//13.<分支语句>—> if <布尔表达式> then <语句>
//| if <布尔表达式> then <语句> else <语句>
void switchStatement(){
if (lookahead == IF){
match(IF);
TFexit tf = booleaexpression();//真假出口
match(THEN);
//填真出口
BackPatch(tf.TC, sno);
statementlists();
if (lookahead == ELSE){
// 1 无条件跳转
int j = sno;
quadruples.push_back(Quadruple(sno++, 0,Val(),Val()));
match(ELSE);
//回填假出口
BackPatch(tf.FC, sno);
statementlists();
//回填 1 无条件跳转
BackPatch(j, sno);
}
else {
// 回填假出口
BackPatch(tf.FC, sno);
}
}
else{
error(24);
}
}
// This generates some fairly heavy trampolines, but it doesn't really hurt.
// Only instructions that access I/O will get these, and there won't be that
// many of them in a typical program/game.
bool Jitx86Base::HandleFault(uintptr_t access_address, SContext* ctx)
{
// TODO: do we properly handle off-the-end?
const auto base_ptr = reinterpret_cast<uintptr_t>(Memory::physical_base);
if (access_address >= base_ptr && access_address < base_ptr + 0x100010000)
return BackPatch(static_cast<u32>(access_address - base_ptr), ctx);
const auto logical_base_ptr = reinterpret_cast<uintptr_t>(Memory::logical_base);
if (access_address >= logical_base_ptr && access_address < logical_base_ptr + 0x100010000)
return BackPatch(static_cast<u32>(access_address - logical_base_ptr), ctx);
return false;
}
//14.<循环语句>—> while <布尔表达式> do <语句>
void loopStatement(){
match(WHILE);
//int boolId = 序号全局变量
int boolId = sno;
TFexit tf = booleaexpression();//真假出口
match(DO);
//回填真出口
BackPatch(tf.TC, sno);
statementlists();
//(j boolId)
quadruples.push_back(Quadruple(sno++, 0, Val(), Val(), boolId));
//回填假出口
BackPatch(tf.FC, sno);
}
TParseTables* GenerateParseTables(void)
{
size_t IP, IPStart;
int NNonTerms, NSymbols;
int iRule, iTerminal;
SymIt NonTerm;
TSymbol* Symbol;
TParseTables* Tables;
SYMBOLS LLNonTerms;
int Reduced;
int TerminalsEmitted;
printf("GenerateParseTables() begins\n");
Tables = NEW(TParseTables);
assert(Tables != NULL);
Tables->LLNonTerms = LLNonTerms = GetLLNonTerms(); /* get list of only nonterminals we care about */
/* assign integers to any undefined tokens */
DefineTokens(Tables);
IP = BLC_HDR_SIZE; /* skip over initial header containing 5 two-byte table sizes */
NNonTerms = SymbolListCount(LLNonTerms);
/* generate terminal symbol table */
IPStart = IP;
TerminalsEmitted = 0;
for(iTerminal=Tables->MinTokenVal; iTerminal <= Tables->MaxTokenVal; ++iTerminal)
{
Symbol = SymbolFromValue(iTerminal);
if(Symbol)
{
/* store token ID, followed by its null-terminated string */
IP = Store8(Tables, IP, iTerminal);
IP = StoreStr(Tables, IP, SymbolStr(Symbol));
++TerminalsEmitted;
}
}
IP = Store8(Tables, IP, 0); /* sentinel byte */
Store16(Tables, BLC_HDR_TERMSYMTAB_SIZE, IP - IPStart);
/* generate nonterminal symbol table */
IPStart = IP;
NonTerm = SymItNew(LLNonTerms);
while(SymbolIterate(&NonTerm))
{
IP = StoreStr(Tables, IP, SymbolStr(NonTerm.Symbol));
}
IP = Store8(Tables, IP, 0); /* sentinel byte */
Store16(Tables, BLC_HDR_NONTERMSYMTAB_SIZE, IP - IPStart);
/* for each production of <start>, add an entry point */
IPStart = IP;
Symbol = SymbolStart();
assert(Symbol != NULL);
for(iRule = 0; iRule < RuleCount(Symbol); ++iRule)
{
/* actual value will have to be backpatched */
MarkPatch(IP, AddRule(Tables, Symbol->Rules[iRule], Symbol));
