/**
* 翻译break 语句
* A break statement terminates the execution of associated
* switch or loop.
*
* break is translated into:
* goto switch or loop's nextBB
* nextBB:
* ...
*/
static void TranslateBreakStatement (AstStatement stmt)
{
AstBreakStatement brkStmt = AsBreak(stmt);
if (brkStmt->target->kind == NK_SwitchStatement) {
/* switch 在跳转 */
GenerateJump (AsSwitch(brkStmt->target)->nextBB);
} else {
/* loop 跳转 */
GenerateJump (AsLoop(brkStmt->target)->nextBB);
}
StartBBlock (CreateBBlock ());
}
/* 翻译switch 语句
* 创建case default 基本块 */
static void TranslateSwitchStatement (AstStatement stmt)
{
AstSwitchStatement swtchStmt = AsSwitch(stmt);
AstCaseStatement p, q;
SwitchBucket bucket, b;
SwitchBucket *bucketArray;
int i, val;
Symbol sym;
/* 翻译switch 的表达式 */
sym = TranslateExpression (swtchStmt->expr);
bucket = b = NULL;
p = swtchStmt->cases;
/* 创建基本块, 并给case 语句排序 */
while ( p ) {
q = p;
p = p->nextCase;
/* 给case 创建基本块 */
q->respBB = CreateBBlock ();
/* case 的表达式 */
val = q->expr->val.i[0];
if (bucket && (bucket->ncase + 1) * 2 > (val - bucket->minVal)) {
bucket->ncase++;
bucket->maxVal = val;
*bucket->tail = q;
bucket->tail = &(q->nextCase);
swtchStmt->nbucket -= MergeSwitchBucket (&bucket);
} else {
CALLOC(b);
b->cases = q;
b->ncase = 1;
/* 初始化最小大值 */
b->minVal = b->maxVal = val;
b->tail = &(q->nextCase);
b->prev = bucket;
bucket = b;
swtchStmt->nbucket++;
}
}
swtchStmt->buckets = bucket;
bucketArray = HeapAllocate (CurrentHeap, swtchStmt->nbucket * sizeof (SwitchBucket));
for (i = swtchStmt->nbucket - 1; i >= 0; i--) {
bucketArray[i] = bucket;
*bucket->tail = NULL;
bucket = bucket->prev;
}
/* default 语句 */
swtchStmt->defBB = CreateBBlock();
if (swtchStmt->defStmt) {
swtchStmt->defStmt->respBB = swtchStmt->defBB;
swtchStmt->nextBB = CreateBBlock();
} else {
swtchStmt->nextBB = swtchStmt->defBB;
}
TranslateSwitchBuckets (bucketArray, 0, swtchStmt->nbucket - 1, sym, NULL, swtchStmt->defBB);
TranslateStatement (swtchStmt->stmt);
StartBBlock (swtchStmt->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);
}
}
