[ARM] PR ld/20608 Relocation truncated to fit: R_ARM_THM_JUMP24 for relocation to PLT entry

2016-09-28  Christophe Lyon  <christophe.lyon@linaro.org>

	PR ld/20608
	bfd/
	* elf32-arm.c (arm_type_of_stub): Handle the case when the pre-PLT
	Thumb-ARM stub is too far.

	ld
	* testsuite/ld-arm/arm-elf.exp: Handle new testcase.
	* testsuite/ld-arm/farcall-mixed-app2.d: New file.
	* testsuite/ld-arm/farcall-mixed-app2.r: Likewise.
	* testsuite/ld-arm/farcall-mixed-app2.s: Likewise.
	* testsuite/ld-arm/farcall-mixed-app2.sym: Likewise.

8 files changed, 262 insertions, 6 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index f332490..03acf6f 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2016-09-28  Christophe Lyon  <christophe.lyon@linaro.org>
+
+	PR ld/20608
+	* elf32-arm.c (arm_type_of_stub): Handle the case when the pre-PLT
+	Thumb-ARM stub is too far.
+
 2016-09-27  Nick Clifton  <nickc@redhat.com>
 
 	PR ld/20634
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index c58b65d..2386a8c 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -3945,17 +3945,43 @@ arm_type_of_stub (struct bfd_link_info *info,
 	  /* Note when dealing with PLT entries: the main PLT stub is in
 	     ARM mode, so if the branch is in Thumb mode, another
 	     Thumb->ARM stub will be inserted later just before the ARM
-	     PLT stub. We don't take this extra distance into account
-	     here, because if a long branch stub is needed, we'll add a
-	     Thumb->Arm one and branch directly to the ARM PLT entry
-	     because it avoids spreading offset corrections in several
-	     places.  */
+	     PLT stub. If a long branch stub is needed, we'll add a
+	     Thumb->Arm one and branch directly to the ARM PLT entry.
+	     Here, we have to check if a pre-PLT Thumb->ARM stub
+	     is needed and if it will be close enough.  */
 
 	  destination = (splt->output_section->vma
 			 + splt->output_offset
 			 + root_plt->offset);
 	  st_type = STT_FUNC;
-	  branch_type = ST_BRANCH_TO_ARM;
+
+	  /* Thumb branch/call to PLT: it can become a branch to ARM
+	     or to Thumb. We must perform the same checks and
+	     corrections as in elf32_arm_final_link_relocate.  */
+	  if ((r_type == R_ARM_THM_CALL)
+	      || (r_type == R_ARM_THM_JUMP24))
+	    {
+	      if (globals->use_blx
+		  && r_type == R_ARM_THM_CALL
+		  && !thumb_only)
+		{
+		  /* If the Thumb BLX instruction is available, convert
+		     the BL to a BLX instruction to call the ARM-mode
+		     PLT entry.  */
+		  branch_type = ST_BRANCH_TO_ARM;
+		}
+	      else
+		{
+		  if (!thumb_only)
+		    /* Target the Thumb stub before the ARM PLT entry.  */
+		    destination -= PLT_THUMB_STUB_SIZE;
+		  branch_type = ST_BRANCH_TO_THUMB;
+		}
+	    }
+	  else
+	    {
+	      branch_type = ST_BRANCH_TO_ARM;
+	    }
 	}
     }
   /* Calls to STT_GNU_IFUNC symbols should go through a PLT.  */
@@ -3991,6 +4017,15 @@ arm_type_of_stub (struct bfd_link_info *info,
                   || (r_type == R_ARM_THM_JUMP19))
 	      && !use_plt))
 	{
+	  /* If we need to insert a Thumb-Thumb long branch stub to a
+	     PLT, use one that branches directly to the ARM PLT
+	     stub. If we pretended we'd use the pre-PLT Thumb->ARM
+	     stub, undo this now.  */
+	  if ((branch_type == ST_BRANCH_TO_THUMB) && use_plt && !thumb_only) {
+	    branch_type = ST_BRANCH_TO_ARM;
+	    branch_offset += PLT_THUMB_STUB_SIZE;
+	  }
+
 	  if (branch_type == ST_BRANCH_TO_THUMB)
 	    {
 	      /* Thumb to thumb.  */
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 1a443bc..988cb65 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,12 @@
+2016-09-28  Christophe Lyon  <christophe.lyon@linaro.org>
+
+	PR ld/20608
+	* testsuite/ld-arm/arm-elf.exp: Handle new testcase.
+	* testsuite/ld-arm/farcall-mixed-app2.d: New file.
+	* testsuite/ld-arm/farcall-mixed-app2.r: Likewise.
+	* testsuite/ld-arm/farcall-mixed-app2.s: Likewise.
+	* testsuite/ld-arm/farcall-mixed-app2.sym: Likewise.
+
 2016-09-26  Vlad Zakharov  <vzakhar@synopsys.com>
 
