Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
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/* Compile-time valid expression checker for GDB, the GNU debugger.
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2022-01-01 22:56:03 +08:00
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Copyright (C) 2017-2022 Free Software Foundation, Inc.
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Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* Helper macros used to build compile-time unit tests that make sure
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that invalid expressions that should not compile would not compile,
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and that expressions that should compile do compile, and have the
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right type. This is mainly used to verify that some utility's API
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is really as safe as intended. */
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#ifndef COMMON_VALID_EXPR_H
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#define COMMON_VALID_EXPR_H
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Rename common to gdbsupport
This is the next patch in the ongoing series to move gdbsever to the
top level.
This patch just renames the "common" directory. The idea is to do
this move in two parts: first rename the directory (this patch), then
move the directory to the top. This approach makes the patches a bit
more tractable.
I chose the name "gdbsupport" for the directory. However, as this
patch was largely written by sed, we could pick a new name without too
much difficulty.
Tested by the buildbot.
gdb/ChangeLog
2019-07-09 Tom Tromey <tom@tromey.com>
* contrib/ari/gdb_ari.sh: Change common to gdbsupport.
* configure: Rebuild.
* configure.ac: Change common to gdbsupport.
* gdbsupport: Rename from common.
* acinclude.m4: Change common to gdbsupport.
* Makefile.in (CONFIG_SRC_SUBDIR, COMMON_SFILES)
(HFILES_NO_SRCDIR, stamp-version, ALLDEPFILES): Change common to
gdbsupport.
* aarch64-tdep.c, ada-lang.c, ada-lang.h, agent.c, alloc.c,
amd64-darwin-tdep.c, amd64-dicos-tdep.c, amd64-fbsd-nat.c,
amd64-fbsd-tdep.c, amd64-linux-nat.c, amd64-linux-tdep.c,
amd64-nbsd-tdep.c, amd64-obsd-tdep.c, amd64-sol2-tdep.c,
amd64-tdep.c, amd64-windows-tdep.c, arch-utils.c,
arch/aarch64-insn.c, arch/aarch64.c, arch/aarch64.h, arch/amd64.c,
arch/amd64.h, arch/arm-get-next-pcs.c, arch/arm-linux.c,
arch/arm.c, arch/i386.c, arch/i386.h, arch/ppc-linux-common.c,
arch/riscv.c, arch/riscv.h, arch/tic6x.c, arm-tdep.c, auto-load.c,
auxv.c, ax-gdb.c, ax-general.c, ax.h, breakpoint.c, breakpoint.h,
btrace.c, btrace.h, build-id.c, build-id.h, c-lang.h, charset.c,
charset.h, cli/cli-cmds.c, cli/cli-cmds.h, cli/cli-decode.c,
cli/cli-dump.c, cli/cli-option.h, cli/cli-script.c,
coff-pe-read.c, command.h, compile/compile-c-support.c,
compile/compile-c.h, compile/compile-cplus-symbols.c,
compile/compile-cplus-types.c, compile/compile-cplus.h,
compile/compile-loc2c.c, compile/compile.c, completer.c,
completer.h, contrib/ari/gdb_ari.sh, corefile.c, corelow.c,
cp-support.c, cp-support.h, cp-valprint.c, csky-tdep.c, ctf.c,
darwin-nat.c, debug.c, defs.h, disasm-selftests.c, disasm.c,
