gdb: Allow gdbarch to override alignment for method and member pointers

Message ID 20190218215623.26529-1-andrew.burgess@embecosm.com
State New
Headers show
Series
  • gdb: Allow gdbarch to override alignment for method and member pointers
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Commit Message

Andrew Burgess Feb. 18, 2019, 9:56 p.m.
The code in type_align (gdbtypes.c) currently hard-codes the rules for
aligning method and member pointers.  It would seem better to forward
these types through the gdbarch hook, so that an architecture could
override the alignment of these types if needed.

Only 3 architectures currently override the gdbarch alignment hook,
these are arc, i386, and nio2.

For arc and nios the alignment rules are that alignment is the minimum
of 4-bytes and the type length.  As pointers are 4-bytes on these
targets, then (assuming method and members pointers are also 4-bytes)
there should be no change to the alignment after this patch.

For i386 the gdbarch alignment hook overrides for some INT and FLOAT
types only.  For method and member pointers we align on the type size
still, so there should be no change to the alignment after this patch.

I tested this on x86-64 GNU Linux with no regressions.

gdb/ChangeLog:

	* gdbtypes.c (type_align): Allow alignment of TYPE_CODE_METHODPTR
	and TYPE_CODE_MEMBERPTR to be overridden by the gdbarch.
---
 gdb/ChangeLog  | 5 +++++
 gdb/gdbtypes.c | 7 ++-----
 2 files changed, 7 insertions(+), 5 deletions(-)

-- 
2.14.5

Comments

Tom Tromey Feb. 18, 2019, 11:08 p.m. | #1
>>>>> "Andrew" == Andrew Burgess <andrew.burgess@embecosm.com> writes:


Andrew> gdb/ChangeLog:
Andrew> 	* gdbtypes.c (type_align): Allow alignment of TYPE_CODE_METHODPTR
Andrew> 	and TYPE_CODE_MEMBERPTR to be overridden by the gdbarch.

This looks good to me.  Thanks for doing this.

Tom

Patch

diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 675878337b3..0d293393dae 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -3011,6 +3011,8 @@  type_align (struct type *type)
     case TYPE_CODE_CHAR:
     case TYPE_CODE_BOOL:
     case TYPE_CODE_DECFLOAT:
+    case TYPE_CODE_METHODPTR:
+    case TYPE_CODE_MEMBERPTR:
       {
 	struct gdbarch *arch = get_type_arch (type);
 	align = gdbarch_type_align (arch, type);
@@ -3053,11 +3055,6 @@  type_align (struct type *type)
 	 anyway.  */
       break;
 
-    case TYPE_CODE_METHODPTR:
-    case TYPE_CODE_MEMBERPTR:
-      align = type_length_units (type);
-      break;
-
     case TYPE_CODE_VOID:
       align = 1;
       break;