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Re: elfutils import
Sami Wagiaalla wrote:
Roland McGrath wrote:
That diff was really not useful. Please post the diff between what you
have in the frysk tree and the corresponding vanilla elfutils source.
Roland,
My mistake. This branch (sami-elfutils_129-merge-20070827-branch) now
contains the vanila elfutils sources plus frysk changes to elfutils. I
attached a diff showing thos changes.
Sami
Thanks! Working through this I found these problems:
GLOBAL(large_global_at_small_global)
GLOBAL(small_global_at_large_global)
STORE(REG0,REG0) <---- HERE
NO_OP
SIZE(small_global_at_large_global)
NO_OP
SIZE(large_global_at_small_global)
this isn't "stable" the first of those symbols is choose.
# A global symbol that has zero size.
GLOBAL(global_st_size_0)
LOAD_IMMED_BYTE (REG0, 0)
STORE (REG0, REG0) <---- HERE
NO_OP
this symbol can be missed entirely because min_label is > global_st_size_0.
# A global symbol, with size, that contains a nested global and local
# symbols each also with sizes.
GLOBAL(global_outer)
STORE(REG0, REG0)
NO_OP
LOCAL(local_in_global)
STORE (REG0, REG0) <----- HERE
NO_OP
SIZE(local_in_global)
.Lglobal_outer:
STORE (REG0, REG0)
NO_OP
SIZE(global_outer)
this isn't stable, the second of local_in_global and global_outer is chosen.
I've attached a context diff of up-stream vs local (they are
sufficiently different to make a unified diff harder to read). I'll see
about mearing that !section and !file test.
Andrew
Index: frysk-imports/elfutils/libdwfl/dwfl_module_addrsym.c
===================================================================
RCS file: /cvs/frysk/frysk-imports/elfutils/libdwfl/dwfl_module_addrsym.c,v
retrieving revision 1.6.2.2
retrieving revision 1.6.2.3
diff -p -r1.6.2.2 -r1.6.2.3
*** frysk-imports/elfutils/libdwfl/dwfl_module_addrsym.c 28 Aug 2007 20:40:47 -0000 1.6.2.2
--- frysk-imports/elfutils/libdwfl/dwfl_module_addrsym.c 30 Aug 2007 19:07:03 -0000 1.6.2.3
*************** dwfl_module_addrsym (Dwfl_Module *mod, G
*** 97,170 ****
return shndx == addr_shndx;
}
! /* Keep track of the closest symbol we have seen so far.
! Here we store only symbols with nonzero st_size. */
const char *closest_name = NULL;
GElf_Word closest_shndx = SHN_UNDEF;
-
- /* Keep track of an eligible symbol with st_size == 0 as a fallback. */
- const char *sizeless_name = NULL;
- GElf_Sym sizeless_sym = { 0, 0, 0, 0, 0, SHN_UNDEF };
- GElf_Word sizeless_shndx = SHN_UNDEF;
-
- /* Keep track of the lowest address a relevant sizeless symbol could have. */
- GElf_Addr min_label = addr;
-
- /* Look through the symbol table for a matching symbol. */
for (int i = 1; i < syments; ++i)
{
GElf_Sym sym;
GElf_Word shndx;
const char *name = INTUSE(dwfl_module_getsym) (mod, i, &sym, &shndx);
! if (name != NULL
! && sym.st_value <= addr
! && (sym.st_size == 0 || addr - sym.st_value < sym.st_size))
{
! /* Even if we don't choose this symbol, its existence
! excludes any sizeless symbol (assembly label) that
! is inside its bounds. */
! if (sym.st_value + sym.st_size > addr)
! min_label = sym.st_value + sym.st_size;
!
! /* This symbol is a better candidate than the current one
! if it's a named symbol, not a section or file symbol,
! and is closer to ADDR or is global when it was local. */
! if (name[0] != '\0'
! && GELF_ST_TYPE (sym.st_info) != STT_SECTION
! && GELF_ST_TYPE (sym.st_info) != STT_FILE
! && (closest_name == NULL
! || closest_sym->st_value < sym.st_value
! || (GELF_ST_BIND (closest_sym->st_info)
! < GELF_ST_BIND (sym.st_info))))
{
! if (sym.st_size != 0)
{
! *closest_sym = sym;
! closest_shndx = shndx;
! closest_name = name;
}
! else if (same_section (&sym, shndx))
{
! /* Handwritten assembly symbols sometimes have no st_size.
! If no symbol with proper size includes the address,
! we'll use the closest one that is in the same section
! as ADDR. */
! sizeless_sym = sym;
! sizeless_shndx = shndx;
! sizeless_name = name;
}
}
}
}
! /* If we found no proper sized symbol to use, fall back to the best
! candidate sizeless symbol we found, if any. */
! if (closest_name == NULL
! && sizeless_name != NULL && sizeless_sym.st_value >= min_label)
{
! *closest_sym = sizeless_sym;
! closest_shndx = sizeless_shndx;
! closest_name = sizeless_name;
}
if (shndxp != NULL)
--- 97,176 ----
return shndx == addr_shndx;
}
! /* Look through the symbol table for a matching symbol. */
const char *closest_name = NULL;
+ memset(closest_sym, 0, sizeof(*closest_sym));
GElf_Word closest_shndx = SHN_UNDEF;
for (int i = 1; i < syments; ++i)
{
GElf_Sym sym;
GElf_Word shndx;
const char *name = INTUSE(dwfl_module_getsym) (mod, i, &sym, &shndx);
! if (name != NULL && sym.st_value <= addr)
{
! inline void closest (void)
{
! *closest_sym = sym;
! closest_shndx = shndx;
! closest_name = name;
! }
!
! /* This symbol contains ADDR; but is it better than the
! previous candidate? */
! if (addr < sym.st_value + sym.st_size)
! {
! if (addr >= closest_sym->st_value + closest_sym->st_size)
! {
! /* Ha! The previous candidate doesn't even contain
! ADDR; replace it. */
! closest();
! continue;
! }
! if (sym.st_value > closest_sym->st_value)
{
! /* This candidate is closer to ADDR. */
! closest ();
! continue;
}
! if (sym.st_value == closest_sym->st_value
! && sym.st_size < closest_sym->st_size)
{
! /* This candidate, while having an identical value,
! is at least smaller. */
! closest ();
! continue;
}
+ /* Discard this candidate, no better than the previous
+ sized symbol that contained ADDR. */
+ continue;
+ }
+
+ /* The current closest symbol contains ADDR, can't do better
+ than that. */
+ if (addr < closest_sym->st_value + closest_sym->st_size)
+ continue;
+
+ /* Save the symbol which is "closer". Use the end-address
+ so that a sized symbol that ends closer to an unsized
+ symbol wins (unsized symbols are typically created using
+ hand-written assembler). */
+ if (sym.st_value + sym.st_size
+ >= closest_sym->st_value + closest_sym->st_size
+ && same_section (&sym, shndx))
+ {
+ closest ();
+ continue;
}
}
}
! /* If the closest symbol has a size doesn't contain ADDR, discard
! it. There must be a hole in the symbol table. */
! if (closest_sym->st_size > 0
! && addr >= closest_sym->st_value + closest_sym->st_size)
{
! memset(closest_sym, 0, sizeof(*closest_sym));
! return NULL;
}
if (shndxp != NULL)