/*****************************************************************************/
/* */
-/* function.c */
+/* function.c */
/* */
-/* Parse function entry/body/exit */
+/* Parse function entry/body/exit */
/* */
/* */
/* */
-/* (C) 2000-2002 Ullrich von Bassewitz */
-/* Wacholderweg 14 */
-/* D-70597 Stuttgart */
-/* EMail: uz@cc65.org */
+/* (C) 2000-2012, Ullrich von Bassewitz */
+/* Roemerstrasse 52 */
+/* D-70794 Filderstadt */
+/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
#include "litpool.h"
#include "locals.h"
#include "scanner.h"
-#include "segments.h"
+#include "stackptr.h"
+#include "standard.h"
#include "stmt.h"
#include "symtab.h"
#include "function.h"
/*****************************************************************************/
-/* Data */
+/* Data */
/*****************************************************************************/
-/* Maximum register variable size */
-#define MAX_REG_SPACE 6
+/* Enumeration for function flags */
+typedef enum {
+ FF_NONE = 0x0000,
+ FF_HAS_RETURN = 0x0001, /* Function has a return statement */
+ FF_IS_MAIN = 0x0002, /* This is the main function */
+ FF_VOID_RETURN = 0x0004, /* Function returning void */
+} funcflags_t;
/* Structure that holds all data needed for function activation */
struct Function {
- struct SymEntry* FuncEntry; /* Symbol table entry */
- type* ReturnType; /* Function return type */
- struct FuncDesc* Desc; /* Function descriptor */
- int Reserved; /* Reserved local space */
- unsigned RetLab; /* Return code label */
- int TopLevelSP; /* SP at function top level */
+ struct SymEntry* FuncEntry; /* Symbol table entry */
+ Type* ReturnType; /* Function return type */
+ FuncDesc* Desc; /* Function descriptor */
+ int Reserved; /* Reserved local space */
+ unsigned RetLab; /* Return code label */
+ int TopLevelSP; /* SP at function top level */
unsigned RegOffs; /* Register variable space offset */
+ funcflags_t Flags; /* Function flags */
};
/* Pointer to current function */
/*****************************************************************************/
-/* Subroutines working with struct Function */
+/* Subroutines working with struct Function */
/*****************************************************************************/
/* Initialize the fields */
F->FuncEntry = Sym;
F->ReturnType = GetFuncReturn (Sym->Type);
- F->Desc = (FuncDesc*) DecodePtr (Sym->Type + 1);
- F->Reserved = 0;
- F->RetLab = GetLocalLabel ();
+ F->Desc = GetFuncDesc (Sym->Type);
+ F->Reserved = 0;
+ F->RetLab = GetLocalLabel ();
F->TopLevelSP = 0;
- F->RegOffs = MAX_REG_SPACE;
+ F->RegOffs = RegisterSpace;
+ F->Flags = IsTypeVoid (F->ReturnType) ? FF_VOID_RETURN : FF_NONE;
/* Return the new structure */
return F;
-type* F_GetReturnType (Function* F)
+Type* F_GetReturnType (Function* F)
/* Get the return type for the function */
{
return F->ReturnType;
int F_HasVoidReturn (const Function* F)
/* Return true if the function does not have a return value */
{
- return IsTypeVoid (F->ReturnType);
+ return (F->Flags & FF_VOID_RETURN) != 0;
+}
+
+
+
+void F_ReturnFound (Function* F)
+/* Mark the function as having a return statement */
+{
+ F->Flags |= FF_HAS_RETURN;
+}
+
+
+
+int F_HasReturn (const Function* F)
+/* Return true if the function contains a return statement*/
+{
+ return (F->Flags & FF_HAS_RETURN) != 0;
+}
+
+
+
+int F_IsMainFunc (const Function* F)
+/* Return true if this is the main function */
+{
+ return (F->Flags & FF_IS_MAIN) != 0;
}
*/
{
F->Reserved += Size;
- return oursp - F->Reserved;
+ return StackPtr - F->Reserved;
+}
+
+
+
+int F_GetStackPtr (const Function* F)
+/* Return the current stack pointer including reserved (but not allocated)
+ * space on the stack.
+ */
+{
+ return StackPtr - F->Reserved;
}
{
if (F->Reserved > 0) {
- /* Create space on the stack */
- g_space (F->Reserved);
+ /* Create space on the stack */
+ g_space (F->Reserved);
- /* Correct the stack pointer */
- oursp -= F->Reserved;
+ /* Correct the stack pointer */
+ StackPtr -= F->Reserved;
- /* Nothing more reserved */
- F->Reserved = 0;
+ /* Nothing more reserved */
+ F->Reserved = 0;
}
}
-int F_AllocRegVar (Function* F, const type* Type)
+int F_AllocRegVar (Function* F, const Type* Type)
/* Allocate a register variable for the given variable type. If the allocation
* was successful, return the offset of the register variable in the register
* bank (zero page storage). If there is no register space left, return -1.
