mirror of
https://github.com/cc65/cc65.git
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0e80187cec
supplied data structures. Re-added the -T option which is much more exact now because of the better line info stuff. Cleanups in the scanner (remove old #defines). git-svn-id: svn://svn.cc65.org/cc65/trunk@740 b7a2c559-68d2-44c3-8de9-860c34a00d81
347 lines
9.5 KiB
C
347 lines
9.5 KiB
C
/*****************************************************************************/
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/* */
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/* function.c */
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/* */
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/* Parse function entry/body/exit */
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/* */
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/* */
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/* */
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/* (C) 2000-2001 Ullrich von Bassewitz */
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/* Wacholderweg 14 */
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/* D-70597 Stuttgart */
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/* EMail: uz@cc65.org */
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/* */
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/* */
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/* This software is provided 'as-is', without any expressed or implied */
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/* warranty. In no event will the authors be held liable for any damages */
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/* arising from the use of this software. */
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/* */
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/* Permission is granted to anyone to use this software for any purpose, */
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/* including commercial applications, and to alter it and redistribute it */
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/* freely, subject to the following restrictions: */
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/* */
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/* 1. The origin of this software must not be misrepresented; you must not */
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/* claim that you wrote the original software. If you use this software */
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/* in a product, an acknowledgment in the product documentation would be */
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/* appreciated but is not required. */
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/* 2. Altered source versions must be plainly marked as such, and must not */
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/* be misrepresented as being the original software. */
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/* 3. This notice may not be removed or altered from any source */
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/* distribution. */
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/* */
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/*****************************************************************************/
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/* common */
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#include "check.h"
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#include "xmalloc.h"
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/* cc65 */
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#include "asmcode.h"
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#include "asmlabel.h"
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#include "codegen.h"
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#include "error.h"
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#include "funcdesc.h"
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#include "global.h"
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#include "litpool.h"
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#include "locals.h"
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#include "scanner.h"
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#include "segments.h"
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#include "stmt.h"
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#include "symtab.h"
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#include "function.h"
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/*****************************************************************************/
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/* Data */
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/*****************************************************************************/
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/* Structure that holds all data needed for function activation */
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struct Function {
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struct SymEntry* FuncEntry; /* Symbol table entry */
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type* ReturnType; /* Function return type */
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struct FuncDesc* Desc; /* Function descriptor */
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int Reserved; /* Reserved local space */
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unsigned RetLab; /* Return code label */
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int TopLevelSP; /* SP at function top level */
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};
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/* Pointer to current function */
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Function* CurrentFunc = 0;
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/*****************************************************************************/
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/* Subroutines working with struct Function */
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/*****************************************************************************/
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static Function* NewFunction (struct SymEntry* Sym)
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/* Create a new function activation structure and return it */
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{
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/* Allocate a new structure */
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Function* F = (Function*) xmalloc (sizeof (Function));
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/* Initialize the fields */
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F->FuncEntry = Sym;
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F->ReturnType = GetFuncReturn (Sym->Type);
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F->Desc = (FuncDesc*) DecodePtr (Sym->Type + 1);
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F->Reserved = 0;
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F->RetLab = GetLocalLabel ();
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F->TopLevelSP = 0;
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/* Return the new structure */
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return F;
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}
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static void FreeFunction (Function* F)
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/* Free a function activation structure */
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{
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xfree (F);
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}
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const char* GetFuncName (const Function* F)
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/* Return the name of the current function */
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{
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return F->FuncEntry->Name;
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}
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unsigned GetParamCount (const Function* F)
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/* Return the parameter count for the current function */
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{
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return F->Desc->ParamCount;
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}
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unsigned GetParamSize (const Function* F)
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/* Return the parameter size for the current function */
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{
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return F->Desc->ParamSize;
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}
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type* GetReturnType (Function* F)
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/* Get the return type for the function */
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{
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return F->ReturnType;
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}
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int HasVoidReturn (const Function* F)
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/* Return true if the function does not have a return value */
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{
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return IsTypeVoid (F->ReturnType);
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}
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int IsVariadic (const Function* F)
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/* Return true if this is a variadic function */
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{
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return (F->Desc->Flags & FD_VARIADIC) != 0;
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}
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unsigned GetRetLab (const Function* F)
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/* Return the return jump label */
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{
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return F->RetLab;
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}
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int GetTopLevelSP (const Function* F)
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/* Get the value of the stack pointer on function top level */
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{
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return F->TopLevelSP;
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}
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int ReserveLocalSpace (Function* F, unsigned Size)
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/* Reserve (but don't allocate) the given local space and return the stack
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* offset.
