From: Maciej W. Rozycki <macro@mips.com>
Date: Mon, 9 Jul 2018 20:30:44 +0000 (+0100)
Subject: MIPS/BFD: Do not redirect to discarded lazy binding stubs
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=4b8377e7dbd9e53149268685ba4810a7b09fb0cb;p=binutils-gdb.git

MIPS/BFD: Do not redirect to discarded lazy binding stubs

Correct a MIPS/BFD linker issue with dynamic symbol and corresponding
GOT entry values being redirected to lazy binding stubs where the stubs
section has been discarded by assigning to the `/DISCARD/' output
section in the linker script used.  The issue manifests itself by the
values entered being relative to the absolute section, which is what any
discarded sections are internally assigned in the linker.

For the `stub-dynsym-2.s' piece of code included as a test case with
this change this issue results in the dynamic symbol table and the GOT
looking like:

Symbol table '.dynsym' contains 3 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 00000010     0 FUNC    GLOBAL DEFAULT  UND bar
     2: 00000000     0 FUNC    GLOBAL DEFAULT  UND foo

Primary GOT:
 Canonical gp value: 00097ff0

 Reserved entries:
   Address     Access  Initial Purpose
  00090000 -32752(gp) 00000000 Lazy resolver
  00090004 -32748(gp) 80000000 Module pointer (GNU extension)

 Global entries:
   Address     Access  Initial Sym.Val. Type    Ndx Name
  00090008 -32744(gp) 00000010 00000010 FUNC    UND bar
  0009000c -32740(gp) 00000000 00000000 FUNC    UND foo

if assembled to regular MIPS code, or:

Symbol table '.dynsym' contains 3 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 0000000d     0 FUNC    GLOBAL DEFAULT  UND bar
     2: 00000001     0 FUNC    GLOBAL DEFAULT  UND foo

Primary GOT:
 Canonical gp value: 00097ff0

 Reserved entries:
   Address     Access  Initial Purpose
  00090000 -32752(gp) 00000000 Lazy resolver
  00090004 -32748(gp) 80000000 Module pointer (GNU extension)

 Global entries:
   Address     Access  Initial Sym.Val. Type    Ndx Name
  00090008 -32744(gp) 0000000d 0000000d FUNC    UND bar
  0009000c -32740(gp) 00000001 00000001 FUNC    UND foo

if assembled to microMIPS code.  Symbol values and GOT entries record
the offset into the inexistent stubs section and the ISA bit rather than
zero, which would be the case if a lazy binding stub was not used for
other reasons, such as the value of the symbol being taken for a purpose
other than making a function call (e.g. an R_MIPS_GOT16 relocation).

Correct the issue by refraining from redirecting symbols to lazy binding
stubs if the stubs section is going to be discarded.

	bfd/
	* elfxx-mips.c (_bfd_mips_elf_adjust_dynamic_symbol): Don't set
	`->needs_lazy_stub' if the stubs output section is the absolute
	section.

	ld/
	* testsuite/ld-mips-elf/stub-dynsym-2.dd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-2.gd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-2.sd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-discard-2.gd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-discard-2.sd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd: New test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd: New
	test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd: New
	test.
	* testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd: New
	test.
	* testsuite/ld-mips-elf/stub-dynsym-2.ld: New test linker
	script.
	* testsuite/ld-mips-elf/stub-dynsym-discard-2.ld: New test
	linker script.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
---

