X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Fi386-linux-tdep.c;h=f42f6b7bddfa9e9f26816c28a6651d1b6b1b9c45;hb=b7c92712fafe022ee189f2125618411f4e8bbd54;hp=97845bf16383208f192453c4a91d62d5f2897f27;hpb=bb489b3c99cfe1484a3bbd37acdaee5f2cf96b98;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c index 97845bf163..f42f6b7bdd 100644 --- a/gdb/i386-linux-tdep.c +++ b/gdb/i386-linux-tdep.c @@ -1,6 +1,6 @@ -/* Target-dependent code for GNU/Linux running on i386's, for GDB. +/* Target-dependent code for GNU/Linux i386. - Copyright 2000, 2001, 2002, 2003 Free Software Foundation, Inc. + Copyright 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. This file is part of GDB. @@ -25,19 +25,15 @@ #include "value.h" #include "regcache.h" #include "inferior.h" +#include "osabi.h" #include "reggroups.h" -/* For i386_linux_skip_solib_resolver. */ -#include "symtab.h" -#include "symfile.h" -#include "objfiles.h" - -#include "solib-svr4.h" /* For struct link_map_offsets. */ - -#include "osabi.h" +#include "gdb_string.h" #include "i386-tdep.h" #include "i386-linux-tdep.h" +#include "glibc-tdep.h" +#include "solib-svr4.h" /* Return the name of register REG. */ @@ -87,13 +83,13 @@ i386_linux_register_reggroup_p (struct gdbarch *gdbarch, int regnum, Checking for the code sequence should be somewhat reliable, because the effect is to call the system call sigreturn. This is unlikely - to occur anywhere other than a signal trampoline. + to occur anywhere other than in a signal trampoline. It kind of sucks that we have to read memory from the process in order to identify a signal trampoline, but there doesn't seem to be - any other way. The PC_IN_SIGTRAMP macro in tm-linux.h arranges to - only call us if no function name could be identified, which should - be the case since the code is on the stack. + any other way. Therefore we only do the memory reads if no + function name could be identified, which should be the case since + the code is on the stack. Detection of signal trampolines for handlers that set the SA_RESTORER flag is in general not possible. Unfortunately this is @@ -119,12 +115,13 @@ static const unsigned char linux_sigtramp_code[] = #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) -/* If PC is in a sigtramp routine, return the address of the start of - the routine. Otherwise, return 0. */ +/* If NEXT_FRAME unwinds into a sigtramp routine, return the address + of the start of the routine. Otherwise, return 0. */ static CORE_ADDR -i386_linux_sigtramp_start (CORE_ADDR pc) +i386_linux_sigtramp_start (struct frame_info *next_frame) { + CORE_ADDR pc = frame_pc_unwind (next_frame); unsigned char buf[LINUX_SIGTRAMP_LEN]; /* We only recognize a signal trampoline if PC is at the start of @@ -134,7 +131,7 @@ i386_linux_sigtramp_start (CORE_ADDR pc) PC is not at the start of the instruction sequence, there will be a few trailing readable bytes on the stack. */ - if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) + if (!safe_frame_unwind_memory (next_frame, pc, buf, LINUX_SIGTRAMP_LEN)) return 0; if (buf[0] != LINUX_SIGTRAMP_INSN0) @@ -155,7 +152,7 @@ i386_linux_sigtramp_start (CORE_ADDR pc) pc -= adjust; - if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) + if (!safe_frame_unwind_memory (next_frame, pc, buf, LINUX_SIGTRAMP_LEN)) return 0; } @@ -186,12 +183,13 @@ static const unsigned char linux_rt_sigtramp_code[] = #define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code) -/* If PC is in a RT sigtramp routine, return the address of the start - of the routine. Otherwise, return 0. */ +/* If NEXT_FRAME unwinds into an RT sigtramp routine, return the + address of the start of the routine. Otherwise, return 0. */ static CORE_ADDR -i386_linux_rt_sigtramp_start (CORE_ADDR pc) +i386_linux_rt_sigtramp_start (struct frame_info *next_frame) { + CORE_ADDR pc = frame_pc_unwind (next_frame); unsigned char buf[LINUX_RT_SIGTRAMP_LEN]; /* We only recognize a signal trampoline if PC is at the start of @@ -201,7 +199,7 @@ i386_linux_rt_sigtramp_start (CORE_ADDR pc) PC is not at the start of the instruction sequence, there will be a few trailing readable bytes on the stack. */ - if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) + if (!safe_frame_unwind_memory (next_frame, pc, buf, LINUX_RT_SIGTRAMP_LEN)) return 0; if (buf[0] != LINUX_RT_SIGTRAMP_INSN0) @@ -211,7 +209,8 @@ i386_linux_rt_sigtramp_start (CORE_ADDR pc) pc -= LINUX_RT_SIGTRAMP_OFFSET1; - if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) + if (!safe_frame_unwind_memory (next_frame, pc, buf, + LINUX_RT_SIGTRAMP_LEN)) return 0; } @@ -221,19 +220,25 @@ i386_linux_rt_sigtramp_start (CORE_ADDR pc) return pc; } -/* Return whether PC is in a GNU/Linux sigtramp routine. */ +/* Return whether the frame preceding NEXT_FRAME corresponds to a + GNU/Linux sigtramp routine. */ static int -i386_linux_pc_in_sigtramp (CORE_ADDR pc, char *name) +i386_linux_sigtramp_p (struct frame_info *next_frame) { + CORE_ADDR pc = frame_pc_unwind (next_frame); + char *name; + + find_pc_partial_function (pc, &name, NULL, NULL); + /* If we have NAME, we can optimize the search. The trampolines are named __restore and __restore_rt. However, they aren't dynamically exported from the shared C library, so the trampoline may appear to be part of the preceding function. This should always be sigaction, __sigaction, or __libc_sigaction (all aliases to the same function). */ if (name == NULL || strstr (name, "sigaction") != NULL) - return (i386_linux_sigtramp_start (pc) != 0 - || i386_linux_rt_sigtramp_start (pc) != 0); + return (i386_linux_sigtramp_start (next_frame) != 0 + || i386_linux_rt_sigtramp_start (next_frame) != 0); return (strcmp ("__restore", name) == 0 || strcmp ("__restore_rt", name) == 0); @@ -255,7 +260,7 @@ i386_linux_sigcontext_addr (struct frame_info *next_frame) frame_unwind_register (next_frame, I386_ESP_REGNUM, buf); sp = extract_unsigned_integer (buf, 4); - pc = i386_linux_sigtramp_start (frame_pc_unwind (next_frame)); + pc = i386_linux_sigtramp_start (next_frame); if (pc) { /* The sigcontext structure lives on the stack, right after @@ -269,7 +274,7 @@ i386_linux_sigcontext_addr (struct frame_info *next_frame) return sp; } - pc = i386_linux_rt_sigtramp_start (frame_pc_unwind (next_frame)); + pc = i386_linux_rt_sigtramp_start (next_frame); if (pc) { CORE_ADDR ucontext_addr; @@ -278,7 +283,7 @@ i386_linux_sigcontext_addr (struct frame_info *next_frame) pointer to the user context is passed as the third argument to the signal handler. */ read_memory (sp + 8, buf, 4); - ucontext_addr = extract_unsigned_integer (buf, 4) + 20; + ucontext_addr = extract_unsigned_integer (buf, 4); return ucontext_addr + I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET; } @@ -310,134 +315,50 @@ i386_linux_write_pc (CORE_ADDR pc, ptid_t ptid) write_register_pid (I386_LINUX_ORIG_EAX_REGNUM, -1, ptid); } -/* Calling functions in shared libraries. */ -/* Find the minimal symbol named NAME, and return both the minsym - struct and its objfile. This probably ought to be in minsym.c, but - everything there is trying to deal with things like C++ and - SOFUN_ADDRESS_MAYBE_TURQUOISE, ... Since this is so simple, it may - be considered too special-purpose for general consumption. */ +/* The register sets used in GNU/Linux ELF core-dumps are identical to + the register sets in `struct user' that are used for a.out + core-dumps. These are also used by ptrace(2). The corresponding + types are `elf_gregset_t' for the general-purpose registers (with + `elf_greg_t' the type of a single GP register) and `elf_fpregset_t' + for the floating-point registers. -static struct minimal_symbol * -find_minsym_and_objfile (char *name, struct objfile **objfilep) -{ - struct objfile *objfile; - - ALL_OBJFILES (objfile) - { - struct minimal_symbol *msym; + Those types used to be available under the names `gregset_t' and + `fpregset_t' too, and GDB used those names in the past. But those + names are now used for the register sets used in the `mcontext_t' + type, which have a different size and layout. */ - ALL_OBJFILE_MSYMBOLS (objfile, msym) - { - if (SYMBOL_LINKAGE_NAME (msym) - && strcmp (SYMBOL_LINKAGE_NAME (msym), name) == 0) - { - *objfilep = objfile; - return msym; - } - } - } +/* Mapping between the general-purpose registers in `struct user' + format and GDB's register cache layout. */ - return 0; -} - -static CORE_ADDR -skip_gnu_resolver (CORE_ADDR pc) +/* From . */ +static int i386_linux_gregset_reg_offset[] = { - /* The GNU dynamic linker is part of the GNU C library, so many - GNU/Linux distributions use it. (All ELF versions, as far as I - know.) An unresolved PLT entry points to "_dl_runtime_resolve", - which calls "fixup" to patch the PLT, and then passes control to - the