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*/
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{
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F->Reserved += Size;
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return oursp - F->Reserved;
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}
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void AllocLocalSpace (Function* F)
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/* Allocate any local space previously reserved. The function will do
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* nothing if there is no reserved local space.
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*/
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{
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if (F->Reserved > 0) {
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/* Create space on the stack */
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g_space (F->Reserved);
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/* Correct the stack pointer */
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oursp -= F->Reserved;
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/* Nothing more reserved */
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F->Reserved = 0;
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}
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}
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/*****************************************************************************/
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/* code */
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/*****************************************************************************/
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void NewFunc (SymEntry* Func)
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/* Parse argument declarations and function body. */
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{
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int HadReturn;
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int IsVoidFunc;
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/* Get the function descriptor from the function entry */
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FuncDesc* D = Func->V.F.Func;
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/* Allocate the function activation record for the function */
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CurrentFunc = NewFunction (Func);
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/* Reenter the lexical level */
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ReenterFunctionLevel (D);
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/* Declare two special functions symbols: __fixargs__ and __argsize__.
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* The latter is different depending on the type of the function (variadic
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* or not).
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*/
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AddConstSym ("__fixargs__", type_uint, SC_DEF | SC_CONST, D->ParamSize);
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if (D->Flags & FD_VARIADIC) {
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/* Variadic function. The variable must be const. */
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static const type T [] = { T_UCHAR | T_QUAL_CONST, T_END };
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AddLocalSym ("__argsize__", T, SC_DEF | SC_REF | SC_AUTO, 0);
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} else {
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/* Non variadic */
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AddConstSym ("__argsize__", type_uchar, SC_DEF | SC_CONST, D->ParamSize);
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}
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/* Function body now defined */
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Func->Flags |= SC_DEF;
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/* Setup register variables */
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InitRegVars ();
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/* Allocate code and data segments for this function */
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Func->V.F.Seg = PushSegments (Func);
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/* If this is a fastcall function, push the last parameter onto the stack */
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if (IsFastCallFunc (Func->Type) && D->ParamCount > 0) {
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SymEntry* LastParam;
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unsigned Flags;
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/* Fastcall functions may never have an ellipsis or the compiler is buggy */
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CHECK ((D->Flags & FD_VARIADIC) == 0);
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/* Get a pointer to the last parameter entry */
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LastParam = D->SymTab->SymTail;
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/* Generate the push */
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if (IsTypeFunc (LastParam->Type)) {
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/* Pointer to function */
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Flags = CF_PTR;
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} else {
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Flags = TypeOf (LastParam->Type) | CF_FORCECHAR;
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}
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g_push (Flags, 0);
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}
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/* If stack checking code is requested, emit a call to the helper routine */
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if (CheckStack) {
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g_stackcheck ();
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}
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/* Generate function entry code if needed */
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g_enter (TypeOf (Func->Type), GetParamSize (CurrentFunc));
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/* Setup the stack */
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oursp = 0;
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/* Need a starting curly brace */
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ConsumeLCurly ();
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/* Parse local variable declarations if any */
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DeclareLocals ();
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/* Remember the current stack pointer. All variables allocated elsewhere
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* must be dropped when doing a return from an inner block.
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*/
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CurrentFunc->TopLevelSP = oursp;
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/* Now process statements in this block */
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HadReturn = 0;
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while (CurTok.Tok != TOK_RCURLY) {
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if (CurTok.Tok != TOK_CEOF) {
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HadReturn = Statement ();
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} else {
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break;
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}
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}
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/* If the function has a return type but no return statement, flag
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* a warning
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*/
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IsVoidFunc = HasVoidReturn (CurrentFunc);
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#if 0
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/* Does not work reliably */
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if (!IsVoidFunc && !HadReturn) {
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Warning ("Function `%s' should return a value", Func->Name);
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}
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#endif
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/* Output the function exit code label */
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g_defcodelabel (GetRetLab (CurrentFunc));
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/* Restore the register variables */
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RestoreRegVars (!IsVoidFunc);
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/* Generate the exit code */
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g_leave ();
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/* Eat the closing brace */
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ConsumeRCurly ();
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/* Emit references to imports/exports */
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EmitExternals ();
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/* Cleanup register variables */
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DoneRegVars ();
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/* Leave the lexical level */
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LeaveFunctionLevel ();
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/* Switch back to the old segments */
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PopSegments ();
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/* Reset the current function pointer */
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FreeFunction (CurrentFunc);
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CurrentFunc = 0;
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}
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