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From fc6141f097056f830a412afebed8d81a9d72b696 Mon Sep 17 00:00:00 2001
From: Nick Clifton <nickc@redhat.com>
Date: Wed, 20 Jun 2018 12:38:10 +0100
Subject: [PATCH] Change the ARM assembler's ADR and ADRl pseudo-ops so that
they will only set the bottom bit of imported thumb function symbols if the
-mthumb-interwork option is active.
For more information see the email thread starting here:
https://www.sourceware.org/ml/binutils/2018-05/msg00348.html
PR 21458
* tc-arm.c (do_adr): Only set the bottom bit of an imported thumb
function symbol address if -mthumb-interwork is active.
(do_adrl): Likewise.
* doc/c-arm.texi: Update descriptions of the -mthumb-interwork
option and the ADR and ADRL pseudo-ops.
* NEWS: Mention the new behaviour of the ADR and ADRL pseudo-ops.
* testsuite/gas/arm/pr21458.d: Add -mthumb-interwork option to
assembler command line.
* testsuite/gas/arm/adr.d: Likewise.
* testsuite/gas/arm/adrl.d: Likewise.
---
gas/ChangeLog | 14 ++++++++++++++
gas/NEWS | 4 ++++
gas/config/tc-arm.c | 10 ++++++----
gas/doc/c-arm.texi | 17 ++++++++++++++++-
gas/testsuite/gas/arm/adr.d | 1 +
gas/testsuite/gas/arm/adrl.d | 1 +
gas/testsuite/gas/arm/pr21458.d | 3 ++-
7 files changed, 44 insertions(+), 6 deletions(-)
Index: git/gas/config/tc-arm.c
===================================================================
--- git.orig/gas/config/tc-arm.c
+++ git/gas/config/tc-arm.c
@@ -8410,11 +8410,12 @@ do_adr (void)
inst.reloc.pc_rel = 1;
inst.reloc.exp.X_add_number -= 8;
- if (inst.reloc.exp.X_op == O_symbol
+ if (support_interwork
+ && inst.reloc.exp.X_op == O_symbol
&& inst.reloc.exp.X_add_symbol != NULL
&& S_IS_DEFINED (inst.reloc.exp.X_add_symbol)
&& THUMB_IS_FUNC (inst.reloc.exp.X_add_symbol))
- inst.reloc.exp.X_add_number += 1;
+ inst.reloc.exp.X_add_number |= 1;
}
/* This is a pseudo-op of the form "adrl rd, label" to be converted
@@ -8434,11 +8435,12 @@ do_adrl (void)
inst.size = INSN_SIZE * 2;
inst.reloc.exp.X_add_number -= 8;
- if (inst.reloc.exp.X_op == O_symbol
+ if (support_interwork
+ && inst.reloc.exp.X_op == O_symbol
&& inst.reloc.exp.X_add_symbol != NULL
&& S_IS_DEFINED (inst.reloc.exp.X_add_symbol)
&& THUMB_IS_FUNC (inst.reloc.exp.X_add_symbol))
- inst.reloc.exp.X_add_number += 1;
+ inst.reloc.exp.X_add_number |= 1;
}
static void
Index: git/gas/doc/c-arm.texi
===================================================================
--- git.orig/gas/doc/c-arm.texi
+++ git/gas/doc/c-arm.texi
@@ -317,7 +317,8 @@ instructions; that is, it should behave
@cindex @code{-mthumb-interwork} command line option, ARM
@item -mthumb-interwork
This option specifies that the output generated by the assembler should
-be marked as supporting interworking.
+be marked as supporting interworking. It also affects the behaviour
+of the @code{ADR} and @code{ADRL} pseudo opcodes.
@cindex @code{-mimplicit-it} command line option, ARM
@item -mimplicit-it=never
@@ -1060,6 +1061,16 @@ out of range, or if it is not defined in
the ADR instruction, then an error will be generated. This instruction
will not make use of the literal pool.
+If @var{label} is a thumb function symbol, and thumb interworking has
+been enabled via the @option{-mthumb-interwork} option then the bottom
+bit of the value stored into @var{register} will be set. This allows
+the following sequence to work as expected:
+
+@smallexample
+ adr r0, thumb_function
+ blx r0
+@end smallexample
+
@cindex @code{ADRL reg,<label>} pseudo op, ARM
@item ADRL
@smallexample
@@ -1076,6 +1087,10 @@ If the label is out of range, or if it i
(and section) as the ADRL instruction, then an error will be generated.
This instruction will not make use of the literal pool.
+If @var{label} is a thumb function symbol, and thumb interworking has
+been enabled via the @option{-mthumb-interwork} option then the bottom
+bit of the value stored into @var{register} will be set.
+
@end table
For information on the ARM or Thumb instruction sets, see @cite{ARM
Index: git/gas/testsuite/gas/arm/adr.d
===================================================================
--- git.orig/gas/testsuite/gas/arm/adr.d
+++ git/gas/testsuite/gas/arm/adr.d
@@ -1,3 +1,4 @@
+#as: -mthumb-interwork
#objdump: -dr --prefix-addresses --show-raw-insn
#name: ADR
Index: git/gas/testsuite/gas/arm/adrl.d
===================================================================
--- git.orig/gas/testsuite/gas/arm/adrl.d
+++ git/gas/testsuite/gas/arm/adrl.d
@@ -1,3 +1,4 @@
+#as: -mthumb-interwork
#objdump: -dr --prefix-addresses --show-raw-insn
#name: ADRL
Index: git/gas/ChangeLog
===================================================================
--- git.orig/gas/ChangeLog
+++ git/gas/ChangeLog
@@ -1,3 +1,17 @@
+2018-06-20 Nick Clifton <nickc@redhat.com>
+
+ PR 21458
+ * tc-arm.c (do_adr): Only set the bottom bit of an imported thumb
+ function symbol address if -mthumb-interwork is active.
+ (do_adrl): Likewise.
+ * doc/c-arm.texi: Update descriptions of the -mthumb-interwork
+ option and the ADR and ADRL pseudo-ops.
+ * NEWS: Mention the new behaviour of the ADR and ADRL pseudo-ops.
+ * testsuite/gas/arm/pr21458.d: Add -mthumb-interwork option to
+ assembler command line.
+ * testsuite/gas/arm/adr.d: Likewise.
+ * testsuite/gas/arm/adrl.d: Likewise.
+
2018-02-05 Nick Clifton <nickc@redhat.com>
* po/ru.po: Updated Russian translation.
Index: git/gas/NEWS
===================================================================
--- git.orig/gas/NEWS
+++ git/gas/NEWS
@@ -1,5 +1,9 @@
-*- text -*-
+* The ADR and ADRL pseudo-instructions supported by the ARM assembler
+ now only set the bottom bit of the address of thumb function symbols
+ if the -mthumb-interwork command line option is active.
+
Changes in 2.30:
* Add support for loaction views in DWARF debug line information.
Index: git/gas/testsuite/gas/arm/pr21458.d
===================================================================
--- git.orig/gas/testsuite/gas/arm/pr21458.d
+++ git/gas/testsuite/gas/arm/pr21458.d
@@ -1,8 +1,9 @@
+#as: -mthumb-interwork
#objdump: -d --prefix-addresses --show-raw-insn
#name: ADR(L) for Thumb functions
#skip: *-*-pe *-wince-* *-*-coff *-*-vxworks
-# Test that using ADR(L) on thumb function symbols sets the T bit.
+# Test that using ADR(L) on thumb function symbols sets the T bit when -mthumb-interwork is active.
.*: +file format .*arm.*
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