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perf build: Don't compile demangle-cxx.cpp if not necessary

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demangle-cxx.cpp requires a C++ compiler, but feature checks may fail
because of the absence of this. Add a CONFIG_CXX_DEMANGLE so that the
source isn't built if not supported. Copy libbfd and cplus demangle
variants to a weak symbol-elf.c version so they aren't dependent on
C++. These variants are only built with the build option
BUILD_NONDISTRO=1.

Committer note:

This also handles this build break when a C++ compiler isn't available:

  CXX     /tmp/build/perf/util/demangle-cxx.o
  /bin/sh: g++: command not found

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Liu <liuqi115@huawei.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20230417192546.99923-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers 2023-04-17 12:25:46 -07:00 committed by Arnaldo Carvalho de Melo
parent a0c2f92d36
commit 65cd8e5534
3 changed files with 29 additions and 1 deletions
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1
tools/perf/Makefile.config
View File

@ -927,6 +927,7 @@ ifndef NO_DEMANGLE
EXTLIBS += -lstdc++
CFLAGS += -DHAVE_CXA_DEMANGLE_SUPPORT
CXXFLAGS += -DHAVE_CXA_DEMANGLE_SUPPORT
$(call detected,CONFIG_CXX_DEMANGLE)
endif
ifdef BUILD_NONDISTRO
ifeq ($(filter -liberty,$(EXTLIBS)),)

2
tools/perf/util/Build
View File

@ -214,7 +214,7 @@ perf-$(CONFIG_ZSTD) += zstd.o
perf-$(CONFIG_LIBCAP) += cap.o
perf-y += demangle-cxx.o
perf-$(CONFIG_CXX_DEMANGLE) += demangle-cxx.o
perf-y += demangle-ocaml.o
perf-y += demangle-java.o
perf-y += demangle-rust.o

27
tools/perf/util/symbol-elf.c
View File

@ -31,6 +31,13 @@
#include <bfd.h>
#endif
#if defined(HAVE_LIBBFD_SUPPORT) || defined(HAVE_CPLUS_DEMANGLE_SUPPORT)
#ifndef DMGL_PARAMS
#define DMGL_PARAMS (1 << 0) /* Include function args */
#define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
#endif
#endif
#ifndef EM_AARCH64
#define EM_AARCH64 183 /* ARM 64 bit */
#endif
@ -271,6 +278,26 @@ static bool want_demangle(bool is_kernel_sym)
return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
}
/*
* Demangle C++ function signature, typically replaced by demangle-cxx.cpp
* version.
*/
__weak char *cxx_demangle_sym(const char *str __maybe_unused, bool params __maybe_unused,
bool modifiers __maybe_unused)
{
#ifdef HAVE_LIBBFD_SUPPORT
int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0);
return bfd_demangle(NULL, str, flags);
#elif defined(HAVE_CPLUS_DEMANGLE_SUPPORT)
int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0);
return cplus_demangle(str, flags);
#else
return NULL;
#endif
}
static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
{
char *demangled = NULL;