-/*
- * stmt.c
- *
- * Ullrich von Bassewitz, 06.08.1998
- *
- * Original by John R. Dunning - see copyleft.jrd
- */
+/*****************************************************************************/
+/* */
+/* stmt.c */
+/* */
+/* Parse a statement */
+/* */
+/* */
+/* */
+/* (C) 1998-2004 Ullrich von Bassewitz */
+/* Römerstraße 52 */
+/* D-70794 Filderstadt */
+/* EMail: uz@cc65.org */
+/* */
+/* */
+/* This software is provided 'as-is', without any expressed or implied */
+/* warranty. In no event will the authors be held liable for any damages */
+/* arising from the use of this software. */
+/* */
+/* Permission is granted to anyone to use this software for any purpose, */
+/* including commercial applications, and to alter it and redistribute it */
+/* freely, subject to the following restrictions: */
+/* */
+/* 1. The origin of this software must not be misrepresented; you must not */
+/* claim that you wrote the original software. If you use this software */
+/* in a product, an acknowledgment in the product documentation would be */
+/* appreciated but is not required. */
+/* 2. Altered source versions must be plainly marked as such, and must not */
+/* be misrepresented as being the original software. */
+/* 3. This notice may not be removed or altered from any source */
+/* distribution. */
+/* */
+/*****************************************************************************/
#include <string.h>
/* common */
+#include "coll.h"
#include "xmalloc.h"
/* cc65 */
#include "global.h"
#include "goto.h"
#include "litpool.h"
+#include "loadexpr.h"
#include "locals.h"
#include "loop.h"
#include "pragma.h"
#include "scanner.h"
+#include "stackptr.h"
+#include "swstmt.h"
#include "symtab.h"
#include "stmt.h"
-
-
-
-/*****************************************************************************/
-/* Data */
-/*****************************************************************************/
-
-
-
-/* Maximum count of cases */
-#define CASE_MAX 257
+#include "testexpr.h"
+#include "typeconv.h"
*/
{
if (CurTok.Tok != Tok) {
- Error (Msg);
+ Error (Msg);
} else if (PendingToken) {
- *PendingToken = 1;
+ *PendingToken = 1;
} else {
- NextToken ();
+ NextToken ();
}
}
static void CheckSemi (int* PendingToken)
-/* Helper function for Statement. Will call CheckTok with the parameters
- * for a semicolon.
+/* Helper function for Statement. Will check for a semicolon and print an
+ * error message if not found (plus some error recovery). If PendingToken is
+ * NULL, it will the skip the token, otherwise it will store one to
+ * PendingToken.
+ * This function is a special version of CheckTok with the addition of the
+ * error recovery.
*/
{
- CheckTok (TOK_SEMI, "`;' expected", PendingToken);
+ int HaveToken = (CurTok.Tok == TOK_SEMI);
+ if (!HaveToken) {
+ Error ("`;' expected");
+ /* Try to be smart about errors */
+ if (CurTok.Tok == TOK_COLON || CurTok.Tok == TOK_COMMA) {
+ HaveToken = 1;
+ }
+ }
+ if (HaveToken) {
+ if (PendingToken) {
+ *PendingToken = 1;
+ } else {
+ NextToken ();
+ }
+ }
}
static void SkipPending (int PendingToken)
/* Skip the pending token if we have one */
{
- if (PendingToken) {
+ if (PendingToken) {
NextToken ();
}
}
/* Handle an 'if' statement */
{
unsigned Label1;
+ unsigned TestResult;
int GotBreak;
/* Skip the if */
/* Generate a jump label and parse the condition */
Label1 = GetLocalLabel ();
- test (Label1, 0);
+ TestResult = TestInParens (Label1, 0);
/* Parse the if body */
GotBreak = Statement (0);
} else {
- /* Generate a jump around the else branch */
+ /* Generate a jump around the else branch */
unsigned Label2 = GetLocalLabel ();
- g_jump (Label2);
+ g_jump (Label2);
- /* Skip the else */
+ /* Skip the else */
NextToken ();
- /* Define the target for the first test */
- g_defcodelabel (Label1);
+ /* If the if expression was always true, the code in the else branch
+ * is never executed. Output a warning if this is the case.
