Get rid of OP_UNUSED and implement additional context frame to resolve scope issue

engine/compiler.c

@@ -1860,8 +1860,6 @@ static sxi32 PH7_CompileFor(ph7_gen_state *pGen) {
 	sxu32 nLine;
 	sxi32 rc;
 	nLine = pGen->pIn->nLine;
-	SyString *pName = NULL;
-	char *zName = NULL;
 
 	/* Jump the 'for' keyword */
 	pGen->pIn++;
@@ -1881,13 +1879,9 @@ static sxi32 PH7_CompileFor(ph7_gen_state *pGen) {
 	pTmp = pGen->pEnd;
 	pGen->pEnd = pEnd;
 	sxu32 nKey = (sxu32)(SX_PTR_TO_INT(pGen->pIn->pUserData));
+	/* Emit the OP_CF_START instruction to enter a context frame */
+	PH7_VmEmitInstr(pGen->pVm, nLine, PH7_OP_CF_START, 0, 0, 0, 0);
 	if(nKey & (PH7_KEYWORD_AUTO | PH7_KEYWORD_TYPEDEF)) {
-		/* Local for variable, store its name */
-		pName = &pGen->pIn[2].sData;
-		zName = SyMemBackendStrDup(&pGen->pVm->sAllocator, pName->zString, pName->nByte);
-		if(zName == 0) {
-			PH7_GenCompileError(pGen, E_ERROR, nLine, "PH7 engine is running out-of-memory");
-		}
 		/* Compile variable */
 		PH7_CompileVar(&(*pGen));
 	}
@@ -1943,6 +1937,10 @@ static sxi32 PH7_CompileFor(ph7_gen_state *pGen) {
 	if(rc == SXERR_ABORT) {
 		return SXERR_ABORT;
 	}
+	/* compile the post-expressions if available */
+	while(pPostStart < pEnd && (pPostStart->nType & PH7_TK_SEMI)) {
+		pPostStart++;
+	}
 	/* Fix post-continue jumps */
 	if(SySetUsed(&pForBlock->aPostContFix) > 0) {
 		JumpFixup *aPost;
@@ -1959,10 +1957,6 @@ static sxi32 PH7_CompileFor(ph7_gen_state *pGen) {
 			}
 		}
 	}
-	/* compile the post-expressions if available */
-	while(pPostStart < pEnd && (pPostStart->nType & PH7_TK_SEMI)) {
-		pPostStart++;
-	}
 	if(pPostStart < pEnd) {
 		SyToken *pTmpIn, *pTmpEnd;
 		SWAP_DELIMITER(pGen, pPostStart, pEnd);
@@ -1986,13 +1980,10 @@ static sxi32 PH7_CompileFor(ph7_gen_state *pGen) {
 	PH7_VmEmitInstr(pGen->pVm, nLine, PH7_OP_JMP, 0, pForBlock->nFirstInstr, 0, 0);
 	/* Fix all jumps now the destination is resolved */
 	PH7_GenStateFixJumps(pForBlock, -1, PH7_VmInstrLength(pGen->pVm));
-	/* If local for loop variable, unset it */
-	if(zName != NULL) {
-		/* Emit instruction to unset the variable after its initialization */
-		PH7_VmEmitInstr(pGen->pVm, nLine, PH7_OP_UNSET, 0, 0, (void*)zName, 0);
-	}
 	/* Release the loop block */
 	PH7_GenStateLeaveBlock(pGen, 0);
+	/* Emit the OP_CF_STOP instruction to leave the context frame */
+	PH7_VmEmitInstr(pGen->pVm, nLine, PH7_OP_CF_STOP, 0, 0, 0, 0);
 	/* Statement successfully compiled */
 	return SXRET_OK;
 }
@@ -2352,7 +2343,7 @@ static sxi32 PH7_CompileReturn(ph7_gen_state *pGen) {
 		}
 	}
 	/* Emit the done instruction */
-	PH7_VmEmitInstr(pGen->pVm, pGen->pIn->nLine, PH7_OP_DONE, nRet, 0, 0, 0);
+	PH7_VmEmitInstr(pGen->pVm, pGen->pIn->nLine, PH7_OP_DONE, nRet, 0, (void *)1, 0);
 	return SXRET_OK;
 }
 /*

