gdb/testsuite/gdb.dwarf2/dw2-bad-abstract-origin.exp

# Copyright 2024-2025 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/>.

# There was a bug in GCC, which appears to be fixed in version 9 and
# later, where GCC would, in some case, create an invalid
# DW_AT_abstract_origin value.
#
# The bug was that there existed a function which could be inlined,
# and so the DWARF contained a DW_TAG_subprogram describing the
# abstract instance of the function.
#
# For whatever reason, the compiler generated a non-inline instance of
# the function, and so we had a DW_TAG_subprogram with a
# DW_AT_abstract_origin that referenced the abstract instance.
#
# Additionally there was an inlined instance of the function, and so
# we had a DW_TAG_inlined_subroutine with a DW_AT_abstract_origin that
# referenced the abstract instance.
#
# Within the function there was a DW_TAG_lexical_block, which also
# appeared in the abstract instance, and both concrete instances.  The
# lexical block also has DW_AT_abstract_origin that should link back
# to the lexical block within the abstract instance.
#
# The bug was that the DW_AT_abstract_origin for the lexical block
# within the inlined instance instead referenced the lexical block
# within the non-inline instance, not within the abstract instance.
#
# The problem this caused is that the non-inline instance defined the
# extents of the lexical block using DW_AT_ranges, while the inline
# instance defined the extend using DW_AT_low_pc and DW_AT_high_pc.
#
# When GDB tried to parse the block ranges for the lexical block for
# the inline function GDB would then find both the DW_AT_ranges and
# the DW_AT_low_pc/DW_AT_high_pc values.  This alone is unexpected.
#
# What is worse though, is that the DW_AT_ranges were not within the
# low-pc/high-pc bounds, and this really confused GDB.
#
# The solution is that, when GDB finds blocks with both ranges AND
# low-pc/high-pc information, GDB should only accept the
# low-pc/high-pc information.
#
# Of course, there's no guarantee which of the information is correct,
# but if GDB tries to hold both piece of information, then we end up
# in a non-consistent state, and this triggers assertions.

load_lib dwarf.exp

require dwarf2_support

standard_testfile

# This compiles the source file and starts and stops GDB, so run it
# before calling prepare_for_testing otherwise GDB will have exited.
get_func_info func_a
get_func_info func_b

# Some line numbers needed in the generated DWARF.
set func_a_decl_line [gdb_get_line_number "func_a decl line"]
set func_b_decl_line [gdb_get_line_number "func_b decl line"]
set call_line [gdb_get_line_number "inline func_a call line"]

# See the problem description at the head of this file.
#
# Create the test program, use DWARF_VERSION to decide which format of
# ranges table to generate.
#
# Then run the test program and check that GDB doesn't crash, and
# check that the block structure is as we expect.
proc run_test { dwarf_version } {
    set dw_testname "${::testfile}-${dwarf_version}"

    set asm_file [standard_output_file "${dw_testname}.S"]
    Dwarf::assemble $asm_file {
	upvar dwarf_version dwarf_version
	upvar entry_label entry_label

	declare_labels lines_table foo_func foo_block block_ranges bad_block \
	    value_label int_label

	cu { version $dwarf_version } {
	    compile_unit {
		{producer "GNU C 14.1.0"}
		{language @DW_LANG_C}
		{name $::srcfile}
		{comp_dir /tmp}
		{stmt_list $lines_table DW_FORM_sec_offset}
		{low_pc 0 addr}
	    } {
		int_label: base_type {
		    {name "int"}
		    {byte_size 4 sdata}
		    {encoding @DW_ATE_signed}
		}
		foo_func: subprogram {
		    {name foo}
		    {inline @DW_INL_declared_inlined}
		    {decl_file 1 data1}
		    {decl_line $::func_a_decl_line data1}
		} {
		    foo_block: lexical_block {
		    } {
			value_label: DW_TAG_variable {
			    {name value}
			    {type :$int_label}
			}
		    }
		}
		subprogram {
		    {abstract_origin %$foo_func}
		    {low_pc func_a_0 addr}
		    {high_pc func_a_6 addr}
		    {external 1 flag}
		} {
		    bad_block: lexical_block {
			{abstract_origin %$foo_block}
			{ranges $block_ranges DW_FORM_sec_offset}
		    } {
			DW_TAG_variable {
			    {abstract_origin %$value_label}
			    {DW_AT_location {
				DW_OP_const1u 23
				DW_OP_stack_value
			    } SPECIAL_expr}
			}
		    }
		}
		subprogram {
		    {name baz}
		    {low_pc func_b_0 addr}
		    {high_pc func_b_5 addr}
		    {external 1 flag}
		} {
		    inlined_subroutine {
			{abstract_origin %$foo_func}
			{call_file 1 data1}
			{call_line $::call_line data1}
			{low_pc func_b_1 addr}
			{high_pc func_b_4 addr}
		    } {
			lexical_block {
			    {abstract_origin %$bad_block}
			    {low_pc func_b_2 addr}
			    {high_pc func_b_3 addr}
			} {
			    DW_TAG_variable {
				{abstract_origin %$value_label}
				{DW_AT_location {
				    DW_OP_const1u 99
				    DW_OP_stack_value
				} SPECIAL_expr}
			    }
			}
		    }
		}
	    }
	}

