Re: [patch,7.3] Fix JIT clang-lli gdb-7.3 regression Re: [gdb-7.3] Error in gdb-llvm integration: Unable to read JIT descriptor from remote memory!

[Paul Pluzhnikov <ppluzhnikov@google.com>]

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On Tue, Jul 5, 2011 at 10:07 AM, Joel Brobecker <brobecker@adacore.com> wrote:

> We're getting ready to produce the first gdb-7.3 candidate release,
> and we're thinking of either:
>  - going with Jan's patch for now, with a view of possibly
>    making it better with a followup patch if necessary;
>  - releasing 7.3 with JIT as a known problem, hopefully to be
>    fixed for 7.3.1, depending on how safe the fix is perceived.

Another option is to apply a better fix (provided it is deemed safe) ...

Certainly it's ok with me if you decide to go with Jan's patch for now.

It took me  much longer to create a test case (I don't have 'lli'), then
it did to fix the problem once I had the repro.

Thanks,
-- 
Paul Pluzhnikov


2011-07-05  Paul Pluzhnikov  <ppluzhnikov@google.com>

	jit.c (jit_breakpoint_re_set_internal): Call jit_inferior_init.


testsuite/ChangeLog:

2011-07-05  Paul Pluzhnikov  <ppluzhnikov@google.com>

	* gdb.base/jit-so.exp: New test.
	* gdb.base/jit-dlmain.c: New file.
	* gdb.base/jit-main.c: Allow "main" to be elsewhere.

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Index: jit.c
===================================================================
RCS file: /cvs/src/src/gdb/jit.c,v
retrieving revision 1.12
diff -u -p -n -p -r1.12 jit.c
*** jit.c	17 Apr 2011 18:38:45 -0000	1.12
--- jit.c	5 Jul 2011 20:58:12 -0000
*************** static const char *const jit_descriptor_
*** 40,45 ****
--- 40,48 ----
  
  static const struct inferior_data *jit_inferior_data = NULL;
  
+ static void
+ jit_inferior_init (struct gdbarch *gdbarch);
+ 
  /* Non-zero if we want to see trace of jit level stuff.  */
  
  static int jit_debug = 0;
*************** jit_breakpoint_re_set_internal (struct g
*** 351,356 ****
--- 354,364 ----
        inf_data->breakpoint_addr = SYMBOL_VALUE_ADDRESS (reg_symbol);
        if (inf_data->breakpoint_addr == 0)
  	return 2;
+ 
+       /* If we have not read the jit descriptor yet (e.g. because the JITer
+ 	 itself is in a shared library which just got loaded), do so now.  */
+       if (inf_data->descriptor_addr == 0)
+ 	jit_inferior_init (gdbarch);
      }
    else
      return 0;
Index: testsuite/gdb.base/jit-dlmain.c
===================================================================
RCS file: testsuite/gdb.base/jit-dlmain.c
diff -N testsuite/gdb.base/jit-dlmain.c
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- testsuite/gdb.base/jit-dlmain.c	5 Jul 2011 20:58:12 -0000
***************
*** 0 ****
--- 1,16 ----
+ #include <dlfcn.h>
+ #include <stdio.h>
+ 
+ int main (int argc, char *argv[])
+ {
+   void *h = dlopen ("jit-dlmain-so.so", RTLD_LAZY);
+   int (*p_main) (int, char **);
+ 
+   if (h == NULL) return 1;
+ 
+   p_main = dlsym (h, "jit_dl_main");
+   if (p_main == NULL) return 2;
+ 
+   h = h;  /* break here after-dlopen */
+   return (*p_main) (argc, argv);
+ }
Index: testsuite/gdb.base/jit-main.c
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.base/jit-main.c,v
retrieving revision 1.2
diff -u -p -n -p -r1.2 jit-main.c
*** testsuite/gdb.base/jit-main.c	15 Mar 2011 21:03:44 -0000	1.2
--- testsuite/gdb.base/jit-main.c	5 Jul 2011 20:58:12 -0000
*************** update_locations (const void *const addr
*** 117,124 ****
      }
  }
  
  int
! main (int argc, char *argv[])
  {
    /* These variables are here so they can easily be set from jit.exp.  */
    const char *libname = NULL;
--- 117,128 ----
      }
  }
  
