Re: [PATCH 3/3] Add a test case for the jit-reader interface.

[Sanjoy Das <sanjoy@playingwithpointers.com>]

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Hi,

Changes from the last series:

> Do not use full binary path in test name, those differ across testsuite runs.
> That is use for example:
>         gdb_test_no_output "jit-reader-load ${jit_reader_bin}" "jit-reader-load"

1. Fixed above issue.

2. Use SLASH_STRING instead of a raw backslash when computing the full
path of a plugin (in the second patch).

Thanks!
--
Sanjoy Das
http://playingwithpointers.com

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From 03cf27011fa85a21112cf21ac0765ce472b561af Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Thu, 6 Sep 2012 04:52:28 +0530
Subject: [PATCH 1/3] Fix segfault when unwinding JIT frames using a custom
 reader.

Issue http://sourceware.org/bugzilla/show_bug.cgi?id=14550
---
 gdb/ChangeLog |    7 +++++++
 gdb/jit.c     |   14 ++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index d9a2e45..b619953 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2012-01-14  Sanjoy Das <sanjoy@playingwithpointers.com>
+
+	PR gdb/14550
+
+	* jit.c (finalize_symtab): Ensure that only the global block has a
+	NULL superblock.
+
 2013-01-13  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	* parse.c (parse_exp_in_context): New variable inner_chain.  Call
diff --git a/gdb/jit.c b/gdb/jit.c
index a930f74..f542f9e 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -724,8 +724,18 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
        gdb_block_iter = gdb_block_iter->next)
     {
       if (gdb_block_iter->parent != NULL)
-        BLOCK_SUPERBLOCK (gdb_block_iter->real_block) =
-          gdb_block_iter->parent->real_block;
+	{
+	  /* If the plugin specifically mentioned a parent block, we
+	     use that.  */
+	  BLOCK_SUPERBLOCK (gdb_block_iter->real_block) =
+	    gdb_block_iter->parent->real_block;
+	}
+      else
+	{
+	  /* And if not, we set a default parent block.  */
+	  BLOCK_SUPERBLOCK (gdb_block_iter->real_block) =
+	    BLOCKVECTOR_BLOCK (symtab->blockvector, STATIC_BLOCK);
+	}
     }
 
   /* Free memory.  */
-- 
1.7.10.4


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From 90b964a0742ab876f8b8648e4fff5e8393b22f08 Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Tue, 18 Sep 2012 08:51:53 +0530
Subject: [PATCH 2/3] Make jit-reader-load accept absolute paths to reader
 shared objects.

---
 gdb/ChangeLog       |    5 +++++
 gdb/doc/ChangeLog   |    4 ++++
 gdb/doc/gdb.texinfo |   22 +++++++++++++---------
 gdb/jit.c           |    6 +++++-
 4 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index b619953..c6f94b6 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2012-01-14  Sanjoy Das <sanjoy@playingwithpointers.com>
 
+	* jit.c (jit_reader_load_command): Interpret the jit reader name
+	as an absolute path if it begins with a forward slash.
+
+2012-01-14  Sanjoy Das <sanjoy@playingwithpointers.com>
+
 	PR gdb/14550
 
 	* jit.c (finalize_symtab): Ensure that only the global block has a
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 0eb574d..6594ea0 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,7 @@
+2012-01-14  Sanjoy Das <sanjoy@playingwithpointers.com>
+	* gdb.texinfo (Using JIT Debug Info Readers): Change documentation
+	to reflect that jit-reader-load now supports absolute file-names.
+
 2013-01-07  Tom Tromey  <tromey@redhat.com>
 
 	* gdb.texinfo (Mode Options): Don't mention -epoch.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index f973263..4731d59 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -33940,15 +33940,19 @@ Readers can be loaded and unloaded using the @code{jit-reader-load}
 and @code{jit-reader-unload} commands.
 
 @table @code
-@item jit-reader-load @var{reader-name}
-Load the JIT reader named @var{reader-name}.  On a UNIX system, this
-will usually load @file{@var{libdir}/gdb/@var{reader-name}}, where
-@var{libdir} is the system library directory, usually
-@file{/usr/local/lib}.  Only one reader can be active at a time;
-trying to load a second reader when one is already loaded will result
-in @value{GDBN} reporting an error.  A new JIT reader can be loaded by
-first unloading the current one using @code{jit-reader-load} and then
-invoking @code{jit-reader-load}.
+@item jit-reader-load @var{reader}
+Load the JIT reader named @var{reader}.  @var{reader} is a shared
+object specified as either an absolute or a relative file name.  In
+the latter case, @value{GDBN} will try to load the reader from a
+pre-configured directory, usually @file{@var{libdir}/gdb/} on a UNIX
+system (here @var{libdir} is the system library directory, often
+@file{/usr/local/lib}).
+
+Only one reader can be active at a time; trying to load a second
+reader when one is already loaded will result in @value{GDBN}
+reporting an error.  A new JIT reader can be loaded by first unloading
+the current one using @code{jit-reader-unload} and then invoking
+@code{jit-reader-load}.
 
