1 /*****************************************************************************/
5 /* Local variable handling for the cc65 C compiler */
9 /* (C) 2000-2013, Ullrich von Bassewitz */
10 /* Roemerstrasse 52 */
11 /* D-70794 Filderstadt */
12 /* EMail: uz@cc65.org */
15 /* This software is provided 'as-is', without any expressed or implied */
16 /* warranty. In no event will the authors be held liable for any damages */
17 /* arising from the use of this software. */
19 /* Permission is granted to anyone to use this software for any purpose, */
20 /* including commercial applications, and to alter it and redistribute it */
21 /* freely, subject to the following restrictions: */
23 /* 1. The origin of this software must not be misrepresented; you must not */
24 /* claim that you wrote the original software. If you use this software */
25 /* in a product, an acknowledgment in the product documentation would be */
26 /* appreciated but is not required. */
27 /* 2. Altered source versions must be plainly marked as such, and must not */
28 /* be misrepresented as being the original software. */
29 /* 3. This notice may not be removed or altered from any source */
32 /*****************************************************************************/
59 /*****************************************************************************/
61 /*****************************************************************************/
65 static unsigned AllocLabel (void (*UseSeg) ())
66 /* Switch to a segment, define a local label and return it */
70 /* Switch to the segment */
73 /* Define the variable label */
74 Label = GetLocalLabel ();
75 g_defdatalabel (Label);
77 /* Return the label */
83 static void AllocStorage (unsigned Label, void (*UseSeg) (), unsigned Size)
84 /* Reserve Size bytes of BSS storage prefixed by a local label. */
86 /* Switch to the segment */
89 /* Define the variable label */
90 g_defdatalabel (Label);
92 /* Reserve space for the data */
98 static void ParseRegisterDecl (Declaration* Decl, int Reg)
99 /* Parse the declaration of a register variable. Reg is the offset of the
100 ** variable in the register bank.
105 /* Determine if this is a compound variable */
106 int IsCompound = IsClassStruct (Decl->Type) || IsTypeArray (Decl->Type);
108 /* Get the size of the variable */
109 unsigned Size = SizeOf (Decl->Type);
111 /* Save the current contents of the register variable on stack */
112 F_AllocLocalSpace (CurrentFunc);
113 g_save_regvars (Reg, Size);
115 /* Add the symbol to the symbol table. We do that now, because for register
116 ** variables the current stack pointer is implicitly used as location for
119 Sym = AddLocalSym (Decl->Ident, Decl->Type, Decl->StorageClass, Reg);
121 /* Check for an optional initialization */
122 if (CurTok.Tok == TOK_ASSIGN) {
129 /* Special handling for compound types */
132 /* Switch to read only data and define a label for the
133 ** initialization data.
135 unsigned InitLabel = AllocLabel (g_userodata);
137 /* Parse the initialization generating a memory image of the
138 ** data in the RODATA segment. The function does return the size
139 ** of the initialization data, which may be greater than the
140 ** actual size of the type, if the type is a structure with a
141 ** flexible array member that has been initialized. Since we must
142 ** know the size of the data in advance for register variables,
143 ** we cannot allow that here.
145 if (ParseInit (Sym->Type) != Size) {
146 Error ("Cannot initialize flexible array members of storage class `register'");
149 /* Generate code to copy this data into the variable space */
150 g_initregister (InitLabel, Reg, Size);
154 /* Parse the expression */
157 /* Convert it to the target type */
158 TypeConversion (&Expr, Sym->Type);
160 /* Load the value into the primary */
161 LoadExpr (CF_NONE, &Expr);
163 /* Store the value into the variable */
164 g_putstatic (CF_REGVAR | TypeOf (Sym->Type), Reg, 0);
168 /* Mark the variable as referenced */
169 Sym->Flags |= SC_REF;
172 /* Cannot allocate a variable of zero size */
174 Error ("Variable `%s' has unknown size", Decl->Ident);
180 static void ParseAutoDecl (Declaration* Decl)
181 /* Parse the declaration of an auto variable. */
186 /* Determine if this is a compound variable */
187 int IsCompound = IsClassStruct (Decl->Type) || IsTypeArray (Decl->Type);
189 /* Get the size of the variable */
190 unsigned Size = SizeOf (Decl->Type);
192 /* Check if this is a variable on the stack or in static memory */
193 if (IS_Get (&StaticLocals) == 0) {
195 /* Add the symbol to the symbol table. The stack offset we use here
196 ** may get corrected later.
198 Sym = AddLocalSym (Decl->Ident, Decl->Type,
200 F_GetStackPtr (CurrentFunc) - (int) Size);
202 /* Check for an optional initialization */
203 if (CurTok.Tok == TOK_ASSIGN) {
210 /* Special handling for compound types */
213 /* Switch to read only data and define a label for the
214 ** initialization data.