+ #ifndef MAIN
+ #define MAIN main
+ #endif
+ 
  int
! MAIN (int argc, char *argv[])
  {
    /* These variables are here so they can easily be set from jit.exp.  */
    const char *libname = NULL;
Index: testsuite/gdb.base/jit-so.exp
===================================================================
RCS file: testsuite/gdb.base/jit-so.exp
diff -N testsuite/gdb.base/jit-so.exp
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- testsuite/gdb.base/jit-so.exp	5 Jul 2011 20:58:12 -0000
***************
*** 0 ****
--- 1,117 ----
+ # Copyright 2011 Free Software Foundation, Inc.
+ 
+ # This program is free software; you can redistribute it and/or modify
+ # it under the terms of the GNU General Public License as published by
+ # the Free Software Foundation; either version 3 of the License, or
+ # (at your option) any later version.
+ #
+ # This program is distributed in the hope that it will be useful,
+ # but WITHOUT ANY WARRANTY; without even the implied warranty of
+ # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ # GNU General Public License for more details.
+ #
+ # You should have received a copy of the GNU General Public License
+ # along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ 
+ # The same tests as in jit.exp, but loading JITer itself from a shared
+ # library.
+ 
+ if $tracelevel {
+     strace $tracelevel
+ }
+ 
+ if {[skip_shlib_tests]} {
+     untested jit-so.exp
+     return -1
+ }
+ 
+ if {[get_compiler_info not-used]} {
+     warning "Could not get compiler info"
+     untested jit-so.exp
+     return 1
+ }
+ 
+ #
+ # test running programs
+ #
+ 
+ set testfile jit-dlmain
+ set srcfile ${testfile}.c
+ set binfile ${objdir}/${subdir}/${testfile}
+ if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug shlib_load}] != "" } {
+     untested jit-so.exp
+     return -1
+ }
+ 
+ set testfile2 jit-main
+ set srcfile2 ${testfile2}.c
+ set binfile2 ${objdir}/${subdir}/${testfile2}.so
+ if { [gdb_compile_shlib "${srcdir}/${subdir}/${srcfile2}" ${binfile2} {debug additional_flags="-DMAIN=jit_dl_main"}] != "" } {
+     untested jit.exp
+     return -1
+ }
+ 
+ set solib_testfile "jit-solib"
+ set solib_srcfile "${srcdir}/${subdir}/${solib_testfile}.c"
+ set solib_binfile "${objdir}/${subdir}/${solib_testfile}.so"
+ set solib_binfile_test_msg "OBJDIR/${subdir}/${solib_testfile}.so"
+ 
+ # Note: compiling without debug info: the library goes through symbol
+ # renaming by munging on its symbol table, and that wouldn't work for .debug
+ # sections.  Also, output for "info function" changes when debug info is resent.
+ if { [gdb_compile_shlib ${solib_srcfile} ${solib_binfile} {}] != "" } {
+     untested jit-so.exp
+     return -1
+ }
+ 
+ proc one_jit_test {count match_str} {
+     global verbose testfile srcfile2 solib_binfile solib_binfile_test_msg pf_prefix
+ 
+     set old_pf_prefix $pf_prefix
+     set pf_prefix "one_jit_test-$count"
+ 
+     clean_restart $testfile
+ 
+     # This is just to help debugging when things fail
+     if {$verbose > 0} {
+ 	gdb_test "set debug jit 1"
+     }
+ 
+     if { ![runto_main] } {
+ 	fail "Can't run to main"
+ 	return
+     }
+ 
+     gdb_breakpoint [gdb_get_line_number "break here after-dlopen" ]
+     gdb_continue_to_breakpoint "break here after-dlopen"
+ 
+     gdb_breakpoint "$srcfile2:[gdb_get_line_number {break here 0} $srcfile2]"
+     gdb_continue_to_breakpoint "break here 0"
+ 
+     # Poke desired values directly into inferior instead of using "set args"
+     # because "set args" does not work under gdbserver.
+     gdb_test_no_output "set var argc = 2"
+     gdb_test_no_output "set var libname = \"$solib_binfile\"" "set var libname = \"$solib_binfile_test_msg\""
+     gdb_test_no_output "set var count = $count"
+ 
+     gdb_breakpoint "$srcfile2:[gdb_get_line_number {break here 1} $srcfile2]"
+     gdb_continue_to_breakpoint "break here 1"
+ 
+     gdb_test "info function jit_function" "$match_str"
+ 
+     # This is just to help debugging when things fail
+     if {$verbose > 0} {
+ 	gdb_test "maintenance print objfiles"
+ 	gdb_test "maintenance info break"
+     }
+ 
+     gdb_breakpoint "$srcfile2:[gdb_get_line_number {break here 2} $srcfile2]"
+     gdb_continue_to_breakpoint "break here 2"
+     # All jit librares must have been unregistered
+     gdb_test "info function jit_function" \
+ 	"All functions matching regular expression \"jit_function\":" \
+     set pf_prefix $old_pf_prefix
+ }
+ 
+ one_jit_test 1 "${hex}  jit_function_0000"
+ one_jit_test 2 "${hex}  jit_function_0000\[\r\n\]+${hex}  jit_function_0001"