gdb/17394: cannot put breakpoint only in selected ASM file.

This patch fixes a problem when trying to insert a breakpoint on
a specific symbol defined in a specific file, eg:

    break foo.c:func

This currently works for files in C/C++/Ada, etc, but doesn't always
work for Asm files. Analysis of the problem showed that this related
to a limitation in gas, which does not generate debug info for functions/
symbols.  Thus, we have a symtab for the file ("info sources" shows
the file), but it contains no symbols.

When find_linespec_symbols is called in linespec_parse_basic, it calls
find_function_symbols, which uses add_matching_symbols_to_info to
collect all matching symbols.

That function does [pardon any mangled formatting]:

  for (ix = 0; VEC_iterate (symtab_ptr, info->file_symtabs, ix, elt); ++ix)
    {
      if (elt == NULL)
        {
          iterate_over_all_matching_symtabs (info->state, name, VAR_DOMAIN,
                                             collect_symbols, info,
                                             pspace, 1);
          search_minsyms_for_name (info, name, pspace);
        }
      else if (pspace == NULL || pspace == SYMTAB_PSPACE (elt))
        {
          /* Program spaces that are executing startup should have
             been filtered out earlier.  */
          gdb_assert (!SYMTAB_PSPACE (elt)->executing_startup);
          set_current_program_space (SYMTAB_PSPACE (elt));
          iterate_over_file_blocks (elt, name, VAR_DOMAIN,
                                    collect_symbols, info);
        }
    }

This iterates over the symtabs. In the failing use case, ELT is
non-NULL (points to the symtab for the .s file), so it calls
iterate_over_file_blocks. Herein is where the problem exists: it is
assumed that if NAME exists, it must exist in the given symtab -- a
reasonable assumption for "normal" (non-asm) cases. It never searches
minimal symbols (or in the global default symtab).

This patch fixes the problem by doing so. It is important to note that
iterating over minsyms is fairly expensive, so this patch only adds
that extra search if the language is language_asm and
iterate_over_file_blocks returns no symbols.

gdb/ChangeLog:
2014-12-20  Keith Seitz  <keiths@redhat.com>
            Mihail-Marian Nistor  <mihail.nistor@freescale.com>

        PR gdb/17394
        * linespec.c (struct collect_minsyms): Add new member `symtab'.
        (add_minsym): Handle cases where info.symtab is non-NULL.
        (search_minsyms_for_name): Add new parameter `symtab'.
        Handle limiting searches to a specific symtab.
        (add_matching_symtabs_to_info): Search through minimal symbols
        for language_asm files for which no new symbols are found.

gdb/testsuite/ChangeLog:
2014-12-20  Mihail-Marian Nistor  <mihail.nistor@freescale.com>

        PR gdb/17394
        * gdb.linespec/break-asm-file.c: New file.
        * gdb.linespec/break-asm-file.exp: New file.
        * gdb.linespec/break-asm-file0.s: New file.
        * gdb.linespec/break-asm-file1.s: New file.

