw",@progbits
+	.align	4
+.Ljmp:
+	.long ifunc
+	.long _start
diff --git a/ld/testsuite/ld-x86-64/report-reloc-1-x32.d b/ld/testsuite/ld-x86-64/report-reloc-1-x32.d
new file mode 100644
index 00000000000..c66f956c473
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/report-reloc-1-x32.d
@@ -0,0 +1,10 @@
+#source: report-reloc-1.s
+#as: --x32
+#ld: -pie -melf32_x86_64 -z report-relative-reloc
+#warning_output: report-reloc-1.l
+#readelf: -r --wide
+
+Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
+ +Offset +Info +Type +Sym.* Value +Symbol's Name \+ Addend
+[0-9a-f]+ +[0-9a-f]+ +R_X86_64_RELATIVE +[0-9a-f]+
+[0-9a-f]+ +[0-9a-f]+ +R_X86_64_IRELATIVE +[0-9a-f]+
diff --git a/ld/testsuite/ld-x86-64/report-reloc-1.d b/ld/testsuite/ld-x86-64/report-reloc-1.d
new file mode 100644
index 00000000000..1b5f91fdd3f
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/report-reloc-1.d
@@ -0,0 +1,10 @@
+#source: report-reloc-1.s
+#as: --64
+#ld: -pie -melf_x86_64 -z report-relative-reloc
+#warning_output: report-reloc-1.l
+#readelf: -r --wide
+
+Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
+ +Offset +Info +Type +Sym.* Value +Symbol's Name \+ Addend
+[0-9a-f]+ +[0-9a-f]+ +R_X86_64_RELATIVE +[0-9a-f]+
+[0-9a-f]+ +[0-9a-f]+ +R_X86_64_IRELATIVE +[0-9a-f]+
diff --git a/ld/testsuite/ld-x86-64/report-reloc-1.l b/ld/testsuite/ld-x86-64/report-reloc-1.l
new file mode 100644
index 00000000000..669dff43bd7
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/report-reloc-1.l
@@ -0,0 +1,2 @@
+tmpdir/dump: R_X86_64_IRELATIVE \(offset: 0x0+2000, info: 0x0+25, addend: 0x0+1007\) against 'ifunc' for section '.data.rel.ro.local' in tmpdir/report-reloc-1.o
+tmpdir/dump: R_X86_64_RELATIVE \(offset: 0x0+2008, info: 0x0+8, addend: 0x0+1000\) against '_start' for section '.data.rel.ro.local' in tmpdir/report-reloc-1.o
diff --git a/ld/testsuite/ld-x86-64/report-reloc-1.s b/ld/testsuite/ld-x86-64/report-reloc-1.s
new file mode 100644
index 00000000000..8a5809ad1c1
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/report-reloc-1.s
@@ -0,0 +1,12 @@
+	.text
+	.globl _start
+	.type ifunc, @gnu_indirect_function
+_start:
+	lea	.Ljmp(%rip), %rax
+ifunc:
+	jmp	*(%rax)
+	.section	.data.rel.ro.local,"aw",@progbits
+	.align	8
+.Ljmp:
+	.quad ifunc
+	.quad _start
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index 83fdaa7db65..662d349d824 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -677,6 +677,8 @@ run_dump_test "pr26939"
 run_dump_test "pr26939-x32"
 run_dump_test "pr27016a"
 run_dump_test "pr27016b"
+run_dump_test "report-reloc-1"
+run_dump_test "report-reloc-1-x32"
 
 proc undefined_weak {cflags ldflags} {
     set testname "Undefined weak symbol"