1 /*****************************************************************************/
5 /* Parse function entry/body/exit */
9 /* (C) 2000 Ullrich von Bassewitz */
11 /* D-70597 Stuttgart */
12 /* EMail: uz@musoftware.de */
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 /*****************************************************************************/
36 #include "../common/xmalloc.h"
52 /*****************************************************************************/
54 /*****************************************************************************/
58 /* Structure that holds all data needed for function activation */
60 struct SymEntry* FuncEntry; /* Symbol table entry */
61 type* ReturnType; /* Function return type */
62 struct FuncDesc* Desc; /* Function descriptor */
63 CodeMark EntryCode; /* Backpatch addr for entry code */
64 int Reserved; /* Reserved local space */
65 unsigned RetLab; /* Return code label */
68 /* Pointer to current function */
69 Function* CurrentFunc = 0;
73 /*****************************************************************************/
74 /* Subroutines working with struct Function */
75 /*****************************************************************************/
79 static Function* NewFunction (struct SymEntry* Sym)
80 /* Create a new function activation structure and return it */
82 /* Allocate a new structure */
83 Function* F = xmalloc (sizeof (Function));
85 /* Initialize the fields */
87 F->ReturnType = Sym->Type + 1 + DECODE_SIZE;
88 F->Desc = DecodePtr (Sym->Type + 1);
91 F->RetLab = GetLabel ();
93 /* Return the new structure */
99 static void FreeFunction (Function* F)
100 /* Free a function activation structure */
107 const char* GetFuncName (const Function* F)
108 /* Return the name of the current function */
110 return F->FuncEntry->Name;
115 unsigned GetParamSize (const Function* F)
116 /* Return the parameter size for the current function */
118 return F->Desc->ParamSize;
123 type* GetReturnType (Function* F)
124 /* Get the return type for the function */
126 return F->ReturnType;
131 int HasVoidReturn (const Function* F)
132 /* Return true if the function does not have a return value */
134 return IsVoid (F->ReturnType);
139 void RememberEntry (Function* F)
140 /* Remember the current output position for local space creation later */
142 F->EntryCode = GetCodePos ();
147 unsigned GetRetLab (const Function* F)
148 /* Return the return jump label */
155 int ReserveLocalSpace (Function* F, unsigned Size)
156 /* Reserve (but don't allocate) the given local space and return the stack
161 return oursp - F->Reserved;
166 void AllocLocalSpace (Function* F)
167 /* Allocate any local space previously reserved. The function will do
168 * nothing if there is no reserved local space.
171 if (F->Reserved > 0) {
173 /* Switch to the code segment */
176 /* Create space on the stack */
177 g_space (F->Reserved);
179 /* Correct the stack pointer */
180 oursp -= F->Reserved;
182 /* Nothing more reserved */
189 /*****************************************************************************/
191 /*****************************************************************************/
195 void NewFunc (SymEntry* Func)
196 /* Parse argument declarations and function body. */
200 /* Get the function descriptor from the function entry */
201 FuncDesc* D = DecodePtr (Func->Type+1);
203 /* Allocate the function activation record for the function */
204 CurrentFunc = NewFunction (Func);
206 /* Reenter the lexical level */
207 ReenterFunctionLevel (D);
209 /* Function body now defined */
210 Func->Flags |= SC_DEF;
212 /* C functions cannot currently have __fastcall__ calling conventions */
213 if (IsFastCallFunc (Func->Type)) {
214 Error (ERR_FASTCALL);
217 /* Need a starting curly brace */
218 if (curtok != TOK_LCURLY) {
219 Error (ERR_LCURLY_EXPECTED);
222 /* Setup register variables */
225 /* Switch to the code segment and define the function name label */
227 g_defgloblabel (Func->Name);
229 /* Generate function entry code if needed */
230 g_enter (TypeOf (Func->Type), GetParamSize (CurrentFunc));
232 /* Remember the current code position. This may be used later to create
233 * local variable space once we have created the function body itself.
234 * Currently this is not possible because the stack offsets of all locals
235 * have to be known in advance.
237 RememberEntry (CurrentFunc);
239 /* Parse the function body */
243 /* If the function did not end with an return statement, create exit code */
246 /* If the function has a return type, flag an error */
248 Error (ERR_MUST_RETURN_VALUE);
252 g_leave (CF_NONE, 0);
255 /* Dump literal data created by the function */
258 /* Cleanup register variables */
261 /* Leave the lexical level */
262 LeaveFunctionLevel ();
264 /* Reset the current function pointer */
265 FreeFunction (CurrentFunc);