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 "runtime.h"
  16 #include "os.h"
  17 #include "sbcl.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 "genesis/code.h"
  25 #include "genesis/fdefn.h"
  26 #include "genesis/symbol.h"
  27 #include "genesis/static-symbols.h"
  28
  29 #define REAL_LRA_SLOT 0
  30 #ifndef __i386__
  31 #define KNOWN_RETURN_P_SLOT 1
  32 #define BOGUS_LRA_CONSTANTS 2
  33 #else
  34 #define KNOWN_RETURN_P_SLOT 2
  35 #define BOGUS_LRA_CONSTANTS 3
  36 #endif
  37
  38 static void *compute_pc(lispobj code_obj, int pc_offset)
  39 {
  40     struct code *code;
  41
  42     code = (struct code *)native_pointer(code_obj);
  43     return (void *)((char *)code + HeaderValue(code->header)*sizeof(lispobj)
  44                     + pc_offset);
  45 }
  46
  47 unsigned long breakpoint_install(lispobj code_obj, int pc_offset)
  48 {
  49     return arch_install_breakpoint(compute_pc(code_obj, pc_offset));
  50 }
  51
  52 void breakpoint_remove(lispobj code_obj, int pc_offset,
  53                        unsigned long orig_inst)
  54 {
  55     arch_remove_breakpoint(compute_pc(code_obj, pc_offset), orig_inst);
  56 }
  57
  58 void breakpoint_do_displaced_inst(os_context_t* context,
  59                                   unsigned long orig_inst)
  60 {
  61     /* on platforms with sigreturn(), we go directly back from
  62      * arch_do_displaced_inst() to lisp code, so we need to clean up
  63      * our bindings now.  (side note: I'd love to know in exactly what
  64      * scenario the speed of breakpoint handling is critical enough to
  65      * justify this maintenance mess)
  66      *
  67      * -dan 2001.08.09 */
  68
  69 #if (defined(sparc) && defined (solaris))
  70     undo_fake_foreign_function_call(context);
  71 #endif
  72     arch_do_displaced_inst(context, orig_inst);
  73 }
  74
  75 #ifndef __i386__
  76 static lispobj find_code(os_context_t *context)
  77 {
  78 #ifdef reg_CODE
  79     lispobj code = *os_context_register_addr(context, reg_CODE);
  80     lispobj header;
  81
  82     if (lowtag_of(code) != OTHER_POINTER_LOWTAG)
  83         return NIL;
  84
  85     header = *(lispobj *)(code-OTHER_POINTER_LOWTAG);
  86
  87     if (widetag_of(header) == CODE_HEADER_WIDETAG)
  88         return code;
  89     else
  90         return code - HeaderValue(header)*sizeof(lispobj);
  91 #else
  92     return NIL;
  93 #endif
  94 }
  95 #endif
  96
  97 #ifdef __i386__
  98 static lispobj find_code(os_context_t *context)
  99 {
 100     lispobj codeptr =
 101         (lispobj)component_ptr_from_pc((lispobj *)(*os_context_pc_addr(context)));
 102
 103     if (codeptr == 0) {
 104         return NIL;
 105     } else {
 106         return codeptr + OTHER_POINTER_LOWTAG;
 107     }
 108 }
 109 #endif
 110
 111 static int compute_offset(os_context_t *context, lispobj code)
 112 {
 113     if (code == NIL)
 114         return 0;
 115     else {
 116         unsigned long code_start;
 117         struct code *codeptr = (struct code *)native_pointer(code);
 118 #ifdef parisc
 119         unsigned long pc = *os_context_pc_addr(context) & ~3;
 120 #else
 121         unsigned long pc = *os_context_pc_addr(context);
 122 #endif
 123
 124         code_start = (unsigned long)codeptr
 125             + HeaderValue(codeptr->header)*sizeof(lispobj);
 126         if (pc < code_start)
 127             return 0;
 128         else {
 129             int offset = pc - code_start;
 130             if (offset >= codeptr->code_size)
 131                 return 0;
 132             else
 133                 return make_fixnum(offset);
 134         }
 135     }
 136 }
 137 /* FIXME: I can see no really good reason these couldn't be merged, but haven't
 138  * tried.  The sigprocmask() call would work just as well on alpha as it
 139  * presumably does on x86   -dan 2001.08.10
 140  */
 141 #ifndef __i386__
 142 void handle_breakpoint(int signal, siginfo_t *info, os_context_t *context)
 143 {
 144     lispobj code;
 145
 146     fake_foreign_function_call(context);
 147
 148     code = find_code(context);
 149
 150     funcall3(SymbolFunction(HANDLE_BREAKPOINT),
 151              compute_offset(context, code),
 152              code,
 153              alloc_sap(context));
 154
 155     undo_fake_foreign_function_call(context);
 156 }
 157 #else
 158 void handle_breakpoint(int signal, siginfo_t* info, os_context_t *context)
 159 {
 160     lispobj code, context_sap = alloc_sap(context);
 161
 162     fake_foreign_function_call(context);
 163
 164     code = find_code(context);
 165
 166     /* Don't disallow recursive breakpoint traps. Otherwise, we can't
 167      * use debugger breakpoints anywhere in here. */
 168     sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 169
 170     funcall3(SymbolFunction(HANDLE_BREAKPOINT),
 171              compute_offset(context, code),
 172              code,
 173              context_sap);
 174
 175     undo_fake_foreign_function_call(context);
 176 }
 177 #endif
 178
 179 #ifndef __i386__
 180 void *handle_fun_end_breakpoint(int signal, siginfo_t *info,
 181                                 os_context_t *context)
 182 {
 183     lispobj code, lra;
 184     struct code *codeptr;
 185
 186     fake_foreign_function_call(context);
 187
 188     code = find_code(context);
 189     codeptr = (struct code *)native_pointer(code);
 190
 191     funcall3(SymbolFunction(HANDLE_BREAKPOINT),
 192              compute_offset(context, code),
 193              code,
 194              alloc_sap(context));
 195
 196     lra = codeptr->constants[REAL_LRA_SLOT];
 197 #ifdef reg_CODE
 198     if (codeptr->constants[KNOWN_RETURN_P_SLOT] == NIL) {
 199         *os_context_register_addr(context, reg_CODE) = lra;
 200     }
 201 #endif
 202     undo_fake_foreign_function_call(context);
 203     return (void *)(lra-OTHER_POINTER_LOWTAG+sizeof(lispobj));
 204 }
 205 #else
 206 void *handle_fun_end_breakpoint(int signal, siginfo_t *info,
 207                                 os_context_t *context)
 208 {
 209     lispobj code, context_sap = alloc_sap(context);
 210     struct code *codeptr;
 211
 212     fake_foreign_function_call(context);
 213
 214     code = find_code(context);
 215     codeptr = (struct code *)native_pointer(code);
 216
 217     /* Don't disallow recursive breakpoint traps. Otherwise, we can't
 218      * use debugger breakpoints anywhere in here. */
 219     sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 220
 221     funcall3(SymbolFunction(HANDLE_BREAKPOINT),
 222              compute_offset(context, code),
 223              code,
 224              context_sap);
 225
 226     undo_fake_foreign_function_call(context);
 227
 228     return compute_pc(codeptr->constants[REAL_LRA_SLOT],
 229                       fixnum_value(codeptr->constants[REAL_LRA_SLOT+1]));
 230 }
 231 #endif