git/config.mak.dev
Johannes Schindelin 27712a73ef mimalloc: offer a build-time option to enable it
By defining `USE_MIMALLOC`, Git can now be compiled with that
nicely-fast and small allocator.

Note that we have to disable a couple `DEVELOPER` options to build
mimalloc's source code, as it makes heavy use of declarations after
statements, among other things that disagree with Git's conventions.

We even have to silence some GCC warnings in non-DEVELOPER mode. For
example, the `-Wno-array-bounds` flag is needed because in `-O2` builds,
trying to call `NtCurrentTeb()` (which `_mi_thread_id()` does on
Windows) causes the bogus warning about a system header, likely related
to https://sourceforge.net/p/mingw-w64/mailman/message/37674519/ and to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578:

C:/git-sdk-64-minimal/mingw64/include/psdk_inc/intrin-impl.h:838:1:
        error: array subscript 0 is outside array bounds of 'long long unsigned int[0]' [-Werror=array-bounds]
  838 | __buildreadseg(__readgsqword, unsigned __int64, "gs", "q")
      | ^~~~~~~~~~~~~~

Also: The `mimalloc` library uses C11-style atomics, therefore we must
require that standard when compiling with GCC if we want to use
`mimalloc` (instead of requiring "only" C99). This is what we do in the
CMake definition already, therefore this commit does not need to touch
`contrib/buildsystems/`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 19:32:46 +01:00

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ifndef COMPILER_FEATURES
COMPILER_FEATURES := $(shell ./detect-compiler $(CC))
endif
ifeq ($(filter no-error,$(DEVOPTS)),)
DEVELOPER_CFLAGS += -Werror
SPARSE_FLAGS += -Wsparse-error
endif
DEVELOPER_CFLAGS += -Wall
ifeq ($(filter no-pedantic,$(DEVOPTS)),)
DEVELOPER_CFLAGS += -pedantic
ifneq ($(or $(filter gcc5,$(COMPILER_FEATURES)),$(filter clang4,$(COMPILER_FEATURES))),)
DEVELOPER_CFLAGS += -Wpedantic
ifneq ($(filter gcc10,$(COMPILER_FEATURES)),)
ifeq ($(uname_S),MINGW)
DEVELOPER_CFLAGS += -Wno-pedantic-ms-format
endif
endif
endif
endif
ifneq ($(uname_S),FreeBSD)
ifneq ($(or $(filter gcc6,$(COMPILER_FEATURES)),$(filter clang7,$(COMPILER_FEATURES))),)
ifndef USE_MIMALLOC
DEVELOPER_CFLAGS += -std=gnu99
endif
endif
else
# FreeBSD cannot limit to C99 because its system headers unconditionally
# rely on C11 features.
endif
DEVELOPER_CFLAGS += -Wdeclaration-after-statement
DEVELOPER_CFLAGS += -Wformat-security
DEVELOPER_CFLAGS += -Wold-style-definition
DEVELOPER_CFLAGS += -Woverflow
DEVELOPER_CFLAGS += -Wpointer-arith
DEVELOPER_CFLAGS += -Wstrict-prototypes
DEVELOPER_CFLAGS += -Wunused
DEVELOPER_CFLAGS += -Wvla
DEVELOPER_CFLAGS += -Wwrite-strings
DEVELOPER_CFLAGS += -fno-common
ifneq ($(filter clang4,$(COMPILER_FEATURES)),)
DEVELOPER_CFLAGS += -Wtautological-constant-out-of-range-compare
endif
ifneq ($(or $(filter gcc6,$(COMPILER_FEATURES)),$(filter clang4,$(COMPILER_FEATURES))),)
DEVELOPER_CFLAGS += -Wextra
# if a function is public, there should be a prototype and the right
# header file should be included. If not, it should be static.
DEVELOPER_CFLAGS += -Wmissing-prototypes
ifeq ($(filter extra-all,$(DEVOPTS)),)
# These are disabled because we have these all over the place.
DEVELOPER_CFLAGS += -Wno-empty-body
DEVELOPER_CFLAGS += -Wno-missing-field-initializers
endif
endif
# uninitialized warnings on gcc 4.9.2 in xdiff/xdiffi.c and config.c
# not worth fixing since newer compilers correctly stop complaining
#
# Likewise, gcc older than 4.9 complains about initializing a
# struct-within-a-struct using just "{ 0 }"
ifneq ($(filter gcc4,$(COMPILER_FEATURES)),)
ifeq ($(filter gcc5,$(COMPILER_FEATURES)),)
DEVELOPER_CFLAGS += -Wno-uninitialized
DEVELOPER_CFLAGS += -Wno-missing-braces
endif
endif
# Old versions of clang complain about initializing a
# struct-within-a-struct using just "{0}" rather than "{{0}}". This
# error is considered a false-positive and not worth fixing, because
# new clang versions do not, so just disable it.
#
# The "bug" was fixed in upstream clang 9.
#
# Complicating this is that versions of clang released by Apple have
# their own version numbers (associated with the corresponding version
# of XCode) unrelated to the official clang version numbers.
#
# The bug was fixed in Apple clang 12.
#
ifneq ($(filter clang1,$(COMPILER_FEATURES)),) # if we are using clang
ifeq ($(uname_S),Darwin) # if we are on darwin
ifeq ($(filter clang12,$(COMPILER_FEATURES)),) # if version < 12
DEVELOPER_CFLAGS += -Wno-missing-braces
endif
else # not darwin
ifeq ($(filter clang9,$(COMPILER_FEATURES)),) # if version < 9
DEVELOPER_CFLAGS += -Wno-missing-braces
endif
endif
endif
# https://bugzilla.redhat.com/show_bug.cgi?id=2075786
ifneq ($(filter gcc12,$(COMPILER_FEATURES)),)
DEVELOPER_CFLAGS += -Wno-error=stringop-overread
endif
GIT_TEST_PERL_FATAL_WARNINGS = YesPlease