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 "thread.h"
  25 #include "genesis/code.h"
  26 #include "genesis/fdefn.h"
  27
  28 #define REAL_LRA_SLOT 0
  29 #ifndef __i386__
  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 long 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 long 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 long 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(sparc) && defined (solaris))
  69     undo_fake_foreign_function_call(context);
  70 #endif
  71     arch_do_displaced_inst(context, orig_inst);
  72 }
  73
  74 #ifndef __i386__
  75 static lispobj find_code(os_context_t *context)
  76 {
  77 #ifdef reg_CODE
  78     lispobj code = *os_context_register_addr(context, reg_CODE);
  79     lispobj header;
  80
  81     if (lowtag_of(code) != OTHER_POINTER_LOWTAG)
  82         return NIL;
  83
  84     header = *(lispobj *)(code-OTHER_POINTER_LOWTAG);
  85
  86     if (widetag_of(header) == CODE_HEADER_WIDETAG)
  87         return code;
  88     else
  89         return code - HeaderValue(header)*sizeof(lispobj);
  90 #else
  91     return NIL;
  92 #endif
  93 }
  94 #endif
  95
  96 #ifdef __i386__
  97 static lispobj find_code(os_context_t *context)
  98 {
  99     lispobj codeptr =
 100         (lispobj)component_ptr_from_pc((lispobj *)(*os_context_pc_addr(context)));
 101
 102     if (codeptr == 0) {
 103         return NIL;
 104     } else {
 105         return codeptr + OTHER_POINTER_LOWTAG;
 106     }
 107 }
 108 #endif
 109
 110 static int compute_offset(os_context_t *context, lispobj code)
 111 {
 112     if (code == NIL)
 113         return 0;
 114     else {
 115         unsigned long code_start;
 116         struct code *codeptr = (struct code *)native_pointer(code);
 117 #ifdef parisc
 118         unsigned long pc = *os_context_pc_addr(context) & ~3;
 119 #else
 120         unsigned long pc = *os_context_pc_addr(context);
 121 #endif
 122
 123         code_start = (unsigned long)codeptr
 124             + HeaderValue(codeptr->header)*sizeof(lispobj);
 125         if (pc < code_start)
 126             return 0;
 127         else {
 128             int offset = pc - code_start;
 129             if (offset >= codeptr->code_size)
 130                 return 0;
 131             else
 132                 return make_fixnum(offset);
 133         }
 134     }
 135 }
 136 /* FIXME: I can see no really good reason these couldn't be merged, but haven't
 137  * tried.  The sigprocmask() call would work just as well on alpha as it
 138  * presumably does on x86   -dan 2001.08.10
 139  */
 140 #ifndef __i386__
 141 void handle_breakpoint(int signal, siginfo_t *info, os_context_t *context)
 142 {
 143     lispobj code;
 144
 145     fake_foreign_function_call(context);
 146
 147     code = find_code(context);
 148
 149     funcall3(SymbolFunction(HANDLE_BREAKPOINT),
 150              compute_offset(context, code),
 151              code,
 152              alloc_sap(context));
 153
 154     undo_fake_foreign_function_call(context);
 155 }
 156 #else
 157 void handle_breakpoint(int signal, siginfo_t* info, os_context_t *context)
 158 {
 159     lispobj code, context_sap = alloc_sap(context);
 160
 161     fake_foreign_function_call(context);
 162
 163     code = find_code(context);
 164
 165     /* Don't disallow recursive breakpoint traps. Otherwise, we can't
 166      * use debugger breakpoints anywhere in here. */
 167     sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 168
 169     funcall3(SymbolFunction(HANDLE_BREAKPOINT),
 170              compute_offset(context, code),
 171              code,
 172              context_sap);
 173
 174     undo_fake_foreign_function_call(context);
 175 }
 176 #endif
 177
 178 #ifndef __i386__
 179 void *handle_fun_end_breakpoint(int signal, siginfo_t *info,
 180                                 os_context_t *context)
 181 {
 182     lispobj code, lra;
 183     struct code *codeptr;
 184
 185     fake_foreign_function_call(context);
 186
 187     code = find_code(context);
 188     codeptr = (struct code *)native_pointer(code);
 189
 190     funcall3(SymbolFunction(HANDLE_BREAKPOINT),
 191              compute_offset(context, code),
 192              code,
 193              alloc_sap(context));
 194
 195     lra = codeptr->constants[REAL_LRA_SLOT];
 196 #ifdef reg_CODE
 197     if (codeptr->constants[KNOWN_RETURN_P_SLOT] == NIL) {
 198         *os_context_register_addr(context, reg_CODE) = lra;
 199     }
 200 #endif
 201     undo_fake_foreign_function_call(context);
 202     return (void *)(lra-OTHER_POINTER_LOWTAG+sizeof(lispobj));
 203 }
 204 #else
 205 void *handle_fun_end_breakpoint(int signal, siginfo_t *info,
 206                                 os_context_t *context)
 207 {
 208     lispobj code, context_sap = alloc_sap(context);
 209     struct code *codeptr;
 210
 211     fake_foreign_function_call(context);
 212
 213     code = find_code(context);
 214     codeptr = (struct code *)native_pointer(code);
 215
 216     /* Don't disallow recursive breakpoint traps. Otherwise, we can't
 217      * use debugger breakpoints anywhere in here. */
 218     sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 219
 220     funcall3(SymbolFunction(HANDLE_BREAKPOINT),
 221              compute_offset(context, code),
 222              code,
 223              context_sap);
 224
 225     undo_fake_foreign_function_call(context);
 226
 227     return compute_pc(codeptr->constants[REAL_LRA_SLOT],
 228                       fixnum_value(codeptr->constants[REAL_LRA_SLOT+1]));
 229 }
 230 #endif