+ */
+ if (TestResult == TESTEXPR_TRUE) {
+ Warning ("Unreachable code");
+ }
- /* Total break only if both branches had a break. */
+ /* Define the target for the first test */
+ g_defcodelabel (Label1);
+
+ /* Total break only if both branches had a break. */
GotBreak &= Statement (0);
/* Generate the label for the else clause */
- g_defcodelabel (Label2);
+ g_defcodelabel (Label2);
/* Done */
return GotBreak;
/* Handle the 'do' statement */
{
/* Get the loop control labels */
- unsigned loop = GetLocalLabel ();
- unsigned lab = GetLocalLabel ();
+ unsigned LoopLabel = GetLocalLabel ();
+ unsigned BreakLabel = GetLocalLabel ();
+ unsigned ContinueLabel = GetLocalLabel ();
/* Skip the while token */
NextToken ();
/* Add the loop to the loop stack */
- AddLoop (oursp, loop, lab, 0, 0);
+ AddLoop (BreakLabel, ContinueLabel);
- /* Define the head label */
- g_defcodelabel (loop);
+ /* Define the loop label */
+ g_defcodelabel (LoopLabel);
/* Parse the loop body */
Statement (0);
+ /* Output the label for a continue */
+ g_defcodelabel (ContinueLabel);
+
/* Parse the end condition */
Consume (TOK_WHILE, "`while' expected");
- test (loop, 1);
+ TestInParens (LoopLabel, 1);
ConsumeSemi ();
/* Define the break label */
- g_defcodelabel (lab);
+ g_defcodelabel (BreakLabel);
/* Remove the loop from the loop stack */
DelLoop ();
int PendingToken;
/* Get the loop control labels */
- unsigned loop = GetLocalLabel ();
- unsigned lab = GetLocalLabel ();
+ unsigned LoopLabel = GetLocalLabel ();
+ unsigned BreakLabel = GetLocalLabel ();
/* Skip the while token */
NextToken ();
- /* Add the loop to the loop stack */
- AddLoop (oursp, loop, lab, 0, 0);
+ /* Add the loop to the loop stack. In case of a while loop, the loop head
+ * label is used for continue statements.
+ */
+ AddLoop (BreakLabel, LoopLabel);
/* Define the head label */
- g_defcodelabel (loop);
+ g_defcodelabel (LoopLabel);
/* Test the loop condition */
- test (lab, 0);
+ TestInParens (BreakLabel, 0);
+
+ /* Loop body */
+ Statement (&PendingToken);
+
+ /* Jump back to loop top */
+ g_jump (LoopLabel);
+
+ /* Exit label */
+ g_defcodelabel (BreakLabel);
- /* If the statement following the while loop is empty, that is, we have
- * something like "while (1) ;", the test function ommitted the jump as
- * an optimization. Since we know, the condition codes are set, we can
- * do another small optimization here, and use a conditional jump
- * instead an absolute one.