216 unsigned InitLabel = AllocLabel (g_userodata);
218 /* Parse the initialization generating a memory image of the
219 ** data in the RODATA segment. The function will return the
220 ** actual size of the initialization data, which may be
221 ** greater than the size of the variable if it is a struct
222 ** that contains a flexible array member and we're not in
225 Size = ParseInit (Sym->Type);
227 /* Now reserve space for the variable on the stack and correct
228 ** the offset in the symbol table entry.
230 Sym->V.Offs = F_ReserveLocalSpace (CurrentFunc, Size);
232 /* Next, allocate the space on the stack. This means that the
233 ** variable is now located at offset 0 from the current sp.
235 F_AllocLocalSpace (CurrentFunc);
237 /* Generate code to copy the initialization data into the
240 g_initauto (InitLabel, Size);
244 /* Allocate previously reserved local space */
245 F_AllocLocalSpace (CurrentFunc);
247 /* Setup the type flags for the assignment */
248 Flags = (Size == SIZEOF_CHAR)? CF_FORCECHAR : CF_NONE;
250 /* Parse the expression */
253 /* Convert it to the target type */
254 TypeConversion (&Expr, Sym->Type);
256 /* If the value is not const, load it into the primary.
257 ** Otherwise pass the information to the code generator.
259 if (ED_IsConstAbsInt (&Expr)) {
262 LoadExpr (CF_NONE, &Expr);
267 g_push (Flags | TypeOf (Sym->Type), Expr.IVal);
271 /* Mark the variable as referenced */
272 Sym->Flags |= SC_REF;
274 /* Make note of auto variables initialized in current block.
275 We abuse the Collection somewhat by using it to store line
277 CollReplace (&CurrentFunc->LocalsBlockStack, (void *)(long)GetCurrentLine (),
278 CollCount (&CurrentFunc->LocalsBlockStack) - 1);
281 /* Non-initialized local variable. Just keep track of
284 F_ReserveLocalSpace (CurrentFunc, Size);
292 /* Static local variables. */
293 Decl->StorageClass = (Decl->StorageClass & ~SC_AUTO) | SC_STATIC;
295 /* Generate a label, but don't define it */
296 DataLabel = GetLocalLabel ();
298 /* Add the symbol to the symbol table. */
299 Sym = AddLocalSym (Decl->Ident, Decl->Type, Decl->StorageClass, DataLabel);
301 /* Allow assignments */
302 if (CurTok.Tok == TOK_ASSIGN) {
311 /* Switch to read only data and define a label for the
312 ** initialization data.
314 unsigned InitLabel = AllocLabel (g_userodata);
316 /* Parse the initialization generating a memory image of the
317 ** data in the RODATA segment.
319 Size = ParseInit (Sym->Type);
321 /* Allocate space for the variable */
322 AllocStorage (DataLabel, g_usebss, Size);
324 /* Generate code to copy this data into the variable space */
325 g_initstatic (InitLabel, DataLabel, Size);
329 /* Allocate space for the variable */
330 AllocStorage (DataLabel, g_usebss, Size);
332 /* Parse the expression */
335 /* Convert it to the target type */
336 TypeConversion (&Expr, Sym->Type);
338 /* Load the value into the primary */
339 LoadExpr (CF_NONE, &Expr);
341 /* Store the value into the variable */
342 g_putstatic (TypeOf (Sym->Type), DataLabel, 0);
345 /* Mark the variable as referenced */
346 Sym->Flags |= SC_REF;
350 /* No assignment - allocate a label and space for the variable */
351 AllocStorage (DataLabel, g_usebss, Size);
356 /* Cannot allocate a variable of zero size */
358 Error ("Variable `%s' has unknown size", Decl->Ident);
364 static void ParseStaticDecl (Declaration* Decl)
365 /* Parse the declaration of a static variable. */
369 /* Generate a label, but don't define it */
370 unsigned DataLabel = GetLocalLabel ();
372 /* Add the symbol to the symbol table. */
373 SymEntry* Sym = AddLocalSym (Decl->Ident, Decl->Type,
378 if (CurTok.Tok == TOK_ASSIGN) {
380 /* Initialization ahead, switch to data segment and define the label.
381 ** For arrays, we need to check the elements of the array for
382 ** constness, not the array itself.
