Added while loops to DECORATE

This commit is contained in:
Leonard2 2016-07-25 06:38:02 +02:00 committed by Christoph Oelckers
parent c4eafc1c38
commit d1749233ec
5 changed files with 160 additions and 1 deletions

View file

@ -48,6 +48,7 @@
#define RESOLVE(p,c) if (p!=NULL) p = p->Resolve(c)
#define ABORT(p) if (!(p)) { delete this; return NULL; }
#define SAFE_RESOLVE(p,c) RESOLVE(p,c); ABORT(p)
#define SAFE_RESOLVE_OPT(p,c) if (p!=NULL) { SAFE_RESOLVE(p,c) }
class VMFunctionBuilder;
class FxJumpStatement;
@ -927,6 +928,24 @@ public:
ExpEmit Emit(VMFunctionBuilder *build);
};
//==========================================================================
//
// FxWhileLoop
//
//==========================================================================
class FxWhileLoop : public FxExpression
{
FxExpression *Condition;
FxExpression *Code;
public:
FxWhileLoop(FxExpression *condition, FxExpression *code, const FScriptPosition &pos);
~FxWhileLoop();
FxExpression *Resolve(FCompileContext&);
ExpEmit Emit(VMFunctionBuilder *build);
};
//==========================================================================
//
// FxJumpStatement

View file

@ -3857,6 +3857,107 @@ ExpEmit FxIfStatement::Emit(VMFunctionBuilder *build)
return ExpEmit();
}
//==========================================================================
//
// FxWhileLoop
//
//==========================================================================
FxWhileLoop::FxWhileLoop(FxExpression *condition, FxExpression *code, const FScriptPosition &pos)
: FxExpression(pos), Condition(condition), Code(code)
{
ValueType = TypeVoid;
}
FxWhileLoop::~FxWhileLoop()
{
SAFE_DELETE(Condition);
SAFE_DELETE(Code);
}
FxExpression *FxWhileLoop::Resolve(FCompileContext &ctx)
{
CHECKRESOLVED();
SAFE_RESOLVE(Condition, ctx);
SAFE_RESOLVE_OPT(Code, ctx);
ctx.HandleJumps(TK_Break, this);
ctx.HandleJumps(TK_Continue, this);
if (Condition->ValueType != TypeBool)
{
Condition = new FxBoolCast(Condition);
SAFE_RESOLVE(Condition, ctx);
}
if (Condition->isConstant())
{
if (static_cast<FxConstant *>(Condition)->GetValue().GetBool() == false)
{ // Nothing happens
FxExpression *nop = new FxNop(ScriptPosition);
delete this;
return nop;
}
else if (Code == nullptr)
{ // "while (true) { }"
// Someone could be using this for testing.
ScriptPosition.Message(MSG_WARNING, "Infinite empty loop");
}
}
return this;
}
ExpEmit FxWhileLoop::Emit(VMFunctionBuilder *build)
{
assert(Condition->ValueType == TypeBool);
size_t loopstart, loopend;
size_t jumpspot;
// Evaluate the condition and execute/break out of the loop.
loopstart = build->GetAddress();
if (!Condition->isConstant())
{
ExpEmit cond = Condition->Emit(build);
build->Emit(OP_TEST, cond.RegNum, 0);
jumpspot = build->Emit(OP_JMP, 0);
cond.Free(build);
}
else assert(static_cast<FxConstant *>(Condition)->GetValue().GetBool() == true);
// Execute the loop's content.
if (Code != nullptr)
{
ExpEmit code = Code->Emit(build);
code.Free(build);
}
// Loop back.
build->Backpatch(build->Emit(OP_JMP, 0), loopstart);
loopend = build->GetAddress();
if (!Condition->isConstant())
{
build->Backpatch(jumpspot, loopend);
}
// Give a proper address to any break/continue statement within this loop.
for (unsigned int i = 0; i < JumpAddresses.Size(); i++)
{
if (JumpAddresses[i]->Token == TK_Break)
{
build->Backpatch(JumpAddresses[i]->Address, loopend);
}
else
{ // Continue statement.
build->Backpatch(JumpAddresses[i]->Address, loopstart);
}
}
return ExpEmit();
}
//==========================================================================
//
// FxJumpStatement

View file

@ -480,6 +480,27 @@ static FxExpression *ParseIf(FScanner &sc, FState state, FString statestring, Ba
return add;
}
static FxExpression *ParseWhile(FScanner &sc, FState state, FString statestring, Baggage &bag,
PPrototype *&retproto, bool &lastwasret)
{
FxExpression *cond, *code;
PPrototype *proto;
bool ret;
sc.MustGetStringName("(");
cond = ParseExpression(sc, bag.Info);
sc.MustGetStringName(")");
sc.MustGetStringName("{"); // Enforce braces like for if statements.
code = ParseActions(sc, state, statestring, bag, proto, ret);
sc.MustGetString();
retproto = ReturnCheck(retproto, proto, sc);
lastwasret = false; // A while loop always jumps back.
return new FxWhileLoop(cond, code, sc);
}
FxExpression *ParseActions(FScanner &sc, FState state, FString statestring, Baggage &bag,
PPrototype *&retproto, bool &endswithret)
{
@ -505,9 +526,13 @@ FxExpression *ParseActions(FScanner &sc, FState state, FString statestring, Bagg
FxExpression *add;
lastwasret = false;
if (sc.Compare("if"))
{ // Hangle an if statement
{ // Handle an if statement
add = ParseIf(sc, state, statestring, bag, proto, lastwasret);
}
else if (sc.Compare("while"))
{ // Handle a while loop
add = ParseWhile(sc, state, statestring, bag, proto, lastwasret);
}
else if (sc.Compare("return"))
{ // Handle a return statement
lastwasret = true;

View file

@ -436,6 +436,17 @@ bool VMFunctionBuilder::RegAvailability::Reuse(int reg)
return true;
}
//==========================================================================
//
// VMFunctionBuilder :: GetAddress
//
//==========================================================================
size_t VMFunctionBuilder::GetAddress()
{
return Code.Size();
}
//==========================================================================
//
// VMFunctionBuilder :: Emit

View file

@ -34,6 +34,9 @@ public:
int GetConstantAddress(void *ptr, VM_ATAG tag);
int GetConstantString(FString str);
// Returns the address of the next instruction to be emitted.
size_t GetAddress();
// Returns the address of the newly-emitted instruction.
size_t Emit(int opcode, int opa, int opb, int opc);
size_t Emit(int opcode, int opa, VM_SHALF opbc);