static void WhileStatement (void) /* Handle the 'while' statement */ { int PendingToken; CodeMark CondCodeStart; /* Start of condition evaluation code */ CodeMark CondCodeEnd; /* End of condition evaluation code */ CodeMark Here; /* "Here" location of code */ /* Get the loop control labels */ unsigned LoopLabel = GetLocalLabel (); unsigned BreakLabel = GetLocalLabel (); unsigned CondLabel = GetLocalLabel (); /* Skip the while token */ NextToken (); /* Add the loop to the loop stack. In case of a while loop, the condition ** label is used for continue statements. */ AddLoop (BreakLabel, CondLabel); /* We will move the code that evaluates the while condition to the end of ** the loop, so generate a jump here. */ g_jump (CondLabel); /* Remember the current position */ GetCodePos (&CondCodeStart); /* Emit the code position label */ g_defcodelabel (CondLabel); /* Test the loop condition */ TestInParens (LoopLabel, 1); /* Remember the end of the condition evaluation code */ GetCodePos (&CondCodeEnd); /* Define the head label */ g_defcodelabel (LoopLabel); /* Loop body */ Statement (&PendingToken); /* Move the test code here */ GetCodePos (&Here); MoveCode (&CondCodeStart, &CondCodeEnd, &Here); /* Exit label */ g_defcodelabel (BreakLabel); /* Eat remaining tokens that were delayed because of line info ** correctness */ SkipPending (PendingToken); /* Remove the loop from the loop stack */ DelLoop (); }
static void ParseArg (ArgDesc* Arg, Type* Type) /* Parse one argument but do not push it onto the stack. Make all fields in * Arg valid. */ { /* We have a prototype, so chars may be pushed as chars */ Arg->Flags = CF_FORCECHAR; /* Remember the required argument type */ Arg->ArgType = Type; /* Read the expression we're going to pass to the function */ MarkedExprWithCheck (hie1, &Arg->Expr); /* Remember the actual argument type */ Arg->Type = Arg->Expr.Type; /* Convert this expression to the expected type */ TypeConversion (&Arg->Expr, Type); /* Remember the following code position */ GetCodePos (&Arg->Load); /* If the value is a constant, set the flag, otherwise load it into the * primary register. */ if (ED_IsConstAbsInt (&Arg->Expr) && ED_CodeRangeIsEmpty (&Arg->Expr)) { /* Remember that we have a constant value */ Arg->Flags |= CF_CONST; } else { /* Load into the primary */ LoadExpr (CF_NONE, &Arg->Expr); } /* Remember the following code position */ GetCodePos (&Arg->Push); GetCodePos (&Arg->End); /* Use the type of the argument for the push */ Arg->Flags |= TypeOf (Arg->Expr.Type); }
void SwitchStatement (void) /* Handle a switch statement for chars with a cmp cascade for the selector */ { ExprDesc SwitchExpr; /* Switch statement expression */ CodeMark CaseCodeStart; /* Start of code marker */ CodeMark SwitchCodeStart;/* Start of switch code */ CodeMark SwitchCodeEnd; /* End of switch code */ unsigned ExitLabel; /* Exit label */ unsigned SwitchCodeLabel;/* Label for the switch code */ int HaveBreak = 0; /* True if the last statement had a break */ int RCurlyBrace; /* True if last token is right curly brace */ SwitchCtrl* OldSwitch; /* Pointer to old switch control data */ SwitchCtrl SwitchData; /* New switch data */ /* Eat the "switch" token */ NextToken (); /* Read the switch expression and load it into the primary. It must have * integer type. */ ConsumeLParen (); Expression0 (&SwitchExpr); if (!IsClassInt (SwitchExpr.Type)) { Error ("Switch quantity is not an integer"); /* To avoid any compiler errors, make the expression a valid int */ ED_MakeConstAbsInt (&SwitchExpr, 1); } ConsumeRParen (); /* Add a jump to the switch code. This jump is usually unnecessary, * because the switch code will moved up just behind the switch * expression. However, in rare cases, there's a label at the end of * the switch expression. This label will not get moved, so the code * jumps around the switch code, and after moving the switch code, * things look really weird. If we add a jump here, we will never have * a label attached to the current code position, and the jump itself * will get removed by the optimizer if it is unnecessary. */ SwitchCodeLabel = GetLocalLabel (); g_jump (SwitchCodeLabel); /* Remember the current code position. We will move the switch code * to this position later. */ GetCodePos (&CaseCodeStart); /* Setup the control structure, save the old and activate the new one */ SwitchData.Nodes = NewCollection (); SwitchData.ExprType = UnqualifiedType (SwitchExpr.Type[0].C); SwitchData.Depth = SizeOf (SwitchExpr.Type); SwitchData.DefaultLabel = 0; OldSwitch = Switch; Switch = &SwitchData; /* Get the exit label for the switch statement */ ExitLabel = GetLocalLabel (); /* Create a loop so we may use break. */ AddLoop (ExitLabel, 0); /* Make sure a curly brace follows */ if (CurTok.Tok != TOK_LCURLY) { Error ("`{' expected"); } /* Parse the following statement, which will actually be a compound * statement because of the curly brace at the current input position */ HaveBreak = Statement (&RCurlyBrace); /* Check if we had any labels */ if (CollCount (SwitchData.Nodes) == 0 && SwitchData.DefaultLabel == 0) { Warning ("No case labels"); } /* If the last statement did not have a break, we may have an open * label (maybe from an if or similar). Emitting code and then moving * this code to the top will also move the label to the top which is * wrong. So if the last statement did not have a break (which would * carry the label), add a jump to the exit. If it is useless, the * optimizer will remove it later. */ if (!HaveBreak) { g_jump (ExitLabel); } /* Remember the current position */ GetCodePos (&SwitchCodeStart); /* Output the switch code label */ g_defcodelabel (SwitchCodeLabel); /* Generate code */ if (SwitchData.DefaultLabel == 0) { /* No default label, use switch exit */ SwitchData.DefaultLabel = ExitLabel; } g_switch (SwitchData.Nodes, SwitchData.DefaultLabel, SwitchData.Depth); /* Move the code to the front */ GetCodePos (&SwitchCodeEnd); MoveCode (&SwitchCodeStart, &SwitchCodeEnd, &CaseCodeStart); /* Define the exit label */ g_defcodelabel (ExitLabel); /* Exit the loop */ DelLoop (); /* Switch back to the enclosing switch statement if any */ Switch = OldSwitch; /* Free the case value tree */ FreeCaseNodeColl (SwitchData.Nodes); /* If the case statement was (correctly) terminated by a closing curly * brace, skip it now. */ if (RCurlyBrace) { NextToken (); } }
int Statement (int* PendingToken) /* Statement parser. Returns 1 if the statement does a return/break, returns ** 0 otherwise. If the PendingToken pointer is not NULL, the function will ** not skip the terminating token of the statement (closing brace or ** semicolon), but store true if there is a pending token, and false if there ** is none. The token is always checked, so there is no need for the caller to ** check this token, it must be skipped, however. If the argument pointer is ** NULL, the function will skip the token. */ { ExprDesc Expr; int GotBreak; CodeMark Start, End; /* Assume no pending token */ if (PendingToken) { *PendingToken = 0; } /* Check for a label. A label is always part of a statement, it does not ** replace one. */ while (CurTok.Tok == TOK_IDENT && NextTok.Tok == TOK_COLON) { /* Handle the label */ DoLabel (); if (CheckLabelWithoutStatement ()) { return 0; } } switch (CurTok.Tok) { case TOK_LCURLY: NextToken (); GotBreak = CompoundStatement (); CheckTok (TOK_RCURLY, "`{' expected", PendingToken); return GotBreak; case TOK_IF: return IfStatement (); case TOK_WHILE: WhileStatement (); break; case TOK_DO: DoStatement (); break; case TOK_SWITCH: SwitchStatement (); break; case TOK_RETURN: ReturnStatement (); CheckSemi (PendingToken); return 1; case TOK_BREAK: BreakStatement (); CheckSemi (PendingToken); return 1; case TOK_CONTINUE: ContinueStatement (); CheckSemi (PendingToken); return 1; case TOK_FOR: ForStatement (); break; case TOK_GOTO: GotoStatement (); CheckSemi (PendingToken); return 1; case TOK_SEMI: /* Ignore it */ CheckSemi (PendingToken); break; case TOK_PRAGMA: DoPragma (); break; case TOK_CASE: CaseLabel (); CheckLabelWithoutStatement (); break; case TOK_DEFAULT: DefaultLabel (); CheckLabelWithoutStatement (); break; default: /* Remember the current code position */ GetCodePos (&Start); /* Actual statement */ 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) && IS_Get (&WarnNoEffect)) { Warning ("Statement has no effect"); } CheckSemi (PendingToken); } return 0; }
static void ForStatement (void) /* Handle a 'for' statement */ { ExprDesc lval1; ExprDesc lval3; int HaveIncExpr; CodeMark IncExprStart; CodeMark IncExprEnd; int PendingToken; /* Get several local labels needed later */ unsigned TestLabel = GetLocalLabel (); unsigned BreakLabel = GetLocalLabel (); unsigned IncLabel = GetLocalLabel (); unsigned BodyLabel = GetLocalLabel (); /* Skip the FOR token */ NextToken (); /* 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) { Expression0 (&lval1); } ConsumeSemi (); /* Label for the test expressions */ g_defcodelabel (TestLabel); /* Parse the test expression */ if (CurTok.Tok != TOK_SEMI) { Test (BodyLabel, 1); g_jump (BreakLabel); } else { 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 */ 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 (BodyLabel); Statement (&PendingToken); /* 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 (BreakLabel); /* Remove the loop from the loop stack */ DelLoop (); }