src/runtime/dynbind.c

   1 /*
   2  * support for dynamic binding from C
   3  * See the "Chapter 9: Specials" of the SBCL Internals Manual.
   4  */
   5
   6 /*
   7  * This software is part of the SBCL system. See the README file for
   8  * more information.
   9  *
  10  * This software is derived from the CMU CL system, which was
  11  * written at Carnegie Mellon University and released into the
  12  * public domain. The software is in the public domain and is
  13  * provided with absolutely no warranty. See the COPYING and CREDITS
  14  * files for more information.
  15  */
  16
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19
  20 #include "sbcl.h"
  21 #include "runtime.h"
  22 #include "globals.h"
  23 #include "dynbind.h"
  24 #include "thread.h"
  25 #include "interr.h"
  26 #include "genesis/symbol.h"
  27 #include "genesis/binding.h"
  28
  29 /* Specially bind SYMBOL to VALUE. In a multithreaded build, SYMBOL must already
  30    have been assigned a thread-local storage index. See *KNOWN-TLS-SYMBOLS* in
  31    compiler/generic/genesis for the symbols whose indices are pre-assigned. */
  32 void bind_variable(lispobj symbol, lispobj value, void *th)
  33 {
  34     struct binding *binding;
  35     struct thread *thread=(struct thread *)th;
  36     binding = (struct binding *)get_binding_stack_pointer(thread);
  37     set_binding_stack_pointer(thread,binding+1);
  38 #ifdef LISP_FEATURE_SB_THREAD
  39     {
  40         struct symbol *sym=(struct symbol *)native_pointer(symbol);
  41         // We could provide a c-callable static Lisp function to assign TLS
  42         // indices if anyone really needs dynamic binding of dynamic symbols.
  43         binding->symbol = tls_index_of(sym);
  44         if(!binding->symbol)
  45             lose("Oops! Static symbol missing from *KNOWN-TLS-SYMBOLS*");
  46         binding->value = SymbolTlValue(symbol, thread);
  47     }
  48 #else
  49     binding->symbol = symbol;
  50     binding->value = SymbolTlValue(symbol, thread);
  51 #endif
  52     SetTlSymbolValue(symbol, value, thread);
  53 }
  54
  55 void
  56 unbind(void *th)
  57 {
  58     struct thread *thread=(struct thread *)th;
  59     struct binding *binding;
  60     lispobj symbol;
  61
  62     binding = ((struct binding *)get_binding_stack_pointer(thread)) - 1;
  63
  64     /* On sb-thread, it's actually a tls-index */
  65     symbol = binding->symbol;
  66
  67 #ifdef LISP_FEATURE_SB_THREAD
  68
  69     ((union per_thread_data *)thread)->dynamic_values[(symbol) >> WORD_SHIFT]
  70         = binding->value;
  71 #else
  72     SetSymbolValue(symbol, binding->value, thread);
  73 #endif
  74
  75     binding->symbol = 0;
  76     binding->value = 0;
  77
  78     set_binding_stack_pointer(thread,binding);
  79 }
  80
  81 void
  82 unbind_to_here(lispobj *bsp,void *th)
  83 {
  84     struct thread *thread=(struct thread *)th;
  85     struct binding *target = (struct binding *)bsp;
  86     struct binding *binding = (struct binding *)get_binding_stack_pointer(thread);
  87     lispobj symbol;
  88
  89     while (target < binding) {
  90         binding--;
  91
  92         symbol = binding->symbol;
  93         if (symbol) {
  94             if (symbol != UNBOUND_MARKER_WIDETAG) {
  95 #ifdef LISP_FEATURE_SB_THREAD
  96                 ((union per_thread_data *)thread)->dynamic_values[(symbol) >> WORD_SHIFT]
  97                     = binding->value;
  98 #else
  99                 SetSymbolValue(symbol, binding->value, thread);
 100 #endif
 101             }
 102             binding->symbol = 0;
 103             binding->value = 0;
 104         }
 105     }
 106     set_binding_stack_pointer(thread,binding);
 107 }