 @item jit-reader-unload
 Unload the currently loaded JIT reader.
diff --git a/gdb/jit.c b/gdb/jit.c
index f542f9e..4623f15 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -25,6 +25,7 @@
 #include "breakpoint.h"
 #include "command.h"
 #include "dictionary.h"
+#include "filenames.h"
 #include "frame-unwind.h"
 #include "gdbcmd.h"
 #include "gdbcore.h"
@@ -208,7 +209,10 @@ jit_reader_load_command (char *args, int from_tty)
   if (loaded_jit_reader != NULL)
     error (_("JIT reader already loaded.  Run jit-reader-unload first."));
 
-  so_name = xstrprintf ("%s/%s", jit_reader_dir, args);
+  if (IS_ABSOLUTE_PATH (args))
+    so_name = xstrdup (args);
+  else
+    so_name = xstrprintf ("%s%s%s", SLASH_STRING, jit_reader_dir, args);
   prev_cleanup = make_cleanup (xfree, so_name);
 
   loaded_jit_reader = jit_reader_load (so_name);
-- 
1.7.10.4


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From 1336918c7e94059cab51ffad4d56fba50e3fe6d4 Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Tue, 18 Sep 2012 08:52:07 +0530
Subject: [PATCH 3/3] Add a test case for the jit-reader interface.

---
 gdb/testsuite/ChangeLog               |    9 ++
 gdb/testsuite/gdb.base/jit-protocol.h |   54 ++++++++++++
 gdb/testsuite/gdb.base/jit-reader.exp |   80 +++++++++++++++++
 gdb/testsuite/gdb.base/jithost.c      |   61 +++++++++++++
 gdb/testsuite/gdb.base/jithost.h      |   27 ++++++
 gdb/testsuite/gdb.base/jitreader.c    |  156 +++++++++++++++++++++++++++++++++
 6 files changed, 387 insertions(+)
 create mode 100644 gdb/testsuite/gdb.base/jit-protocol.h
 create mode 100644 gdb/testsuite/gdb.base/jit-reader.exp
 create mode 100644 gdb/testsuite/gdb.base/jithost.c
 create mode 100644 gdb/testsuite/gdb.base/jithost.h
 create mode 100644 gdb/testsuite/gdb.base/jitreader.c