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 4b0454d8a8d..7e8cf8caf98 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2018-07-09  Maciej W. Rozycki  <macro@mips.com>
+
+	* elfxx-mips.c (_bfd_mips_elf_adjust_dynamic_symbol): Don't set
+	`->needs_lazy_stub' if the stubs output section is the absolute
+	section.
+
 2018-07-09  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/23388
diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
index c33b276ceff..990e3a1e551 100644
--- a/bfd/elfxx-mips.c
+++ b/bfd/elfxx-mips.c
@@ -9043,7 +9043,8 @@ _bfd_mips_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
 	 the symbol to the stub location.  This is required to make
 	 function pointers compare as equal between the normal
 	 executable and the shared library.  */
-      if (!h->def_regular)
+      if (!h->def_regular
+	  && !bfd_is_abs_section (htab->sstubs->output_section))
 	{
 	  hmips->needs_lazy_stub = TRUE;
 	  htab->lazy_stub_count++;
diff --git a/ld/ChangeLog b/ld/ChangeLog
index c146f5cf937..7d382b9f4a1 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,25 @@
+2018-07-09  Maciej W. Rozycki  <macro@mips.com>
+
+	* testsuite/ld-mips-elf/stub-dynsym-2.dd: New test.
+	* testsuite/ld-mips-elf/stub-dynsym-2.gd: New test.
+	* testsuite/ld-mips-elf/stub-dynsym-2.sd: New test.
+	* testsuite/ld-mips-elf/stub-dynsym-discard-2.gd: New test.
+	* testsuite/ld-mips-elf/stub-dynsym-discard-2.sd: New test.
+	* testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd: New test.
+	* testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd: New test.
+	* testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd: New test.
+	* testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd: New
+	test.
+	* testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd: New
+	test.
+	* testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd: New
+	test.
+	* testsuite/ld-mips-elf/stub-dynsym-2.ld: New test linker
+	script.
+	* testsuite/ld-mips-elf/stub-dynsym-discard-2.ld: New test
+	linker script.
+	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
+
 2018-07-09  Maciej W. Rozycki  <macro@mips.com>
 
 	* testsuite/lib/ld-lib.exp (run_dump_test): Call `unsupported'
diff --git a/ld/testsuite/ld-mips-elf/mips-elf.exp b/ld/testsuite/ld-mips-elf/mips-elf.exp
index ddd90f25ee2..8b0594afc54 100644
--- a/ld/testsuite/ld-mips-elf/mips-elf.exp
+++ b/ld/testsuite/ld-mips-elf/mips-elf.exp
@@ -807,6 +807,42 @@ if { $linux_gnu } {
 				      "stub-dynsym$suffix-1-$dynsym.d"]] \
 			   "stub-dynsym$suffix-1-$dynsym"]]
 	}
+	run_ld_link_tests [list \
+	     [list \
+		 "Retained stubs for dynsyms ($isa)" \
+		 "-shared -melf32btsmip -T stub-dynsym-2.ld $lflag" "" \
+		 "-EB $aflag -32 -KPIC" \
+		 [list "stub-dynsym-2.s"] \
+		 [list \
+		     [list \
+			"objdump" \
+			"-dz -j .MIPS.stubs" \
+			"stub-dynsym$suffix-2.dd"] \
+		     [list \
+			"readelf" \
+			"--dyn-syms" \
+			"stub-dynsym$suffix-2.sd"] \
+		     [list \
+			"readelf" \
+			"-A" \
+			"stub-dynsym$suffix-2.gd"]] \
+		 "stub-dynsym$suffix-2"] \
+	     [list \
+		 "Discarded stubs for dynsyms ($isa)" \
+		 "-shared -melf32btsmip -T stub-dynsym-discard-2.ld $lflag" \
+		 "" \
+		 "-EB $aflag -32 -KPIC" \
+		 [list "stub-dynsym-2.s"] \
+		 [list \
+		     [list \
+			"readelf" \
+			"--dyn-syms" \
+			"stub-dynsym-discard-2.sd"] \
+		     [list \
+			"readelf" \
+			"-A" \
+			"stub-dynsym-discard-2.gd"]] \
+		 "stub-dynsym-discard$suffix-2"]]
     }
 }
 