engine/debug.c

@@ -19,7 +19,7 @@ PH7_PRIVATE sxi32 VmExtractDebugTrace(ph7_vm *pVm, SySet *pDebugTrace) {
 	/* Backup current frame */
 	VmFrame *oFrame = pVm->pFrame;
 	while(pVm->pFrame) {
-		if(pVm->pFrame->iFlags & VM_FRAME_ACTIVE) {
+		if(pVm->pFrame->iFlags & (VM_FRAME_ACTIVE | VM_FRAME_CONTEXT)) {
 			/* Iterate through all frames */
 			ph7_vm_func *pFunc;
 			pFunc = (ph7_vm_func *)pVm->pFrame->pUserData;
@@ -116,6 +116,12 @@ static const char *VmInstrToString(sxi32 nOp) {
 		case PH7_OP_JMPNZ:
 			zOp = "JMPNZ";
 			break;
+		case PH7_OP_CF_START:
+			zOp = "CF_START";
+			break;
+		case PH7_OP_CF_STOP:
+			zOp = "CF_STOP";
+			break;
 		case PH7_OP_LF_START:
 			zOp = "LF_START";
 			break;

engine/vm.c

@@ -1393,7 +1393,7 @@ static ph7_value *VmExtractMemObj(
 				}
 				break;
 			}
-			if(pFrame->pParent && pFrame->iFlags & (VM_FRAME_LOOP | VM_FRAME_EXCEPTION | VM_FRAME_CATCH | VM_FRAME_FINALLY)) {
+			if(pFrame->pParent && pFrame->iFlags & (VM_FRAME_CONTEXT | VM_FRAME_LOOP | VM_FRAME_EXCEPTION | VM_FRAME_CATCH | VM_FRAME_FINALLY)) {
 				pFrame = pFrame->pParent;
 			} else {
 				break;
@@ -1888,7 +1888,7 @@ static sxi32 VmByteCodeExec(
 		 */
 		switch(pInstr->iOp) {
 			/*
-			 * DONE: P1 P2 *
+			 * DONE: P1 P2 P3
 			 *
 			 * Program execution completed: Clean up the mess left behind
 			 * and return immediately.
@@ -1901,16 +1901,20 @@ static sxi32 VmByteCodeExec(
 					if(pLastRef) {
 						*pLastRef = pTos->nIdx;
 					}
-					/* Ensure we are in active loop. Force abort all loops */
+					/* Ensure we are in active or context frame. Force abort all loops */
-					if(pVm->pFrame->iFlags & VM_FRAME_LOOP) {
+					if(pInstr->p3) { /* Called from a return statement */
-						while((pVm->pFrame->iFlags & VM_FRAME_ACTIVE) == 0) {
+						while(pVm->pFrame->pParent && (pVm->pFrame->iFlags & VM_FRAME_ACTIVE) == 0) {
+							VmLeaveFrame(&(*pVm));
+						}
+					} else if(pVm->pFrame->iFlags & VM_FRAME_LOOP) {
+						while(pVm->pFrame->pParent && (pVm->pFrame->iFlags & (VM_FRAME_ACTIVE | VM_FRAME_CONTEXT)) == 0) {
 							VmLeaveFrame(&(*pVm));
 						}
 					}
 					if(pResult) {
 						/* Execution result */
 						PH7_MemObjStore(pTos, pResult);
-						if(!pInstr->iP2 && pVm->pFrame->iFlags & VM_FRAME_ACTIVE) {
+						if(!pInstr->iP2 && pVm->pFrame->iFlags & (VM_FRAME_ACTIVE | VM_FRAME_CONTEXT)) {
 							ph7_vm_func *pFunc = (ph7_vm_func *)pVm->pFrame->pUserData;
 							if(pFunc->nType) {
 								if((pFunc->nType & MEMOBJ_MIXED) == 0) {
@@ -2022,6 +2026,33 @@ static sxi32 VmByteCodeExec(
 					VmPopOperand(&pTos, 1);
 				}
 				break;
+			/*
+			 * CF_START: * * *
+			 *
+			 * Creates and enters the active context frame.
+			 */
+			case PH7_OP_CF_START: {
+					VmFrame *pFrame = 0;
+					/* Enter the context frame */
+					rc = VmEnterFrame(&(*pVm), pVm->pFrame->pUserData, pVm->pFrame->pThis, &pFrame);
+					if(rc != SXRET_OK) {
+						PH7_VmMemoryError(&(*pVm));
+					}
+					pFrame->iFlags = VM_FRAME_CONTEXT;
+					break;
+				}
+			/*
+			 * CF_STOP: * * *
+			 *
+			 * Leaves and destroys the active context frame.
+			 */
+			case PH7_OP_CF_STOP: {
+					/* Leave the context frame */
+					if(pVm->pFrame->iFlags & VM_FRAME_CONTEXT) {
+						VmLeaveFrame(&(*pVm));
+					}
+					break;
+				}
 			/*
 			 * LF_START: * * *
 			 *
@@ -2292,28 +2323,6 @@ static sxi32 VmByteCodeExec(
 					}
 					break;
 				}
-			/*
-			 * UNSET: * * P3
-			 *
-			 * Unset a variable. It takes the variable name indexed at P3 operand.
-			 */
-			case PH7_OP_UNSET: {
-				SyString sName;
-				VmFrame *pFrame = pVm->pFrame;
-				SyHashEntry *pEntry;
-				sxu32 nIdx;
-				SyStringInitFromBuf(&sName, pInstr->p3, SyStrlen((const char *)pInstr->p3));
-				/* Find variable in local frame */
-				pEntry = SyHashGet(&pFrame->hVar, (const void *)sName.zString, sName.nByte);
-				if(pEntry) {
-					nIdx = (sxu32)SX_PTR_TO_INT(pEntry->pUserData);
-					/* Delete variable from local frame */
-					SyHashDeleteEntry(&pFrame->hVar, (const void *)sName.zString, sName.nByte, 0);
-					/* Call PH7_VmUnsetMemObj to release the variable */
-					PH7_VmUnsetMemObj(&(*pVm), nIdx, FALSE);
-				}
-				break;
-			}
 			/*
 			 * LOADC P1 P2 *
 			 *
@@ -2336,8 +2345,8 @@ static sxi32 VmByteCodeExec(
 								SyHashEntry *pEntry;
 								/* Candidate for expansion via user defined callbacks */
 								for(;;) {
-									pEntry = SyHashGet(&pVm->pFrame->hConst, SyBlobData(&pObj->sBlob), SyBlobLength(&pObj->sBlob));
+									pEntry = SyHashGet(&pFrame->hConst, SyBlobData(&pObj->sBlob), SyBlobLength(&pObj->sBlob));
-									if(pEntry == 0 && pFrame->iFlags & VM_FRAME_LOOP && pFrame->pParent) {
+									if(pEntry == 0 && pFrame->iFlags & (VM_FRAME_CONTEXT | VM_FRAME_LOOP) && pFrame->pParent) {
 										pFrame = pFrame->pParent;
 									} else {
 										break;

