diff mbox

Handle DW_AT_ranges when reading partial symtabs

Message ID 20190329200030.8368-1-tromey@adacore.com
State New
Headers show

Commit Message

Tom Tromey March 29, 2019, 8 p.m. UTC
add_partial_subprogram does not handle DW_AT_ranges, while the full
symtab reader does.  This can lead to discrepancies where a function
is not put into a partial symtab, and so is not available to "break"
and the like -- but is available if the full symtab has somehow been
read.

This patch fixes the bug by arranging to read DW_AT_ranges when
reading partial DIEs.

This is PR symtab/23331.

The new test case is derived from dw2-ranges-func.exp, which is why I
kept the copyright dates.

gdb/ChangeLog
2019-03-29  Tom Tromey  <tromey@adacore.com>

	PR symtab/23331:
	* dwarf2read.c (partial_die_info::read): Handle DW_AT_ranges.

gdb/testsuite/ChangeLog
2019-03-29  Tom Tromey  <tromey@adacore.com>

	PR symtab/23331:
	* gdb.dwarf2/dw2-ranges-main.c: New file.
	* gdb.dwarf2/dw2-ranges-psym.c: New file.
	* gdb.dwarf2/dw2-ranges-psym.exp: New file.
---
 gdb/ChangeLog                                |   5 +
 gdb/dwarf2read.c                             |  19 +++
 gdb/testsuite/ChangeLog                      |   7 +
 gdb/testsuite/gdb.dwarf2/dw2-ranges-main.c   |  19 +++
 gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.c   |  46 +++++++
 gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.exp | 134 +++++++++++++++++++
 6 files changed, 230 insertions(+)
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-ranges-main.c
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.c
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.exp

Comments

Simon Marchi March 29, 2019, 10:01 p.m. UTC | #1
On 2019-03-29 16:00, Tom Tromey wrote:
> add_partial_subprogram does not handle DW_AT_ranges, while the full
> symtab reader does.  This can lead to discrepancies where a function
> is not put into a partial symtab, and so is not available to "break"
> and the like -- but is available if the full symtab has somehow been
> read.
> 
> This patch fixes the bug by arranging to read DW_AT_ranges when
> reading partial DIEs.
> 
> This is PR symtab/23331.
> 
> The new test case is derived from dw2-ranges-func.exp, which is why I
> kept the copyright dates.
> 
> gdb/ChangeLog
> 2019-03-29  Tom Tromey  <tromey@adacore.com>
> 
> 	PR symtab/23331:
> 	* dwarf2read.c (partial_die_info::read): Handle DW_AT_ranges.
> 
> gdb/testsuite/ChangeLog
> 2019-03-29  Tom Tromey  <tromey@adacore.com>
> 
> 	PR symtab/23331:
> 	* gdb.dwarf2/dw2-ranges-main.c: New file.
> 	* gdb.dwarf2/dw2-ranges-psym.c: New file.
> 	* gdb.dwarf2/dw2-ranges-psym.exp: New file.

I don't have much experience in this area, but I read the patch and it 
seems to make sense.

I just have one tiny comment to help readability in the test.