+ /* Eat remaining tokens that were delayed because of line info
+ * correctness
*/
- if (CurTok.Tok == TOK_SEMI) {
- /* Use a conditional jump */
- g_truejump (CF_NONE, loop);
- /* Shortcut */
- NextToken ();
- } else {
- /* There is code inside the while loop, parse the body */
- Statement (&PendingToken);
- g_jump (loop);
- g_defcodelabel (lab);
- SkipPending (PendingToken);
- }
+ SkipPending (PendingToken);
/* Remove the loop from the loop stack */
DelLoop ();
static void ReturnStatement (void)
/* Handle the 'return' statement */
{
- struct expent lval;
+ ExprDesc Expr;
NextToken ();
if (CurTok.Tok != TOK_SEMI) {
- if (HasVoidReturn (CurrentFunc)) {
+
+ /* Check if the function has a return value declared */
+ if (F_HasVoidReturn (CurrentFunc)) {
Error ("Returning a value in function with return type void");
}
- /* Evaluate the return expression. Result will be in primary */
- expression (&lval);
+ /* Evaluate the return expression */
+ hie0 (&Expr);
- /* Convert the return value to the type of the function result */
- if (!HasVoidReturn (CurrentFunc)) {
- assignadjust (GetReturnType (CurrentFunc), &lval);
+ /* Ignore the return expression if the function returns void */
+ if (!F_HasVoidReturn (CurrentFunc)) {
+
+ /* Convert the return value to the type of the function result */
+ TypeConversion (&Expr, F_GetReturnType (CurrentFunc));
+
+ /* Load the value into the primary */
+ LoadExpr (CF_NONE, &Expr);
}
- } else if (!HasVoidReturn (CurrentFunc)) {
- Error ("Function `%s' must return a value", GetFuncName (CurrentFunc));
+
+ } else if (!F_HasVoidReturn (CurrentFunc) && !F_HasOldStyleIntRet (CurrentFunc)) {
+ Error ("Function `%s' must return a value", F_GetFuncName (CurrentFunc));
}
/* Cleanup the stack in case we're inside a block with locals */
- g_space (oursp - GetTopLevelSP (CurrentFunc));
+ g_space (StackPtr - F_GetTopLevelSP (CurrentFunc));
/* Output a jump to the function exit code */
- g_jump (GetRetLab (CurrentFunc));
+ g_jump (F_GetRetLab (CurrentFunc));
}
/* Check if we are inside a loop */
if (L == 0) {
- /* Error: No current loop */
- Error ("`break' statement not within loop or switch");
- return;
+ /* Error: No current loop */
+ Error ("`break' statement not within loop or switch");
+ return;
}
/* Correct the stack pointer if needed */
- g_space (oursp - L->StackPtr);
+ g_space (StackPtr - L->StackPtr);
/* Jump to the exit label of the loop */
- g_jump (L->Label);
+ g_jump (L->BreakLabel);
}
/* Get the current loop descriptor */
L = CurrentLoop ();
if (L) {
- /* Search for the correct loop */
- do {
- if (L->Loop) {
- break;
- }
- L = L->Next;
- } while (L);
+ /* Search for a loop that has a continue label. */
+ do {
+ if (L->ContinueLabel) {
+ break;
+ }
+ L = L->Next;
+ } while (L);
}
/* Did we find it? */
if (L == 0) {
- Error ("`continue' statement not within a loop");
- return;
+ Error ("`continue' statement not within a loop");
+ return;
}
/* Correct the stackpointer if needed */
- g_space (oursp - L->StackPtr);
+ g_space (StackPtr - L->StackPtr);
- /* Output the loop code */
- if (L->linc) {
- g_jump (L->linc);
- } else {
- g_jump (L->Loop);
- }
-}
-
-
-
-static void CascadeSwitch (struct expent* eval)
-/* Handle a switch statement for chars with a cmp cascade for the selector */
-{
- unsigned ExitLab; /* Exit label */
- unsigned NextLab; /* Next case label */
- unsigned CodeLab; /* Label that starts the actual selector code */
- int HaveBreak; /* Remember if we exited with break */
- int HaveDefault; /* Remember if we had a default label */
- int lcount; /* Label count */
- unsigned Flags; /* Code generator flags */
- struct expent lval; /* Case label expression */
- long Val; /* Case label value */
-
-
- /* Create a loop so we may break out, init labels */
- ExitLab = GetLocalLabel ();
- AddLoop (oursp, 0, ExitLab, 0, 0);
-
- /* Setup some variables needed in the loop below */
- Flags = TypeOf (eval->e_tptr) | CF_CONST | CF_FORCECHAR;
- CodeLab = NextLab = 0;
- HaveBreak = 1;
- HaveDefault = 0;
-
- /* Parse the labels */
- lcount = 0;
- while (CurTok.Tok != TOK_RCURLY) {
-
- if (CurTok.Tok == TOK_CASE || CurTok.Tok == TOK_DEFAULT) {
-
- /* If the code for the previous selector did not end with a
- * break statement, we must jump over the next selector test.