disasm.h, dtrace-probe.c, dwarf-index-cache.c,
dwarf-index-cache.h, dwarf-index-write.c, dwarf2-frame.c,
dwarf2expr.c, dwarf2loc.c, dwarf2read.c, event-loop.c,
event-top.c, exceptions.c, exec.c, extension.h, fbsd-nat.c,
features/aarch64-core.c, features/aarch64-fpu.c,
features/aarch64-pauth.c, features/aarch64-sve.c,
features/i386/32bit-avx.c, features/i386/32bit-avx512.c,
features/i386/32bit-core.c, features/i386/32bit-linux.c,
features/i386/32bit-mpx.c, features/i386/32bit-pkeys.c,
features/i386/32bit-segments.c, features/i386/32bit-sse.c,
features/i386/64bit-avx.c, features/i386/64bit-avx512.c,
features/i386/64bit-core.c, features/i386/64bit-linux.c,
features/i386/64bit-mpx.c, features/i386/64bit-pkeys.c,
features/i386/64bit-segments.c, features/i386/64bit-sse.c,
features/i386/x32-core.c, features/riscv/32bit-cpu.c,
features/riscv/32bit-csr.c, features/riscv/32bit-fpu.c,
features/riscv/64bit-cpu.c, features/riscv/64bit-csr.c,
features/riscv/64bit-fpu.c, features/tic6x-c6xp.c,
features/tic6x-core.c, features/tic6x-gp.c, filename-seen-cache.h,
findcmd.c, findvar.c, fork-child.c, gcore.c, gdb_bfd.c, gdb_bfd.h,
gdb_proc_service.h, gdb_regex.c, gdb_select.h, gdb_usleep.c,
gdbarch-selftests.c, gdbthread.h, gdbtypes.h, gnu-nat.c,
go32-nat.c, guile/guile.c, guile/scm-ports.c,
guile/scm-safe-call.c, guile/scm-type.c, i386-fbsd-nat.c,
i386-fbsd-tdep.c, i386-go32-tdep.c, i386-linux-nat.c,
i386-linux-tdep.c, i386-tdep.c, i387-tdep.c,
ia64-libunwind-tdep.c, ia64-linux-nat.c, inf-child.c,
inf-ptrace.c, infcall.c, infcall.h, infcmd.c, inferior-iter.h,
inferior.c, inferior.h, inflow.c, inflow.h, infrun.c, infrun.h,
inline-frame.c, language.h, linespec.c, linux-fork.c, linux-nat.c,
linux-tdep.c, linux-thread-db.c, location.c, machoread.c,
macrotab.h, main.c, maint.c, maint.h, memattr.c, memrange.h,
mi/mi-cmd-break.h, mi/mi-cmd-env.c, mi/mi-cmd-stack.c,
mi/mi-cmd-var.c, mi/mi-interp.c, mi/mi-main.c, mi/mi-parse.h,
minsyms.c, mips-linux-tdep.c, namespace.h,
nat/aarch64-linux-hw-point.c, nat/aarch64-linux-hw-point.h,
nat/aarch64-linux.c, nat/aarch64-sve-linux-ptrace.c,
nat/amd64-linux-siginfo.c, nat/fork-inferior.c,
nat/linux-btrace.c, nat/linux-btrace.h, nat/linux-namespaces.c,
nat/linux-nat.h, nat/linux-osdata.c, nat/linux-personality.c,
nat/linux-procfs.c, nat/linux-ptrace.c, nat/linux-ptrace.h,
nat/linux-waitpid.c, nat/mips-linux-watch.c,
nat/mips-linux-watch.h, nat/ppc-linux.c, nat/x86-dregs.c,
nat/x86-dregs.h, nat/x86-linux-dregs.c, nat/x86-linux.c,
nto-procfs.c, nto-tdep.c, objfile-flags.h, objfiles.c, objfiles.h,
obsd-nat.c, observable.h, osdata.c, p-valprint.c, parse.c,
parser-defs.h, ppc-linux-nat.c, printcmd.c, probe.c, proc-api.c,
procfs.c, producer.c, progspace.h, psymtab.h,
python/py-framefilter.c, python/py-inferior.c, python/py-ref.h,
python/py-type.c, python/python.c, record-btrace.c, record-full.c,
record.c, record.h, regcache-dump.c, regcache.c, regcache.h,
remote-fileio.c, remote-fileio.h, remote-sim.c, remote.c,
riscv-tdep.c, rs6000-aix-tdep.c, rust-exp.y, s12z-tdep.c,
selftest-arch.c, ser-base.c, ser-event.c, ser-pipe.c, ser-tcp.c,
ser-unix.c, skip.c, solib-aix.c, solib-target.c, solib.c,
source-cache.c, source.c, source.h, sparc-nat.c, spu-linux-nat.c,
stack.c, stap-probe.c, symfile-add-flags.h, symfile.c, symfile.h,