 	* Makefile.in: Regenerate.
diff --git a/ld/testsuite/ld-arm/arm-elf.exp b/ld/testsuite/ld-arm/arm-elf.exp
index 24d0b4c..02a35f4 100644
--- a/ld/testsuite/ld-arm/arm-elf.exp
+++ b/ld/testsuite/ld-arm/arm-elf.exp
@@ -559,6 +559,12 @@ set armeabitests_nonacl {
       {readelf -Ds farcall-mixed-app.sym}}
      "farcall-mixed-app-v5"}
 
+    {"Mixed ARM/Thumb2 dynamic application with farcalls" "tmpdir/mixed-lib.so -T arm-dyn.ld --section-start .mid_thumb=0x10081c0 --section-start .far_arm=0x2100000 --section-start .far_thumb=0x2200000" "" ""
+     {farcall-mixed-app2.s}
+     {{objdump -fdw farcall-mixed-app2.d} {objdump -Rw farcall-mixed-app2.r}
+      {readelf -Ds farcall-mixed-app2.sym}}
+     "farcall-mixed-app2"}
+
     {"Mixed ARM/Thumb shared library with long branches (v4t)" "-shared -T arm-lib.ld" "" "-march=armv4t"
      {farcall-mixed-lib1.s farcall-mixed-lib2.s}
      {{objdump -fdw farcall-mixed-lib-v4t.d}}
diff --git a/ld/testsuite/ld-arm/farcall-mixed-app2.d b/ld/testsuite/ld-arm/farcall-mixed-app2.d
new file mode 100644
index 0000000..54338d0
--- /dev/null
+++ b/ld/testsuite/ld-arm/farcall-mixed-app2.d
@@ -0,0 +1,99 @@
+
+tmpdir/farcall-mixed-app2:     file format elf32-(little|big)arm
+architecture: arm.*, flags 0x00000112:
+EXEC_P, HAS_SYMS, D_PAGED
+start address 0x.*
+
+Disassembly of section .plt:
+
+.* <lib_func2@plt-0x14>:
+ .*:	e52de004 	push	{lr}		; \(str lr, \[sp, #-4\]!\)
+ .*:	e59fe004 	ldr	lr, \[pc, #4\]	; .* <lib_func2@plt-0x4>
+ .*:	e08fe00e 	add	lr, pc, lr
+ .*:	e5bef008 	ldr	pc, \[lr, #8\]!
+ .*:	.*
+.* <lib_func2@plt>:
+ .*:	4778      	bx	pc
+ .*:	46c0      	nop			; \(mov r8, r8\)
+ .*:	e28fc6.* 	add	ip, pc, #.*
+ .*:	e28cca.* 	add	ip, ip, #.*	; 0x.*
+ .*:	e5bcf.* 	ldr	pc, \[ip, #.*\]!.*
+.* <lib_func1@plt>:
+ .*:	e28fc6.* 	add	ip, pc, #.*
+ .*:	e28cca.* 	add	ip, ip, #.*	; 0x.*
+ .*:	e5bcf.* 	ldr	pc, \[ip, #.*\]!.*
+
+Disassembly of section .text:
+
+.* <_start>:
+ .*:	e1a0c00d 	mov	ip, sp
+ .*:	e92dd800 	push	{fp, ip, lr, pc}
+ .*:	eb000008 	bl	.* <__app_func_veneer>
+ .*:	ebfffff6 	bl	.* <lib_func1@plt>
+ .*:	ebfffff2 	bl	.* <lib_func2@plt\+0x4>
+ .*:	e89d6800 	ldm	sp, {fp, sp, lr}
+ .*:	e12fff1e 	bx	lr
+ .*:	e1a00000 	nop			; \(mov r0, r0\)
+
+.* <app_tfunc_close>:
+ .*:	b500      	push	{lr}