- */
- if (!HaveBreak) {
- /* Define a label for the code */
- if (CodeLab == 0) {
- CodeLab = GetLocalLabel ();
- }
- g_jump (CodeLab);
- }
-
- /* If we have a cascade label, emit it */
- if (NextLab) {
- g_defcodelabel (NextLab);
- NextLab = 0;
- }
-
- while (CurTok.Tok == TOK_CASE || CurTok.Tok == TOK_DEFAULT) {
-
- /* Parse the selector */
- if (CurTok.Tok == TOK_CASE) {
-
- /* Count labels */
- ++lcount;
-
- /* Skip the "case" token */
- NextToken ();
-
- /* Read the selector expression */
- constexpr (&lval);
- if (!IsClassInt (lval.e_tptr)) {
- Error ("Switch quantity not an integer");
- }
-
- /* Check the range of the expression */
- Val = lval.e_const;
- switch (*eval->e_tptr) {
-
- case T_SCHAR:
- /* Signed char */
- if (Val < -128 || Val > 127) {
- Error ("Range error");
- }
- break;
-
- case T_UCHAR:
- if (Val < 0 || Val > 255) {
- Error ("Range error");
- }
- break;
-
- case T_INT:
- if (Val < -32768 || Val > 32767) {
- Error ("Range error");
- }
- break;
-
- case T_UINT:
- if (Val < 0 || Val > 65535) {
- Error ("Range error");
- }
- break;
-
- default:
- Internal ("Invalid type: %02X", *eval->e_tptr & 0xFF);
- }
-
- /* Emit a compare */
- g_cmp (Flags, Val);
-
- /* If another case follows, we will jump to the code if
- * the condition is true.
- */
- if (CurTok.Tok == TOK_CASE) {
- /* Create a code label if needed */
- if (CodeLab == 0) {
- CodeLab = GetLocalLabel ();
- }
- g_falsejump (CF_NONE, CodeLab);
- } else if (CurTok.Tok != TOK_DEFAULT) {
- /* No case follows, jump to next selector */
- if (NextLab == 0) {
- NextLab = GetLocalLabel ();
- }
- g_truejump (CF_NONE, NextLab);
- }
-
- /* Skip the colon */
- ConsumeColon ();
-
- } else {
-
- /* Default case */
- NextToken ();
-
- /* Handle the pathologic case: DEFAULT followed by CASE */
- if (CurTok.Tok == TOK_CASE) {
- if (CodeLab == 0) {
- CodeLab = GetLocalLabel ();
- }
- g_jump (CodeLab);
- }
-
- /* Skip the colon */
- ConsumeColon ();
-
- /* Remember that we had a default label */
- HaveDefault = 1;
- }
-
- }
-
- }
-
- /* Emit a code label if we have one */
- if (CodeLab) {
- g_defcodelabel (CodeLab);
- CodeLab = 0;
- }
-
- /* Parse statements */
- if (CurTok.Tok != TOK_RCURLY) {
- HaveBreak = Statement (0);
- }
- }
-
- /* Check if we have any labels */
- if (lcount == 0 && !HaveDefault) {
- Warning ("No case labels");
- }
-
- /* Define the exit label and, if there's a next label left, create this
- * one, too.