function. - - We look for the symbol `_dl_runtime_resolve', and find `fixup' in - the same objfile. If we are at the entry point of `fixup', then - we set a breakpoint at the return address (at the top of the - stack), and continue. - - It's kind of gross to do all these checks every time we're - called, since they don't change once the executable has gotten - started. But this is only a temporary hack --- upcoming versions - of GNU/Linux will provide a portable, efficient interface for - debugging programs that use shared libraries. */ - - struct objfile *objfile; - struct minimal_symbol *resolver - = find_minsym_and_objfile ("_dl_runtime_resolve", &objfile); - - if (resolver) - { - struct minimal_symbol *fixup - = lookup_minimal_symbol ("fixup", NULL, objfile); - - if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc) - return frame_pc_unwind (get_current_frame ()); - } - - return 0; -} - -/* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c. - This function: - 1) decides whether a PLT has sent us into the linker to resolve - a function reference, and - 2) if so, tells us where to set a temporary breakpoint that will - trigger when the dynamic linker is done. */ - -CORE_ADDR -i386_linux_skip_solib_resolver (CORE_ADDR pc) -{ - CORE_ADDR result; - - /* Plug in functions for other kinds of resolvers here. */ - result = skip_gnu_resolver (pc); - if (result) - return result; - - return 0; -} - -/* Fetch (and possibly build) an appropriate link_map_offsets - structure for native GNU/Linux x86 targets using the struct offsets - defined in link.h (but without actual reference to that file). - - This makes it possible to access GNU/Linux x86 shared libraries - from a GDB that was not built on an GNU/Linux x86 host (for cross - debugging). */ - -static struct link_map_offsets * -i386_linux_svr4_fetch_link_map_offsets (void) -{ - static struct link_map_offsets lmo; - static struct link_map_offsets *lmp = NULL; - - if (lmp == NULL) - { - lmp = &lmo; - - lmo.r_debug_size = 8; /* The actual size is 20 bytes, but - this is all we need. */ - lmo.r_map_offset = 4; - lmo.r_map_size = 4; - - lmo.link_map_size = 20; /* The actual size is 552 bytes, but - this is all we need. */ - lmo.l_addr_offset = 0; - lmo.l_addr_size = 4; - - lmo.l_name_offset = 4; - lmo.l_name_size = 4; - - lmo.l_next_offset = 12; - lmo.l_next_size = 4; - - lmo.l_prev_offset = 16; - lmo.l_prev_size = 4; - } + 6 * 4, /* %eax */ + 1 * 4, /* %ecx */ + 2 * 4, /* %edx */ + 0 * 4, /* %ebx */ + 15 * 4, /* %esp */ + 5 * 4, /* %ebp */ + 3 * 4, /* %esi */ + 4 * 4, /* %edi */ + 12 * 4, /* %eip */ + 14 * 4, /* %eflags */ + 13 * 4, /* %cs */ + 16 * 4, /* %ss */ + 7 * 4, /* %ds */ + 8 * 4, /* %es */ + 9 * 4, /* %fs */ + 10 * 4, /* %gs */ + -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, + -1, + 11 * 4 /* "orig_eax" */ +}; - return lmp; -} - +/* Mapping between the general-purpose registers in `struct + sigcontext' format and GDB's register cache layout. */ /* From . */ static int i386_linux_sc_reg_offset[] = @@ -476,20 +397,23 @@ i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) set_gdbarch_register_name (gdbarch, i386_linux_register_name); set_gdbarch_register_reggroup_p (gdbarch, i386_linux_register_reggroup_p); + tdep->gregset_reg_offset = i386_linux_gregset_reg_offset; + tdep->gregset_num_regs = ARRAY_SIZE (i386_linux_gregset_reg_offset); + tdep->sizeof_gregset = 17 * 4; + tdep->jb_pc_offset = 20; /* From . */ + tdep->sigtramp_p = i386_linux_sigtramp_p; tdep->sigcontext_addr = i386_linux_sigcontext_addr; tdep->sc_reg_offset = i386_linux_sc_reg_offset; tdep->sc_num_regs = ARRAY_SIZE (i386_linux_sc_reg_offset); - /* When the i386 Linux kernel calls a signal handler, the return - address points to a bit of code on the stack. This function is - used to identify this bit of code as a signal trampoline in order - to support backtracing through calls to signal handlers. */ - set_gdbarch_pc_in_sigtramp (gdbarch, i386_linux_pc_in_sigtramp); + /* GNU/Linux uses SVR4-style shared libraries. */ + set_solib_svr4_fetch_link_map_offsets + (gdbarch, svr4_ilp32_fetch_link_map_offsets); - set_solib_svr4_fetch_link_map_offsets (gdbarch, - i386_linux_svr4_fetch_link_map_offsets); + /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ + set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); } /* Provide a prototype to silence -Wmissing-prototypes. */