src/runtime/breakpoint.c

   1 /*
   2  * This software is part of the SBCL system. See the README file for
   3  * more information.
   4  *
   5  * This software is derived from the CMU CL system, which was
   6  * written at Carnegie Mellon University and released into the
   7  * public domain. The software is in the public domain and is
   8  * provided with absolutely no warranty. See the COPYING and CREDITS
   9  * files for more information.
  10  */
  11
  12 #include <stdio.h>
  13 #include <signal.h>
  14
  15 #include "sbcl.h"
  16 #include "runtime.h"
  17 #include "os.h"
  18 #include "interrupt.h"
  19 #include "arch.h"
  20 #include "lispregs.h"
  21 #include "globals.h"
  22 #include "alloc.h"
  23 #include "breakpoint.h"
  24 #include "thread.h"
  25 #include "genesis/code.h"
  26 #include "genesis/fdefn.h"
  27
  28 #define REAL_LRA_SLOT 0
  29 #if !(defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
  30 #define KNOWN_RETURN_P_SLOT 1
  31 #define BOGUS_LRA_CONSTANTS 2
  32 #else
  33 #define KNOWN_RETURN_P_SLOT 2
  34 #define BOGUS_LRA_CONSTANTS 3
  35 #endif
  36
  37 static void *compute_pc(lispobj code_obj, int pc_offset)
  38 {
  39     struct code *code;
  40
  41     code = (struct code *)native_pointer(code_obj);
  42     return (void *)((char *)code + HeaderValue(code->header)*sizeof(lispobj)
  43                     + pc_offset);
  44 }
  45
  46 unsigned int breakpoint_install(lispobj code_obj, int pc_offset)
  47 {
  48     return arch_install_breakpoint(compute_pc(code_obj, pc_offset));
  49 }
  50
  51 void breakpoint_remove(lispobj code_obj, int pc_offset,
  52                        unsigned int orig_inst)
  53 {
  54     arch_remove_breakpoint(compute_pc(code_obj, pc_offset), orig_inst);
  55 }
  56
  57 void breakpoint_do_displaced_inst(os_context_t* context,
  58                                   unsigned int orig_inst)
  59 {
  60     /* on platforms with sigreturn(), we go directly back from
  61      * arch_do_displaced_inst() to lisp code, so we need to clean up
  62      * our bindings now.  (side note: I'd love to know in exactly what
  63      * scenario the speed of breakpoint handling is critical enough to
  64      * justify this maintenance mess)
  65      *
  66      * -dan 2001.08.09 */
  67
  68 #if (defined(LISP_FEATURE_SPARC) && defined (solaris))
  69     undo_fake_foreign_function_call(context);
  70 #endif
  71     arch_do_displaced_inst(context, orig_inst);
  72 }
  73
  74 static lispobj find_code(os_context_t *context)
  75 {
  76 #ifdef reg_CODE
  77     lispobj code = *os_context_register_addr(context, reg_CODE);
  78     lispobj header;
  79
  80     if (lowtag_of(code) != OTHER_POINTER_LOWTAG)
  81         return NIL;
  82
  83     header = *(lispobj *)(code-OTHER_POINTER_LOWTAG);
  84
  85     if (widetag_of(header) == CODE_HEADER_WIDETAG)
  86         return code;
  87     else
  88         return code - HeaderValue(header)*sizeof(lispobj);
  89 #else
  90     lispobj codeptr =
  91         (lispobj)component_ptr_from_pc((lispobj *)(*os_context_pc_addr(context)));
  92
  93     if (codeptr == 0)
  94         return NIL;
  95     else
  96         return codeptr + OTHER_POINTER_LOWTAG;
  97 #endif
  98 }
  99
 100 static long compute_offset(os_context_t *context, lispobj code)
 101 {
 102     if (code == NIL)
 103         return 0;
 104     else {
 105         unsigned long code_start;
 106         struct code *codeptr = (struct code *)native_pointer(code);
 107 #ifdef LISP_FEATURE_HPPA
 108         unsigned long pc = *os_context_pc_addr(context) & ~3;
 109 #else
 110         unsigned long pc = *os_context_pc_addr(context);
 111 #endif
 112
 113         code_start = (unsigned long)codeptr
 114             + HeaderValue(codeptr->header)*sizeof(lispobj);
 115         if (pc < code_start)
 116             return 0;
 117         else {
 118             unsigned long offset = pc - code_start;
 119             if (offset >= codeptr->code_size)
 120                 return 0;
 121             else
 122                 return make_fixnum(offset);
 123         }
 124     }
 125 }
 126
 127 void handle_breakpoint(os_context_t *context)
 128 {
 129     lispobj code, context_sap;
 130
 131     fake_foreign_function_call(context);
 132
 133     unblock_gc_signals(0, 0);
 134     context_sap = alloc_sap(context);
 135     code = find_code(context);
 136
 137 #ifndef LISP_FEATURE_WIN32
 138     /* Don't disallow recursive breakpoint traps. Otherwise, we can't
 139      * use debugger breakpoints anywhere in here. */
 140     thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 141 #endif
 142
 143     funcall3(StaticSymbolFunction(HANDLE_BREAKPOINT),
 144              compute_offset(context, code),
 145              code,
 146              context_sap);
 147
 148     undo_fake_foreign_function_call(context);
 149 }
 150
 151 void *handle_fun_end_breakpoint(os_context_t *context)
 152 {
 153     lispobj code, context_sap, lra;
 154     struct code *codeptr;
 155
 156     fake_foreign_function_call(context);
 157
 158     unblock_gc_signals(0, 0);
 159     context_sap = alloc_sap(context);
 160     code = find_code(context);
 161     codeptr = (struct code *)native_pointer(code);
 162
 163 #ifndef LISP_FEATURE_WIN32
 164     /* Don't disallow recursive breakpoint traps. Otherwise, we can't
 165      * use debugger breakpoints anywhere in here. */
 166     thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 167 #endif
 168
 169     funcall3(StaticSymbolFunction(HANDLE_BREAKPOINT),
 170              compute_offset(context, code),
 171              code,
 172              context_sap);
 173
 174     lra = codeptr->constants[REAL_LRA_SLOT];
 175
 176 #ifdef reg_CODE
 177     if (codeptr->constants[KNOWN_RETURN_P_SLOT] == NIL)
 178         *os_context_register_addr(context, reg_CODE) = lra;
 179 #endif
 180
 181     undo_fake_foreign_function_call(context);
 182
 183 #ifdef reg_LRA
 184     return (void *)(lra-OTHER_POINTER_LOWTAG+sizeof(lispobj));
 185 #else
 186     return compute_pc(lra, fixnum_value(codeptr->constants[REAL_LRA_SLOT+1]));
 187 #endif
 188 }
 189
 190 void
 191 handle_single_step_trap (os_context_t *context, int kind, int register_offset)
 192 {
 193     fake_foreign_function_call(context);
 194
 195 #ifndef LISP_FEATURE_WIN32
 196     thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 197 #endif
 198
 199     funcall2(StaticSymbolFunction(HANDLE_SINGLE_STEP_TRAP),
 200              make_fixnum(kind),
 201              make_fixnum(register_offset));
 202
 203     undo_fake_foreign_function_call(context); /* blocks signals again */
 204 }