symtab.c, symtab.h, target-descriptions.c, target-descriptions.h,
target-memory.c, target.c, target.h, target/waitstatus.c,
target/waitstatus.h, thread-iter.h, thread.c, tilegx-tdep.c,
top.c, top.h, tracefile-tfile.c, tracefile.c, tracepoint.c,
tracepoint.h, tui/tui-io.c, ui-file.c, ui-out.h,
unittests/array-view-selftests.c,
unittests/child-path-selftests.c, unittests/cli-utils-selftests.c,
unittests/common-utils-selftests.c,
unittests/copy_bitwise-selftests.c, unittests/environ-selftests.c,
unittests/format_pieces-selftests.c,
unittests/function-view-selftests.c,
unittests/lookup_name_info-selftests.c,
unittests/memory-map-selftests.c, unittests/memrange-selftests.c,
unittests/mkdir-recursive-selftests.c,
unittests/observable-selftests.c,
unittests/offset-type-selftests.c, unittests/optional-selftests.c,
unittests/parse-connection-spec-selftests.c,
unittests/ptid-selftests.c, unittests/rsp-low-selftests.c,
unittests/scoped_fd-selftests.c,
unittests/scoped_mmap-selftests.c,
unittests/scoped_restore-selftests.c,
unittests/string_view-selftests.c, unittests/style-selftests.c,
unittests/tracepoint-selftests.c, unittests/unpack-selftests.c,
unittests/utils-selftests.c, unittests/xml-utils-selftests.c,
utils.c, utils.h, valarith.c, valops.c, valprint.c, value.c,
value.h, varobj.c, varobj.h, windows-nat.c, x86-linux-nat.c,
xml-support.c, xml-support.h, xml-tdesc.h, xstormy16-tdep.c,
xtensa-linux-nat.c, dwarf2read.h: Change common to gdbsupport.
gdb/gdbserver/ChangeLog
2019-07-09 Tom Tromey <tom@tromey.com>
* configure: Rebuild.
* configure.ac: Change common to gdbsupport.
* acinclude.m4: Change common to gdbsupport.
* Makefile.in (SFILES, OBS, GDBREPLAY_OBS, IPA_OBJS)
(version-generated.c, gdbsupport/%-ipa.o, gdbsupport/%.o): Change
common to gdbsupport.
* ax.c, event-loop.c, fork-child.c, gdb_proc_service.h,
gdbreplay.c, gdbthread.h, hostio-errno.c, hostio.c, i387-fp.c,
inferiors.c, inferiors.h, linux-aarch64-tdesc-selftest.c,
linux-amd64-ipa.c, linux-i386-ipa.c, linux-low.c,
linux-tic6x-low.c, linux-x86-low.c, linux-x86-tdesc-selftest.c,
linux-x86-tdesc.c, lynx-i386-low.c, lynx-low.c, mem-break.h,
nto-x86-low.c, regcache.c, regcache.h, remote-utils.c, server.c,
server.h, spu-low.c, symbol.c, target.h, tdesc.c, tdesc.h,
thread-db.c, tracepoint.c, win32-i386-low.c, win32-low.c: Change
common to gdbsupport.
2019-05-06 10:29:24 +08:00
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#include "gdbsupport/preprocessor.h"
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#include "gdbsupport/traits.h"
|
Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
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/* Macro that uses SFINAE magic to detect whether the EXPR expression
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is either valid or ill-formed, at compile time, without actually
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producing compile-time errors. I.e., check that bad uses of the
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types (e.g., involving mismatching types) would be caught at
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compile time. If the expression is valid, also check whether the
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expression has the right type.
