Fix x86-64 GNU/Linux crashes
Ref: https://sourceware.org/ml/gdb-patches/2017-07/msg00162.html Debugging x86-64 GNU/Linux programs currently crashes GDB in tdesc_use_registers during gdbarch initialization: Program received signal SIGSEGV, Segmentation fault. 0x0000000001093eaf in htab_remove_elt_with_hash (htab=0x2ef9fa0, element=0x26af960, hash=557151073) at src/libiberty/hashtab.c:728 728 if (*slot == HTAB_EMPTY_ENTRY) (top-gdb) p slot $1 = (void **) 0x0 (top-gdb) bt #0 0x0000000001093eaf in htab_remove_elt_with_hash (htab=0x2ef9fa0, element=0x26af960, hash=557151073) at src/libiberty/hashtab.c:728 #1 0x0000000001093e79 in htab_remove_elt (htab=0x2ef9fa0, element=0x26af960) at src/libiberty/hashtab.c:714 #2 0x00000000009121b0 in tdesc_use_registers (gdbarch=0x3001240, target_desc=0x2659cb0, early_data=0x2881cb0) at src/gdb/target-descriptions.c:1328 #3 0x000000000047c93e in i386_gdbarch_init (info=..., arches=0x0) at src/gdb/i386-tdep.c:8634 #4 0x0000000000818d5f in gdbarch_find_by_info (info=...) at src/gdb/gdbarch.c:5394 #5 0x00000000007198a8 in set_gdbarch_from_file (abfd=0x2f48250) at src/gdb/arch-utils.c:618 #6 0x00000000007f21cb in exec_file_attach (filename=0x7fffffffddb0 "/home/pedro/gdb/tests/threads", from_tty=1) at src/gdb/exec.c:380 #7 0x0000000000865c18 in catch_command_errors_const (command=0x7f1d83 <exec_file_attach(char const*, int)>, arg=0x7fffffffddb0 "/home/pedro/gdb/tests/threads", from_tty=1) at src/gdb/main.c:403 #8 0x00000000008669cf in captured_main_1 (context=0x7fffffffd860) at src/gdb/main.c:1035 #9 0x0000000000866de2 in captured_main (data=0x7fffffffd860) at src/gdb/main.c:1142 #10 0x0000000000866e24 in gdb_main (args=0x7fffffffd860) at src/gdb/main.c:1160 #11 0x000000000041312d in main (argc=3, argv=0x7fffffffd968) at src/gdb/gdb.c:32 The direct cause of the crash is that we tried to remove an element from the hash which supposedly exists, but does not. (htab_remove_elt shouldn't really crash in this case, but that's secondary.) The real problem is that early_data passed to tdesc_use_registers includes regs from a target description that is not the target_desc, which violates its assumptions. The registers in question are the fs_base/gs_base registers, added by amd64_init_abi: tdesc_numbered_register (feature, tdesc_data_segments, AMD64_FSBASE_REGNUM, "fs_base"); tdesc_numbered_register (feature, tdesc_data_segments, AMD64_GSBASE_REGNUM, "gs_base"); and that happens because amd64_linux_init_abi uses amd64_init_abi as helper, but they don't coordinate on which fallback tdesc to use. amd64_init_abi does: if (! tdesc_has_registers (tdesc)) tdesc = tdesc_amd64; and then adds the fs_base/gs_base registers of the "tdesc_amd64" tdesc to the tdesc_arch_data. After amd64_init_abi returns, amd64_linux_init_abi does: if (! tdesc_has_registers (tdesc)) tdesc = tdesc_amd64_linux; tdep->tdesc = tdesc; and we end up tdesc_amd64_linux installed in tdep->tdesc. The fix is to make sure that amd64_linux_init_abi and amd64_init_abi agree on default tdesc, by adding a "default tdesc" parameter to amd64_init_abi, instead of having amd64_init_abi hardcode a default. With this, amd64_init_abi creates the fs_base/gs_base registers using the tdesc_amd64_linux tdesc. Tested on x86-64 GNU/Linux, -m64. I don't have an x32 setup handy. Thanks to John Baldwin, Yao Qi and Simon Marchi for the investigation. gdb/ChangeLog: 2017-07-13 Pedro Alves <palves@redhat.com> * amd64-darwin-tdep.c (x86_darwin_init_abi_64): Pass tdesc_amd64 as default tdesc. * amd64-dicos-tdep.c (amd64_dicos_init_abi): * amd64-fbsd-tdep.c (amd64fbsd_init_abi): * amd64-linux-tdep.c (amd64_linux_init_abi): Pass tdesc_amd64_linux as default tdesc. Get final tdesc from the tdep. (amd64_x32_linux_init_abi): Pass tdesc_x32_linux as default tdesc. Get final tdesc from the tdep. * amd64-nbsd-tdep.c (amd64nbsd_init_abi): Pass tdesc_amd64 as default tdesc. * amd64-obsd-tdep.c (amd64obsd_init_abi): Likewise. * amd64-sol2-tdep.c (amd64_sol2_init_abi): Likewise. * amd64-tdep.c (amd64_init_abi): Add 'default_tdesc' parameter. Use it as default tdesc. (amd64_x32_init_abi): Add 'default_tdesc' parameter, and pass it down to amd_init_abi. No longer handle fallback tdesc here. * amd64-tdep.h (tdesc_x32): Declare. (amd64_init_abi, amd64_x32_init_abi): Add 'default_tdesc' parameter. * amd64-windows-tdep.c (amd64_windows_init_abi): Pass tdesc_amd64 as default tdesc.