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 717ea18..0fdd82c 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2012-01-14  Sanjoy Das <sanjoy@playingwithpointers.com>
+
+	* gdb.base/jit-reader.exp: New file. Test case for the jit-reader
+	interface.
+	* gdb.base/jithost.c: New file.
+	* gdb.base/jithost.h: New file.
+	* gdb.base/jitreader.c : New file.
+	* gdb.base/jit-protocol.h: New file.
+
 2013-01-13  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	* gdb.cp/parse-lang.cc: New file.
diff --git a/gdb/testsuite/gdb.base/jit-protocol.h b/gdb/testsuite/gdb.base/jit-protocol.h
new file mode 100644
index 0000000..f7f9285
--- /dev/null
+++ b/gdb/testsuite/gdb.base/jit-protocol.h
@@ -0,0 +1,54 @@
+/* Copyright (C) 2009-2013 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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/>.  */
+
+#ifdef JIT_H
+#error "We don't include jit.h directly since we'd like the jit-reader unit  \
+        tests to break if we make ABI incompatible changes to the structures \
+        re-declared here."
+#endif
+
+#ifndef JIT_PROTOCOL_H
+#define JIT_PROTOCOL_H
+
+#include <stdint.h>
+
+typedef enum
+{
+  JIT_NOACTION = 0,
+  JIT_REGISTER,
+  JIT_UNREGISTER
+} jit_actions_t;
+
+
+struct jit_code_entry
+{
+  struct jit_code_entry *next_entry;
+  struct jit_code_entry *prev_entry;
+  void *symfile_addr;
+  uint64_t symfile_size;
+};
+
+
+struct jit_descriptor
+{
+  uint32_t version;
+  uint32_t action_flag;
+  struct jit_code_entry *relevant_entry;
+  struct jit_code_entry *first_entry;
+};
+
+#endif /* JIT_PROTOCOL_H */
diff --git a/gdb/testsuite/gdb.base/jit-reader.exp b/gdb/testsuite/gdb.base/jit-reader.exp
new file mode 100644
index 0000000..6080564
--- /dev/null
+++ b/gdb/testsuite/gdb.base/jit-reader.exp
@@ -0,0 +1,80 @@
+# Copyright 2012 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/>.
+
+standard_testfile jithost.c
+
+if { (![istarget x86_64-*-*] && ![istarget i?86-*-*]) || ![is_lp64_target] } {
+    return -1;
+}
+
+if {[skip_shlib_tests]} {
+    return -1
+}
+
+if { ![isnative] } {
+    return -1
+}
+
+if {[get_compiler_info]} {
+    untested "could not get compiler info"
+    return 1
+}
+
+set jit_host_src ${srcfile}
+set jit_host_bin ${binfile}
+
+# We inject the complete path to jit-reader.h into the source file
+# lest we end up (incorrectly) building against a system-installed
+# version.
+set jit_reader_header [standard_output_file "../../../gdb/jit-reader.h"]
+set jit_reader_flag "-DJIT_READER_H=\"$jit_reader_header\""
+
+if  { [gdb_compile "${srcdir}/${subdir}/${jit_host_src}" "${jit_host_bin}" \
+       executable  [list debug additional_flags=$jit_reader_flag]] != "" } {
+    untested jit-reader.exp
+    return -1
+}
+
+set jit_reader jitreader
+set jit_reader_src ${jit_reader}.c
+set jit_reader_bin [standard_output_file ${jit_reader}.so]
+
+if { [gdb_compile_shlib "${srcdir}/${subdir}/${jit_reader_src}" "${jit_reader_bin}" \
+	  [list debug additional_flags=$jit_reader_flag]] != "" } {
+    untested jit-reader.exp
+    return -1
+}
+
+gdb_load_shlibs "${jit_reader_bin}"
+
+proc jit_reader_test {} {
+    global jit_host_bin
+    global jit_reader_bin
+    global verbose
+
+    clean_restart $jit_host_bin
+
+    if {$verbose > 0} {
+	gdb_test_no_output "set debug jit 1"
+    }
+
+    gdb_test_no_output "jit-reader-load ${jit_reader_bin}" "jit-reader-load"
+    gdb_run_cmd
+    gdb_test "" "Program received signal SIGTRAP, .*" "expect SIGTRAP"
+
+    gdb_test "bt" "jit_function_00.*"
+}
+
+jit_reader_test
diff --git a/gdb/testsuite/gdb.base/jithost.c b/gdb/testsuite/gdb.base/jithost.c
new file mode 100644
index 0000000..413c4cd
--- /dev/null
+++ b/gdb/testsuite/gdb.base/jithost.c
@@ -0,0 +1,61 @@
+/* Copyright (C) 2009-2012 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/mman.h>
+
+#include JIT_READER_H  /* Please see jit-reader.exp for an explanation.  */
+#include "jithost.h"
+#include "jit-protocol.h"
+
+void __attribute__((noinline)) __jit_debug_register_code () { }
+
+struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
+struct jit_code_entry only_entry;
+
+typedef void (jit_function_t) ();
+
+int main (int argc, char **argv)
+{
+  char *code = mmap (NULL, getpagesize (), PROT_WRITE | PROT_EXEC,
+		     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  jit_function_t *function = (jit_function_t *) code;
+
+  code[0] = 0xcc; /* SIGTRAP  */
+  code[1] = 0xc3; /* RET  */
+
+  struct jithost_abi *symfile = malloc (sizeof (struct jithost_abi));
+  symfile->begin = code;
+  symfile->end = code + 2;
+
+  only_entry.symfile_addr = symfile;
+  only_entry.symfile_size = sizeof (struct jithost_abi);
+
+  __jit_debug_descriptor.first_entry = &only_entry;