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EXPR must be defined in terms of some of the template parameters,
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so that template substitution failure discards the overload instead
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of causing a real compile error. TYPES is thus the list of types
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involved in the expression, and TYPENAMES is the same list, but
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with each element prefixed by "typename". These are passed as
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template parameter types to the templates within the macro.
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VALID is a boolean that indicates whether the expression is
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supposed to be valid or invalid.
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EXPR_TYPE is the expected type of EXPR. Only meaningful iff VALID
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is true. If VALID is false, then you must pass "void" as expected
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type.
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Each invocation of the macro is wrapped in its own namespace to
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avoid ODR violations. The generated namespace only includes the
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line number, so client code should wrap sets of calls in a
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test-specific namespace too, to fully guarantee uniqueness between
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the multiple clients in the codebase. */
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#define CHECK_VALID_EXPR_INT(TYPENAMES, TYPES, VALID, EXPR_TYPE, EXPR) \
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namespace CONCAT (check_valid_expr, __LINE__) { \
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\
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Tweak gdbsupport/valid-expr.h for GCC 6, fix build
With GCC 6.4 and 6.5 (at least), unit tests that use
gdbsupport/valid-expr.h's CHECK_VALID fail to compile, with:
In file included from src/gdb/unittests/offset-type-selftests.c:24:0:
src/gdb/unittests/offset-type-selftests.c: In substitution of 'template<class Expected, template<class ...> class Op, class ... Args> using is_detected_exact = std::is_same<Expected, typename gdb::detection_detail::detector<gdb::nonesuch, void, Op, Args ...>::type> [with Expected = selftests::offset_type::off_A&; Op = selftests::offset_type::check_valid_expr75::archetype; Args = {selftests::offset_type::off_A, selftests::offset_type::off_B}]':
src/gdb/unittests/offset-type-selftests.c:75:1: required from here
src/gdb/../gdbsupport/valid-expr.h:65:20: error: type/value mismatch at argument 2 in template parameter list for 'template<class Expected, template<class ...> class Op, class ... Args> using is_detected_exact = std::is_same<Expected, typename gdb::detection_detail::detector<gdb::nonesuch, void, Op, Args ...>::type>'
archetype, TYPES>::value == VALID, \
^
The important part is the "error: type/value mismatch" error. Seems
like that GCC doesn't understand that archetype is an alias template,
and is being strict in requiring a template class.
The fix here is then to make archetype a template class, to pacify
GCC. The resulting code looks like this:
template <TYPENAMES, typename = decltype (EXPR)>
struct archetype
{
};
static_assert (gdb::is_detected_exact<archetype<TYPES, EXPR_TYPE>,
archetype, TYPES>::value == VALID, "");
is_detected_exact<Expected, Op, Args> checks whether Op<Args> is type
Expected:
- For Expected, we pass the explicit EXPR_TYPE, overriding the
default parameter type of archetype.
- For Args we don't pass the last template parameter, so archtype
defaults to the EXPR's decltype.
So in essence, we're really checking whether EXPR_TYPE is the same as
decltype(EXPR).
We need to do the decltype in a template context in order to trigger
SFINAE instead of failing to compile.
The hunk in unittests/enum-flags-selftests.c becomes necessary,
because unlike with the current alias template version, this new
version makes GCC trigger -Wenum-compare warnings as well:
src/gdb/unittests/enum-flags-selftests.c:328:33: error: comparison between 'enum selftests::enum_flags_tests::RE' and 'enum selftests::enum_flags_tests::RE2' [-Werror=enum-compare]
CHECK_VALID (true, bool, RE () != RE2 ())
^
src/gdb/../gdbsupport/valid-expr.h:61:45: note: in definition of macro 'CHECK_VALID_EXPR_INT'
template <TYPENAMES, typename = decltype (EXPR)> \
^
Build-tested with:
- GCC {4.8.5, 6.4, 6.5, 7.3.1, 9.3.0, 11.0.0-20200910}
- Clang 10.0.0
gdbsupport/ChangeLog:
* valid-expr.h (CHECK_VALID_EXPR_INT): Make archetype a template
class instead of an alias template and adjust static_assert.
