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 "genesis/symbol.h"
  26 #include "genesis/binding.h"
  27
  28 /* Specially bind SYMBOL to VALUE. In a multithreaded build, SYMBOL must already
  29    have been assigned a thread-local storage index. See *KNOWN-TLS-SYMBOLS* in
  30    compiler/generic/genesis for the symbols whose indices are pre-assigned. */
  31 void bind_variable(lispobj symbol, lispobj value, void *th)
  32 {
  33     struct binding *binding;
  34     struct thread *thread=(struct thread *)th;
  35     binding = (struct binding *)get_binding_stack_pointer(thread);
  36     set_binding_stack_pointer(thread,binding+1);
  37 #ifdef LISP_FEATURE_SB_THREAD
  38     {
  39         struct symbol *sym=(struct symbol *)native_pointer(symbol);
  40         // We could provide a c-callable static Lisp function to assign TLS
  41         // indices if anyone really needs dynamic binding of dynamic symbols.
  42         binding->symbol = tls_index_of(sym);
  43         if(!binding->symbol)
  44             lose("Oops! Static symbol missing from *KNOWN-TLS-SYMBOLS*");
  45         binding->value = SymbolTlValue(symbol, thread);
  46     }
  47 #else
  48     binding->symbol = symbol;
  49     binding->value = SymbolTlValue(symbol, thread);
  50 #endif
  51     SetTlSymbolValue(symbol, value, thread);
  52 }
  53
  54 void
  55 unbind(void *th)
  56 {
  57     struct thread *thread=(struct thread *)th;
  58     struct binding *binding;
  59     lispobj symbol;
  60
  61     binding = ((struct binding *)get_binding_stack_pointer(thread)) - 1;
  62
  63     /* On sb-thread, it's actually a tls-index */
  64     symbol = binding->symbol;
  65
  66 #ifdef LISP_FEATURE_SB_THREAD
  67
  68     ((union per_thread_data *)thread)->dynamic_values[(symbol) >> WORD_SHIFT]
  69         = binding->value;
  70 #else
  71     SetSymbolValue(symbol, binding->value, thread);
  72 #endif
  73
  74     binding->symbol = 0;
  75     binding->value = 0;
  76
  77     set_binding_stack_pointer(thread,binding);
  78 }
  79
  80 void
  81 unbind_to_here(lispobj *bsp,void *th)
  82 {
  83     struct thread *thread=(struct thread *)th;
  84     struct binding *target = (struct binding *)bsp;
  85     struct binding *binding = (struct binding *)get_binding_stack_pointer(thread);
  86     lispobj symbol;
  87
  88     while (target < binding) {
  89         binding--;
  90
  91         symbol = binding->symbol;
  92         if (symbol) {
  93             if (symbol != UNBOUND_MARKER_WIDETAG) {
  94 #ifdef LISP_FEATURE_SB_THREAD
  95                 ((union per_thread_data *)thread)->dynamic_values[(symbol) >> WORD_SHIFT]
  96                     = binding->value;
  97 #else
  98                 SetSymbolValue(symbol, binding->value, thread);
  99 #endif
 100             }
 101             binding->symbol = 0;
 102             binding->value = 0;
 103         }
 104     }
 105     set_binding_stack_pointer(thread,binding);
 106 }