IP = Store16(Tables, IP, 0);
}
Store16(Tables, BLC_HDR_ENTRYTABLE_SIZE, IP - IPStart);
/* for each nonterminal, generate its SELECT body*/
IPStart = IP;
Tables->SelSectOfs = IPStart;
NonTerm = SymItNew(LLNonTerms);
while(SymbolIterate(&NonTerm))
IP = GenerateSelect(Tables, IP, NonTerm.Symbol);
Store16(Tables, BLC_HDR_SELECTTABLE_SIZE, IP - IPStart);
Dump("Generate opcodes for each unique rule\n");
/* generate opcodes for each unique rule */
IPStart = IP;
Tables->RuleSectOfs = IPStart;
for(iRule = 0; iRule < Tables->NRules; ++iRule)
{
int iProdItem;
TRule* Rule = Tables->Rules[iRule];
IntAdd(&Tables->RuleOffsets, IP);
Reduced = FALSE; /* have not performed a reduction for this rule yet */
NSymbols = SymbolListCount(Rule->Symbols);
fprintf(stdout, "-> ");
SymbolListDump(stdout, Rule->Symbols, " ");
fprintf(stdout, "\n");
for(iProdItem = 0; iProdItem < NSymbols; ++iProdItem)
{
TSymbol* Symbol = SymbolListGet(Rule->Symbols, iProdItem);
if(SymbolGetBit(Symbol, SYM_TERMINAL))
{
IP = Store8(Tables, IP, BLCOP_MATCH);
IP = Store8(Tables, IP, Symbol->Value);
if(Symbol == SymbolFind(EOFToken))
{
IP = Store8(Tables, IP, BLCOP_HALT);
Reduced = TRUE;
}
}
else if(SymbolIsAction(Symbol))
{
int FinalAction, ArgCount;
assert(Rule->RuleId < 255);
assert(iProdItem < 255);
FinalAction = FALSE;
if(iProdItem == NSymbols-1)
FinalAction = TRUE;
else if(Rule->TailRecursive && iProdItem == NSymbols-2)
FinalAction = TRUE;
ArgCount = iProdItem;
if(Rule->TailRecursive == 2)
++ArgCount;
fprintf(stdout, "iProdItem=%d, NSymbols=%d,TailRecursive=%d,FinalAction=%d\n", iProdItem, NSymbols, Rule->TailRecursive, FinalAction);
IP = Store8(Tables, IP, FinalAction?BLCOP_ACTRED:BLCOP_ACTION8);
IP = Store8(Tables, IP, Symbol->Action->Number);
IP = Store8(Tables, IP, ArgCount);
Symbol->Action->ArgCount = ArgCount;
if(FinalAction)
Reduced = TRUE;
}
else if(SymbolListContains(LLNonTerms, Symbol)) /* non-terminal */
{
int iSymbol = SymbolListContains(LLNonTerms, Symbol);
if(RuleCount(Symbol) > 1)
{
if(Symbol->Name.Text[0] == '`') /* if a tail recursive rule... */
{
IP = Store8(Tables, IP, BLCOP_TAILSELECT);
IP = Store8(Tables, IP, iProdItem);
Reduced = TRUE; /* TAILSELECT opcode must do the reducing to shuffle stack correctly */
}
else
IP = Store8(Tables, IP, BLCOP_LLSELECT);
IP = Store16(Tables, IP, Symbol->SelectOffset);
}
/* else, only 1 rule to choose from, so just transfer control to that rule! */
else
{
int iRule = AddRule(Tables, Symbol->Rules[0], Symbol);
IP = Store8(Tables, IP, BLCOP_CALL);
IP = MarkPatch(IP, iRule);
}
assert(iSymbol>0); /* ???TODO why is this???*/
}
else // else, it's an operator trigger
{
assert(Symbol->LR0 != NULL);
fprintf(stderr, "watch out: we don't handle LR(0) yet!\n");
}
}
if(!Reduced)
{
IP = Store8(Tables, IP, BLCOP_REDUCE);
IP = Store8(Tables, IP, NSymbols);
}
}
Store16(Tables, BLC_HDR_RULEOPCODE_SIZE, IP - IPStart);
DumpVerbose("Backpatch opcode addresses.\n");
for(iRule = 0; iRule < Tables->NRules; ++iRule)
BackPatch(Tables, iRule, Tables->RuleOffsets.v[iRule] - IPStart);
DumpVerbose("Backpatching complete.\n");
assert(IP < (1024*64));
// Opcodes = realloc(Opcodes, IP * sizeof(Opcodes[0]));
Tables->NOpcodes = IP;
Dump("GenerateParseTables() returns after %d opcodes\n", Tables->NOpcodes);
return Tables;
}