gdb/ChangeLog:
* unittests/enum-flags-selftests.c: Check whether __GNUC__ is
defined before using '#pragma GCC diagnostic' instead of checking
__clang__.
2020-09-30 03:08:51 +08:00
|
|
|
template <TYPENAMES, typename = decltype (EXPR)> \
|
|
|
|
|
struct archetype \
|
|
|
|
|
{ \
|
|
|
|
|
}; \
|
Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
|
|
|
\
|
Tweak gdbsupport/valid-expr.h for GCC 6, fix build
With GCC 6.4 and 6.5 (at least), unit tests that use
gdbsupport/valid-expr.h's CHECK_VALID fail to compile, with:
In file included from src/gdb/unittests/offset-type-selftests.c:24:0:
src/gdb/unittests/offset-type-selftests.c: In substitution of 'template<class Expected, template<class ...> class Op, class ... Args> using is_detected_exact = std::is_same<Expected, typename gdb::detection_detail::detector<gdb::nonesuch, void, Op, Args ...>::type> [with Expected = selftests::offset_type::off_A&; Op = selftests::offset_type::check_valid_expr75::archetype; Args = {selftests::offset_type::off_A, selftests::offset_type::off_B}]':
src/gdb/unittests/offset-type-selftests.c:75:1: required from here
src/gdb/../gdbsupport/valid-expr.h:65:20: error: type/value mismatch at argument 2 in template parameter list for 'template<class Expected, template<class ...> class Op, class ... Args> using is_detected_exact = std::is_same<Expected, typename gdb::detection_detail::detector<gdb::nonesuch, void, Op, Args ...>::type>'
archetype, TYPES>::value == VALID, \
^
The important part is the "error: type/value mismatch" error. Seems
like that GCC doesn't understand that archetype is an alias template,
and is being strict in requiring a template class.
The fix here is then to make archetype a template class, to pacify
GCC. The resulting code looks like this:
template <TYPENAMES, typename = decltype (EXPR)>
struct archetype
{
};
static_assert (gdb::is_detected_exact<archetype<TYPES, EXPR_TYPE>,
archetype, TYPES>::value == VALID, "");
is_detected_exact<Expected, Op, Args> checks whether Op<Args> is type
Expected:
- For Expected, we pass the explicit EXPR_TYPE, overriding the
default parameter type of archetype.
- For Args we don't pass the last template parameter, so archtype
defaults to the EXPR's decltype.
So in essence, we're really checking whether EXPR_TYPE is the same as
decltype(EXPR).
We need to do the decltype in a template context in order to trigger
SFINAE instead of failing to compile.
The hunk in unittests/enum-flags-selftests.c becomes necessary,
because unlike with the current alias template version, this new
version makes GCC trigger -Wenum-compare warnings as well:
src/gdb/unittests/enum-flags-selftests.c:328:33: error: comparison between 'enum selftests::enum_flags_tests::RE' and 'enum selftests::enum_flags_tests::RE2' [-Werror=enum-compare]
CHECK_VALID (true, bool, RE () != RE2 ())
^
src/gdb/../gdbsupport/valid-expr.h:61:45: note: in definition of macro 'CHECK_VALID_EXPR_INT'
template <TYPENAMES, typename = decltype (EXPR)> \
^
Build-tested with:
- GCC {4.8.5, 6.4, 6.5, 7.3.1, 9.3.0, 11.0.0-20200910}
- Clang 10.0.0
gdbsupport/ChangeLog:
* valid-expr.h (CHECK_VALID_EXPR_INT): Make archetype a template
class instead of an alias template and adjust static_assert.
gdb/ChangeLog:
* unittests/enum-flags-selftests.c: Check whether __GNUC__ is
defined before using '#pragma GCC diagnostic' instead of checking
__clang__.
2020-09-30 03:08:51 +08:00
|
|
|
static_assert (gdb::is_detected_exact<archetype<TYPES, EXPR_TYPE>, \
|
Rewrite valid-expr.h's internals in terms of the detection idiom (C++17/N4502)
An earlier attempt at doing this had failed (wouldn't work in GCCs
around 4.8, IIRC), but now that I try again, it works. I suspect that
my previous attempt did not use the pre C++14-safe void_t (in
traits.h).
