bfd: xtensa: fix callx relaxation

Message ID 20190220035011.2070-1-jcmvbkbc@gmail.com
State New
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Series
  • bfd: xtensa: fix callx relaxation
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Commit Message

Max Filippov Feb. 20, 2019, 3:50 a.m.
Big section alignment requirements between source and destination of a
long call can result in making call range bigger than what's reachable
by the call opcode. Add biggest section alignment of sections between
the call site and call destination to the call distance when making
long call relaxation decision.

2019-02-19  Eric Tsai  <erictsai@cadence.com>
bfd/
	* elf32-xtensa.c (is_resolvable_asm_expansion): Scan output
	sections between the call site and call destination and adjust
	call distance by the largest alignment.

ld/
	* testsuite/ld-xtensa/call_overflow.d: New test definition.
	* testsuite/ld-xtensa/call_overflow1.s: New test source.
	* testsuite/ld-xtensa/call_overflow2.s: New test source.
	* testsuite/ld-xtensa/call_overflow3.s: New test source.
	* testsuite/ld-xtensa/xtensa.exp: Add call_overflow test.
---
 bfd/elf32-xtensa.c                      | 55 +++++++++++++++++++++++++++++++++
 ld/testsuite/ld-xtensa/call_overflow.d  |  7 +++++
 ld/testsuite/ld-xtensa/call_overflow1.s |  9 ++++++
 ld/testsuite/ld-xtensa/call_overflow2.s | 14 +++++++++
 ld/testsuite/ld-xtensa/call_overflow3.s |  5 +++
 ld/testsuite/ld-xtensa/xtensa.exp       |  1 +
 6 files changed, 91 insertions(+)
 create mode 100644 ld/testsuite/ld-xtensa/call_overflow.d
 create mode 100644 ld/testsuite/ld-xtensa/call_overflow1.s
 create mode 100644 ld/testsuite/ld-xtensa/call_overflow2.s
 create mode 100644 ld/testsuite/ld-xtensa/call_overflow3.s

-- 
2.11.0

Comments

augustine.sterling@gmail.com Feb. 20, 2019, 6:54 a.m. | #1
On Tue, Feb 19, 2019 at 7:50 PM Max Filippov <jcmvbkbc@gmail.com> wrote:
> 2019-02-19  Eric Tsai  <erictsai@cadence.com>

> bfd/

>         * elf32-xtensa.c (is_resolvable_asm_expansion): Scan output

>         sections between the call site and call destination and adjust

>         call distance by the largest alignment.

>

> ld/

>         * testsuite/ld-xtensa/call_overflow.d: New test definition.

>         * testsuite/ld-xtensa/call_overflow1.s: New test source.

>         * testsuite/ld-xtensa/call_overflow2.s: New test source.

>         * testsuite/ld-xtensa/call_overflow3.s: New test source.

>         * testsuite/ld-xtensa/xtensa.exp: Add call_overflow test.


approved
Max Filippov Feb. 20, 2019, 10:53 a.m. | #2
On Tue, Feb 19, 2019 at 10:54 PM augustine.sterling@gmail.com
<augustine.sterling@gmail.com> wrote:
>

> On Tue, Feb 19, 2019 at 7:50 PM Max Filippov <jcmvbkbc@gmail.com> wrote:

> > 2019-02-19  Eric Tsai  <erictsai@cadence.com>

> > bfd/

> >         * elf32-xtensa.c (is_resolvable_asm_expansion): Scan output

> >         sections between the call site and call destination and adjust

> >         call distance by the largest alignment.

> >

> > ld/

> >         * testsuite/ld-xtensa/call_overflow.d: New test definition.

> >         * testsuite/ld-xtensa/call_overflow1.s: New test source.

> >         * testsuite/ld-xtensa/call_overflow2.s: New test source.

> >         * testsuite/ld-xtensa/call_overflow3.s: New test source.

> >         * testsuite/ld-xtensa/xtensa.exp: Add call_overflow test.

>

> approved


Thanks! Applied to master.