+ .*:	f7ff efde 	blx	81e0 <lib_func2@plt\+0x4>
+ .*:	bd00      	pop	{pc}
+ .*:	4770      	bx	lr
+ .*:	46c0      	nop			; \(mov r8, r8\)
+#...
+
+.* <__app_func_veneer>:
+ .*:	e51ff004 	ldr	pc, \[pc, #-4\]	; 8234 <__app_func_veneer\+0x4>
+ .*:	02100000 	.word	0x02100000
+
+Disassembly of section .mid_thumb:
+
+.* <mid_tfunc>:
+#...
+ .*:	f400 9000 	b.w	.* <lib_func2@plt>
+ .*:	f000 b800 	b.w	.* <__lib_func2_from_thumb>
+
+.* <__lib_func2_from_thumb>:
+ .*:	4778      	bx	pc
+ .*:	46c0      	nop			; \(mov r8, r8\)
+ .*:	e51ff004 	ldr	pc, \[pc, #-4\]	; 10081e8 <__lib_func2_from_thumb\+0x8>
+ .*:	000081e0 	.word	0x000081e0
+ .*:	00000000 	.word	0x00000000
+
+Disassembly of section .far_arm:
+
+.* <app_func>:
+ .*:	e1a0c00d 	mov	ip, sp
+ .*:	e92dd800 	push	{fp, ip, lr, pc}
+ .*:	eb000006 	bl	.* <__lib_func1_veneer>
+ .*:	eb000007 	bl	.* <__lib_func2_veneer>
+ .*:	e89d6800 	ldm	sp, {fp, sp, lr}
+ .*:	e12fff1e 	bx	lr
+ .*:	e1a00000 	nop			; \(mov r0, r0\)
+ .*:	e1a00000 	nop			; \(mov r0, r0\)
+
+.* <app_func2>:
+ .*:	e12fff1e 	bx	lr
+#...
+
+.* <__lib_func1_veneer>:
+ .*:	e51ff004 	ldr	pc, \[pc, #-4\]	; .* <__lib_func1_veneer\+0x4>
+ .*:	000081ec 	.word	0x000081ec
+.* <__lib_func2_veneer>:
+ .*:	e51ff004 	ldr	pc, \[pc, #-4\]	; .* <__lib_func2_veneer\+0x4>
+ .*:	000081e0 	.word	0x000081e0
+
+Disassembly of section .far_thumb:
+
+.* <app_tfunc>:
+ .*:	b500      	push	{lr}
+ .*:	f000 e806 	blx	.* <__lib_func2_from_thumb>
+ .*:	bd00      	pop	{pc}
+ .*:	4770      	bx	lr
+ .*:	46c0      	nop			; \(mov r8, r8\)
+#...
+
+.* <__lib_func2_from_thumb>:
+ .*:	e51ff004 	ldr	pc, \[pc, #-4\]	; 2200014 <__lib_func2_from_thumb\+0x4>
+ .*:	000081e0 	.word	0x000081e0
diff --git a/ld/testsuite/ld-arm/farcall-mixed-app2.r b/ld/testsuite/ld-arm/farcall-mixed-app2.r
new file mode 100644
index 0000000..910a361
--- /dev/null
+++ b/ld/testsuite/ld-arm/farcall-mixed-app2.r
@@ -0,0 +1,10 @@
+
+tmpdir/farcall-mixed-app.*:     file format elf32-(little|big)arm
+
+DYNAMIC RELOCATION RECORDS
+OFFSET   TYPE              VALUE 
+.* R_ARM_COPY        data_obj
+.* R_ARM_JUMP_SLOT   lib_func2
+.* R_ARM_JUMP_SLOT   lib_func1
+
+
diff --git a/ld/testsuite/ld-arm/farcall-mixed-app2.s b/ld/testsuite/ld-arm/farcall-mixed-app2.s
new file mode 100644
index 0000000..ee315e9
--- /dev/null
+++ b/ld/testsuite/ld-arm/farcall-mixed-app2.s