4 files changed, 552 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.linespec/break-asm-file.c b/gdb/testsuite/gdb.linespec/break-asm-file.c
new file mode 100644
index 0000000000..525726be83
--- /dev/null
+++ b/gdb/testsuite/gdb.linespec/break-asm-file.c
@@ -0,0 +1,35 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2004-2014 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/>.  */
+
+void func3();
+void func2();
+
+static func()
+{
+}
+
+void func1()
+{
+  func3();
+  func2();
+  func();
+}
+
+int main()
+{
+  func1();
+}
diff --git a/gdb/testsuite/gdb.linespec/break-asm-file.exp b/gdb/testsuite/gdb.linespec/break-asm-file.exp
new file mode 100644
index 0000000000..de1ed19a86
--- /dev/null
+++ b/gdb/testsuite/gdb.linespec/break-asm-file.exp
@@ -0,0 +1,55 @@
+# Copyright 2012-2014 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/>.
+
+# Bug 17394
+# Test for break-point at a function only for a selected ASM file.
+
+load_lib dwarf.exp
+
+standard_testfile .c
+set execfile $testfile
+set asm_file1 break-asm-file1.s
+set asm_file0 break-asm-file0.s
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if {![dwarf2_support]} {
+    return 0
+}
+
+if {[prepare_for_testing ${testfile}.exp $execfile \
+	 [list $srcfile $asm_file1 $asm_file0] \
+	 {debug nowarnings optimize=-O0}]} {
+    untested "Skipping ${testfile}."
+    return
+}
+
+clean_restart $execfile
+
+gdb_test "break a/$asm_file0:func" \
+    "Breakpoint 1 at 0x\[0-9a-fA-F\]+: file .*a/$asm_file0, line 7\\\." \
+    "set a break-point at a global function only for a selected ASM file."
+
+gdb_test "delete 1"
+
+gdb_test "break b/$asm_file0:func" \
+    "Breakpoint 2 at 0x\[0-9a-fA-F\]+: file .*b/$asm_file0, line 7\\\." \
+    "set a break-point at a function only for a selected ASM file."
+
+gdb_test "delete 2"
+
+gdb_test "break $asm_file0:func" \
+    "Breakpoint 3 at 0x\[0-9a-fA-F\]+: .*$asm_file0.*(2 locations).*" \
+    "set a break-point at function in all instances for a selected ASM file."
+
diff --git a/gdb/testsuite/gdb.linespec/break-asm-file0.s b/gdb/testsuite/gdb.linespec/break-asm-file0.s
new file mode 100644
index 0000000000..4d1176cc4f
--- /dev/null
+++ b/gdb/testsuite/gdb.linespec/break-asm-file0.s
@@ -0,0 +1,218 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2004-2014 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 "a/break-asm-file0.s"
+	.text
+.Lbegin_text1:
+	.globl _func2
+_func2:
+	.globl func2
+	.type func2, %function
+func2:
+.Lbegin_func2:
+	.int 0
+	.int 0
+.Lend_func2:
+	.size func2, .-func2
+	.globl _func
+_func:
+  .globl func
+	.type func, %function
+func:
+.Lbegin_func:
+	.file 1 "a/break-asm-file0.s"
+	.int 0
+	.int 0
+.Lend_func:
+	.size func, .-func
+.Lend_text1:
+
+/* Debug information */
+
+	.section .debug_info
+.Lcu1_begin:
+	/* CU header */
+	.4byte	.Lcu1_end - .Lcu1_start		/* Length of Compilation Unit */
+.Lcu1_start:
+	.2byte	2				/* DWARF Version */
+	.4byte	.Labbrev1_begin			/* Offset into abbrev section */
+	.byte	4				/* Pointer size */
+
+	/* CU die */
+	.uleb128 1				/* Abbrev: DW_TAG_compile_unit */
+	.4byte	.Lline1_begin			/* DW_AT_stmt_list */
+	.4byte	.Lend_text1			/* DW_AT_high_pc */
+	.4byte	.Lbegin_text1			/* DW_AT_low_pc */
+	.ascii	"a/break-asm-file0.s\0"			/* DW_AT_name */
+	.ascii	"GNU C 3.3.3\0"			/* DW_AT_producer */
+	.2byte	0x8001				/* DW_AT_language (Mips Assembler) */
+
+	.byte		0			/* End of children of CU */
+
+.Lcu1_end:
+
+/* Abbrev table */
+	.section .debug_abbrev
+.Labbrev1_begin:
+	.uleb128	1			/* Abbrev code */
+	.uleb128	0x11			/* DW_TAG_compile_unit */
+	.byte		1			/* has_children */
+	.uleb128	0x10			/* DW_AT_stmt_list */
+	.uleb128	0x6			/* DW_FORM_data4 */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x25			/* DW_AT_producer */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x13			/* DW_AT_language */
+	.uleb128	0x5			/* DW_FORM_data2 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	2			/* Abbrev code */
+	.uleb128	0x2e			/* DW_TAG_subprogram */
+	.byte		0			/* has_children */
+	.uleb128	0x3f			/* DW_AT_external */
+	.uleb128	0xc			/* DW_FORM_flag */
+	.uleb128	0x3a			/* DW_AT_decl_file */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3b			/* DW_AT_decl_line */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.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	0x1			/* DW_FORM_addr */
+	.uleb128	0x40			/* DW_AT_frame_base */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	3			/* Abbrev code */
+	.uleb128	0x24			/* DW_TAG_base_type */
+	.byte		0			/* has_children */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0xb			/* DW_AT_byte_size */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3e			/* DW_AT_encoding */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+/* Line table */
+	.section .debug_line
+.Lline1_begin:
+	.4byte		.Lline1_end - .Lline1_start	/* Initial length */
+.Lline1_start:
+	.2byte		2			/* Version */
+	.4byte		.Lline1_lines - .Lline1_hdr	/* header_length */
+.Lline1_hdr:
+	.byte		1			/* Minimum insn length */
+	.byte		1			/* default_is_stmt */
+	.byte		1			/* line_base */
+	.byte		1			/* line_range */
+	.byte		0x10			/* opcode_base */
+
+	/* Standard lengths */
+	.byte		0
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+
+	/* Include directories */
+	.byte		0
+
+	/* File names */
+	.ascii		"a/break-asm-file0.s\0"
+	.uleb128	0
+	.uleb128	0
+	.uleb128	0
+
+	.byte		0
+
