The cooked index scanner has special code to handle forward DIE
references. However, a bug report lead to the discovery that this
code does not work -- the "deferred_entry::spec_offset" field is
written to but never used, i.e., the lookup is done using the wrong
key.
This patch fixes the bug and adds a regression test.
The test in the bug itself used a thread_local variable, which
provoked a failure at runtime. This test instead uses "maint print
objfiles" and then inspects to ensure that the entry in question has a
parent. This lets us avoid a clang dependency in the test.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30271
(cherry picked from commit b10f2cd3f3)
When building with clang 16, I see:
/home/smarchi/src/binutils-gdb/gdb/z80-tdep.c:338:32: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
info->prologue_type.load_args = 1;
^ ~
/home/smarchi/src/binutils-gdb/gdb/z80-tdep.c:345:36: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
info->prologue_type.critical = 1;
^ ~
/home/smarchi/src/binutils-gdb/gdb/z80-tdep.c:351:37: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
info->prologue_type.interrupt = 1;
^ ~
/home/smarchi/src/binutils-gdb/gdb/z80-tdep.c:367:36: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
info->prologue_type.fp_sdcc = 1;
^ ~
/home/smarchi/src/binutils-gdb/gdb/z80-tdep.c:375:35: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
info->prologue_type.fp_sdcc = 1;
^ ~
/home/smarchi/src/binutils-gdb/gdb/z80-tdep.c:380:35: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion]
info->prologue_type.fp_sdcc = 1;
^ ~
Fix that by using "unsigned int" as the bitfield's underlying type.
(cherry picked from commit 07f2859348)
Change-Id: I3550a0112f993865dc70b18f02ab11bb5012693d
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30423
Approved-By: Tom Tromey <tom@tromey.com>
When building with clang 16, we get:
CXX gdb.o
In file included from /home/smarchi/src/binutils-gdb/gdb/gdb.c:19:
In file included from /home/smarchi/src/binutils-gdb/gdb/defs.h:65:
/home/smarchi/src/binutils-gdb/gdb/../gdbsupport/enum-flags.h:95:52: error: integer value -1 is outside the valid range of values [0, 15] for this enumeration type [-Wenum-constexpr-conversion]
integer_for_size<sizeof (T), static_cast<bool>(T (-1) < T (0))>::type
^
The error message does not make it clear in the context of which enum
flag this fails (i.e. what is T in this context), but it doesn't really
matter, we have similar warning/errors for many of them, if we let the
build go through.
clang is right that the value -1 is invalid for the enum type we cast -1
to. However, we do need this expression in order to select an integer
type with the appropriate signedness. That is, with the same signedness
as the underlying type of the enum.
I first wondered if that was really needed, if we couldn't use
std::underlying_type for that. It turns out that the comment just above
says:
/* Note that std::underlying_type<enum_type> is not what we want here,
since that returns unsigned int even when the enum decays to signed
int. */
I was surprised, because std::is_signed<std::underlying_type<enum_type>>
returns the right thing. So I tried replacing all this with
std::underlying_type, see if that would work. Doing so causes some
build failures in unittests/enum-flags-selftests.c:
CXX unittests/enum-flags-selftests.o
/home/smarchi/src/binutils-gdb/gdb/unittests/enum-flags-selftests.c:254:1: error: static assertion failed due to requirement 'gdb::is_same<selftests::enum_flags_tests::check_valid_expr254::archetype<enum_flags<s
elftests::enum_flags_tests::RE>, selftests::enum_flags_tests::RE, enum_flags<selftests::enum_flags_tests::RE2>, selftests::enum_flags_tests::RE2, enum_flags<selftests::enum_flags_tests::URE>, selftests::enum_fla
