* config/rs6000/tm-rs6000.h (IN_SOLIB_RETURN_TRAMPOLINE): Define.
(rs6000_in_solib_return_trampoline): Declare. * rs6000-tdep.c (rs6000_in_solib_return_trampoline): New function. (rs6000_skip_trampoline_code): Skip bigtoc fixup code. * xcoffread.c (read_xcoff_symtab): Perform the ISFCN function check after the CSECT check rather than before it. Allocate separate symtabs for CSECTs whose names begin with '@'. (scan_xcoff_symtab): Don't ignore symbols beginning with '@'. Activate the misc_func_recorded mechanism for whose names begin with '@'.
This commit is contained in:
Nicholas Duffek
parent
f5a6fc0555
commit
977adac5db
4 changed files with 96 additions and 23 deletions
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@ -1,3 +1,17 @@
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2001-05-01 Nicholas Duffek <nsd@redhat.com>
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* config/rs6000/tm-rs6000.h (IN_SOLIB_RETURN_TRAMPOLINE): Define.
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(rs6000_in_solib_return_trampoline): Declare.
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* rs6000-tdep.c (rs6000_in_solib_return_trampoline): New
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function.
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(rs6000_skip_trampoline_code): Skip bigtoc fixup code.
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* xcoffread.c (read_xcoff_symtab): Perform the ISFCN function
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check after the CSECT check rather than before it. Allocate
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separate symtabs for CSECTs whose names begin with '@'.
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(scan_xcoff_symtab): Don't ignore symbols beginning with '@'.
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Activate the misc_func_recorded mechanism for whose names begin
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with '@'.
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2001-04-30 J.T. Conklin <jtc@redback.com>
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* ppcnbsd-nat.c (fetch_inferior_registers)
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@ -32,6 +32,13 @@
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#undef CPLUS_MARKER
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#define CPLUS_MARKER '.'
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/* Return whether PC in function NAME is in code that should be skipped when
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single-stepping. */
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#define IN_SOLIB_RETURN_TRAMPOLINE(pc, name) \
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rs6000_in_solib_return_trampoline (pc, name)
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extern int rs6000_in_solib_return_trampoline (CORE_ADDR, char *);
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/* If PC is in some function-call trampoline code, return the PC
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where the function itself actually starts. If not, return NULL. */
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@ -1132,19 +1132,55 @@ rs6000_extract_return_value (struct type *valtype, char *regbuf, char *valbuf)
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static CORE_ADDR rs6000_struct_return_address;
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/* Indirect function calls use a piece of trampoline code to do context
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switching, i.e. to set the new TOC table. Skip such code if we are on
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its first instruction (as when we have single-stepped to here).
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Also skip shared library trampoline code (which is different from
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/* Return whether handle_inferior_event() should proceed through code
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starting at PC in function NAME when stepping.
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The AIX -bbigtoc linker option generates functions @FIX0, @FIX1, etc. to
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handle memory references that are too distant to fit in instructions
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generated by the compiler. For example, if 'foo' in the following
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instruction:
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lwz r9,foo(r2)
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is greater than 32767, the linker might replace the lwz with a branch to
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somewhere in @FIX1 that does the load in 2 instructions and then branches
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back to where execution should continue.
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GDB should silently step over @FIX code, just like AIX dbx does.
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Unfortunately, the linker uses the "b" instruction for the branches,
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meaning that the link register doesn't get set. Therefore, GDB's usual
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step_over_function() mechanism won't work.
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Instead, use the IN_SOLIB_RETURN_TRAMPOLINE and SKIP_TRAMPOLINE_CODE hooks
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in handle_inferior_event() to skip past @FIX code. */
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int
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rs6000_in_solib_return_trampoline (CORE_ADDR pc, char *name)
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{
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return name && !strncmp (name, "@FIX", 4);
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}
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/* Skip code that the user doesn't want to see when stepping:
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1. Indirect function calls use a piece of trampoline code to do context
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switching, i.e. to set the new TOC table. Skip such code if we are on
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its first instruction (as when we have single-stepped to here).
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2. Skip shared library trampoline code (which is different from
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indirect function call trampolines).
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3. Skip bigtoc fixup code.
