win32: handle __declspec(dllimport)

i386-gen.c

@@ -184,6 +184,32 @@ static void gen_modrm(int op_reg, int r, Sym *sym, int c)
     }
 }
 
+#ifdef TCC_TARGET_PE
+static void mk_pointer(CType *type);
+static void indir(void);
+
+int handle_dllimport(int r, SValue *sv, void (*fn)(int r, SValue *sv))
+{
+    if ((sv->r & (VT_VALMASK|VT_SYM|VT_CONST)) != (VT_SYM|VT_CONST))
+        return 0;
+    if (0 == (sv->sym->type.t & VT_IMPORT))
+        return 0;
+
+    printf("import %d %04x %s\n", r, ind, get_tok_str(sv->sym->v, NULL));
+
+    sv->sym->type.t &= ~VT_IMPORT;
+    ++vtop;
+
+    *vtop = *sv;
+    mk_pointer(&vtop->type);
+    indir();
+    fn(r, vtop);
+
+    --vtop;
+    sv->sym->type.t |= VT_IMPORT;
+    return 1;
+}
+#endif
 
 /* load 'r' from value 'sv' */
 void load(int r, SValue *sv)
@@ -191,6 +217,10 @@ void load(int r, SValue *sv)
     int v, t, ft, fc, fr;
     SValue v1;
 
+#ifdef TCC_TARGET_PE
+    if (handle_dllimport(r, sv, load))
+        return;
+#endif
     fr = sv->r;
     ft = sv->type.t;
     fc = sv->c.ul;
@@ -255,6 +285,10 @@ void store(int r, SValue *v)
 {
     int fr, bt, ft, fc;
 
+#ifdef TCC_TARGET_PE
+    if (handle_dllimport(r, v, store))
+        return;
+#endif
     ft = v->type.t;
     fc = v->c.ul;
     fr = v->r & VT_VALMASK;

tcc.h

@@ -276,11 +276,13 @@ typedef struct {
     unsigned
       func_call : 8,
       func_args : 8,
-      func_export : 1;
+      func_export : 1,
+      func_import : 1;
 } func_attr_t;
 
 #define FUNC_CALL(r) (((func_attr_t*)&(r))->func_call)
 #define FUNC_EXPORT(r) (((func_attr_t*)&(r))->func_export)
+#define FUNC_IMPORT(r) (((func_attr_t*)&(r))->func_import)
 #define FUNC_ARGS(r) (((func_attr_t*)&(r))->func_args)
 /* -------------------------------------------------- */
 
@@ -570,11 +572,12 @@ struct TCCState {
 #define VT_STATIC  0x00000100  /* static variable */
 #define VT_TYPEDEF 0x00000200  /* typedef definition */
 #define VT_INLINE  0x00000400  /* inline definition */
+#define VT_IMPORT  0x00004000  /* win32: extern data imported from dll */
 
 #define VT_STRUCT_SHIFT 16   /* shift for bitfield shift values */
 
 /* type mask (except storage) */
-#define VT_STORAGE (VT_EXTERN | VT_STATIC | VT_TYPEDEF | VT_INLINE)
+#define VT_STORAGE (VT_EXTERN | VT_STATIC | VT_TYPEDEF | VT_INLINE | VT_IMPORT)
 #define VT_TYPE    (~(VT_STORAGE))
 
 /* token values */

tccgen.c

@@ -1100,8 +1100,9 @@ void gen_opic(int op)
             }
             goto general_case;
         } else if (c2 && (op == '+' || op == '-') &&
-                   ((vtop[-1].r & (VT_VALMASK | VT_LVAL | VT_SYM)) ==
-                   (VT_CONST | VT_SYM) ||
+                   (((vtop[-1].r & (VT_VALMASK | VT_LVAL | VT_SYM)) == (VT_CONST | VT_SYM)
+                    && !(vtop[-1].sym->type.t & VT_IMPORT))
+                   ||
                    (vtop[-1].r & (VT_VALMASK | VT_LVAL)) == VT_LOCAL)) {
             /* symbol + constant case */
             if (op == '-')
@@ -2257,6 +2258,9 @@ static void parse_attribute(AttributeDef *ad)
         case TOK_DLLEXPORT:
             FUNC_EXPORT(ad->func_attr) = 1;
             break;
+        case TOK_DLLIMPORT:
+            FUNC_IMPORT(ad->func_attr) = 1;
+            break;
         default:
             if (tcc_state->warn_unsupported)
                 warning("'%s' attribute ignored", get_tok_str(t, NULL));
@@ -5131,6 +5135,10 @@ static void decl(int l)
                         /* NOTE: as GCC, uninitialized global static
                            arrays of null size are considered as
                            extern */
+#ifdef TCC_TARGET_PE
+                        if (FUNC_IMPORT(ad.func_attr))
+                            type.t |= VT_IMPORT;
+#endif
                         external_sym(v, &type, r);
                     } else {
                         type.t |= (btype.t & VT_STATIC); /* Retain "static". */

tcctok.h

@@ -105,6 +105,7 @@
      DEF(TOK_FASTCALL2, "__fastcall")
      DEF(TOK_FASTCALL3, "__fastcall__")
      DEF(TOK_DLLEXPORT, "dllexport")
+     DEF(TOK_DLLIMPORT, "dllimport")
      DEF(TOK_NORETURN1, "noreturn")
      DEF(TOK_NORETURN2, "__noreturn__")
      DEF(TOK_builtin_types_compatible_p, "__builtin_types_compatible_p")