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 #ifdef LISP_FEATURE_X86_64
  29 #define REAL_LRA_SLOT 0
  30 #define KNOWN_RETURN_P_SLOT 2
  31 #define BOGUS_LRA_CONSTANTS 3
  32 #elif defined(LISP_FEATURE_X86)
  33 #define REAL_LRA_SLOT 1
  34 #define KNOWN_RETURN_P_SLOT 3
  35 #define BOGUS_LRA_CONSTANTS 4
  36 #else
  37 #define REAL_LRA_SLOT 0
  38 #define KNOWN_RETURN_P_SLOT 1
  39 #define BOGUS_LRA_CONSTANTS 2
  40 #endif
  41
  42 static void *compute_pc(lispobj code_obj, int pc_offset)
  43 {
  44     struct code *code;
  45
  46     code = (struct code *)native_pointer(code_obj);
  47     return (void *)((char *)code + code_header_words(code->header)*sizeof(lispobj)
  48                     + pc_offset);
  49 }
  50
  51 unsigned int breakpoint_install(lispobj code_obj, int pc_offset)
  52 {
  53     return arch_install_breakpoint(compute_pc(code_obj, pc_offset));
  54 }
  55
  56 void breakpoint_remove(lispobj code_obj, int pc_offset,
  57                        unsigned int orig_inst)
  58 {
  59     arch_remove_breakpoint(compute_pc(code_obj, pc_offset), orig_inst);
  60 }
  61
  62 void breakpoint_do_displaced_inst(os_context_t* context,
  63                                   unsigned int orig_inst)
  64 {
  65     /* on platforms with sigreturn(), we go directly back from
  66      * arch_do_displaced_inst() to lisp code, so we need to clean up
  67      * our bindings now.  (side note: I'd love to know in exactly what
  68      * scenario the speed of breakpoint handling is critical enough to
  69      * justify this maintenance mess)
  70      *
  71      * -dan 2001.08.09 */
  72
  73 #if (defined(LISP_FEATURE_SPARC) && defined (solaris))
  74     undo_fake_foreign_function_call(context);
  75 #endif
  76     arch_do_displaced_inst(context, orig_inst);
  77 }
  78
  79 lispobj find_code(os_context_t *context)
  80 {
  81 #ifdef reg_CODE
  82     lispobj code = *os_context_register_addr(context, reg_CODE);
  83     lispobj header;
  84
  85     if (lowtag_of(code) != OTHER_POINTER_LOWTAG)
  86         return NIL;
  87
  88     header = *(lispobj *)(code-OTHER_POINTER_LOWTAG);
  89
  90     if (widetag_of(header) == CODE_HEADER_WIDETAG)
  91         return code;
  92     else
  93         return code - HeaderValue(header)*sizeof(lispobj);
  94 #else
  95     lispobj codeptr =
  96         (lispobj)component_ptr_from_pc((lispobj *)(*os_context_pc_addr(context)));
  97
  98     if (codeptr == 0)
  99         return NIL;
 100     else
 101         return codeptr + OTHER_POINTER_LOWTAG;
 102 #endif
 103 }
 104
 105 static long compute_offset(os_context_t *context, lispobj code)
 106 {
 107     if (code == NIL)
 108         return 0;
 109     else {
 110         uword_t code_start;
 111         struct code *codeptr = (struct code *)native_pointer(code);
 112 #ifdef LISP_FEATURE_HPPA
 113         uword_t pc = *os_context_pc_addr(context) & ~3;
 114 #else
 115         uword_t pc = *os_context_pc_addr(context);
 116 #endif
 117
 118         code_start = (uword_t)codeptr
 119             + code_header_words(codeptr->header)*sizeof(lispobj);
 120         if (pc < code_start)
 121             return 0;
 122         else {
 123             uword_t offset = pc - code_start;
 124             if (offset >= (uword_t)fixnum_value(codeptr->code_size))
 125                 return 0;
 126             else
 127                 return make_fixnum(offset);
 128         }
 129     }
 130 }
 131
 132 void handle_breakpoint(os_context_t *context)
 133 {
 134     lispobj code;
 135     DX_ALLOC_SAP(context_sap, context);
 136
 137     fake_foreign_function_call(context);
 138
 139 #ifndef LISP_FEATURE_SB_SAFEPOINT
 140     unblock_gc_signals(0, 0);
 141 #endif
 142     code = find_code(context);
 143
 144 #ifndef LISP_FEATURE_WIN32
 145     /* Don't disallow recursive breakpoint traps. Otherwise, we can't
 146      * use debugger breakpoints anywhere in here. */
 147     thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 148 #endif
 149
 150     funcall3(StaticSymbolFunction(HANDLE_BREAKPOINT),
 151              compute_offset(context, code),
 152              code,
 153              context_sap);
 154
 155     undo_fake_foreign_function_call(context);
 156 }
 157
 158 void *handle_fun_end_breakpoint(os_context_t *context)
 159 {
 160     lispobj code, lra;
 161     struct code *codeptr;
 162     DX_ALLOC_SAP(context_sap, context);
 163
 164     fake_foreign_function_call(context);
 165
 166 #ifndef LISP_FEATURE_SB_SAFEPOINT
 167     unblock_gc_signals(0, 0);
 168 #endif
 169
 170     code = find_code(context);
 171     codeptr = (struct code *)native_pointer(code);
 172
 173 #ifndef LISP_FEATURE_WIN32
 174     /* Don't disallow recursive breakpoint traps. Otherwise, we can't
 175      * use debugger breakpoints anywhere in here. */
 176     thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 177 #endif
 178
 179     funcall3(StaticSymbolFunction(HANDLE_BREAKPOINT),
 180              compute_offset(context, code),
 181              code,
 182              context_sap);
 183
 184     lra = codeptr->constants[REAL_LRA_SLOT];
 185
 186 #ifdef LISP_FEATURE_PPC
 187     /* PPC now passes LRA objects in reg_LRA during return.  Other
 188      * platforms should as well, but haven't been fixed yet. */
 189     *os_context_register_addr(context, reg_LRA) = lra;
 190 #else
 191 #ifdef reg_CODE
 192     *os_context_register_addr(context, reg_CODE) = lra;
 193 #endif
 194 #endif
 195
 196     undo_fake_foreign_function_call(context);
 197
 198 #ifdef reg_LRA
 199     return (void *)(lra-OTHER_POINTER_LOWTAG+sizeof(lispobj));
 200 #else
 201     return compute_pc(lra, fixnum_value(codeptr->constants[REAL_LRA_SLOT+1]));
 202 #endif
 203 }
 204
 205 void
 206 handle_single_step_trap (os_context_t *context, int kind, int register_offset)
 207 {
 208     fake_foreign_function_call(context);
 209
 210 #ifndef LISP_FEATURE_WIN32
 211     thread_sigmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
 212 #endif
 213
 214     funcall2(StaticSymbolFunction(HANDLE_SINGLE_STEP_TRAP),
 215              make_fixnum(kind),
 216              make_fixnum(register_offset));
 217
 218     undo_fake_foreign_function_call(context); /* blocks signals again */
 219 }