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Result is desired PC to step until, or NULL if we are not in
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trampoline code. */
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code that should be skipped. */
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CORE_ADDR
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rs6000_skip_trampoline_code (CORE_ADDR pc)
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{
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register unsigned int ii, op;
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int rel;
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CORE_ADDR solib_target_pc;
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struct minimal_symbol *msymbol;
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static unsigned trampoline_code[] =
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{
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@ -1158,6 +1194,21 @@ rs6000_skip_trampoline_code (CORE_ADDR pc)
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0
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};
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/* Check for bigtoc fixup code. */
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msymbol = lookup_minimal_symbol_by_pc (pc);
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if (msymbol && rs6000_in_solib_return_trampoline (pc, SYMBOL_NAME (msymbol)))
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{
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/* Double-check that the third instruction from PC is relative "b". */
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op = read_memory_integer (pc + 8, 4);
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if ((op & 0xfc000003) == 0x48000000)
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{
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/* Extract bits 6-29 as a signed 24-bit relative word address and
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add it to the containing PC. */
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rel = ((int)(op << 6) >> 6);
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return pc + 8 + rel;
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}
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}
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/* If pc is in a shared library trampoline, return its target. */
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solib_target_pc = find_solib_trampoline_target (pc);
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if (solib_target_pc)
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@ -1081,14 +1081,6 @@ read_xcoff_symtab (struct partial_symtab *pst)
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/* done with all files, everything from here on is globals */
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}
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/* if explicitly specified as a function, treat is as one. */
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if (ISFCN (cs->c_type) && cs->c_sclass != C_TPDEF)
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{
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bfd_coff_swap_aux_in (abfd, raw_auxptr, cs->c_type, cs->c_sclass,
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0, cs->c_naux, &main_aux);
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goto function_entry_point;
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}
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if ((cs->c_sclass == C_EXT || cs->c_sclass == C_HIDEXT)
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&& cs->c_naux == 1)
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{
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@ -1158,7 +1150,8 @@ read_xcoff_symtab (struct partial_symtab *pst)
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SECT_OFF_TEXT (objfile));
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file_end_addr = file_start_addr + CSECT_LEN (&main_aux);
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if (cs->c_name && cs->c_name[0] == '.')
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if (cs->c_name && (cs->c_name[0] == '.'
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|| cs->c_name[0] == '@'))
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{
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last_csect_name = cs->c_name;
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last_csect_val = cs->c_value;
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@ -1232,6 +1225,16 @@ read_xcoff_symtab (struct partial_symtab *pst)
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}
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}
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/* If explicitly specified as a function, treat is as one. This check
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evaluates to true for @FIX* bigtoc CSECT symbols, so it must occur
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after the above CSECT check. */
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if (ISFCN (cs->c_type) && cs->c_sclass != C_TPDEF)
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{
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bfd_coff_swap_aux_in (abfd, raw_auxptr, cs->c_type, cs->c_sclass,
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0, cs->c_naux, &main_aux);
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goto function_entry_point;
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}
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switch (cs->c_sclass)
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{
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@ -2243,14 +2246,8 @@ scan_xcoff_symtab (struct objfile *objfile)
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else
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csect_aux = main_aux[0];
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/* If symbol name starts with ".$" or "$", ignore it.
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A symbol like "@FIX1" introduces a section for -bbigtoc jump
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tables, which contain anonymous linker-generated code.
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Ignore those sections to avoid "pc 0x... in read in psymtab,
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but not in symtab" warnings from find_pc_sect_symtab. */
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if (namestring[0] == '$' || namestring[0] == '@'
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/* If symbol name starts with ".$" or "$", ignore it. */
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if (namestring[0] == '$'
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|| (namestring[0] == '.' && namestring[1] == '$'))
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break;
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@ -2296,7 +2293,11 @@ scan_xcoff_symtab (struct objfile *objfile)
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objfile->static_psymbols.next);
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}
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}
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if (namestring && namestring[0] == '.')
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/* Activate the misc_func_recorded mechanism for
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compiler- and linker-generated CSECTs like ".strcmp"
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and "@FIX1". */
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if (namestring && (namestring[0] == '.'
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|| namestring[0] == '@'))
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{
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last_csect_name = namestring;
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last_csect_val = symbol.n_value;
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