From e385593eef98ac92be57159e141f4b805dadbbb3 Mon Sep 17 00:00:00 2001

From: Jan Kratochvil <jan.kratochvil@redhat.com>

Date: Mon, 30 May 2016 14:14:43 +0200

Subject: [PATCH 2/2] PR 15231: import bare DW_TAG_lexical_block

Local variables in lambdas are not accessible

https://sourceware.org/bugzilla/show_bug.cgi?id=15231

GDB: read_lexical_block_scope

  /* Ignore blocks with missing or invalid low and high pc attributes.  */

[...]

  if (!dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL))

    return;

But sometimes there is:

FAIL: gcc-5.3.1-6.fc23.x86_64

 <2><92>: Abbrev Number: 11 (DW_TAG_lexical_block)

 <3><9c>: Abbrev Number: 13 (DW_TAG_structure_type)

    <9d>   DW_AT_name        : (indirect string, offset: 0x3c): <lambda()>

    [...]

Where DW_TAG_lexical_block has no attributes.  Such whole subtree is currently

dropped by GDB while I think it should just import all its children DIEs.

It even XFAIL->XPASSes gdb.ada/out_of_line_in_inlined.exp:

	commit 0fa7fe506c242b459c4c05d331e7c7d66fb52390

	Author: Joel Brobecker <brobecker@adacore.com>

	    out of line functions nested inside inline functions.

So I have removed that xfail.

gdb/ChangeLog

2016-05-30  Jan Kratochvil  <jan.kratochvil@redhat.com>

	PR c++/15231

	* dwarf2read.c (enum pc_bounds_kind): Add PC_BOUNDS_INVALID.

	(process_psymtab_comp_unit_reader, read_func_scope): Adjust callers.

	(read_lexical_block_scope): Import DIEs from bare DW_TAG_lexical_block.

	(read_call_site_scope): Adjust callers.

	(dwarf2_get_pc_bounds): Implement pc_bounds_invalid.

	(dwarf2_get_subprogram_pc_bounds, get_scope_pc_bounds): Adjust callers.

gdb/testsuite/ChangeLog

2016-05-30  Jan Kratochvil  <jan.kratochvil@redhat.com>

	PR c++/15231

	* gdb.ada/out_of_line_in_inlined.exp: Remove xfails.

	* gdb.dwarf2/dw2-lexical-block-bare.exp: New file.

---

 gdb/ChangeLog                                      | 10 ++++

 gdb/dwarf2read.c                                   | 53 ++++++++++------

 gdb/testsuite/ChangeLog                            |  6 ++

 gdb/testsuite/gdb.ada/out_of_line_in_inlined.exp   |  6 --

 .../gdb.dwarf2/dw2-lexical-block-bare.exp          | 70 ++++++++++++++++++++++

 5 files changed, 120 insertions(+), 25 deletions(-)

 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-lexical-block-bare.exp

### a/gdb/ChangeLog

### b/gdb/ChangeLog

## -1,5 +1,15 @@

 2016-05-30  Jan Kratochvil  <jan.kratochvil@redhat.com>

+	PR c++/15231

+	* dwarf2read.c (enum pc_bounds_kind): Add PC_BOUNDS_INVALID.

+	(process_psymtab_comp_unit_reader, read_func_scope): Adjust callers.

+	(read_lexical_block_scope): Import DIEs from bare DW_TAG_lexical_block.

+	(read_call_site_scope): Adjust callers.

+	(dwarf2_get_pc_bounds): Implement pc_bounds_invalid.

+	(dwarf2_get_subprogram_pc_bounds, get_scope_pc_bounds): Adjust callers.

+

+2016-05-30  Jan Kratochvil  <jan.kratochvil@redhat.com>

+

 	Code cleanup: dwarf2_get_pc_bounds: -1/0/+1 -> enum

 	* dwarf2read.c (enum pc_bounds_kind) New.

 	(dwarf2_get_pc_bounds): Use it in the declaration.