> diff --git a/gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.exp
> b/gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.exp
> new file mode 100644
> index 00000000000..eb1130a2238
> --- /dev/null
> +++ b/gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.exp
> @@ -0,0 +1,134 @@
> +# Copyright 2018-2019 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/>.
> +
> +load_lib dwarf.exp
> +
> +# Test that psymbols are made when DW_AT_ranges is used.
> +
> +# This test can only be run on targets which support DWARF-2 and use 
> gas.
> +if {![dwarf2_support]} {
> +    unsupported "dwarf2 support required for this test"
> +    return 0
> +}
> +
> +if [get_compiler_info] {
> +    return -1
> +}
> +if !$gcc_compiled {
> +    unsupported "gcc required for this test"
> +    return 0
> +}
> +
> +standard_testfile dw2-ranges-main.c dw2-ranges-psym.c 
> dw2-ranges-psym-dw.S
> +
> +# We need to know the size of integer and address types in order to
> +# write some of the debugging info we'd like to generate.
> +#
> +# For that, we ask GDB by debugging our test program.  Any program
> +# would do, but since we already have it specifically for this
> +# testcase, might as well use that.
> +
> +if { [prepare_for_testing "failed to prepare" ${testfile} \
> +	  [list ${srcfile} ${srcfile2}]] } {
> +    return -1
> +}
> +
> +set asm_file [standard_output_file $srcfile3]
> +Dwarf::assemble $asm_file {
> +    global srcdir subdir srcfile srcfile2
> +    declare_labels integer_label volatile_label func_ranges_label
> cu_ranges_label
> +    set int_size [get_sizeof "int" 4]
> +
> +    # Find start address and length for our functions.
> +    set sources  [list ${srcdir}/${subdir}/$srcfile
> ${srcdir}/${subdir}/$srcfile2]
> +    lassign [function_range foo $sources] \
> +	foo_start foo_len
> +    set foo_end "$foo_start + $foo_len"
> +    lassign [function_range foo_low $sources] \
> +	foo_low_start foo_low_len
> +    set foo_low_end "$foo_low_start + $foo_low_len"
> +    lassign [function_range bar $sources] \
> +	bar_start bar_len
> +    set bar_end "$bar_start + $bar_len"
> +    lassign [function_range baz $sources] \
> +	baz_start baz_len
> +    set baz_end "$baz_start + $baz_len"

To help readability, I'd suggest adding some empty lines in there, 
between each pair of lassign+set statements.  At first it looked like a 
bit cryptic blob to me until I split it in smaller pieces.

Simon
Tom Tromey April 1, 2019, 4:28 p.m. UTC | #2
>>>>> "Simon" == Simon Marchi <simon.marchi@polymtl.ca> writes:

Simon> To help readability, I'd suggest adding some empty lines in there,
Simon> between each pair of lassign+set statements.  At first it looked like
Simon> a bit cryptic blob to me until I split it in smaller pieces.

Thanks, I made this change.

Tom
diff mbox

Patch

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 658c86264bf..a5e953bd427 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -18751,6 +18751,25 @@  partial_die_info::read (const struct die_reader_specs *reader,
 	  main_subprogram = DW_UNSND (&attr);
 	  break;
 