I want to switch to this model because:
- It's the standard detection idiom that folks will learn starting
with C++17.
- In the enum_flags unit tests, I have a static_assert that triggers
a warning (resulting in build error), which GCC does not suppress
because the warning is not being triggered in the SFINAE context.
Switching to the detection idiom fixes that. Alternatively,
switching to the C++03-style expression-validity checking with a
varargs overload would allow addressing that, but I think that
would be going backwards idiomatically speaking.
- While this patch shows a net increase of lines of code, the magic
being added to traits.h can be removed in a few years when we start
requiring C++17.
gdbsupport/ChangeLog:
* traits.h (struct nonesuch, struct detector, detected_or)
(detected_or_t, is_detected, detected_t, detected_or)
(detected_or_t, is_detected_exact, is_detected_convertible): New.
* valid-expr.h (CHECK_VALID_EXPR_INT): Use gdb::is_detected_exact.
2020-09-15 04:16:57 +08:00
|
|
|
archetype, TYPES>::value == VALID, \
|
Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
|
|
|
""); \
|
|
|
|
|
} /* namespace */
|
|
|
|
|
|
|
|
|
|
/* A few convenience macros that support expressions involving a
|
|
|
|
|
varying numbers of types. If you need more types, feel free to add
|
|
|
|
|
another variant. */
|
|
|
|
|
|
|
|
|
|
#define CHECK_VALID_EXPR_1(T1, VALID, EXPR_TYPE, EXPR) \
|
2019-01-24 02:58:28 +08:00
|
|
|
CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1), \
|
|
|
|
|
ESC_PARENS (T1), \
|
Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
|
|
|
VALID, EXPR_TYPE, EXPR)
|
|
|
|
|
|
|
|
|
|
#define CHECK_VALID_EXPR_2(T1, T2, VALID, EXPR_TYPE, EXPR) \
|
2019-01-24 02:58:28 +08:00
|
|
|
CHECK_VALID_EXPR_INT (ESC_PARENS(typename T1, typename T2), \
|
|
|
|
|
ESC_PARENS (T1, T2), \
|
Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
|
|
|
VALID, EXPR_TYPE, EXPR)
|
|
|
|
|
|
|
|
|
|
#define CHECK_VALID_EXPR_3(T1, T2, T3, VALID, EXPR_TYPE, EXPR) \
|
2019-01-24 02:58:28 +08:00
|
|
|
CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1, typename T2, typename T3), \
|
|
|
|
|
ESC_PARENS (T1, T2, T3), \
|
Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
|
|
|
VALID, EXPR_TYPE, EXPR)
|
|
|
|
|
|
|
|
|
|
#define CHECK_VALID_EXPR_4(T1, T2, T3, T4, VALID, EXPR_TYPE, EXPR) \
|
2019-01-24 02:58:28 +08:00
|
|
|
CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1, typename T2, \
|
|
|
|
|
typename T3, typename T4), \
|
|
|
|
|
ESC_PARENS (T1, T2, T3, T4), \
|
Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
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VALID, EXPR_TYPE, EXPR)
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Rewrite enum_flags, add unit tests, fix problems
This patch started by adding comprehensive unit tests for enum_flags.
For the testing part, it adds:
- tests of normal expected uses of the API.
- checks that _invalid_ uses of the API would fail to compile. I.e.,
it validates that enum_flags really is a strong type, and that
incorrect mixing of enum types would be caught at compile time. It
pulls that off making use of SFINEA and C++11's decltype/constexpr.