--- a/gdb/dwarf2read.c

+++ b/gdb/dwarf2read.c

@@ -1607,13 +1607,16 @@ static int dwarf2_ranges_read (unsigned, CORE_ADDR *, CORE_ADDR *,

 			       struct dwarf2_cu *, struct partial_symtab *);

 /* How dwarf2_get_pc_bounds constructed its *LOWPC and *HIGHPC return

-   values.  */

+   values.  Keep the items ordered with increasing constraints compliance.  */

 enum pc_bounds_kind

 {

-  /* No valid combination of DW_AT_low_pc, DW_AT_high_pc or DW_AT_ranges

-     was found.  */

+  /* No attribute DW_AT_low_pc, DW_AT_high_pc or DW_AT_ranges was found.  */

   PC_BOUNDS_NOT_PRESENT,

+  /* Some of the attributes DW_AT_low_pc, DW_AT_high_pc or DW_AT_ranges

+     were present but they do not form a valid range of PC addresses.  */

+  PC_BOUNDS_INVALID,

+

   /* Discontiguous range was found - that is DW_AT_ranges was found.  */

   PC_BOUNDS_RANGES,

@@ -6019,7 +6022,7 @@ process_psymtab_comp_unit_reader (const struct die_reader_specs *reader,

       first_die = load_partial_dies (reader, info_ptr, 1);

       scan_partial_symbols (first_die, &lowpc, &highpc,

-			    cu_bounds_kind == PC_BOUNDS_NOT_PRESENT, cu);

+			    cu_bounds_kind <= PC_BOUNDS_INVALID, cu);

       /* If we didn't find a lowpc, set it to highpc to avoid

 	 complaints from `maint check'.	 */

@@ -6028,7 +6031,7 @@ process_psymtab_comp_unit_reader (const struct die_reader_specs *reader,

       /* If the compilation unit didn't have an explicit address range,

 	 then use the information extracted from its child dies.  */

-      if (cu_bounds_kind == PC_BOUNDS_NOT_PRESENT)

+      if (cu_bounds_kind <= PC_BOUNDS_INVALID)

 	{

 	  best_lowpc = lowpc;

 	  best_highpc = highpc;

@@ -11390,7 +11393,7 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)

   /* Ignore functions with missing or invalid low and high pc attributes.  */

   if (dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL)

-      == PC_BOUNDS_NOT_PRESENT)

+      <= PC_BOUNDS_INVALID)

     {

       attr = dwarf2_attr (die, DW_AT_external, cu);

       if (!attr || !DW_UNSND (attr))

@@ -11552,9 +11555,20 @@ read_lexical_block_scope (struct die_info *die, struct dwarf2_cu *cu)

      as multiple lexical blocks?  Handling children in a sane way would

      be nasty.  Might be easier to properly extend generic blocks to

      describe ranges.  */

-  if (dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL)

-      == PC_BOUNDS_NOT_PRESENT)

-    return;

+  switch (dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL))

+    {

+    case PC_BOUNDS_NOT_PRESENT:

+      /* DW_TAG_lexical_block has no attributes, process its children as if

+	 there was no wrapping by that DW_TAG_lexical_block.

+	 GCC does no longer produces such DWARF since GCC r224161.  */

+      for (child_die = die->child;

+	   child_die != NULL && child_die->tag;

+	   child_die = sibling_die (child_die))

+	process_die (child_die, cu);

+      return;

+    case PC_BOUNDS_INVALID:

+      return;

+    }

   lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);

   highpc = gdbarch_adjust_dwarf2_addr (gdbarch, highpc + baseaddr);

@@ -11764,7 +11778,7 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)

 	  /* DW_AT_entry_pc should be preferred.  */

 	  if (dwarf2_get_pc_bounds (target_die, &lowpc, NULL, target_cu, NULL)

-	      == PC_BOUNDS_NOT_PRESENT)

+	      <= PC_BOUNDS_INVALID)

 	    complaint (&symfile_complaints,

 		       _("DW_AT_GNU_call_site_target target DIE has invalid "