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.dd b/ld/testsuite/ld-mips-elf/stub-dynsym-2.dd
new file mode 100644
index 00000000000..6013a4763e6
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.dd
@@ -0,0 +1,17 @@
+.*: +file format .*mips.*
+
+Disassembly of section \.MIPS\.stubs:
+
+000800ec <_MIPS_STUBS_>:
+   800ec:	8f998010 	lw	t9,-32752\(gp\)
+   800f0:	03e07825 	move	t7,ra
+   800f4:	0320f809 	jalr	t9
+   800f8:	24180002 	li	t8,2
+   800fc:	8f998010 	lw	t9,-32752\(gp\)
+   80100:	03e07825 	move	t7,ra
+   80104:	0320f809 	jalr	t9
+   80108:	24180001 	li	t8,1
+   8010c:	00000000 	nop
+   80110:	00000000 	nop
+   80114:	00000000 	nop
+   80118:	00000000 	nop
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.gd b/ld/testsuite/ld-mips-elf/stub-dynsym-2.gd
new file mode 100644
index 00000000000..411cdf12bfd
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.gd
@@ -0,0 +1,12 @@
+Primary GOT:
+ Canonical gp value: 00097ff0
+
+ Reserved entries:
+   Address     Access  Initial Purpose
+  00090000 -32752\(gp\) 00000000 Lazy resolver
+  00090004 -32748\(gp\) 80000000 Module pointer \(GNU extension\)
+
+ Global entries:
+   Address     Access  Initial Sym\.Val\. Type    Ndx Name
+  00090008 -32744\(gp\) 000800fc 000800fc FUNC    UND bar
+  0009000c -32740\(gp\) 000800ec 000800ec FUNC    UND foo
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.ld b/ld/testsuite/ld-mips-elf/stub-dynsym-2.ld
new file mode 100644
index 00000000000..a385012f4ae
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.ld
@@ -0,0 +1,21 @@
+SECTIONS
+{
+  . = 0x80000;
+  .interp : { *(.interp) }
+  .hash : { *(.hash) }
+  .dynsym : { *(.dynsym) }
+  .dynstr : { *(.dynstr) }
+  .rel.dyn : { *(.rel.dyn) }
+  .MIPS.stubs : { *(.MIPS.stubs) }
+  .text : { *(.text) }
+
+  . = ALIGN (0x10000);
+  HIDDEN (_gp = . + 0x7ff0);
+  .got : { *(.got) }
+
+  .symtab : { *(.symtab) }
+  .strtab : { *(.strtab) }
+  .shstrtab : { *(.shstrtab) }
+
+  /DISCARD/ : { *(.reginfo) *(.MIPS.abiflags) *(.gnu.attributes) }
+}
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.s b/ld/testsuite/ld-mips-elf/stub-dynsym-2.s
new file mode 100644
index 00000000000..9c5f166d693
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.s
@@ -0,0 +1,2 @@
+	lw	$25,%call16(foo)($gp)
+	lw	$25,%call16(bar)($gp)
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-2.sd b/ld/testsuite/ld-mips-elf/stub-dynsym-2.sd
new file mode 100644
index 00000000000..4960ae7ed35
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-2.sd
@@ -0,0 +1,5 @@
+Symbol table '\.dynsym' contains 3 entries:
+   Num:    Value  Size Type    Bind   Vis      Ndx Name
+     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
+     1: 000800fc     0 FUNC    GLOBAL DEFAULT  UND bar
+     2: 000800ec     0 FUNC    GLOBAL DEFAULT  UND foo
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.gd b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.gd
new file mode 100644
index 00000000000..f56553ac0cb
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.gd
@@ -0,0 +1,12 @@
+Primary GOT:
+ Canonical gp value: 00097ff0
+
+ Reserved entries:
+   Address     Access  Initial Purpose
+  00090000 -32752\(gp\) 00000000 Lazy resolver
+  00090004 -32748\(gp\) 80000000 Module pointer \(GNU extension\)
+
+ Global entries:
+   Address     Access  Initial Sym\.Val\. Type    Ndx Name
+  00090008 -32744\(gp\) 00000000 00000000 FUNC    UND bar
+  0009000c -32740\(gp\) 00000000 00000000 FUNC    UND foo
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.ld b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.ld
new file mode 100644
index 00000000000..e6d89bd3459
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.ld
@@ -0,0 +1,22 @@
+SECTIONS
+{
+  . = 0x80000;
+  .interp : { *(.interp) }
+  .hash : { *(.hash) }
+  .dynsym : { *(.dynsym) }
+  .dynstr : { *(.dynstr) }
+  .rel.dyn : { *(.rel.dyn) }
+  .text : { *(.text) }
+
+  . = ALIGN (0x10000);
+  HIDDEN (_gp = . + 0x7ff0);
+  .got : { *(.got) }
+
+  .symtab : { *(.symtab) }
+  .strtab : { *(.strtab) }
+  .shstrtab : { *(.shstrtab) }