+.Lline1_lines:
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func2
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	1	/* ... to 2 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func2+1
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	1	/* ... to 3 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	4	/* ... to 7 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func+2
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	1	/* ... to 8 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lend_func
+
+	.byte		0	/* DW_LNE_end_of_sequence */
+	.uleb128	1
+	.byte		1
+
+.Lline1_end:
diff --git a/gdb/testsuite/gdb.linespec/break-asm-file1.s b/gdb/testsuite/gdb.linespec/break-asm-file1.s
new file mode 100644
index 0000000000..36bcb8698b
--- /dev/null
+++ b/gdb/testsuite/gdb.linespec/break-asm-file1.s
@@ -0,0 +1,244 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2004-2014 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/>.  */
+
+	.text
+.Lbegin_text1:
+	.globl _func3
+_func3:
+	.globl func3
+	.type func3, %function
+func3:
+.Lbegin_func3:
+	.int 0
+	.int 0
+.Lend_func3:
+	.size func3, .-func3
+_func:
+	.type func, %function
+func:
+.Lbegin_func:
+	.int 0
+	.int 0
+.Lend_func:
+	.size func, .-func
+.Lend_text1:
+
+/* Debug information */
+
+	.section .debug_info
+.Lcu1_begin:
+	/* CU header */
+	.4byte	.Lcu1_end - .Lcu1_start		/* Length of Compilation Unit */
+.Lcu1_start:
+	.2byte	2				/* DWARF Version */
+	.4byte	.Labbrev1_begin			/* Offset into abbrev section */
+	.byte	4				/* Pointer size */
+
+	/* CU die */
+	.uleb128 1				/* Abbrev: DW_TAG_compile_unit */
+	.4byte	.Lline1_begin			/* DW_AT_stmt_list */
+	.4byte	.Lend_text1			/* DW_AT_high_pc */
+	.4byte	.Lbegin_text1			/* DW_AT_low_pc */
+	.ascii	"b/break-asm-file0.s\0"			/* DW_AT_name */
+	.ascii	"GNU C 3.3.3\0"			/* DW_AT_producer */
+	.2byte	0x8001				/* DW_AT_language (Mips Assembler) */
+
+	/* func3 */
+	.uleb128	2			/* Abbrev: DW_TAG_subprogram */
+	.byte		1			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		2			/* DW_AT_decl_line */
+	.ascii		"func3\0"		/* DW_AT_name */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func3	/* DW_AT_low_pc */
+	.4byte		.Lend_func3		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+
+	/* func */
+	.uleb128	2			/* Abbrev: DW_TAG_subprogram */
+	.byte		0			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		4			/* DW_AT_decl_line */
+	.ascii		"func\0"		/* DW_AT_name */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func	/* DW_AT_low_pc */
+	.4byte		.Lend_func		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+
+.Ltype_int:
+	.uleb128	3			/* Abbrev: DW_TAG_base_type */
+	.ascii		"int\0"			/* DW_AT_name */
+	.byte		4			/* DW_AT_byte_size */
+	.byte		5			/* DW_AT_encoding */
+
+	.byte		0			/* End of children of CU */
+
+.Lcu1_end:
+
+/* Abbrev table */
+	.section .debug_abbrev
+.Labbrev1_begin:
+	.uleb128	1			/* Abbrev code */
+	.uleb128	0x11			/* DW_TAG_compile_unit */
+	.byte		1			/* has_children */
+	.uleb128	0x10			/* DW_AT_stmt_list */
+	.uleb128	0x6			/* DW_FORM_data4 */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x25			/* DW_AT_producer */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x13			/* DW_AT_language */
+	.uleb128	0x5			/* DW_FORM_data2 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	2			/* Abbrev code */
+	.uleb128	0x2e			/* DW_TAG_subprogram */
+	.byte		0			/* has_children */
+	.uleb128	0x3f			/* DW_AT_external */
+	.uleb128	0xc			/* DW_FORM_flag */
+	.uleb128	0x3a			/* DW_AT_decl_file */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3b			/* DW_AT_decl_line */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.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	0x1			/* DW_FORM_addr */
+	.uleb128	0x40			/* DW_AT_frame_base */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	3			/* Abbrev code */
+	.uleb128	0x24			/* DW_TAG_base_type */
+	.byte		0			/* has_children */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0xb			/* DW_AT_byte_size */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3e			/* DW_AT_encoding */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+/* Line table */
+	.section .debug_line
+.Lline1_begin:
+	.4byte		.Lline1_end - .Lline1_start	/* Initial length */
+.Lline1_start:
+	.2byte		2			/* Version */
+	.4byte		.Lline1_lines - .Lline1_hdr	/* header_length */
+.Lline1_hdr:
+	.byte		1			/* Minimum insn length */
+	.byte		1			/* default_is_stmt */
+	.byte		1			/* line_base */
+	.byte		1			/* line_range */
+	.byte		0x10			/* opcode_base */
+
+	/* Standard lengths */
+	.byte		0
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+
+	/* Include directories */
+	.byte		0
+
+	/* File names */
+	.ascii		"b/break-asm-file0.s\0"
+	.uleb128	0
+	.uleb128	0
+	.uleb128	0
+
+	.byte		0
+
+.Lline1_lines:
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func3
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	1	/* ... to 2 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func3+1
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	1	/* ... to 3 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	4	/* ... to 7 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func+1
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	1	/* ... to 8 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lend_func
+
+	.byte		0	/* DW_LNE_end_of_sequence */
+	.uleb128	1
+	.byte		1
+
+.Lline1_end: