Fix JIT clang-lli regression (unable to read JIT descriptor from memory)

2011-07-06  Paul Pluzhnikov  <ppluzhnikov@google.com>

        * jit.c (jit_inferior_init): Forward declare.
        (jit_breakpoint_re_set_internal): Call jit_inferior_init.

testsuite/ChangeLog:

2011-07-06  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.

gdb/ChangeLog

@@ -37,6 +37,11 @@
 	* reverse.c: Likewise.
 	* s390-tdep.c: Likewise.
 
+2011-07-06  Paul Pluzhnikov  <ppluzhnikov@google.com>
+
+	* jit.c (jit_inferior_init): Forward declare.
+	(jit_breakpoint_re_set_internal): Call jit_inferior_init.
+
 2011-07-04  Joel Brobecker  <brobecker@adacore.com>
 
         * osabi.c (generic_elf_osabi_sniffer): Minor comment reformatting.

gdb/jit.c

@@ -40,6 +40,9 @@ static const char *const jit_descriptor_name = "__jit_debug_descriptor";
 
 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;
@@ -351,6 +354,11 @@ jit_breakpoint_re_set_internal (struct gdbarch *gdbarch,
       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;

gdb/testsuite/ChangeLog

@@ -24,6 +24,12 @@
 	* gdb.base/ifelse.exp: Likewise.
 	* gdb.base/structs.c: Likewise.
 
+2011-07-06  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.
+
 2011-07-02  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	* gdb.cp/m-static.exp: Call get_compiler_info.

gdb/testsuite/gdb.base/jit-dlmain.c

@@ -0,0 +1,20 @@
+#include <dlfcn.h>
+#include <stdio.h>
+
+int main (int argc, char *argv[])
+{
+  /* jit_libname is updated by jit-so.exp  */
+  const char *jit_libname = "jit-dlmain-so.so";
+  void *h;
+  int (*p_main) (int, char **);
+
+  h = NULL;  /* break here before-dlopen  */
+  h = dlopen (jit_libname, RTLD_LAZY);
+  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);
+}

gdb/testsuite/gdb.base/jit-main.c

@@ -117,8 +117,12 @@ update_locations (const void *const addr, int idx)
     }
 }
 
+#ifndef MAIN
+#define MAIN main
+#endif
+
 int
-main (int argc, char *argv[])
+MAIN (int argc, char *argv[])
 {
   /* These variables are here so they can easily be set from jit.exp.  */
   const char *libname = NULL;

gdb/testsuite/gdb.base/jit-so.exp

@@ -0,0 +1,121 @@
+# 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 binfile2 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 before-dlopen" ]
+    gdb_continue_to_breakpoint "break here before-dlopen"
+    # 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 jit_libname = \"$binfile2\""
+
+    gdb_breakpoint [gdb_get_line_number "break here after-dlopen" ]
+    gdb_continue_to_breakpoint "break here after-dlopen"
+
+    gdb_breakpoint "$srcfile2:[gdb_get_line_number {break here 0} $srcfile2]"
+    gdb_continue_to_breakpoint "break here 0"
+
+    gdb_test_no_output "set var argc = 2"
+    gdb_test_no_output "set var libname = \"$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"