This commit is contained in:
Pedro Alves
parent
5d2cbaa526
commit
c55a47e723
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@ -1,3 +1,28 @@
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2017-07-13 Pedro Alves <palves@redhat.com>
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* amd64-darwin-tdep.c (x86_darwin_init_abi_64): Pass tdesc_amd64
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as default tdesc.
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* amd64-dicos-tdep.c (amd64_dicos_init_abi):
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* amd64-fbsd-tdep.c (amd64fbsd_init_abi):
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* amd64-linux-tdep.c (amd64_linux_init_abi): Pass
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tdesc_amd64_linux as default tdesc. Get final tdesc from the
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tdep.
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(amd64_x32_linux_init_abi): Pass tdesc_x32_linux as default tdesc.
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Get final tdesc from the tdep.
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* amd64-nbsd-tdep.c (amd64nbsd_init_abi): Pass tdesc_amd64 as
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default tdesc.
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* amd64-obsd-tdep.c (amd64obsd_init_abi): Likewise.
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* amd64-sol2-tdep.c (amd64_sol2_init_abi): Likewise.
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* amd64-tdep.c (amd64_init_abi): Add 'default_tdesc' parameter.
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Use it as default tdesc.
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(amd64_x32_init_abi): Add 'default_tdesc' parameter, and pass it
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down to amd_init_abi. No longer handle fallback tdesc here.
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* amd64-tdep.h (tdesc_x32): Declare.
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(amd64_init_abi, amd64_x32_init_abi): Add 'default_tdesc'
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parameter.
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* amd64-windows-tdep.c (amd64_windows_init_abi): Pass tdesc_amd64
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as default tdesc.
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2017-07-13 Andreas Arnez <arnez@linux.vnet.ibm.com>
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* s390-linux-tdep.c (s390_process_record): Add support for
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@ -99,7 +99,7 @@ x86_darwin_init_abi_64 (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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amd64_init_abi (info, gdbarch);
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amd64_init_abi (info, gdbarch, tdesc_amd64);
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tdep->struct_return = reg_struct_return;
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@ -25,7 +25,7 @@
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static void
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amd64_dicos_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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amd64_init_abi (info, gdbarch);
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amd64_init_abi (info, gdbarch, tdesc_amd64);
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dicos_init_abi (gdbarch);
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}
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@ -217,7 +217,7 @@ amd64fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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tdep->gregset_num_regs = ARRAY_SIZE (amd64fbsd_r_reg_offset);
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tdep->sizeof_gregset = 22 * 8;
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amd64_init_abi (info, gdbarch);
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amd64_init_abi (info, gdbarch, tdesc_amd64);
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tdep->sigtramp_p = amd64fbsd_sigtramp_p;
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tdep->sigtramp_start = amd64fbsd_sigtramp_start_addr;
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@ -1863,7 +1863,6 @@ static void
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amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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const struct target_desc *tdesc = info.target_desc;
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struct tdesc_arch_data *tdesc_data
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= (struct tdesc_arch_data *) info.tdep_info;
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const struct tdesc_feature *feature;
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@ -1875,15 +1874,13 @@ amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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tdep->gregset_num_regs = ARRAY_SIZE (amd64_linux_gregset_reg_offset);
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tdep->sizeof_gregset = 27 * 8;
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amd64_init_abi (info, gdbarch);
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amd64_init_abi (info, gdbarch, tdesc_amd64_linux);
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const target_desc *tdesc = tdep->tdesc;
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/* Reserve a number for orig_rax. */
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set_gdbarch_num_regs (gdbarch, AMD64_LINUX_NUM_REGS);
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if (! tdesc_has_registers (tdesc))
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tdesc = tdesc_amd64_linux;
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tdep->tdesc = tdesc;
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feature = tdesc_find_feature (tdesc, "org.gnu.gdb.i386.linux");
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if (feature == NULL)
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return;
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@ -2080,7 +2077,6 @@ static void
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amd64_x32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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const struct target_desc *tdesc = info.target_desc;
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struct tdesc_arch_data *tdesc_data
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= (struct tdesc_arch_data *) info.tdep_info;
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const struct tdesc_feature *feature;
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@ -2092,14 +2088,12 @@ amd64_x32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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tdep->gregset_num_regs = ARRAY_SIZE (amd64_linux_gregset_reg_offset);
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tdep->sizeof_gregset = 27 * 8;
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amd64_x32_init_abi (info, gdbarch);
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amd64_x32_init_abi (info, gdbarch, tdesc_x32_linux);
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/* Reserve a number for orig_rax. */
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set_gdbarch_num_regs (gdbarch, AMD64_LINUX_NUM_REGS);
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if (! tdesc_has_registers (tdesc))
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tdesc = tdesc_x32_linux;
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tdep->tdesc = tdesc;
