/**
* 翻译for 语句
*
* for (expr1; expr2; expr3) stmt is translated into
* expr1
* goto testBB
* loopBB:
* stmt
* contBB:
* expr3
* testBB:
* if expr2 goto loopBB (goto loopBB if expr2 is NULL)
* nextBB:
* ...
* Please pay attention to the difference between for and while
* The continue point and loop test point is same for a while statemnt,
* but different for a for statment.
*/
static void TranslateForStatement(AstStatement stmt)
{
AstForStatement forStmt = AsFor(stmt);
forStmt->loopBB = CreateBBlock ();
forStmt->contBB = CreateBBlock ();
forStmt->testBB = CreateBBlock ();
forStmt->nextBB = CreateBBlock ();
/* for 的初始条件 */
if (forStmt->initExpr) {
TranslateExpression (forStmt->initExpr);
}
/* 跳转到条件判断 */
GenerateJump (forStmt->testBB);
/* 循环体 */
StartBBlock (forStmt->loopBB);
TranslateStatement (forStmt->stmt);
/* 步长 */
StartBBlock (forStmt->contBB);
if (forStmt->incrExpr) {
TranslateExpression (forStmt->incrExpr);
}
/* 测试条件,是否跳转 */
StartBBlock (forStmt->testBB);
if (forStmt->expr) {
TranslateBranch (forStmt->expr, forStmt->loopBB, forStmt->nextBB);
} else {
GenerateJump (forStmt->loopBB);
}
StartBBlock (forStmt->nextBB);
}
static void DumpStatement(AstStatement stmt, int pos)
{
switch (stmt->kind)
{
case NK_ExpressionStatement:
DumpExpression(AsExpr(stmt)->expr, pos);
break;
case NK_LabelStatement:
fprintf(ASTFile, "(label %s:\n", AsLabel(stmt)->id);
LeftAlign(ASTFile, pos + 2);
DumpStatement(AsLabel(stmt)->stmt, pos + 2);
LeftAlign(ASTFile, pos);
fprintf(ASTFile, "end-label)");
break;
case NK_CaseStatement:
fprintf(ASTFile, "(case ");
DumpExpression(AsCase(stmt)->expr, pos + 7);
LeftAlign(ASTFile, pos + 2);
DumpStatement(AsCase(stmt)->stmt, pos + 2);
LeftAlign(ASTFile, pos);
fprintf(ASTFile, "end-case)");
break;
case NK_DefaultStatement:
fprintf(ASTFile, "(default ");
DumpStatement(AsDef(stmt)->stmt, pos + 10);
LeftAlign(ASTFile, pos);
fprintf(ASTFile, "end-default)");
break;
case NK_IfStatement:
fprintf(ASTFile, "(if ");
DumpExpression(AsIf(stmt)->expr, pos + 5);
LeftAlign(ASTFile, pos + 2);
fprintf(ASTFile, "(then ");
LeftAlign(ASTFile, pos + 4);
DumpStatement(AsIf(stmt)->thenStmt, pos + 4);
LeftAlign(ASTFile, pos + 2);
fprintf(ASTFile, "end-then)");
if (AsIf(stmt)->elseStmt != NULL)
{
LeftAlign(ASTFile, pos + 2);
fprintf(ASTFile, "(else ");
LeftAlign(ASTFile, pos + 4);
DumpStatement(AsIf(stmt)->elseStmt, pos + 4);
LeftAlign(ASTFile, pos + 2);
fprintf(ASTFile, "end-else)");
}
LeftAlign(ASTFile, pos);
fprintf(ASTFile, "end-if)");
break;
case NK_SwitchStatement:
fprintf(ASTFile, "(switch ");
DumpExpression(AsSwitch(stmt)->expr, pos + 9);
LeftAlign(ASTFile, pos + 2);
DumpStatement(AsSwitch(stmt)->stmt, pos + 2);
LeftAlign(ASTFile, pos);
fprintf(ASTFile, "end-switch)");
break;
case NK_WhileStatement:
fprintf(ASTFile, "(while ");
DumpExpression(AsLoop(stmt)->expr, pos + 8);
LeftAlign(ASTFile, pos + 2);
DumpStatement(AsLoop(stmt)->stmt, pos + 2);
LeftAlign(ASTFile, pos);
fprintf(ASTFile, "end-while)");
break;
case NK_DoStatement:
fprintf(ASTFile, "(do ");
DumpExpression(AsLoop(stmt)->expr, pos + 5);
LeftAlign(ASTFile, pos + 2);
DumpStatement(AsLoop(stmt)->stmt, pos + 2);
LeftAlign(ASTFile, pos);
fprintf(ASTFile, ")");
break;
case NK_ForStatement:
fprintf(ASTFile, "(for ");
DumpExpression(AsFor(stmt)->initExpr, pos + 6);
LeftAlign(ASTFile, pos + 6);
DumpExpression(AsFor(stmt)->expr, pos + 6);
LeftAlign(ASTFile, pos + 6);
DumpExpression(AsFor(stmt)->incrExpr, pos + 6);
LeftAlign(ASTFile, pos + 2);
DumpStatement(AsFor(stmt)->stmt, pos + 2);
LeftAlign(ASTFile, pos);
fprintf(ASTFile, "end-for)");
break;
case NK_GotoStatement:
fprintf(ASTFile, "(goto %s)", AsGoto(stmt)->id);
break;
case NK_ContinueStatement:
fprintf(ASTFile, "(continue)");
break;
case NK_BreakStatement:
fprintf(ASTFile, "(break)");
break;
case NK_ReturnStatement:
fprintf(ASTFile, "(ret ");
DumpExpression(AsRet(stmt)->expr, pos + 5);
fprintf(ASTFile, ")");
break;
case NK_CompoundStatement:
{
AstNode p = ((AstCompoundStatement)stmt)->stmts;
fprintf(ASTFile, "{");
while (p != NULL)
{
LeftAlign(ASTFile, pos + 2);
DumpStatement((AstStatement)p, pos + 2);
if (p->next != NULL)
fprintf(ASTFile, "\n");
p = p->next;
}
LeftAlign(ASTFile, pos);
fprintf(ASTFile, "}");
break;
}
default:
assert(0);
}
}