*/
{
/* Allow register variables only on top level and if enabled */
- if (EnableRegVars && GetLexicalLevel () == LEX_LEVEL_FUNCTION) {
-
- /* Get the size of the variable */
- unsigned Size = CheckedSizeOf (Type);
-
- /* Do we have space left? */
- if (F->RegOffs >= Size) {
- /* Space left. We allocate the variables from high to low addresses,
- * so the adressing is compatible with the saved values on stack.
- * This allows shorter code when saving/restoring the variables.
- */
- F->RegOffs -= Size;
- return F->RegOffs;
- }
+ if (IS_Get (&EnableRegVars) && GetLexicalLevel () == LEX_LEVEL_FUNCTION) {
+
+ /* Get the size of the variable */
+ unsigned Size = CheckedSizeOf (Type);
+
+ /* Do we have space left? */
+ if (F->RegOffs >= Size) {
+ /* Space left. We allocate the variables from high to low addresses,
+ * so the adressing is compatible with the saved values on stack.
+ * This allows shorter code when saving/restoring the variables.
+ */
+ F->RegOffs -= Size;
+ return F->RegOffs;
+ }
}
/* No space left or no allocation */
const SymEntry* Sym;
/* If we don't have register variables in this function, bail out early */
- if (F->RegOffs == MAX_REG_SPACE) {
- return;
+ if (F->RegOffs == RegisterSpace) {
+ return;
}
/* Save the accumulator if needed */
if (!F_HasVoidReturn (F)) {
- g_save (CF_CHAR | CF_FORCECHAR);
+ g_save (CF_CHAR | CF_FORCECHAR);
}
/* Get the first symbol from the function symbol table */
/* Restore the accumulator if needed */
if (!F_HasVoidReturn (F)) {
- g_restore (CF_CHAR | CF_FORCECHAR);
+ g_restore (CF_CHAR | CF_FORCECHAR);
+ }
+}
+
+
+
+static void F_EmitDebugInfo (void)
+/* Emit debug infos for the current function */
+{
+ if (DebugInfo) {
+ /* Get the current function */
+ const SymEntry* Sym = CurrentFunc->FuncEntry;
+
+ /* Output info for the function itself */
+ AddTextLine ("\t.dbg\tfunc, \"%s\", \"00\", %s, \"%s\"",
+ Sym->Name,
+ (Sym->Flags & SC_EXTERN)? "extern" : "static",
+ Sym->AsmName);
}
}
/*****************************************************************************/
-/* code */
+/* code */
/*****************************************************************************/
void NewFunc (SymEntry* Func)
/* Parse argument declarations and function body. */
{
- int HadReturn;
- SymEntry* LastParam;
- SymEntry* Param;
+ int C99MainFunc = 0;/* Flag for C99 main function returning int */
+ SymEntry* Param;
/* Get the function descriptor from the function entry */
FuncDesc* D = Func->V.F.Func;
/* Reenter the lexical level */
ReenterFunctionLevel (D);
- /* Before adding more symbols, remember the last parameter for later */
- LastParam = D->SymTab->SymTail;
+ /* Check if the function header contains unnamed parameters. These are
+ * only allowed in cc65 mode.
+ */
+ if ((D->Flags & FD_UNNAMED_PARAMS) != 0 && (IS_Get (&Standard) != STD_CC65)) {
+ Error ("Parameter name omitted");
+ }
/* Declare two special functions symbols: __fixargs__ and __argsize__.
* The latter is different depending on the type of the function (variadic
*/
AddConstSym ("__fixargs__", type_uint, SC_DEF | SC_CONST, D->ParamSize);
if (D->Flags & FD_VARIADIC) {
- /* Variadic function. The variable must be const. */
- static const type T [] = { T_UCHAR | T_QUAL_CONST, T_END };
- AddLocalSym ("__argsize__", T, SC_DEF | SC_REF | SC_AUTO, 0);
+ /* Variadic function. The variable must be const. */
+ static const Type T[] = { TYPE(T_UCHAR | T_QUAL_CONST), TYPE(T_END) };
+ AddLocalSym ("__argsize__", T, SC_DEF | SC_REF | SC_AUTO, 0);
} else {
- /* Non variadic */
- AddConstSym ("__argsize__", type_uchar, SC_DEF | SC_CONST, D->ParamSize);
+ /* Non variadic */
+ AddConstSym ("__argsize__", type_uchar, SC_DEF | SC_CONST, D->ParamSize);
}
/* Function body now defined */
Func->Flags |= SC_DEF;
+ /* Special handling for main() */
+ if (strcmp (Func->Name, "main") == 0) {
+
+ /* Mark this as the main function */
+ CurrentFunc->Flags |= FF_IS_MAIN;
+
+ /* Main cannot be a fastcall function */
+ if (IsQualFastcall (Func->Type)) {
+ Error ("`main' cannot be declared as __fastcall__");
+ }
+
+ /* If cc65 extensions aren't enabled, don't allow a main function that
+ * doesn't return an int.