@@ -0,0 +1,76 @@
+	.text
+	.p2align 4
+	.globl _start
+_start:
+	mov	ip, sp
+	stmdb	sp!, {r11, ip, lr, pc}
+	bl	app_func
+	bl	lib_func1
+	bl	lib_func2
+	ldmia	sp, {r11, sp, lr}
+	bx lr
+
+	.p2align 4
+	.globl app_tfunc_close
+	.type app_tfunc_close,%function
+	.thumb_func
+	.code 16
+app_tfunc_close:
+	push	{lr}
+	bl	lib_func2
+	pop	{pc}
+	bx	lr
+
+@ We will place the section .mid_thumb at 0xFFFEF8.
+@ Just far enough for XXXX
+	.section .mid_thumb, "xa"
+
+	.p2align 4
+	.globl mid_tfunc
+	.type mid_tfunc,%function
+	.thumb_func
+	.code 16
+mid_tfunc:
+	.syntax unified
+	.space 24
+	b.w	lib_func2
+	b.w	lib_func2
+
+@ We will place the section .far_arm at 0x2100000.
+	.section .far_arm, "xa"
+
+	.arm
+	.p2align 4
+	.globl app_func
+	.type app_func,%function
+app_func:
+	mov	ip, sp
+	stmdb	sp!, {r11, ip, lr, pc}
+	bl	lib_func1
+	bl	lib_func2
+	ldmia	sp, {r11, sp, lr}
+	bx lr
+
+	.arm
+	.p2align 4
+	.globl app_func2
+	.type app_func2,%function
+app_func2:
+	bx	lr
+
+@ We will place the section .far_thumb at 0x2200000.
+	.section .far_thumb, "xa"
+
+	.p2align 4
+	.globl app_tfunc
+	.type app_tfunc,%function
+	.thumb_func
+	.code 16
+app_tfunc:
+	push	{lr}
+	bl	lib_func2
+	pop	{pc}
+	bx	lr
+
+	.data
+	.long data_obj
diff --git a/ld/testsuite/ld-arm/farcall-mixed-app2.sym b/ld/testsuite/ld-arm/farcall-mixed-app2.sym
new file mode 100644
index 0000000..1d3bd1d
--- /dev/null
+++ b/ld/testsuite/ld-arm/farcall-mixed-app2.sym
@@ -0,0 +1,15 @@
+
+Symbol table for image:
+ +Num +Buc: +Value +Size +Type +Bind +Vis +Ndx +Name
+ +.. +..: ........ +0 +NOTYPE +GLOBAL +DEFAULT +11 _edata
+ +.. +..: ........ +0 +NOTYPE +GLOBAL +DEFAULT +12 __bss_start__
+ +.. +..: ........ +0 +NOTYPE +GLOBAL +DEFAULT +12 _end
+ +.. +..: ........ +4 +OBJECT +GLOBAL +DEFAULT +12 data_obj
+ +.. +..: ........ +0 +NOTYPE +GLOBAL +DEFAULT +12 __bss_end__
+ +.. +..: 0*[^0]*.* +0 +FUNC +GLOBAL +DEFAULT +UND lib_func1
+ +.. +..: ........ +0 +NOTYPE +GLOBAL +DEFAULT +11 __data_start
+ +.. +..: ........ +0 +NOTYPE +GLOBAL +DEFAULT +12 __end__
+ +.. +..: ........ +0 +NOTYPE +GLOBAL +DEFAULT +12 __bss_start
+ +.. +..: .......0 +0 +FUNC +GLOBAL +DEFAULT +15 app_func2
+ +.. +..: 0*[^0]*.* +0 +FUNC +GLOBAL +DEFAULT +UND lib_func2
+ +.. +..: ........ +0 +NOTYPE +GLOBAL +DEFAULT +12 _bss_end__