384 if (IsQualConst (GetBaseElementType (Sym->Type))) {
389 g_defdatalabel (DataLabel);
394 /* Allow initialization of static vars */
395 Size = ParseInit (Sym->Type);
397 /* Mark the variable as referenced */
398 Sym->Flags |= SC_REF;
402 /* Get the size of the variable */
403 Size = SizeOf (Decl->Type);
405 /* Allocate a label and space for the variable in the BSS segment */
406 AllocStorage (DataLabel, g_usebss, Size);
410 /* Cannot allocate a variable of zero size */
412 Error ("Variable `%s' has unknown size", Decl->Ident);
418 static void ParseOneDecl (const DeclSpec* Spec)
419 /* Parse one variable declaration */
421 Declaration Decl; /* Declaration data structure */
424 /* Read the declaration */
425 ParseDecl (Spec, &Decl, DM_NEED_IDENT);
427 /* Set the correct storage class for functions */
428 if ((Decl.StorageClass & SC_FUNC) == SC_FUNC) {
429 /* Function prototypes are always external */
430 if ((Decl.StorageClass & SC_EXTERN) == 0) {
431 Warning ("Function must be extern");
433 Decl.StorageClass |= SC_EXTERN;
436 /* If we don't have a name, this was flagged as an error earlier.
437 ** To avoid problems later, use an anonymous name here.
439 if (Decl.Ident[0] == '\0') {
440 AnonName (Decl.Ident, "param");
443 /* If the symbol is not marked as external, it will be defined now */
444 if ((Decl.StorageClass & SC_EXTERN) == 0) {
445 Decl.StorageClass |= SC_DEF;
448 /* Handle anything that needs storage (no functions, no typdefs) */
449 if ((Decl.StorageClass & SC_FUNC) != SC_FUNC &&
450 (Decl.StorageClass & SC_TYPEMASK) != SC_TYPEDEF) {
452 /* If we have a register variable, try to allocate a register and
453 ** convert the declaration to "auto" if this is not possible.
455 int Reg = 0; /* Initialize to avoid gcc complains */
456 if ((Decl.StorageClass & SC_REGISTER) != 0 &&
457 (Reg = F_AllocRegVar (CurrentFunc, Decl.Type)) < 0) {
458 /* No space for this register variable, convert to auto */
459 Decl.StorageClass = (Decl.StorageClass & ~SC_REGISTER) | SC_AUTO;
462 /* Check the variable type */
463 if ((Decl.StorageClass & SC_REGISTER) == SC_REGISTER) {
464 /* Register variable */
465 ParseRegisterDecl (&Decl, Reg);
466 } else if ((Decl.StorageClass & SC_AUTO) == SC_AUTO) {
468 ParseAutoDecl (&Decl);
469 } else if ((Decl.StorageClass & SC_EXTERN) == SC_EXTERN) {
470 /* External identifier - may not get initialized */
471 if (CurTok.Tok == TOK_ASSIGN) {
472 Error ("Cannot initialize externals");
474 /* Add the external symbol to the symbol table */
475 AddLocalSym (Decl.Ident, Decl.Type, Decl.StorageClass, 0);
476 } else if ((Decl.StorageClass & SC_STATIC) == SC_STATIC) {
477 /* Static variable */
478 ParseStaticDecl (&Decl);
480 Internal ("Invalid storage class in ParseOneDecl: %04X", Decl.StorageClass);
485 /* Add the symbol to the symbol table */
486 AddLocalSym (Decl.Ident, Decl.Type, Decl.StorageClass, 0);
493 void DeclareLocals (void)
494 /* Declare local variables and types. */
496 /* Remember the current stack pointer */
497 int InitialStack = StackPtr;
499 /* A place to store info about potential initializations of auto variables */
500 CollAppend (&CurrentFunc->LocalsBlockStack, 0);
502 /* Loop until we don't find any more variables */
505 /* Check variable declarations. We need to distinguish between a
506 ** default int type and the end of variable declarations. So we
507 ** will do the following: If there is no explicit storage class
508 ** specifier *and* no explicit type given, *and* no type qualifiers
509 ** have been read, it is assumed that we have reached the end of
513 ParseDeclSpec (&Spec, SC_AUTO, T_INT);
514 if ((Spec.Flags & DS_DEF_STORAGE) != 0 && /* No storage spec */
515 (Spec.Flags & DS_DEF_TYPE) != 0 && /* No type given */
516 GetQualifier (Spec.Type) == T_QUAL_NONE) { /* No type qualifier */
520 /* Accept type only declarations */
521 if (CurTok.Tok == TOK_SEMI) {
522 /* Type declaration only */
523 CheckEmptyDecl (&Spec);
528 /* Parse a comma separated variable list */
531 /* Parse one declaration */
532 ParseOneDecl (&Spec);
534 /* Check if there is more */
535 if (CurTok.Tok == TOK_COMMA) {
544 /* A semicolon must follow */
548 /* Be sure to allocate any reserved space for locals */
549 F_AllocLocalSpace (CurrentFunc);
551 /* No auto variables were inited. No new block on the stack then. */
552 if (CollLast (&CurrentFunc->LocalsBlockStack) == NULL) {
553 CollPop (&CurrentFunc->LocalsBlockStack);
556 /* In case we've allocated local variables in this block, emit a call to
557 ** the stack checking routine if stack checks are enabled.
559 if (IS_Get (&CheckStack) && InitialStack != StackPtr) {