This revealed many holes in the enum_flags API. For example, the f1
assignment below currently incorrectly fails to compile:
enum_flags<flags> f1 = FLAG1;
enum_flags<flags> f2 = FLAG2 | f1;
The unit tests also revealed that this useful use case doesn't work:
enum flag { FLAG1 = 1, FLAG2 = 2 };
enum_flags<flag> src = FLAG1;
enum_flags<flag> f1 = condition ? src : FLAG2;
It fails to compile because enum_flags<flag> and flag are convertible
to each other.
Turns out that making enum_flags be implicitly convertible to the
backing raw enum type was not a good idea.
If we make it convertible to the underlying type instead, we fix that
ternary operator use case, and, we find cases throughout the codebase
that should be using the enum_flags but were using the raw backing
enum instead. So it's a good change overall.
Also, several operators were missing.
These holes and more are plugged by this patch, by reworking how the
enum_flags operators are implemented, and making use of C++11's
feature of being able to delete methods/functions.
There are cases in gdb/compile/ where we need to call a function in a
C plugin API that expects the raw enum. To address cases like that,
this adds a "raw()" method to enum_flags. This way we can keep using
the safer enum_flags to construct the value, and then be explicit when
we need to get at the raw enum.
This makes most of the enum_flags operators constexpr. Beyond
enabling more compiler optimizations and enabling the new unit tests,
this has other advantages, like making it possible to use operator|
with enum_flags values in switch cases, where only compile-time
constants are allowed:
enum_flags<flags> f = FLAG1 | FLAG2;
switch (f)
{
case FLAG1 | FLAG2:
break;
}
Currently that fails to compile.
It also switches to a different mechanism of enabling the global
operators. The current mechanism isn't namespace friendly, the new
one is.
It also switches to C++11-style SFINAE -- instead of wrapping the
return type in a SFINAE-friently structure, we use an unnamed template
parameter. I.e., this:
template <typename enum_type,
typename = is_enum_flags_enum_type_t<enum_type>>
enum_type
operator& (enum_type e1, enum_type e2)
instead of:
template <typename enum_type>
typename enum_flags_type<enum_type>::type
operator& (enum_type e1, enum_type e2)
Note that the static_assert inside operator~() was converted to a
couple overloads (signed vs unsigned), because static_assert is too
late for SFINAE-based tests, which is important for the CHECK_VALID
unit tests.
Tested with gcc {4.8, 7.1, 9.3} and clang {5.0.2, 10.0.0}.
gdb/ChangeLog:
* Makefile.in (SELFTESTS_SRCS): Add
unittests/enum-flags-selftests.c.
* btrace.c (ftrace_update_caller, ftrace_fixup_calle): Use
btrace_function_flags instead of enum btrace_function_flag.
* compile/compile-c-types.c (convert_qualified): Use
enum_flags::raw.
* compile/compile-cplus-symbols.c (convert_one_symbol)
(convert_symbol_bmsym):
* compile/compile-cplus-types.c (compile_cplus_convert_method)
(compile_cplus_convert_struct_or_union_methods)
(compile_cplus_instance::convert_qualified_base):
* go-exp.y (parse_string_or_char): Add cast to int.
* unittests/enum-flags-selftests.c: New file.
* record-btrace.c (btrace_thread_flag_to_str): Change parameter's
type to btrace_thread_flags from btrace_thread_flag.
(record_btrace_cancel_resume, record_btrace_step_thread): Change
local's type to btrace_thread_flags from btrace_thread_flag. Add
cast in DEBUG call.
gdbsupport/ChangeLog:
* enum-flags.h: Include "traits.h".
(DEF_ENUM_FLAGS_TYPE): Declare a function instead of defining a
structure.
(enum_underlying_type): Update comment.
(namespace enum_flags_detail): New. Move struct zero_type here.
(EnumIsUnsigned, EnumIsSigned): New.
(class enum_flags): Make most methods constexpr.
(operator&=, operator|=, operator^=): Take an enum_flags instead
of an enum_type. Make rvalue ref versions deleted.
(operator enum_type()): Delete.
(operator&, operator|, operator^, operator~): Delete, moved out of
class.
