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 int RCurlyBrace; /* True if last token is right curly brace */
97 SwitchCtrl* OldSwitch; /* Pointer to old switch control data */
98 SwitchCtrl SwitchData; /* New switch data */
101 /* Eat the "switch" token */
104 /* Read the switch expression and load it into the primary. It must have
108 Expression0 (&SwitchExpr);
109 if (!IsClassInt (SwitchExpr.Type)) {
110 Error ("Switch quantity is not an integer");
111 /* To avoid any compiler errors, make the expression a valid int */
112 ED_MakeConstAbsInt (&SwitchExpr, 1);
116 /* Add a jump to the switch code. This jump is usually unnecessary,
117 ** because the switch code will moved up just behind the switch
118 ** expression. However, in rare cases, there's a label at the end of
119 ** the switch expression. This label will not get moved, so the code
120 ** jumps around the switch code, and after moving the switch code,
121 ** things look really weird. If we add a jump here, we will never have
122 ** a label attached to the current code position, and the jump itself
123 ** will get removed by the optimizer if it is unnecessary.
125 SwitchCodeLabel = GetLocalLabel ();
126 g_jump (SwitchCodeLabel);
128 /* Remember the current code position. We will move the switch code
129 ** to this position later.
131 GetCodePos (&CaseCodeStart);
133 /* Setup the control structure, save the old and activate the new one */
134 SwitchData.Nodes = NewCollection ();
135 SwitchData.ExprType = UnqualifiedType (SwitchExpr.Type[0].C);
136 SwitchData.Depth = SizeOf (SwitchExpr.Type);
137 SwitchData.DefaultLabel = 0;
139 Switch = &SwitchData;
141 /* Get the exit label for the switch statement */
142 ExitLabel = GetLocalLabel ();
144 /* Create a loop so we may use break. */
145 AddLoop (ExitLabel, 0);
147 /* Make sure a curly brace follows */
148 if (CurTok.Tok != TOK_LCURLY) {
149 Error ("`{' expected");
152 /* Parse the following statement, which will actually be a compound
153 ** statement because of the curly brace at the current input position
155 HaveBreak = Statement (&RCurlyBrace);
157 /* Check if we had any labels */
158 if (CollCount (SwitchData.Nodes) == 0 && SwitchData.DefaultLabel == 0) {
159 Warning ("No case labels");
162 /* If the last statement did not have a break, we may have an open
163 ** label (maybe from an if or similar). Emitting code and then moving
164 ** this code to the top will also move the label to the top which is
165 ** wrong. So if the last statement did not have a break (which would
166 ** carry the label), add a jump to the exit. If it is useless, the
167 ** optimizer will remove it later.
173 /* Remember the current position */
174 GetCodePos (&SwitchCodeStart);
176 /* Output the switch code label */
177 g_defcodelabel (SwitchCodeLabel);
180 if (SwitchData.DefaultLabel == 0) {
181 /* No default label, use switch exit */
182 SwitchData.DefaultLabel = ExitLabel;
184 g_switch (SwitchData.Nodes, SwitchData.DefaultLabel, SwitchData.Depth);
186 /* Move the code to the front */
187 GetCodePos (&SwitchCodeEnd);
188 MoveCode (&SwitchCodeStart, &SwitchCodeEnd, &CaseCodeStart);
190 /* Define the exit label */
191 g_defcodelabel (ExitLabel);
196 /* Switch back to the enclosing switch statement if any */
199 /* Free the case value tree */
200 FreeCaseNodeColl (SwitchData.Nodes);
202 /* If the case statement was (correctly) terminated by a closing curly
203 ** brace, skip it now.
212 void CaseLabel (void)
213 /* Handle a case sabel */
215 ExprDesc CaseExpr; /* Case label expression */
216 long Val; /* Case label value */
217 unsigned CodeLabel; /* Code label for this case */
220 /* Skip the "case" token */
223 /* Read the selector expression */
224 ConstAbsIntExpr (hie1, &CaseExpr);
227 /* Now check if we're inside a switch statement */
230 /* Check the range of the expression */
231 switch (Switch->ExprType) {
235 if (Val < -128 || Val > 127) {
236 Error ("Range error");
241 if (Val < 0 || Val > 255) {
242 Error ("Range error");
248 if (Val < -32768 || Val > 32767) {
249 Error ("Range error");
255 if (Val < 0 || Val > 65535) {
256 Error ("Range error");
265 Internal ("Invalid type: %06lX", Switch->ExprType);
268 /* Insert the case selector into the selector table */
269 CodeLabel = InsertCaseValue (Switch->Nodes, Val, Switch->Depth);
271 /* Define this label */
272 g_defcodelabel (CodeLabel);
276 /* case keyword outside a switch statement */
277 Error ("Case label not within a switch statement");
287 void DefaultLabel (void)
288 /* Handle a default label */
293 /* Now check if we're inside a switch statement */
296 /* Check if we do already have a default branch */
297 if (Switch->DefaultLabel == 0) {
299 /* Generate and emit the default label */
300 Switch->DefaultLabel = GetLocalLabel ();
301 g_defcodelabel (Switch->DefaultLabel);
304 /* We had the default label already */
305 Error ("Multiple default labels in one switch");
310 /* case keyword outside a switch statement */
311 Error ("`default' label not within a switch statement");