+	case DW_AT_ranges:
+	  {
+	    /* It would be nice to reuse dwarf2_get_pc_bounds here,
+	       but that requires a full DIE, so instead we just
+	       reimplement it.  */
+	    int need_ranges_base = tag != DW_TAG_compile_unit;
+	    unsigned int ranges_offset = (DW_UNSND (&attr)
+					  + (need_ranges_base
+					     ? cu->ranges_base
+					     : 0));
+
+	    /* Value of the DW_AT_ranges attribute is the offset in the
+	       .debug_ranges section.  */
+	    if (dwarf2_ranges_read (ranges_offset, &lowpc, &highpc, cu,
+				    nullptr))
+	      has_pc_info = 1;
+	  }
+	  break;
+
 	default:
 	  break;
 	}
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-ranges-main.c b/gdb/testsuite/gdb.dwarf2/dw2-ranges-main.c
new file mode 100644
index 00000000000..35a4d4c07e1
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-ranges-main.c
@@ -0,0 +1,19 @@ 
+/* Copyright 2019 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 ()
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.c b/gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.c
new file mode 100644
index 00000000000..7d0408a56a9
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.c
@@ -0,0 +1,46 @@ 
+/* Copyright 2018-2019 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/>.  */
+
+volatile int e = 0;
+
+void
+baz (void)
+{
+  asm ("baz_label: .globl baz_label");
+}						/* baz end */
+
+void
+foo_low (void)
+{						/* foo_low prologue */
+  asm ("foo_low_label: .globl foo_low_label");
+  baz ();					/* foo_low baz call */
+  asm ("foo_low_label2: .globl foo_low_label2");
+}						/* foo_low end */
+
+void
+bar (void)
+{
+  asm ("bar_label: .globl bar_label");
+}						/* bar end */
+
+void
+foo (void)
+{						/* foo prologue */
+  asm ("foo_label: .globl foo_label");
+  bar ();					/* foo bar call */
+  asm ("foo_label2: .globl foo_label2");
+  if (e) foo_low ();				/* foo foo_low call */
+  asm ("foo_label3: .globl foo_label3");
+}						/* foo end */
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.exp b/gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.exp
new file mode 100644
index 00000000000..eb1130a2238
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-ranges-psym.exp
@@ -0,0 +1,134 @@ 
+# Copyright 2018-2019 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/>.
+
+load_lib dwarf.exp
+
+# Test that psymbols are made when DW_AT_ranges is used.
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if {![dwarf2_support]} {
+    unsupported "dwarf2 support required for this test"
+    return 0
+}
+
+if [get_compiler_info] {
+    return -1
+}
+if !$gcc_compiled {
+    unsupported "gcc required for this test"
+    return 0
+}
+
+standard_testfile dw2-ranges-main.c dw2-ranges-psym.c dw2-ranges-psym-dw.S
+
+# We need to know the size of integer and address types in order to
+# write some of the debugging info we'd like to generate.
+#
+# For that, we ask GDB by debugging our test program.  Any program
+# would do, but since we already have it specifically for this
+# testcase, might as well use that.
+
+if { [prepare_for_testing "failed to prepare" ${testfile} \
+	  [list ${srcfile} ${srcfile2}]] } {
+    return -1
+}
+
+set asm_file [standard_output_file $srcfile3]
+Dwarf::assemble $asm_file {
+    global srcdir subdir srcfile srcfile2
+    declare_labels integer_label volatile_label func_ranges_label cu_ranges_label
+    set int_size [get_sizeof "int" 4]
+
+    # Find start address and length for our functions.
+    set sources  [list ${srcdir}/${subdir}/$srcfile ${srcdir}/${subdir}/$srcfile2]
+    lassign [function_range foo $sources] \
+	foo_start foo_len
+    set foo_end "$foo_start + $foo_len"
+    lassign [function_range foo_low $sources] \
+	foo_low_start foo_low_len
+    set foo_low_end "$foo_low_start + $foo_low_len"
+    lassign [function_range bar $sources] \
+	bar_start bar_len
+    set bar_end "$bar_start + $bar_len"
+    lassign [function_range baz $sources] \
+	baz_start baz_len
+    set baz_end "$baz_start + $baz_len"
+
+    cu {} {
+	compile_unit {
+	    {language @DW_LANG_C}
+	    {name dw-ranges-psym.c}
+	    {low_pc 0 addr}
+	    {ranges ${cu_ranges_label} DW_FORM_sec_offset}
+	} {
+	    integer_label: DW_TAG_base_type {
+		{DW_AT_byte_size $int_size DW_FORM_sdata}
+		{DW_AT_encoding  @DW_ATE_signed}
+		{DW_AT_name      integer}
+	    }
+	    volatile_label: DW_TAG_volatile_type {
+		{type :$integer_label}
+	    }
+	    subprogram {
+		{external 1 flag}
+		{name someothername}
+		{ranges ${func_ranges_label} DW_FORM_sec_offset}
+	    }
+	    subprogram {
+		{external 1 flag}
+		{name bar}
+		{low_pc $bar_start addr}
+		{high_pc $bar_len DW_FORM_data4}
+	    }
+	    subprogram {
+		{external 1 flag}
+		{name baz}
+		{low_pc $baz_start addr}
+		{high_pc $baz_len DW_FORM_data4}
+	    }
+	}
+    }
+
+    # Generate ranges data.
+    ranges {is_64 [is_64_target]} {
+	func_ranges_label: sequence {
+	    {range {$foo_start } $foo_end}
+	    {range {$foo_low_start} $foo_low_end}
+	}
+	cu_ranges_label: sequence {
+	    {range {$foo_start } $foo_end}
+	    {range {$foo_low_start} $foo_low_end}
+	    {range {$bar_start} $bar_end}
+	    {range {$baz_start} $baz_end}
+	}
+    }
+}
+
+if { [prepare_for_testing "failed to prepare" ${testfile} \
+	  [list $srcfile $srcfile2 $asm_file] {nodebug}] } {
+    return -1
+}
+
+if ![runto_main] {
+    return -1
+}
+
+# "someothername" should be put into the partial symbol table, but
+# there was a bug causing functions using DW_AT_ranges not to be.
+# Note we use a name that is very different from the linkage name, in
+# order to not set the breakpoint via minsyms.
+gdb_test "break someothername" \
+    "Breakpoint.*at.*" \
+    "break someothername"