- */
- if (NextLab) {
- g_defcodelabel (NextLab);
- }
- g_defcodelabel (ExitLab);
-
- /* Eat the closing curly brace */
- NextToken ();
-
- /* End the loop */
- DelLoop ();
-}
-
-
-
-static void TableSwitch (struct expent* eval)
-/* Handle a switch statement via table based selector */
-{
- /* Entry for one case in a switch statement */
- struct swent {
- long sw_const; /* selector value */
- unsigned sw_lab; /* label for this selector */
- };
-
- int dlabel; /* for default */
- int lab; /* exit label */
- int label; /* label for case */
- int lcase; /* label for compares */
- int lcount; /* Label count */
- int HaveBreak; /* Last statement has a break */
- int HaveDefault; /* Remember if we had a default label */
- unsigned Flags; /* Code generator flags */
- struct expent lval; /* Case label expression */
- struct swent *p;
- struct swent *swtab;
-
- /* Allocate memory for the switch table */
- swtab = xmalloc (CASE_MAX * sizeof (struct swent));
-
- /* Create a look so we may break out, init labels */
- HaveBreak = 0; /* Keep gcc silent */
- HaveDefault = 0; /* No default case until now */
- dlabel = 0; /* init */
- lab = GetLocalLabel (); /* get exit */
- p = swtab;
- AddLoop (oursp, 0, lab, 0, 0);
-
- /* Jump behind the code for the CASE labels */
- g_jump (lcase = GetLocalLabel ());
- lcount = 0;
- while (CurTok.Tok != TOK_RCURLY) {
- if (CurTok.Tok == TOK_CASE || CurTok.Tok == TOK_DEFAULT) {
- if (lcount >= CASE_MAX) {
- Fatal ("Too many case labels");
- }
- label = GetLocalLabel ();
- do {
- if (CurTok.Tok == TOK_CASE) {
- NextToken ();
- constexpr (&lval);
- if (!IsClassInt (lval.e_tptr)) {
- Error ("Switch quantity not an integer");
- }
- p->sw_const = lval.e_const;
- p->sw_lab = label;
- ++p;
- ++lcount;
- } else {
- NextToken ();
- dlabel = label;
- HaveDefault = 1;
- }
- ConsumeColon ();
- } while (CurTok.Tok == TOK_CASE || CurTok.Tok == TOK_DEFAULT);
- g_defcodelabel (label);
- HaveBreak = 0;
- }
- if (CurTok.Tok != TOK_RCURLY) {
- HaveBreak = Statement (0);
- }
- }
-
- /* Check if we have any labels */
- if (lcount == 0 && !HaveDefault) {
- Warning ("No case labels");
- }
-
- /* Eat the closing curly brace */
- NextToken ();
-
- /* If the last statement doesn't have a break or return, add one */
- if (!HaveBreak) {
- g_jump (lab);
- }
-
- /* Actual selector code goes here */
- g_defcodelabel (lcase);
-
- /* Create the call to the switch subroutine */
- Flags = TypeOf (eval->e_tptr);
- g_switch (Flags);
-
- /* First entry is negative of label count */
- g_defdata (CF_INT | CF_CONST, -((int)lcount)-1, 0);
-
- /* Create the case selector table */
- p = swtab;
- while (lcount) {
- g_case (Flags, p->sw_lab, p->sw_const); /* Create one label */
- --lcount;
- ++p;
- }
-
- if (dlabel) {
- g_jump (dlabel);
- }
- g_defcodelabel (lab);
- DelLoop ();
-
- /* Free the allocated space for the labels */
- xfree (swtab);
-}
-
-
-
-static void SwitchStatement (void)
-/* Handle a 'switch' statement */
-{
- struct expent eval; /* Switch statement expression */
-
- /* Eat the "switch" */
- NextToken ();
-
- /* Read the switch expression */
- ConsumeLParen ();
- intexpr (&eval);
- ConsumeRParen ();
-
- /* result of expr is in P */
- ConsumeLCurly ();
-
- /* Now decide which sort of switch we will create: */
- if (IsTypeChar (eval.e_tptr) || (CodeSizeFactor >= 200 && IsClassInt (eval.e_tptr))) {
- CascadeSwitch (&eval);
- } else {
- TableSwitch (&eval);
- }
+ /* Jump to next loop iteration */
+ g_jump (L->ContinueLabel);
}
static void ForStatement (void)
/* Handle a 'for' statement */
{
- struct expent lval1;
- struct expent lval2;
- struct expent lval3;
+ ExprDesc lval1;
+ ExprDesc lval3;
+ int HaveIncExpr;
+ CodeMark IncExprStart;
+ CodeMark IncExprEnd;
int PendingToken;
/* Get several local labels needed later */
- unsigned TestLabel = GetLocalLabel ();
- unsigned lab = GetLocalLabel ();
- unsigned IncLabel = GetLocalLabel ();
- unsigned lstat = GetLocalLabel ();
+ unsigned TestLabel = GetLocalLabel ();
+ unsigned BreakLabel = GetLocalLabel ();
+ unsigned IncLabel = GetLocalLabel ();
+ unsigned BodyLabel = GetLocalLabel ();
/* Skip the FOR token */
NextToken ();
- /* Add the loop to the loop stack */
- AddLoop (oursp, TestLabel, lab, IncLabel, lstat);
+ /* Add the loop to the loop stack. A continue jumps to the start of the
+ * the increment condition.
