1 /*****************************************************************************/
5 /* Parse the switch statement */
9 /* (C) 1998-2008 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 /*****************************************************************************/
58 /*****************************************************************************/
60 /*****************************************************************************/
64 typedef struct SwitchCtrl SwitchCtrl;
66 Collection* Nodes; /* CaseNode tree */
67 TypeCode ExprType; /* Basic switch expression type */
68 unsigned Depth; /* Number of bytes the selector type has */
69 unsigned DefaultLabel; /* Label for the default branch */
75 /* Pointer to current switch control struct */
76 static SwitchCtrl* Switch = 0;
80 /*****************************************************************************/
82 /*****************************************************************************/
86 void SwitchStatement (void)
87 /* Handle a switch statement for chars with a cmp cascade for the selector */
89 ExprDesc SwitchExpr; /* Switch statement expression */
90 CodeMark CaseCodeStart; /* Start of code marker */
91 CodeMark SwitchCodeStart;/* Start of switch code */
92 CodeMark SwitchCodeEnd; /* End of switch code */
93 unsigned ExitLabel; /* Exit label */
94 unsigned SwitchCodeLabel;/* Label for the switch code */
95 int HaveBreak = 0; /* True if the last statement had a break */
96 SwitchCtrl* OldSwitch; /* Pointer to old switch control data */
97 SwitchCtrl SwitchData; /* New switch data */
100 /* Eat the "switch" token */
103 /* Read the switch expression and load it into the primary. It must have
107 Expression0 (&SwitchExpr);
108 if (!IsClassInt (SwitchExpr.Type)) {
109 Error ("Switch quantity is not an integer");
110 /* To avoid any compiler errors, make the expression a valid int */
111 ED_MakeConstAbsInt (&SwitchExpr, 1);
115 /* Add a jump to the switch code. This jump is usually unnecessary,
116 * because the switch code will moved up just behind the switch
117 * expression. However, in rare cases, there's a label at the end of
118 * the switch expression. This label will not get moved, so the code
119 * jumps around the switch code, and after moving the switch code,
120 * things look really weird. If we add a jump here, we will never have
121 * a label attached to the current code position, and the jump itself
122 * will get removed by the optimizer if it is unnecessary.
124 SwitchCodeLabel = GetLocalLabel ();
125 g_jump (SwitchCodeLabel);
127 /* Remember the current code position. We will move the switch code
128 * to this position later.
130 GetCodePos (&CaseCodeStart);
132 /* Setup the control structure, save the old and activate the new one */
133 SwitchData.Nodes = NewCollection ();
134 SwitchData.ExprType = UnqualifiedType (SwitchExpr.Type[0].C);
135 SwitchData.Depth = SizeOf (SwitchExpr.Type);
136 SwitchData.DefaultLabel = 0;
138 Switch = &SwitchData;
140 /* Get the exit label for the switch statement */
141 ExitLabel = GetLocalLabel ();
143 /* Create a loop so we may use break. */
144 AddLoop (ExitLabel, 0);
146 /* Make sure a curly brace follows */
147 if (CurTok.Tok != TOK_LCURLY) {
148 Error ("`{' expected");
151 /* Parse the following statement, which will actually be a compound
152 * statement because of the curly brace at the current input position
154 HaveBreak = Statement (0);
156 /* Check if we had any labels */
157 if (CollCount (SwitchData.Nodes) == 0 && SwitchData.DefaultLabel == 0) {
158 Warning ("No case labels");
161 /* If the last statement did not have a break, we may have an open
162 * label (maybe from an if or similar). Emitting code and then moving
163 * this code to the top will also move the label to the top which is
164 * wrong. So if the last statement did not have a break (which would
165 * carry the label), add a jump to the exit. If it is useless, the
166 * optimizer will remove it later.
172 /* Remember the current position */
173 GetCodePos (&SwitchCodeStart);
175 /* Output the switch code label */
176 g_defcodelabel (SwitchCodeLabel);
179 if (SwitchData.DefaultLabel == 0) {
180 /* No default label, use switch exit */
181 SwitchData.DefaultLabel = ExitLabel;
183 g_switch (SwitchData.Nodes, SwitchData.DefaultLabel, SwitchData.Depth);
185 /* Move the code to the front */
186 GetCodePos (&SwitchCodeEnd);
187 MoveCode (&SwitchCodeStart, &SwitchCodeEnd, &CaseCodeStart);
189 /* Define the exit label */
190 g_defcodelabel (ExitLabel);
195 /* Switch back to the enclosing switch statement if any */
198 /* Free the case value tree */
199 FreeCaseNodeColl (SwitchData.Nodes);
204 void CaseLabel (void)
205 /* Handle a case sabel */
207 ExprDesc CaseExpr; /* Case label expression */
208 long Val; /* Case label value */
209 unsigned CodeLabel; /* Code label for this case */
212 /* Skip the "case" token */
215 /* Read the selector expression */
216 ConstAbsIntExpr (hie1, &CaseExpr);
219 /* Now check if we're inside a switch statement */
222 /* Check the range of the expression */
223 switch (Switch->ExprType) {
227 if (Val < -128 || Val > 127) {
228 Error ("Range error");
233 if (Val < 0 || Val > 255) {
234 Error ("Range error");
240 if (Val < -32768 || Val > 32767) {
241 Error ("Range error");
247 if (Val < 0 || Val > 65535) {
248 Error ("Range error");
257 Internal ("Invalid type: %06lX", Switch->ExprType);
260 /* Insert the case selector into the selector table */
261 CodeLabel = InsertCaseValue (Switch->Nodes, Val, Switch->Depth);
263 /* Define this label */
264 g_defcodelabel (CodeLabel);
268 /* case keyword outside a switch statement */
269 Error ("Case label not within a switch statement");
279 void DefaultLabel (void)
280 /* Handle a default label */
285 /* Now check if we're inside a switch statement */
288 /* Check if we do already have a default branch */
289 if (Switch->DefaultLabel == 0) {
291 /* Generate and emit the default label */
292 Switch->DefaultLabel = GetLocalLabel ();
293 g_defcodelabel (Switch->DefaultLabel);
296 /* We had the default label already */
297 Error ("Multiple default labels in one switch");
302 /* case keyword outside a switch statement */
303 Error ("`default' label not within a switch statement");