gs_tests::URE, int>, selftests::enum_flags_tests::check_valid_expr254::archetype<enum_flags<selftests::enum_flags_tests::RE>, selftests::enum_flags_tests::RE, enum_flags<selftests::enum_flags_tests::RE2>, selfte
sts::enum_flags_tests::RE2, enum_flags<selftests::enum_flags_tests::URE>, selftests::enum_flags_tests::URE, unsigned int>>::value == true':
CHECK_VALID (true, int, true ? EF () : EF2 ())
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/smarchi/src/binutils-gdb/gdb/unittests/enum-flags-selftests.c:91:3: note: expanded from macro 'CHECK_VALID'
CHECK_VALID_EXPR_6 (EF, RE, EF2, RE2, UEF, URE, VALID, EXPR_TYPE, EXPR)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/smarchi/src/binutils-gdb/gdb/../gdbsupport/valid-expr.h:105:3: note: expanded from macro 'CHECK_VALID_EXPR_6'
CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1, typename T2, \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/smarchi/src/binutils-gdb/gdb/../gdbsupport/valid-expr.h:66:3: note: expanded from macro 'CHECK_VALID_EXPR_INT'
static_assert (gdb::is_detected_exact<archetype<TYPES, EXPR_TYPE>, \
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is a bit hard to decode, but basically enumerations have the
following funny property that they decay into a signed int, even if
their implicit underlying type is unsigned. This code:
enum A {};
enum B {};
int main() {
std::cout << std::is_signed<std::underlying_type<A>::type>::value
<< std::endl;
std::cout << std::is_signed<std::underlying_type<B>::type>::value
<< std::endl;
auto result = true ? A() : B();
std::cout << std::is_signed<decltype(result)>::value << std::endl;
}
produces:
0
0
1
So, the "CHECK_VALID" above checks that this property works for enum flags the
same way as it would if you were using their underlying enum types. And
somehow, changing integer_for_size to use std::underlying_type breaks that.
Since the current code does what we want, and I don't see any way of doing it
differently, ignore -Wenum-constexpr-conversion around it.
(cherry picked from commit ae61525fcf)
Change-Id: Ibc82ae7bbdb812102ae3f1dd099fc859dc6f3cc2
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30423
Approved-By: Tom Tromey <tom@tromey.com>
[ Changes in v2:
- rebase on trunk
Changes in v3:
- add test-case ]
We should exclude matches to the ending PC to prevent false matches with the
next function, as prologue_end is located at the end PC.
<fun1>:
0x00: ... <-- start_pc
0x04: ...
0x08: ... <-- breakpoint
0x0c: ret
<fun2>:
0x10: ret <-- end_pc | prologue_end of fun2
Tested on x86_64-linux.
Co-Authored-By: WANG Rui <r@hev.cc> (fix, tiny change [1])
Co-Authored-By: Tom de Vries <tdevries@suse.de> (test-case)
Approved-by: Kevin Buettner <kevinb@redhat.com>
[1] https://www.gnu.org/prep/maintain/html_node/Legally-Significant.html
PR symtab/30369
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30369
With DWARF 5, it's possible to produce an empty file name in the File Name
Table of the .debug_line section:
...
The File Name Table (offset 0x112, lines 1, columns 2):
Entry Dir Name
0 1 (indirect line string, offset: 0x2d):
...
Currently, when gdb reads an exec containing such debug info, it segfaults:
...
Thread 1 "gdb" received signal SIGSEGV, Segmentation fault.
0x000000000072cd38 in dwarf2_start_subfile (cu=0x2badc50, fe=..., lh=...) at \
gdb/dwarf2/read.c:18716
18716 if (!IS_ABSOLUTE_PATH (filename) && dirname != NULL)
...
because read_direct_string transforms "" into a nullptr, and we end up
dereferencing the nullptr.
Note that the behaviour of read_direct_string has been present since repo
creation.
Fix this in read_formatted_entries, by transforming nullptr filenames in to ""
filenames.
Tested on x86_64-linux.
Reviewed-By: Tom Tromey <tom@tromey.com>
PR symtab/30357
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30357