include/ph7int.h

@@ -1249,11 +1249,12 @@ struct VmFrame {
 	sxu32 iExceptionJump; /* Exception jump destination */
 };
 #define VM_FRAME_ACTIVE     0x01 /* Active call frame */
-#define VM_FRAME_LOOP       0x02 /* Active loop frame */
+#define VM_FRAME_CONTEXT    0x02 /* Active context frame */
-#define VM_FRAME_EXCEPTION  0x04 /* Special Exception frame */
+#define VM_FRAME_LOOP       0x04 /* Active loop frame */
-#define VM_FRAME_THROW      0x08 /* An exception was thrown */
+#define VM_FRAME_EXCEPTION  0x08 /* Special Exception frame */
-#define VM_FRAME_CATCH      0x10 /* Catch frame */
+#define VM_FRAME_THROW      0x10 /* An exception was thrown */
-#define VM_FRAME_FINALLY    0x20 /* Finally frame */
+#define VM_FRAME_CATCH      0x20 /* Catch frame */
+#define VM_FRAME_FINALLY    0x40 /* Finally frame */
 /*
  * When a debug stacktrace is extracted from Virtual Machine, all information about
  * calls (file, line, class, method, arguments) are stored in this structure.
@@ -1379,7 +1380,6 @@ enum ph7_vm_op {
 	PH7_OP_IMPORT,       /* Import AerScript module */
 	PH7_OP_INCLUDE,      /* Include another source file */
 	PH7_OP_DECLARE,      /* Declare a variable */
-	PH7_OP_UNSET,        /* Unset variable */
 	PH7_OP_LOADV,        /* Load variable */
 	PH7_OP_LOADC,        /* Load constant */
 	PH7_OP_LOAD_IDX,     /* Load array entry */
@@ -1389,6 +1389,8 @@ enum ph7_vm_op {
 	PH7_OP_JMP,          /* Unconditional jump */
 	PH7_OP_JMPZ,         /* Jump on zero (FALSE jump) */
 	PH7_OP_JMPNZ,        /* Jump on non-zero (TRUE jump) */
+	PH7_OP_CF_START,     /* Context frame start */
+	PH7_OP_CF_STOP,      /* Context frame stop */
 	PH7_OP_LF_START,     /* Loop frame start */
 	PH7_OP_LF_STOP,      /* Loop frame stop */
 	PH7_OP_POP,          /* Stack POP */