 		         "low pc, for referencing DIE 0x%x [in module %s]"),

@@ -12041,7 +12055,7 @@ dwarf2_ranges_read (unsigned offset, CORE_ADDR *low_return,

 /* Get low and high pc attributes from a die.  See enum pc_bounds_kind

    definition for the return value.  *LOWPC and *HIGHPC are set iff

-   PC_BOUNDS_NOT_PRESENT is not returned.  */

+   neither PC_BOUNDS_NOT_PRESENT nor PC_BOUNDS_INVALID are returned.  */

 static enum pc_bounds_kind

 dwarf2_get_pc_bounds (struct die_info *die, CORE_ADDR *lowpc,

@@ -12052,7 +12066,7 @@ dwarf2_get_pc_bounds (struct die_info *die, CORE_ADDR *lowpc,

   struct attribute *attr_high;

   CORE_ADDR low = 0;

   CORE_ADDR high = 0;

-  enum pc_bounds_kind ret = PC_BOUNDS_NOT_PRESENT;

+  enum pc_bounds_kind ret;

   attr_high = dwarf2_attr (die, DW_AT_high_pc, cu);

   if (attr_high)

@@ -12067,7 +12081,7 @@ dwarf2_get_pc_bounds (struct die_info *die, CORE_ADDR *lowpc,

 	}

       else

 	/* Found high w/o low attribute.  */

-	return PC_BOUNDS_NOT_PRESENT;

+	return PC_BOUNDS_INVALID;

       /* Found consecutive range of addresses.  */

       ret = PC_BOUNDS_HIGH_LOW;

@@ -12089,15 +12103,17 @@ dwarf2_get_pc_bounds (struct die_info *die, CORE_ADDR *lowpc,

 	  /* Value of the DW_AT_ranges attribute is the offset in the

 	     .debug_ranges section.  */

 	  if (!dwarf2_ranges_read (ranges_offset, &low, &high, cu, pst))

-	    return PC_BOUNDS_NOT_PRESENT;

+	    return PC_BOUNDS_INVALID;

 	  /* Found discontinuous range of addresses.  */

 	  ret = PC_BOUNDS_RANGES;

 	}

+      else

+	return PC_BOUNDS_NOT_PRESENT;

     }

   /* read_partial_die has also the strict LOW < HIGH requirement.  */

   if (high <= low)

-    return PC_BOUNDS_NOT_PRESENT;

+    return PC_BOUNDS_INVALID;

   /* When using the GNU linker, .gnu.linkonce. sections are used to

      eliminate duplicate copies of functions and vtables and such.

@@ -12108,7 +12124,7 @@ dwarf2_get_pc_bounds (struct die_info *die, CORE_ADDR *lowpc,

      If this is a discarded function, mark the pc bounds as invalid,

      so that GDB will ignore it.  */

   if (low == 0 && !dwarf2_per_objfile->has_section_at_zero)

-    return PC_BOUNDS_NOT_PRESENT;

+    return PC_BOUNDS_INVALID;

   *lowpc = low;

   if (highpc)

@@ -12129,8 +12145,7 @@ dwarf2_get_subprogram_pc_bounds (struct die_info *die,

   CORE_ADDR low, high;

   struct die_info *child = die->child;

-  if (dwarf2_get_pc_bounds (die, &low, &high, cu, NULL)

-      != PC_BOUNDS_NOT_PRESENT)

+  if (dwarf2_get_pc_bounds (die, &low, &high, cu, NULL) >= PC_BOUNDS_RANGES)

     {

       *lowpc = min (*lowpc, low);

       *highpc = max (*highpc, high);

@@ -12168,7 +12183,7 @@ get_scope_pc_bounds (struct die_info *die,

   CORE_ADDR current_low, current_high;

   if (dwarf2_get_pc_bounds (die, &current_low, &current_high, cu, NULL)

-      != PC_BOUNDS_NOT_PRESENT)

+      >= PC_BOUNDS_RANGES)

     {

       best_low = current_low;

       best_high = current_high;

### a/gdb/testsuite/ChangeLog

### b/gdb/testsuite/ChangeLog

## -1,3 +1,9 @@

+2016-05-30  Jan Kratochvil  <jan.kratochvil@redhat.com>

+

+	PR c++/15231

+	* gdb.ada/out_of_line_in_inlined.exp: Remove xfails.