	lines {version 2} lines_table {
	    include_dir "$::srcdir/$::subdir"
	    file_name "$::srcfile" 1
	}

	if { $dwarf_version == 5 } {
	    rnglists {} {
		table {} {
		    block_ranges: list_ {
			start_end func_a_1 func_a_2
			start_end func_a_4 func_a_5
		    }
		}
	    }
	} else {
	    ranges { } {
		block_ranges: sequence {
		    range func_a_1 func_a_2
		    range func_a_4 func_a_5
		}
	    }
	}
    }

    if {[prepare_for_testing "failed to prepare" "${dw_testname}" \
	     [list $::srcfile $asm_file] {nodebug}]} {
	return false
    }

    if {![runto_main]} {
	return false
    }

    # Breakpoint on the inline function `foo'.
    gdb_breakpoint foo

    # Breakpoint within the lexical block inside of `foo'.
    gdb_breakpoint func_a_1
    gdb_breakpoint func_b_2

    gdb_continue_to_breakpoint "continue to first foo breakpoint"
    gdb_continue_to_breakpoint "continue to func_b_2 breakpoint"

    gdb_test "print value" " = 99" "print value at func_b_2"

    # Some addresses we need to look for in the 'maint info blocks'
    # output.
    set func_b_0 [get_hexadecimal_valueof "&func_b_0" "*UNKNOWN*"]
    set func_b_1 [get_hexadecimal_valueof "&func_b_1" "*UNKNOWN*"]
    set func_b_2 [get_hexadecimal_valueof "&func_b_2" "*UNKNOWN*"]
    set func_b_3 [get_hexadecimal_valueof "&func_b_3" "*UNKNOWN*"]
    set func_b_4 [get_hexadecimal_valueof "&func_b_4" "*UNKNOWN*"]
    set func_b_5 [get_hexadecimal_valueof "&func_b_5" "*UNKNOWN*"]

    gdb_test "maint info blocks" \
	[multi_line \
	     "\\\[\\(block \\*\\) $::hex\\\] $func_b_0\\.\\.$func_b_5" \
	     "  entry pc: $func_b_0" \
	     "  function: baz" \
	     "  is contiguous" \
	     "\\\[\\(block \\*\\) $::hex\\\] $func_b_1\\.\\.$func_b_4" \
	     "  entry pc: $func_b_1" \
	     "  inline function: foo" \
	     "  symbol count: $::decimal" \
	     "  is contiguous" \
	     "\\\[\\(block \\*\\) $::hex\\\] $func_b_2\\.\\.$func_b_3" \
	     "  entry pc: $func_b_2" \
	     "  symbol count: $::decimal" \
	     "  is contiguous"] \
	"check block structure at func_b_2"

    gdb_continue_to_breakpoint "continue to second foo breakpoint"
    gdb_continue_to_breakpoint "continue to func_a_1 breakpoint"

    gdb_test "print value" " = 23" "print value at func_a_1"

    # Some addresses we need to look for in the 'maint info blocks'
    # output.
    set func_a_0 [get_hexadecimal_valueof "&func_a_0" "*UNKNOWN*"]
    set func_a_1 [get_hexadecimal_valueof "&func_a_1" "*UNKNOWN*"]
    set func_a_2 [get_hexadecimal_valueof "&func_a_2" "*UNKNOWN*"]
    set func_a_4 [get_hexadecimal_valueof "&func_a_4" "*UNKNOWN*"]
    set func_a_5 [get_hexadecimal_valueof "&func_a_5" "*UNKNOWN*"]
    set func_a_6 [get_hexadecimal_valueof "&func_a_6" "*UNKNOWN*"]

    gdb_test "maint info blocks" \
	[multi_line \
	     "\\\[\\(block \\*\\) $::hex\\\] $func_a_0\\.\\.$func_a_6" \
	     "  entry pc: $func_a_0" \
	     "  function: foo" \
	     "  is contiguous" \
	     "\\\[\\(block \\*\\) $::hex\\\] $func_a_1\\.\\.$func_a_5" \
	     "  entry pc: $func_a_1" \
	     "  symbol count: $::decimal" \
	     "  address ranges:" \
	     "    $func_a_1\\.\\.$func_a_2" \
	     "    $func_a_4\\.\\.$func_a_5"] \
	"check block structure at func_a_1"
}

foreach_with_prefix dwarf_version { 4 5 } {
    run_test $dwarf_version
}