Commit 65cd8e55 authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

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



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: default avatarIan Rogers <irogers@google.com>
Tested-by: default avatarArnaldo 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent a0c2f92d

tools/perf/Makefile.config

+1 −0
Original line number Diff line number Diff line
@@ -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)),)

tools/perf/util/Build

+1 −1
Original line number Diff line number Diff line
@@ -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

tools/perf/util/symbol-elf.c

+27 −0
Original line number Diff line number Diff line
@@ -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;