+	* gdb.dwarf2/dw2-lexical-block-bare.exp: New file.

+

 2016-05-27  Pedro Alves  <palves@redhat.com>

 	* gdb.threads/attach-many-short-lived-threads.exp (bad_dejagnu):

--- a/gdb/testsuite/gdb.ada/out_of_line_in_inlined.exp

+++ b/gdb/testsuite/gdb.ada/out_of_line_in_inlined.exp

@@ -23,20 +23,14 @@ if {[gdb_compile_ada "${srcfile}" "${binfile}" executable {debug optimize=-O2}]

 clean_restart ${testfile}

-# GCC currently is missing a DW_AT_origin attribute in one of the

-# lexical blocks, preventing GDB from creating a symbol for the

-# subprogram we want to break on.

-setup_xfail "*-*-*"

 gdb_test "break foo_o224_021.child1.child2" \

          "Breakpoint \[0-9\]+ at.*: file .*foo_o224_021.adb, line \[0-9\]+."

 gdb_run_cmd

-setup_xfail "*-*-*"

 gdb_test "" \

          "Breakpoint $decimal, foo_o224_021\\.child1\\.child2 \\(s=\\.\\.\\.\\).*"

 set opt_addr_in "($hex in)?"

-setup_xfail "*-*-*"

 gdb_test "bt" \

     [multi_line "#0 +$opt_addr_in +foo_o224_021\\.child1\\.child2 \\(s=\\.\\.\\.\\).*" \

                 "#1 +$opt_addr_in +foo_o224_021\\.child1 \\(\\).*" \

--- /dev/null

+++ b/gdb/testsuite/gdb.dwarf2/dw2-lexical-block-bare.exp

@@ -0,0 +1,70 @@

+# Copyright 2016 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

+

+# This test can only be run on targets which support DWARF-2 and use gas.

+if {![dwarf2_support]} {

+    return 0

+}

+

+standard_testfile .S main.c

+

+# Make some DWARF for the test.

+set asm_file [standard_output_file $srcfile]

+Dwarf::assemble $asm_file {

+    cu {} {

+	compile_unit {

+	    {low_pc [gdb_target_symbol main] DW_FORM_addr}

+	    {high_pc [gdb_target_symbol main]+0x10000 DW_FORM_addr}

+	} {

+	    declare_labels integer_label

+

+	    integer_label: DW_TAG_base_type {

+		{DW_AT_byte_size 4 DW_FORM_sdata}

+		{DW_AT_encoding  @DW_ATE_signed}

+		{DW_AT_name      integer}

+	    }

+

+	    DW_TAG_subprogram {

+		{name main}

+		{DW_AT_external 1 flag}

+		{low_pc [gdb_target_symbol main] DW_FORM_addr}

+		{high_pc [gdb_target_symbol main]+0x10000 DW_FORM_addr}

+	    } {

+		DW_TAG_lexical_block {

+		} {

+		    DW_TAG_variable {

+			{DW_AT_name testvar}

+			    {DW_AT_type :$integer_label}

+			    {DW_AT_external 1 flag}

+			{DW_AT_location {

+			    DW_OP_addr [gdb_target_symbol main]

+			} SPECIAL_expr}

+		    }

+		}

+	    }

+	}

+    }

+}

+

+if { [prepare_for_testing ${testfile}.exp ${testfile} \

+			  [list $srcfile2 $asm_file] {nodebug}] } {

+    return -1

+}

+

+runto_main

+

+# FAILing GDB did print: No symbol "testvar" in current context.

+gdb_test "p testvar" { = -?[0-9]+}

-- 

2.5.5