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