+  __jit_debug_descriptor.relevant_entry = &only_entry;
+  __jit_debug_descriptor.action_flag = JIT_REGISTER;
+  __jit_debug_descriptor.version = 1;
+  __jit_debug_register_code ();
+
+  function ();
+
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/jithost.h b/gdb/testsuite/gdb.base/jithost.h
new file mode 100644
index 0000000..52ca87a
--- /dev/null
+++ b/gdb/testsuite/gdb.base/jithost.h
@@ -0,0 +1,27 @@
+/* Copyright (C) 2009-2012 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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/>.  */
+
+#ifndef JITHOST_H
+#define JITHOST_H
+
+struct jithost_abi
+{
+  const char *begin;
+  const char *end;
+};
+
+#endif /* JITHOST_H */
diff --git a/gdb/testsuite/gdb.base/jitreader.c b/gdb/testsuite/gdb.base/jitreader.c
new file mode 100644
index 0000000..0c935c4
--- /dev/null
+++ b/gdb/testsuite/gdb.base/jitreader.c
@@ -0,0 +1,156 @@
+/* Copyright (C) 2009-2012 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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/>.  */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include JIT_READER_H  /* Please see jit-reader.exp for an explanation.  */
+#include "jithost.h"
+
+GDB_DECLARE_GPL_COMPATIBLE_READER;
+
+enum register_mapping
+{
+  AMD64_RA = 16,
+  AMD64_RSP = 7,
+};
+
+struct reader_state
+{
+  uintptr_t code_begin;
+  uintptr_t code_end;
+};
+
+static enum gdb_status
+read_debug_info (struct gdb_reader_funcs *self,
+		 struct gdb_symbol_callbacks *cbs,
+                 void *memory, long memory_sz)
+{
+  struct jithost_abi *symfile = memory;
+  struct gdb_object *object = cbs->object_open (cbs);
+  struct gdb_symtab *symtab = cbs->symtab_open (cbs, object, "");
+  GDB_CORE_ADDR begin = (GDB_CORE_ADDR) symfile->begin;
+  GDB_CORE_ADDR end = (GDB_CORE_ADDR) symfile->end;
+
+  cbs->block_open (cbs, symtab, NULL, begin, end, "jit_function_00");
+
+  cbs->symtab_close (cbs, symtab);
+  cbs->object_close (cbs, object);
+  return GDB_SUCCESS;
+}
+
+static void
+free_reg_value (struct gdb_reg_value *value)
+{
+  free (value);
+}
+
+static void
+write_register (struct gdb_unwind_callbacks *callbacks, int dw_reg,
+                uintptr_t value)
+{
+  const int size = sizeof (uintptr_t);
+  struct gdb_reg_value *reg_val =
+    malloc (sizeof (struct gdb_reg_value) + size - 1);
+  reg_val->defined = 1;
+  reg_val->free = free_reg_value;
+
+  memcpy (reg_val->value, &value, size);
+  callbacks->reg_set (callbacks, dw_reg, reg_val);
+}
+
+static int
+read_register (struct gdb_unwind_callbacks *callbacks, int dw_reg,
+	       uintptr_t *value)
+{
+  const int size = sizeof (uintptr_t);
+  struct gdb_reg_value *reg_val = callbacks->reg_get (callbacks, dw_reg);
+  if (reg_val->size != size || !reg_val->defined)
+    {
+      reg_val->free (reg_val);
+      return 0;
+    }
+  memcpy (value, reg_val->value, size);
+  reg_val->free (reg_val);
+  return 1;
+}
+
+static enum gdb_status
+unwind_frame (struct gdb_reader_funcs *self, struct gdb_unwind_callbacks *cbs)
+{
+  const int word_size = sizeof (uintptr_t);
+  uintptr_t this_sp, this_ip, prev_ip, prev_sp;
+  struct reader_state *state = (struct reader_state *) self->priv_data;
+
+  if (!read_register (cbs, AMD64_RA, &this_ip))
+    return GDB_FAIL;
+
+  if (this_ip >= state->code_end || this_ip < state->code_begin)
+    return GDB_FAIL;
+
+  if (!read_register (cbs, AMD64_RSP, &this_sp))
+    return GDB_FAIL;
+
+  if (cbs->target_read (this_sp, &prev_ip, word_size) == GDB_FAIL)
+    return GDB_FAIL;
+
+  prev_sp = this_sp + word_size;
+  write_register (cbs, AMD64_RA, prev_ip);
+  write_register (cbs, AMD64_RSP, prev_sp);
+  return GDB_SUCCESS;
+}
+
+static struct gdb_frame_id
+get_frame_id (struct gdb_reader_funcs *self, struct gdb_unwind_callbacks *cbs)
+{
+  struct reader_state *state = (struct reader_state *) self->priv_data;
+  struct gdb_frame_id frame_id;
+
+  uintptr_t sp;
+  read_register (cbs, AMD64_RSP, &sp);
+
+  frame_id.code_address = (GDB_CORE_ADDR) state->code_begin;
+  frame_id.stack_address = (GDB_CORE_ADDR) sp;
+
+  return frame_id;
+}
+
+static void
+destroy_reader (struct gdb_reader_funcs *self)
+{
+  free (self->priv_data);
+  free (self);
+}
+
+extern struct gdb_reader_funcs *
+gdb_init_reader (void)
+{
+  struct reader_state *state = malloc (sizeof (struct reader_state));
+  struct gdb_reader_funcs *reader_funcs =
+    malloc (sizeof (struct gdb_reader_funcs));
+
+  reader_funcs->reader_version = GDB_READER_INTERFACE_VERSION;
+  reader_funcs->priv_data = state;
+  reader_funcs->read = read_debug_info;
+  reader_funcs->unwind = unwind_frame;
+  reader_funcs->get_frame_id = get_frame_id;
+  reader_funcs->destroy = destroy_reader;
+
+  return reader_funcs;
+}
-- 
1.7.10.4