From: Christian Eggers <ceggers@gmx.de>
To: binutils@sourceware.org
Cc: Christian Eggers <ceggers@gmx.de>
Subject: [PATCH 6/7] [gas] dwarf2: Pad size of .debug_line section.
Date: Sun, 10 Mar 2019 18:22:00 -0000 [thread overview]
Message-ID: <20190310182158.23705-7-ceggers@gmx.de> (raw)
In-Reply-To: <20190310182158.23705-1-ceggers@gmx.de>
As all dwarf debug information is organized in octets, the size of all
dwarf sections must be aligned to OCTETS_PER_BYTE. Most DWARF sections
meet this requirement, only the .debug_line section can reach an
arbitrary octet size.
In order to align the size to a multiple of OCTETS_PER_BYTE, the section
is padded with "nop" statements at the end.
This change should not affect existing targets as all targets currently
using DWARF2 have 8 bit per byte.
Signed-off-by: Christian Eggers <ceggers@gmx.de>
---
gas/ChangeLog | 4 ++++
gas/dwarf2dbg.c | 14 ++++++++++++++
2 files changed, 18 insertions(+)
diff --git a/gas/ChangeLog b/gas/ChangeLog
index 2d7dabc299..c6a857b93c 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,7 @@
+2019-03-10 Christian Eggers <ceggers@gmx.de>
+
+ * dwarf2dbg.c (out_debug_line): Pad size of .debug_line section.
+
2019-03-10 Christian Eggers <ceggers@gmx.de>
* dwarf2dbg.c: Use octets for .debug_string pointers.
diff --git a/gas/dwarf2dbg.c b/gas/dwarf2dbg.c
index d469138576..9e68233ad3 100644
--- a/gas/dwarf2dbg.c
+++ b/gas/dwarf2dbg.c
@@ -1787,6 +1787,7 @@ out_debug_line (segT line_seg)
symbolS *line_end;
struct line_seg *s;
int sizeof_offset;
+ addressT section_end, section_end_aligned;
memset (&exp, 0, sizeof exp);
sizeof_offset = out_header (line_seg, &exp);
@@ -1848,6 +1849,19 @@ out_debug_line (segT line_seg)
in the DWARF Line Number header. */
subseg_set (subseg_get (".debug_line_end", FALSE), 0);
+ /* Pad size of .debug_line section to a multiple of OCTETS_PER_BYTE. Simply
+ sizing the section in md_section_align() is not sufficient, also the size
+ field in the .debug_line header must be a multiple of OCTETS_PER_BYTE. Not
+ doing so will introduce gaps within the .debug_line sections after linking.
+ */
+ section_end = frag_now_fix_octets ();
+ section_end_aligned = (section_end + OCTETS_PER_BYTE - 1) &
+ ~(OCTETS_PER_BYTE - 1);
+ for ( ; section_end != section_end_aligned; section_end++)
+ {
+ out_inc_line_addr (0, 0); /* NOP */
+ }
+
symbol_set_value_now_octets (line_end);
}
--
2.16.4
next prev parent reply other threads:[~2019-03-10 18:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-10 18:22 [PATCH 0/7] gas: Fixes for DWARF2 debug info with OCTETS_PER_BYTE>1 Christian Eggers
2019-03-10 18:22 ` [PATCH 1/7] [gas] dwarf2: Fix calculation of line info offset Christian Eggers
2019-03-10 18:22 ` [PATCH 3/7] [gas] dwarf2: Use octets for dwarf2 headers Christian Eggers
2019-03-10 18:22 ` [PATCH 7/7] [gas] dwarf2: Align relocation within .debug_line section Christian Eggers
2019-03-10 18:22 ` Christian Eggers [this message]
2019-03-10 18:22 ` [PATCH 5/7] [gas] dwarf2: Use octets for .debug_string offsets Christian Eggers
2019-03-10 18:22 ` [PATCH 4/7] [gas] dwarf2: Use octets for .debug_line prologue Christian Eggers
2019-03-10 18:27 ` [PATCH 2/7] [gas] Allow to create symbols with octets value Christian Eggers
2019-03-13 4:49 ` [PATCH 0/7] gas: Fixes for DWARF2 debug info with OCTETS_PER_BYTE>1 Alan Modra
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