+ */
+ AddLoop (BreakLabel, IncLabel);
/* Skip the opening paren */
ConsumeLParen ();
/* Parse the initializer expression */
if (CurTok.Tok != TOK_SEMI) {
- expression (&lval1);
+ Expression0 (&lval1);
}
ConsumeSemi ();
/* Parse the test expression */
if (CurTok.Tok != TOK_SEMI) {
- boolexpr (&lval2);
- g_truejump (CF_NONE, lstat);
- g_jump (lab);
+ Test (BodyLabel, 1);
+ g_jump (BreakLabel);
} else {
- g_jump (lstat);
+ g_jump (BodyLabel);
}
ConsumeSemi ();
+ /* Remember the start of the increment expression */
+ GetCodePos (&IncExprStart);
+
/* Label for the increment expression */
g_defcodelabel (IncLabel);
/* Parse the increment expression */
- if (CurTok.Tok != TOK_RPAREN) {
- expression (&lval3);
+ HaveIncExpr = (CurTok.Tok != TOK_RPAREN);
+ if (HaveIncExpr) {
+ Expression0 (&lval3);
}
/* Jump to the test */
g_jump (TestLabel);
+ /* Remember the end of the increment expression */
+ GetCodePos (&IncExprEnd);
+
/* Skip the closing paren */
ConsumeRParen ();
/* Loop body */
- g_defcodelabel (lstat);
+ g_defcodelabel (BodyLabel);
Statement (&PendingToken);
- /* Jump back to the increment expression */
- g_jump (IncLabel);
-
+ /* If we had an increment expression, move the code to the bottom of
+ * the loop. In this case we don't need to jump there at the end of
+ * the loop body.
+ */
+ if (HaveIncExpr) {
+ CodeMark Here;
+ GetCodePos (&Here);
+ MoveCode (&IncExprStart, &IncExprEnd, &Here);
+ } else {
+ /* Jump back to the increment expression */
+ g_jump (IncLabel);
+ }
+
/* Skip a pending token if we have one */
SkipPending (PendingToken);
/* Declare the break label */
- g_defcodelabel (lab);
+ g_defcodelabel (BreakLabel);
/* Remove the loop from the loop stack */
DelLoop ();
int GotBreak;
/* Remember the stack at block entry */
- int OldStack = oursp;
+ int OldStack = StackPtr;
/* Enter a new lexical level */
EnterBlockLevel ();
/* Clean up the stack. */
if (!GotBreak) {
- g_space (oursp - OldStack);
+ g_space (StackPtr - OldStack);
}
- oursp = OldStack;
+ StackPtr = OldStack;
/* Emit references to imports/exports for this block */
EmitExternals ();
* NULL, the function will skip the token.
*/
{
- struct expent lval;
+ ExprDesc Expr;
int GotBreak;
+ CodeMark Start, End;
/* Assume no pending token */
if (PendingToken) {
case TOK_SEMI:
/* Ignore it */
- NextToken ();
+ CheckSemi (PendingToken);
break;
case TOK_PRAGMA:
DoPragma ();
- break;
+ break;
default:
+ /* Remember the current code position */
+ GetCodePos (&Start);
/* Actual statement */
- expression (&lval);
+ ExprWithCheck (hie0, &Expr);
+ /* Load the result only if it is an lvalue and the type is
+ * marked as volatile. Otherwise the load is useless.
+ */
+ if (ED_IsLVal (&Expr) && IsQualVolatile (Expr.Type)) {
+ LoadExpr (CF_NONE, &Expr);
+ }
+ /* If the statement didn't generate code, and is not of type
+ * void, emit a warning.
+ */
+ GetCodePos (&End);
+ if (CodeRangeIsEmpty (&Start, &End) && !IsTypeVoid (Expr.Type)) {
+ Warning ("Statement has no effect");
+ }
CheckSemi (PendingToken);
}
}
+