+
+  /DISCARD/ : {
+    *(.reginfo) *(.MIPS.abiflags) *(.MIPS.stubs) *(.gnu.attributes)
+  }
+}
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.sd b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.sd
new file mode 100644
index 00000000000..f78f9391162
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-discard-2.sd
@@ -0,0 +1,5 @@
+Symbol table '\.dynsym' contains 3 entries:
+   Num:    Value  Size Type    Bind   Vis      Ndx Name
+     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
+     1: 00000000     0 FUNC    GLOBAL DEFAULT  UND bar
+     2: 00000000     0 FUNC    GLOBAL DEFAULT  UND foo
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd
new file mode 100644
index 00000000000..7c3bf25a854
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.dd
@@ -0,0 +1,16 @@
+.*: +file format .*mips.*
+
+Disassembly of section \.MIPS\.stubs:
+
+000800ec <_MIPS_STUBS_>:
+   800ec:	ff3c 8010 	lw	t9,-32752\(gp\)
+   800f0:	0dff      	move	t7,ra
+   800f2:	45d9      	jalr	t9
+   800f4:	3300 0002 	li	t8,2
+   800f8:	ff3c 8010 	lw	t9,-32752\(gp\)
+   800fc:	0dff      	move	t7,ra
+   800fe:	45d9      	jalr	t9
+   80100:	3300 0001 	li	t8,1
+   80104:	0000 0000 	nop
+   80108:	0000 0000 	nop
+   8010c:	0000 0000 	nop
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd
new file mode 100644
index 00000000000..2691d1db968
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.gd
@@ -0,0 +1,12 @@
+Primary GOT:
+ Canonical gp value: 00097ff0
+
+ Reserved entries:
+   Address     Access  Initial Purpose
+  00090000 -32752\(gp\) 00000000 Lazy resolver
+  00090004 -32748\(gp\) 80000000 Module pointer \(GNU extension\)
+
+ Global entries:
+   Address     Access  Initial Sym\.Val\. Type    Ndx Name
+  00090008 -32744\(gp\) 000800f9 000800f9 FUNC    UND bar
+  0009000c -32740\(gp\) 000800ed 000800ed FUNC    UND foo
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd
new file mode 100644
index 00000000000..d0b8d49a7fc
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-2.sd
@@ -0,0 +1,5 @@
+Symbol table '\.dynsym' contains 3 entries:
+   Num:    Value  Size Type    Bind   Vis      Ndx Name
+     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
+     1: 000800f9     0 FUNC    GLOBAL DEFAULT  UND bar
+     2: 000800ed     0 FUNC    GLOBAL DEFAULT  UND foo
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd
new file mode 100644
index 00000000000..8c3374131ad
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.dd
@@ -0,0 +1,17 @@
+.*: +file format .*mips.*
+
+Disassembly of section \.MIPS\.stubs:
+
+000800ec <_MIPS_STUBS_>:
+   800ec:	ff3c 8010 	lw	t9,-32752\(gp\)
+   800f0:	001f 7a90 	move	t7,ra
+   800f4:	03f9 0f3c 	jalr	t9
+   800f8:	3300 0002 	li	t8,2
+   800fc:	ff3c 8010 	lw	t9,-32752\(gp\)
+   80100:	001f 7a90 	move	t7,ra
+   80104:	03f9 0f3c 	jalr	t9
+   80108:	3300 0001 	li	t8,1
+   8010c:	0000 0000 	nop
+   80110:	0000 0000 	nop
+   80114:	0000 0000 	nop
+   80118:	0000 0000 	nop
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd
new file mode 100644
index 00000000000..1ebc071cd70
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.gd
@@ -0,0 +1,12 @@
+Primary GOT:
+ Canonical gp value: 00097ff0
+
+ Reserved entries:
+   Address     Access  Initial Purpose
+  00090000 -32752\(gp\) 00000000 Lazy resolver
+  00090004 -32748\(gp\) 80000000 Module pointer \(GNU extension\)
+
+ Global entries:
+   Address     Access  Initial Sym\.Val\. Type    Ndx Name
+  00090008 -32744\(gp\) 000800fd 000800fd FUNC    UND bar
+  0009000c -32740\(gp\) 000800ed 000800ed FUNC    UND foo
diff --git a/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd
new file mode 100644
index 00000000000..860fd485567
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/stub-dynsym-micromips-insn32-2.sd
@@ -0,0 +1,5 @@
+Symbol table '\.dynsym' contains 3 entries:
+   Num:    Value  Size Type    Bind   Vis      Ndx Name
+     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
+     1: 000800fd     0 FUNC    GLOBAL DEFAULT  UND bar
+     2: 000800ed     0 FUNC    GLOBAL DEFAULT  UND foo