-- Max

Patch

diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c
index edd9a0d6d835..c3df3d6db756 100644
--- a/bfd/elf32-xtensa.c
+++ b/bfd/elf32-xtensa.c
@@ -7195,6 +7195,11 @@  is_resolvable_asm_expansion (bfd *abfd,
 			     bfd_boolean *is_reachable_p)
 {
   asection *target_sec;
+  asection *s;
+  bfd_vma first_vma;
+  bfd_vma last_vma;
+  unsigned int first_align;
+  unsigned int adjust;
   bfd_vma target_offset;
   r_reloc r_rel;
   xtensa_opcode opcode, direct_call_opcode;
@@ -7283,6 +7288,56 @@  is_resolvable_asm_expansion (bfd *abfd,
 		      + target_sec->output_offset + target_offset);
     }
 
+  /* Adjust addresses with alignments for the worst case to see if call insn
+     can fit.  Don't relax l32r + callx to call if the target can be out of
+     range due to alignment.
+     Caller and target addresses are highest and lowest address.
+     Search all sections between caller and target, looking for max alignment.
+     The adjustment is max alignment bytes.  If the alignment at the lowest
+     address is less than the adjustment, apply the adjustment to highest
+     address.  */
+
+  /* Start from lowest address.
+     Lowest address aligmnet is from input section.
+     Initial alignment (adjust) is from input section.  */
+  if (dest_address > self_address)
+    {
+      s = sec->output_section;
+      last_vma = dest_address;
+      first_align = sec->alignment_power;
+      adjust = target_sec->alignment_power;
+    }
+  else
+    {
+      s = target_sec->output_section;
+      last_vma = self_address;
+      first_align = target_sec->alignment_power;
+      adjust = sec->alignment_power;
+    }
+
+  first_vma = s->vma;
+
+  /* Find the largest alignment in output section list.  */
+  for (; s && s->vma >= first_vma && s->vma <= last_vma ; s = s->next)
+    {
+      if (s->alignment_power > adjust)
+	adjust = s->alignment_power;
+    }
+
+  if (adjust > first_align)
+    {
+      /* Alignment may enlarge the range, adjust highest address.  */
+      adjust = 1 << adjust;
+      if (dest_address > self_address)
+	{
+	  dest_address += adjust;
+	}
+      else
+	{
+	  self_address += adjust;
+	}
+    }
+
   *is_reachable_p = pcrel_reloc_fits (direct_call_opcode, 0,
 				      self_address, dest_address);
 
diff --git a/ld/testsuite/ld-xtensa/call_overflow.d b/ld/testsuite/ld-xtensa/call_overflow.d
new file mode 100644
index 000000000000..95728488567f
--- /dev/null
+++ b/ld/testsuite/ld-xtensa/call_overflow.d
@@ -0,0 +1,7 @@ 
+#source: call_overflow1.s
+#source: call_overflow2.s
+#source: call_overflow3.s
+#as: --longcalls
+#ld:
+#objdump: -d
+#...
diff --git a/ld/testsuite/ld-xtensa/call_overflow1.s b/ld/testsuite/ld-xtensa/call_overflow1.s
new file mode 100644
index 000000000000..8b032892e20f
--- /dev/null
+++ b/ld/testsuite/ld-xtensa/call_overflow1.s
@@ -0,0 +1,9 @@ 
+	.text
+	.global _start
+	.align 4
+_start:
+	call8	a
+	.rep	2051
+	nop.n
+	nop.n
+	.endr
diff --git a/ld/testsuite/ld-xtensa/call_overflow2.s b/ld/testsuite/ld-xtensa/call_overflow2.s
new file mode 100644
index 000000000000..588b3d9fa4aa
--- /dev/null
+++ b/ld/testsuite/ld-xtensa/call_overflow2.s
@@ -0,0 +1,14 @@ 
+	.text
+	.global a
+	.align	4		
+a:
+	j	a
+
+	.align	4
+x:
+	call8	b
+#29
+	.rep	131070
+	nop.n
+	nop.n
+	.endr
diff --git a/ld/testsuite/ld-xtensa/call_overflow3.s b/ld/testsuite/ld-xtensa/call_overflow3.s
new file mode 100644
index 000000000000..33f59d8bc0bb
--- /dev/null
+++ b/ld/testsuite/ld-xtensa/call_overflow3.s
@@ -0,0 +1,5 @@ 
+	.text
+	.align 32
+	.global b
+b:
+	j	b
diff --git a/ld/testsuite/ld-xtensa/xtensa.exp b/ld/testsuite/ld-xtensa/xtensa.exp
index e8befa9c530f..91b23142b126 100644
--- a/ld/testsuite/ld-xtensa/xtensa.exp
+++ b/ld/testsuite/ld-xtensa/xtensa.exp
@@ -23,6 +23,7 @@  if { !([istarget "xtensa*-*-*"]) } {
     return
 }
 
+run_dump_test "call_overflow"
 run_dump_test "coalesce"
 run_dump_test "diff_overflow"
 run_dump_test "lcall"