Messages in this thread | | | Date | Sun, 15 Dec 2013 20:16:22 -0700 | From | David Ahern <> | Subject | Re: [PATCH v0 07/71] perf tools: Record whether a dso is 64-bit |
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On 12/11/13, 5:36 AM, Alexander Shishkin wrote: > diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c > index a0c7c59..80817ec 100644 > --- a/tools/perf/util/dso.c > +++ b/tools/perf/util/dso.c > @@ -446,6 +446,7 @@ struct dso *dso__new(const char *name) > dso->cache = RB_ROOT; > dso->symtab_type = DSO_BINARY_TYPE__NOT_FOUND; > dso->data_type = DSO_BINARY_TYPE__NOT_FOUND; > + dso->is_64_bit = (sizeof(void *) == 8); > dso->loaded = 0; > dso->rel = 0; > dso->sorted_by_name = 0; > diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h > index 384f2d9..62680e1 100644 > --- a/tools/perf/util/dso.h > +++ b/tools/perf/util/dso.h > @@ -91,6 +91,7 @@ struct dso { > u8 annotate_warned:1; > u8 sname_alloc:1; > u8 lname_alloc:1; > + u8 is_64_bit:1; > u8 sorted_by_name; > u8 loaded; > u8 rel; > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > index eed0b96..a0fc81b 100644 > --- a/tools/perf/util/symbol-elf.c > +++ b/tools/perf/util/symbol-elf.c > @@ -595,6 +595,8 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, > goto out_elf_end; > } > > + ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64); > + > ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab", > NULL); > if (ss->symshdr.sh_type != SHT_SYMTAB) > @@ -694,6 +696,7 @@ int dso__load_sym(struct dso *dso, struct map *map, > bool remap_kernel = false, adjust_kernel_syms = false; > > dso->symtab_type = syms_ss->type; > + dso->is_64_bit = syms_ss->is_64_bit; > dso->rel = syms_ss->ehdr.e_type == ET_REL; > > /* > diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c > index ac7070a..b9d1119 100644 > --- a/tools/perf/util/symbol-minimal.c > +++ b/tools/perf/util/symbol-minimal.c > @@ -1,3 +1,4 @@ > +#include "util.h" > #include "symbol.h" > > #include <stdio.h> > @@ -287,6 +288,23 @@ int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused, > return 0; > } > > +static int fd__is_64_bit(int fd) > +{ > + u8 e_ident[EI_NIDENT]; > + > + if (lseek(fd, 0, SEEK_SET)) > + return -1; > + > + if (readn(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident)) > + return -1; > + > + if (memcmp(e_ident, ELFMAG, SELFMAG) || > + e_ident[EI_VERSION] != EV_CURRENT) > + return -1; > + > + return e_ident[EI_CLASS] == ELFCLASS64; > +} > + > int dso__load_sym(struct dso *dso, struct map *map __maybe_unused, > struct symsrc *ss, > struct symsrc *runtime_ss __maybe_unused, > @@ -294,6 +312,11 @@ int dso__load_sym(struct dso *dso, struct map *map __maybe_unused, > int kmodule __maybe_unused) > { > unsigned char *build_id[BUILD_ID_SIZE]; > + int ret; > + > + ret = fd__is_64_bit(ss->fd); > + if (ret >= 0) > + dso->is_64_bit = ret; > > if (filename__read_build_id(ss->name, build_id, BUILD_ID_SIZE) > 0) { > dso__set_build_id(dso, build_id);
Here's what is wrong with this API: you are determining DSO bitness at symbol load time, not when the DSO is created and added to the maps.
As I pointed out in a prior comment you are initializing dso->is_64_bit to perf's bitness when the dso object is created (dso__new) but the value is not correctly set until dso__load time. Some tools (perf-trace) never load symbols, so that value is always wrong in the sense that its value has no correlation to the dso object.
David
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