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Luis Machado f8e3fe0d27 [AArch64] Improve prologue handling (and fix PR26310)
I initially noticed the problem with the addition of
gdb.dwarf2/dw2-line-number-zero.exp.  The following failures showed up:

FAIL: gdb.dwarf2/dw2-line-number-zero.exp: continue to breakpoint: bar1
FAIL: gdb.dwarf2/dw2-line-number-zero.exp: bar1, 1st next
FAIL: gdb.dwarf2/dw2-line-number-zero.exp: bar1, 2nd next
FAIL: gdb.dwarf2/dw2-line-number-zero.exp: continue to breakpoint: bar2
FAIL: gdb.dwarf2/dw2-line-number-zero.exp: bar2, 1st next
FAIL: gdb.dwarf2/dw2-line-number-zero.exp: bar2, 2nd next

They happen because AArch64's prologue analyzer skips too many instructions
and ends up indicating a stopping point further into user code.

Dump of assembler code for function bar1:
   0x00000000000006f8 <+0>:	stp	x29, x30, [sp, #-16]!
   0x00000000000006fc <+4>:	mov	x29, sp
   0x0000000000000700 <+8>:	mov	w0, #0x1                   	// #1
   0x0000000000000704 <+12>:	bl	0x6e4 <foo>
   0x0000000000000708 <+16>:	mov	w0, #0x2                   	// #2

We should've stopped at 0x700, but the analyzer actually skips
that instruction and stops at 0x704.  Then GDB ends up adjusting
the address further, and pushes the stopping point to 0x708 based on the
SAL information.

I'm not sure if this adjustment to 0x708 is correct though, as it ends up
skipping past a branch. But I'm leaving that aside for now.

One other complicating factor is that GCC seems to be hoisting up instructions
from user code, mixing them up with prologue instructions.

The following patch adjusts the heuristics a little bit, and tracks when the
SP and FP get used.  If we notice an instruction that is not supposed to be
in the prologue, and this happens *after* SP/FP adjustments and saving of
registers, we stop the analysis.

This means, for PR26310, that we will now stop at 0x700.

I've also added a few more unit tests to make sure the updated behavior is
validated.

gdb/ChangeLog:

2020-08-10  Luis Machado  <luis.machado@linaro.org>

	PR gdb/26310

	* aarch64-tdep.c (aarch64_analyze_prologue): Track use of SP/FP and
	act accordingly.
	(aarch64_analyze_prologue_test): Add more unit tests to exercise
	movz/str/stur/stp skipping behavior.
2020-08-10 11:56:19 -03:00
bfd Automatic date update in version.in 2020-08-10 00:00:09 +00:00
binutils nm: Remove --with-symbol-versions 2020-08-10 05:17:41 -07:00
config Unify Solaris procfs and largefile handling 2020-07-30 15:41:50 +02:00
contrib contrib: Update dg-extract-results.* from gcc 2020-05-15 11:41:22 +01:00
cpu Add markers for binutils 2.35 branch 2020-07-04 10:16:22 +01:00
elfcpp Add markers for binutils 2.35 branch 2020-07-04 10:16:22 +01:00
etc
gas Implement missing powerpc extended mnemonics 2020-08-10 21:52:17 +09:30
gdb [AArch64] Improve prologue handling (and fix PR26310) 2020-08-10 11:56:19 -03:00
gdbserver Unify Solaris procfs and largefile handling 2020-07-30 15:41:50 +02:00
gdbsupport gdb: change regcache list to be a map 2020-08-07 11:29:00 -04:00
gnulib Unify Solaris procfs and largefile handling 2020-07-30 15:41:50 +02:00
gold [GOLD] Power10 stub selection 2020-07-27 22:31:37 +09:30
gprof Unify Solaris procfs and largefile handling 2020-07-30 15:41:50 +02:00
include For DWARF v5 Dwarf Package Files (.dwp files), the section identifier encodings have changed. This patch updates dwarf2.h to contain the new encodings. (see http://dwarfstd.org/doc/DWARF5.pdf, section 7.3.5). 2020-07-29 16:33:07 +01:00
intl
ld nm: Remove --with-symbol-versions 2020-08-10 05:17:41 -07:00
libctf libctf: compilation failure on MinGW due to missing errno values 2020-07-26 16:11:36 -07:00
libdecnumber Run autoreconf -vf throughout 2020-07-29 16:03:55 -04:00
libiberty Sync config, include and libiberty with GCC 2020-06-24 16:52:48 -07:00
opcodes Implement missing powerpc mtspr and mfspr extended insns 2020-08-10 21:52:17 +09:30
readline Update readline/README to mention patchlevel 2020-06-30 15:17:07 -06:00
sim MSP430: sim: Increase main memory region size 2020-08-07 11:01:22 +01:00
texinfo
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ChangeLog PKG_CHECK_MODULES: Check if $pkg_cv_[]$1[]_LIBS works 2020-07-28 03:56:34 -07:00
compile
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config.guess
config.rpath
config.sub
configure config/debuginfod.m4: Use PKG_CHECK_MODULES 2020-07-24 15:16:20 -04:00
configure.ac config/debuginfod.m4: Use PKG_CHECK_MODULES 2020-07-24 15:16:20 -04:00
COPYING
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
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If you are receiving this as part of a GDB release, see the file gdb/README.
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	make

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	CC=gcc ./configure
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