(raw()): New method.
(is_enum_flags_enum_type_t): Declare.
(ENUM_FLAGS_GEN_BINOP, ENUM_FLAGS_GEN_COMPOUND_ASSIGN)
(ENUM_FLAGS_GEN_COMP): New. Use them to reimplement global
operators.
(operator~): Now constexpr and reimplemented.
(operator<<, operator>>): New deleted functions.
* valid-expr.h (CHECK_VALID_EXPR_5, CHECK_VALID_EXPR_6): New.
2020-09-15 04:16:59 +08:00
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#define CHECK_VALID_EXPR_5(T1, T2, T3, T4, T5, VALID, EXPR_TYPE, EXPR) \
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CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1, typename T2, \
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typename T3, typename T4, \
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typename T5), \
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ESC_PARENS (T1, T2, T3, T4, T5), \
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VALID, EXPR_TYPE, EXPR)
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#define CHECK_VALID_EXPR_6(T1, T2, T3, T4, T5, T6, \
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VALID, EXPR_TYPE, EXPR) \
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CHECK_VALID_EXPR_INT (ESC_PARENS (typename T1, typename T2, \
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typename T3, typename T4, \
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typename T5, typename T6), \
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ESC_PARENS (T1, T2, T3, T4, T5, T6), \
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VALID, EXPR_TYPE, EXPR)
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Make sect_offset and cu_offset strong typedefs instead of structs
A while ago, back when GDB was a C program, the sect_offset and
cu_offset types were made structs in order to prevent incorrect mixing
of those offsets. Now that we require C++11, we can make them
integers again, while keeping the safety, by exploiting "enum class".
We can add a bit more safety, even, by defining operators that the
types _should_ support, helping making the suspicious uses stand out
more.
Getting at the underlying type is done with the new to_underlying
function added by the previous patch, which also helps better spot
where do we need to step out of the safety net. Mostly, that's around
parsing the DWARF, and when we print the offset for complaint/debug
purposes. But there are other occasional uses.
Since we have to define the sect_offset/cu_offset types in a header
anyway, I went ahead and generalized/library-fied the idea of "offset"
types, making it trivial to add more such types if we find a use. See
common/offset-type.h and the DEFINE_OFFSET_TYPE macro.
I needed a couple generaly-useful preprocessor bits (e.g., yet another
CONCAT implementation), so I started a new common/preprocessor.h file.
I included units tests covering the "offset" types API. These are
mostly compile-time tests, using SFINAE to check that expressions that
shouldn't compile (e.g., comparing unrelated offset types) really are
invalid and would fail to compile. This same idea appeared in my
pending enum-flags revamp from a few months ago (though this version
is a bit further modernized compared to what I had posted), and I plan
on reusing the "check valid expression" bits added here in that
series, so I went ahead and defined the CHECK_VALID_EXPR macro in its
own header -- common/valid-expr.h. I think that's nicer regardless.
I was borderline between calling the new types "offset" types, or
"index" types, BTW. I stuck with "offset" simply because that's what
we're already calling them, mostly.
gdb/ChangeLog:
2017-04-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/offset-type-selftests.c.
(SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o.
* common/offset-type.h: New file.
* common/preprocessor.h: New file.
* common/traits.h: New file.
* common/valid-expr.h: New file.
* dwarf2expr.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2expr.h: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* dwarf2loc.c: Include "common/underlying.h". Adjust to use
sect_offset and cu_offset strong typedefs throughout.
* dwarf2read.c: Adjust to use sect_offset and cu_offset strong
typedefs throughout.
* gdbtypes.h: Include "common/offset-type.h".
(cu_offset): Now an offset type (strong typedef) instead of a
struct.
(sect_offset): Likewise.
(union call_site_parameter_u): Rename "param_offset" field to
"param_cu_off".
* unittests/offset-type-selftests.c: New file.
2017-04-05 03:03:26 +08:00
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#endif /* COMMON_VALID_EXPR_H */
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