+ */
+ if (IS_Get (&Standard) != STD_CC65 && CurrentFunc->ReturnType[0].C != T_INT) {
+ Error ("`main' must always return an int");
+ }
+
+ /* Add a forced import of a symbol that is contained in the startup
+ * code. This will force the startup code to be linked in.
+ */
+ g_importstartup ();
+
+ /* If main() takes parameters, generate a forced import to a function
+ * that will setup these parameters. This way, programs that do not
+ * need the additional code will not get it.
+ */
+ if (D->ParamCount > 0 || (D->Flags & FD_VARIADIC) != 0) {
+ g_importmainargs ();
+ }
+
+ /* Determine if this is a main function in a C99 environment that
+ * returns an int.
+ */
+ if (IsTypeInt (F_GetReturnType (CurrentFunc)) &&
+ IS_Get (&Standard) == STD_C99) {
+ C99MainFunc = 1;
+ }
+ }
+
/* Allocate code and data segments for this function */
Func->V.F.Seg = PushSegments (Func);
+ /* Allocate a new literal pool */
+ PushLiteralPool (Func);
+
/* If this is a fastcall function, push the last parameter onto the stack */
- if (IsFastCallFunc (Func->Type) && D->ParamCount > 0) {
+ if (IsQualFastcall (Func->Type) && D->ParamCount > 0) {
- unsigned Flags;
+ unsigned Flags;
- /* Fastcall functions may never have an ellipsis or the compiler is buggy */
- CHECK ((D->Flags & FD_VARIADIC) == 0);
+ /* Fastcall functions may never have an ellipsis or the compiler is buggy */
+ CHECK ((D->Flags & FD_VARIADIC) == 0);
- /* Generate the push */
- if (IsTypeFunc (LastParam->Type)) {
- /* Pointer to function */
- Flags = CF_PTR;
- } else {
- Flags = TypeOf (LastParam->Type) | CF_FORCECHAR;
- }
- g_push (Flags, 0);
+ /* Generate the push */
+ if (IsTypeFunc (D->LastParam->Type)) {
+ /* Pointer to function */
+ Flags = CF_PTR;
+ } else {
+ Flags = TypeOf (D->LastParam->Type) | CF_FORCECHAR;
+ }
+ g_push (Flags, 0);
}
/* Generate function entry code if needed */
g_enter (TypeOf (Func->Type), F_GetParamSize (CurrentFunc));
/* If stack checking code is requested, emit a call to the helper routine */
- if (CheckStack) {
- g_stackcheck ();
+ if (IS_Get (&CheckStack)) {
+ g_stackcheck ();
}
+ /* Setup the stack */
+ StackPtr = 0;
+
/* Walk through the parameter list and allocate register variable space
* for parameters declared as register. Generate code to swap the contents
* of the register bank with the save area on the stack.
/* Generate swap code */
g_swap_regvars (Param->V.R.SaveOffs, Reg, CheckedSizeOf (Param->Type));
-
}
}
Param = Param->NextSym;
}
- /* Setup the stack */
- oursp = 0;
-
/* Need a starting curly brace */
ConsumeLCurly ();
/* Remember the current stack pointer. All variables allocated elsewhere
* must be dropped when doing a return from an inner block.
*/
- CurrentFunc->TopLevelSP = oursp;
+ CurrentFunc->TopLevelSP = StackPtr;
/* Now process statements in this block */
- HadReturn = 0;
- while (CurTok.Tok != TOK_RCURLY) {
- if (CurTok.Tok != TOK_CEOF) {
- HadReturn = Statement (0);
- } else {
- break;
- }
+ while (CurTok.Tok != TOK_RCURLY && CurTok.Tok != TOK_CEOF) {
+ Statement (0);
+ }
+
+ /* If this is not a void function, and not the main function in a C99
+ * environment returning int, output a warning if we didn't see a return
+ * statement.
+ */
+ if (!F_HasVoidReturn (CurrentFunc) && !F_HasReturn (CurrentFunc) && !C99MainFunc) {
+ Warning ("Control reaches end of non-void function");
+ }
+
+ /* If this is the main function in a C99 environment returning an int, let
+ * it always return zero. Note: Actual return statements jump to the return
+ * label defined below.
+ * The code is removed by the optimizer if unused.
+ */
+ if (C99MainFunc) {
+ g_getimmed (CF_INT | CF_CONST, 0, 0);
}
/* Output the function exit code label */
/* Generate the exit code */
g_leave ();
- /* Eat the closing brace */
- ConsumeRCurly ();
-
/* Emit references to imports/exports */
EmitExternals ();
+ /* Emit function debug info */
+ F_EmitDebugInfo ();
+ EmitDebugInfo ();
+
/* Leave the lexical level */
LeaveFunctionLevel ();
+ /* Eat the closing brace */
+ ConsumeRCurly ();
+
+ /* Restore the old literal pool, remembering the one for the function */
+ Func->V.F.LitPool = PopLiteralPool ();
+
/* Switch back to the old segments */
PopSegments ();
FreeFunction (CurrentFunc);
CurrentFunc = 0;
}
-
-
-
projects / cc65 / blobdiff