[v2] Fix segfault in ltpy_iternext() when symtab has no linetable.

diff mbox series

diff --git a/gdb/python/py-linetable.c b/gdb/python/py-linetable.c
index e989204a7f5..6daf97ae356 100644
--- a/gdb/python/py-linetable.c
+++ b/gdb/python/py-linetable.c
@@ -399,7 +399,8 @@  ltpy_iternext (PyObject *self)
 
   LTPY_REQUIRE_VALID (iter_obj->source, symtab);
 
-  if (iter_obj->current_index >= SYMTAB_LINETABLE (symtab)->nitems)
+  if (SYMTAB_LINETABLE (symtab) == NULL
+      || iter_obj->current_index >= SYMTAB_LINETABLE (symtab)->nitems)
     {
       PyErr_SetNone (PyExc_StopIteration);
       return NULL;
diff --git a/gdb/testsuite/gdb.python/py-linetable-empty-main-body.h b/gdb/testsuite/gdb.python/py-linetable-empty-main-body.h
new file mode 100644
index 00000000000..bac1c2a1a01
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-linetable-empty-main-body.h
@@ -0,0 +1,20 @@ 
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2021 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/>.  */
+
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.python/py-linetable-empty.S b/gdb/testsuite/gdb.python/py-linetable-empty.S
new file mode 100644
index 00000000000..4cf51d5ad39
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-linetable-empty.S
@@ -0,0 +1,183 @@ 
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2021 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/>.  */
+
+	.file	"py-linetable-empty.c"
+	.text
+.Ltext0:
+	.globl	main
+	.type	main, @function
+main:
+.LFB0:
+	.file 1 "./py-linetable-empty-main-body.h"
+	# ./py-linetable-empty-main-body.h:18:1
+	.loc 1 18 1
+	.cfi_startproc
+	endbr64
+# BLOCK 2 seq:0
+# PRED: ENTRY (FALLTHRU)
+	pushq	%rbp
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	movq	%rsp, %rbp
+	.cfi_def_cfa_register 6
+	# ./py-linetable-empty-main-body.h:19:10
+	.loc 1 19 10
+	movl	$0, %eax
+	# ./py-linetable-empty-main-body.h:20:1
+	.loc 1 20 1
+	popq	%rbp
+	.cfi_def_cfa 7, 8
+# SUCC: EXIT [always] 
+	ret
+	.cfi_endproc
+.LFE0:
+	.size	main, .-main
+.Letext0:
+	.file 2 "py-linetable-empty.c"
+	.section	.debug_info,"",@progbits
+.Ldebug_info0:
+	.long	0x4f	# Length of Compilation Unit Info
+	.value	0x4	# DWARF version number
+	.long	.Ldebug_abbrev0	# Offset Into Abbrev. Section
+	.byte	0x8	# Pointer Size (in bytes)
+	.uleb128 0x1	# (DIE (0xb) DW_TAG_compile_unit)
+	.long	.LASF0	# DW_AT_producer: "GNU C17 9.3.0 -mtune=generic -march=x86-64 -g -fasynchronous-unwind-tables -fstack-protector-strong -fstack-clash-protection -fcf-protection"
+	.byte	0xc	# DW_AT_language
+	.long	.LASF1	# DW_AT_name: "py-linetable-empty.c"
+	.long	.LASF2	# DW_AT_comp_dir: ""
+	.quad	.Ltext0	# DW_AT_low_pc
+	.quad	.Letext0-.Ltext0	# DW_AT_high_pc
+	.long	.Ldebug_line0	# DW_AT_stmt_list
+	.uleb128 0x2	# (DIE (0x2d) DW_TAG_subprogram)
+			# DW_AT_external
+	.long	.LASF3	# DW_AT_name: "main"
+	.byte	0x2	# DW_AT_decl_file (py-linetable-empty.c)
+	.byte	0x13	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_decl_column
+			# DW_AT_prototyped
+	.long	0x4b	# DW_AT_type
+	.quad	.LFB0	# DW_AT_low_pc
+	.quad	.LFE0-.LFB0	# DW_AT_high_pc
+	.uleb128 0x1	# DW_AT_frame_base
+	.byte	0x9c	# DW_OP_call_frame_cfa
+			# DW_AT_GNU_all_call_sites
+	.uleb128 0x3	# (DIE (0x4b) DW_TAG_base_type)
+	.byte	0x4	# DW_AT_byte_size
+	.byte	0x5	# DW_AT_encoding
+	.ascii "int\0"	# DW_AT_name
+	.byte	0	# end of children of DIE 0xb
+	.section	.debug_abbrev,"",@progbits
+.Ldebug_abbrev0:
+	.uleb128 0x1	# (abbrev code)
+	.uleb128 0x11	# (TAG: DW_TAG_compile_unit)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x25	# (DW_AT_producer)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x13	# (DW_AT_language)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x1b	# (DW_AT_comp_dir)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x7	# (DW_FORM_data8)
+	.uleb128 0x10	# (DW_AT_stmt_list)
+	.uleb128 0x17	# (DW_FORM_sec_offset)
+	.byte	0
+	.byte	0
+	.uleb128 0x2	# (abbrev code)
+	.uleb128 0x2e	# (TAG: DW_TAG_subprogram)