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const target_desc *tdesc = tdep->tdesc;
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feature = tdesc_find_feature (tdesc, "org.gnu.gdb.i386.linux");
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if (feature == NULL)
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@ -103,7 +103,7 @@ amd64nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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tdep->gregset_num_regs = ARRAY_SIZE (amd64nbsd_r_reg_offset);
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tdep->sizeof_gregset = 26 * 8;
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amd64_init_abi (info, gdbarch);
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amd64_init_abi (info, gdbarch, tdesc_amd64);
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tdep->jb_pc_offset = 7 * 8;
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@ -419,7 +419,7 @@ amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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amd64_init_abi (info, gdbarch);
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amd64_init_abi (info, gdbarch, tdesc_amd64);
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obsd_init_abi (info, gdbarch);
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/* Initialize general-purpose register set details. */
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@ -99,7 +99,7 @@ amd64_sol2_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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tdep->gregset_num_regs = ARRAY_SIZE (amd64_sol2_gregset_reg_offset);
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tdep->sizeof_gregset = 28 * 8;
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amd64_init_abi (info, gdbarch);
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amd64_init_abi (info, gdbarch, tdesc_amd64);
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tdep->sigtramp_p = amd64_sol2_sigtramp_p;
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tdep->sigcontext_addr = amd64_sol2_mcontext_addr;
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@ -3005,7 +3005,8 @@ static const int amd64_record_regmap[] =
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};
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void
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amd64_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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amd64_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch,
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target_desc *default_tdesc)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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const struct target_desc *tdesc = info.target_desc;
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@ -3022,7 +3023,7 @@ amd64_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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tdep->fpregset = &amd64_fpregset;
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if (! tdesc_has_registers (tdesc))
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tdesc = tdesc_amd64;
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tdesc = default_tdesc;
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tdep->tdesc = tdesc;
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tdep->num_core_regs = AMD64_NUM_GREGS + I387_NUM_REGS;
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@ -3196,16 +3197,12 @@ amd64_x32_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
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}
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void
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amd64_x32_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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amd64_x32_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch,
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target_desc *default_tdesc)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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const struct target_desc *tdesc = info.target_desc;
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amd64_init_abi (info, gdbarch);
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if (! tdesc_has_registers (tdesc))
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tdesc = tdesc_x32;
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tdep->tdesc = tdesc;
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amd64_init_abi (info, gdbarch, default_tdesc);
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tdep->num_dword_regs = 17;
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set_tdesc_pseudo_register_type (gdbarch, amd64_x32_pseudo_register_type);
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@ -88,6 +88,7 @@ enum amd64_regnum
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#define AMD64_NUM_REGS (AMD64_GSBASE_REGNUM + 1)
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extern struct target_desc *tdesc_amd64;
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extern struct target_desc *tdesc_x32;
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extern struct displaced_step_closure *amd64_displaced_step_copy_insn
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(struct gdbarch *gdbarch, CORE_ADDR from, CORE_ADDR to,
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@ -97,9 +98,17 @@ extern void amd64_displaced_step_fixup (struct gdbarch *gdbarch,
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CORE_ADDR from, CORE_ADDR to,
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struct regcache *regs);
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extern void amd64_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch);
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/* Initialize the ABI for amd64. Uses DEFAULT_TDESC as fallback
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tdesc, if INFO does not specify one. */
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extern void amd64_init_abi (struct gdbarch_info info,
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struct gdbarch *gdbarch,
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target_desc *default_tdesc);
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/* Initialize the ABI for x32. Uses DEFAULT_TDESC as fallback tdesc,
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if INFO does not specify one. */
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extern void amd64_x32_init_abi (struct gdbarch_info info,
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struct gdbarch *gdbarch);
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struct gdbarch *gdbarch,
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target_desc *default_tdesc);
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extern const struct target_desc *amd64_target_description (uint64_t xcr0);
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/* Fill register REGNUM in REGCACHE with the appropriate
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@ -1224,7 +1224,7 @@ amd64_windows_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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*/
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frame_unwind_append_unwinder (gdbarch, &amd64_windows_frame_unwind);
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amd64_init_abi (info, gdbarch);
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amd64_init_abi (info, gdbarch, tdesc_amd64);
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windows_init_abi (info, gdbarch);
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