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 LocalMax; /* Total space for locals */
65 int LocalSize; /* Current space for locals */
66 unsigned RetLab; /* Return code label */
69 /* Pointer to current function */
70 Function* CurrentFunc = 0;
74 /*****************************************************************************/
75 /* Subroutines working with struct Function */
76 /*****************************************************************************/
80 static Function* NewFunction (struct SymEntry* Sym)
81 /* Create a new function activation structure and return it */
83 /* Allocate a new structure */
84 Function* F = xmalloc (sizeof (Function));
86 /* Initialize the fields */
88 F->ReturnType = Sym->Type + 1 + DECODE_SIZE;
89 F->Desc = DecodePtr (Sym->Type + 1);
93 F->RetLab = GetLabel ();
95 /* Return the new structure */
101 static void FreeFunction (Function* F)
102 /* Free a function activation structure */
109 const char* GetFuncName (const Function* F)
110 /* Return the name of the current function */
112 return F->FuncEntry->Name;
117 unsigned GetParamSize (const Function* F)
118 /* Return the parameter size for the current function */
120 return F->Desc->ParamSize;
125 type* GetReturnType (Function* F)
126 /* Get the return type for the function */
128 return F->ReturnType;
133 int HasVoidReturn (const Function* F)
134 /* Return true if the function does not have a return value */
136 return IsVoid (F->ReturnType);
141 void RememberEntry (Function* F)
142 /* Remember the current output position for local space creation later */
144 F->EntryCode = GetCodePos ();
149 unsigned GetRetLab (const Function* F)
150 /* Return the return jump label */
157 int AllocLocalSpace (Function* F, unsigned Size)
158 /* Allocate space for the function locals, return stack offset */
161 F->LocalSize += Size;
162 if (F->LocalSize > F->LocalMax) {
163 F->LocalMax = F->LocalSize;
166 /* Return the offset, it is below the initial stack pointer */
167 return -F->LocalSize;;
172 void FreeLocalSpace (Function* F, unsigned Size)
173 /* Free space allocated for function locals */
175 F->LocalSize -= Size;
180 unsigned GetLocalSpace (const Function* F)
181 /* Get the local variable space needed for the function */
188 /*****************************************************************************/
190 /*****************************************************************************/
194 void NewFunc (SymEntry* Func)
195 /* Parse argument declarations and function body. */
199 /* Get the function descriptor from the function entry */
200 FuncDesc* D = DecodePtr (Func->Type+1);
202 /* Allocate the function activation record for the function */
203 CurrentFunc = NewFunction (Func);
205 /* Reenter the lexical level */
206 ReenterFunctionLevel (D);
208 /* Function body now defined */
209 Func->Flags |= SC_DEF;
211 /* C functions cannot currently have __fastcall__ calling conventions */
212 if (IsFastCallFunc (Func->Type)) {
213 Error (ERR_FASTCALL);
216 /* Need a starting curly brace */
217 if (curtok != TOK_LCURLY) {
218 Error (ERR_LCURLY_EXPECTED);
221 /* Setup register variables */
224 /* Switch to the code segment and define the function name label */
226 g_defgloblabel (Func->Name);
228 /* Generate function entry code if needed */
229 g_enter (TypeOf (Func->Type), GetParamSize (CurrentFunc));
231 /* Remember the current code position. This may be used later to create
232 * local variable space once we have created the function body itself.
233 * Currently this is not possible because the stack offsets of all locals
234 * have to be known in advance.
236 RememberEntry (CurrentFunc);
238 /* Parse the function body */
242 /* If the function did not end with an return statement, create exit code */
245 /* If the function has a return type, flag an error */
247 Error (ERR_MUST_RETURN_VALUE);
251 g_leave (CF_NONE, 0);
254 /* Dump literal data created by the function */
257 /* Cleanup register variables */
260 /* Leave the lexical level */
261 LeaveFunctionLevel ();
263 /* Reset the current function pointer */
264 FreeFunction (CurrentFunc);