+	.byte	0	# DW_children_no
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x39	# (DW_AT_decl_column)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x27	# (DW_AT_prototyped)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x7	# (DW_FORM_data8)
+	.uleb128 0x40	# (DW_AT_frame_base)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.uleb128 0x2117	# (DW_AT_GNU_all_call_sites)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.byte	0
+	.byte	0
+	.uleb128 0x3	# (abbrev code)
+	.uleb128 0x24	# (TAG: DW_TAG_base_type)
+	.byte	0	# DW_children_no
+	.uleb128 0xb	# (DW_AT_byte_size)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3e	# (DW_AT_encoding)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.byte	0
+	.byte	0
+	.byte	0
+	.section	.debug_aranges,"",@progbits
+	.long	0x2c	# Length of Address Ranges Info
+	.value	0x2	# DWARF aranges version
+	.long	.Ldebug_info0	# Offset of Compilation Unit Info
+	.byte	0x8	# Size of Address
+	.byte	0	# Size of Segment Descriptor
+	.value	0	# Pad to 16 byte boundary
+	.value	0
+	.quad	.Ltext0	# Address
+	.quad	.Letext0-.Ltext0	# Length
+	.quad	0
+	.quad	0
+	.section	.debug_line,"",@progbits
+.Ldebug_line0:
+	.section	.debug_str,"MS",@progbits,1
+.LASF0:
+	.string	"GNU C17 9.3.0 -mtune=generic -march=x86-64 -g -fasynchronous-unwind-tables -fstack-protector-strong -fstack-clash-protection -fcf-protection"
+.LASF2:
+	.string	""
+.LASF3:
+	.string	"main"
+.LASF1:
+	.string	"py-linetable-empty.c"
+	.ident	"GCC: (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0"
+	.section	.note.GNU-stack,"",@progbits
+	.section	.note.gnu.property,"a"
+	.align 8
+	.long	 1f - 0f
+	.long	 4f - 1f
+	.long	 5
+0:
+	.string	 "GNU"
+1:
+	.align 8
+	.long	 0xc0000002
+	.long	 3f - 2f
+2:
+	.long	 0x3
+3:
+	.align 8
+4:
diff --git a/gdb/testsuite/gdb.python/py-linetable-empty.c b/gdb/testsuite/gdb.python/py-linetable-empty.c
new file mode 100644
index 00000000000..e0fc00b51f7
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-linetable-empty.c
@@ -0,0 +1,20 @@ 
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2021 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/>.  */
+
+int
+main (void)
+#include "./py-linetable-empty-main-body.h"
diff --git a/gdb/testsuite/gdb.python/py-linetable-empty.exp b/gdb/testsuite/gdb.python/py-linetable-empty.exp
new file mode 100644
index 00000000000..a00e929a17a
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-linetable-empty.exp
@@ -0,0 +1,62 @@ 
+# Copyright 2021 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/>.
+
+# Test Python API linetable methods on an empty linetable.
+
+load_lib gdb-python.exp
+standard_testfile .S
+
+if [info exists COMPILE] {
+    # make check RUNTESTFLAGS="gdb.python/py-linetable-empty.exp COMPILE=1"
+    standard_testfile
+} elseif { ![istarget x86_64-*-* ] || ![is_lp64_target] } {
+    verbose "Skipping ${testfile}."
+    return
+}
+
+if { [prepare_for_testing "failed to prepare" \
+	${testfile} ${srcfile}] } {
+    return
+}
+
+if { ![runto_main] } {
+    untested "could not run to main"
+    return
+}
+
+# Skip all tests if Python scripting is not enabled.
+if { [skip_python_tests] } { continue }
+
+# Get the linetable for main's symbol table. This is empty as
+# main's body was included from another file.
+gdb_py_test_silent_cmd "python lt = gdb.selected_frame().function().symtab.linetable()" \
+    "get linetable" 0
+
+gdb_test "python print(lt.is_valid())" "True" \
+	"Test linetable is valid"
+
+gdb_test "python print(lt.line(1))" "None" \
+	"Test line() returns None"
+
+gdb_test "python print(lt.has_line(1))" \
+	".*RuntimeError: Linetable information not found in symbol table.*" \
+	"Test has_line() throws exception"
+
+gdb_test "python print(lt.source_lines())" \
+	".*RuntimeError: Linetable information not found in symbol table.*" \
+	"Test source_lines() throws exception"
+
+gdb_test "python print(list(lt))" "\\\[\\\]" \
+	"Test iterating over linetable"