Validate Program entry points and resolve accessible zero-argument constructors

engine/vm.c

@@ -944,6 +944,7 @@ static sxi32 VmOverloadDominates(const sxi32 *aFirst, const sxi32 *aSecond, sxu3
 #define VM_INCLUDE_JUMP 4
 #define VM_INCLUDE_EXCEPTION 5
 #define VM_RETURN_VOID 6
+#define VM_CALL_ENTRY 2
 static sxi32 VmExecIncludedFile(ph7_vm *pVm, SyString *pPath, int iFlags, ph7_value *pResult, ph7_include *pInclude);
 static sxi32 VmLocalExec(ph7_vm *pVm, SySet *pByteCode, ph7_value *pResult);
 static sxi32 VmClassMemberAccess(ph7_vm *pVm, ph7_class *pClass, sxi32 iProtection);
@@ -5721,9 +5722,11 @@ Resume:
 								}
 							}
 						}
-						/* Select an appropriate function to call, if not entry point */
+						/* Only the explicitly validated entry point bypasses overload resolution. */
 						if((pInstr->iP2 & 1) == 0) {
 							pVmFunc = VmOverload(&(*pVm), pVmFunc, pArg, (sxi32)(pTos - pArg), pLookup, pThis == 0, bParent, pInstr->iP2 & 2);
+						} else {
+							pVmFunc = (ph7_vm_func *)pInstr->p3;
 						}
 						if(pThis && (pVmFunc->iFlags & VM_FUNC_CLASS_METHOD)) {
 							pSelf = pVmFunc->pClass;
@@ -6329,6 +6332,46 @@ static void VmInvokeShutdownCallbacks(ph7_vm *pVm) {
 	}
 	SySetReset(&pVm->aShutdown);
 }
+/* Apply the usual C3 identical-signature hiding, but never choose between
+ * different public main signatures based on the CLI arguments. */
+static ph7_class_method *VmEntryPoint(ph7_vm *pVm, ph7_class *pClass) {
+	ph7_class_method *pMain = 0;
+	sxu32 i;
+	for(i = 0; i < SySetUsed(&pClass->aMro); i++) {
+		ph7_class *pOwner = *(ph7_class **)SySetAt(&pClass->aMro, i);
+		ph7_class_method *pMethod = PH7_ClassExtractMethod(pOwner, "main", sizeof("main") - 1);
+		SyHashEntry *pEntry;
+		ph7_vm_func *pFunc;
+		if(!pMethod || pMethod->sFunc.pClass != pOwner) {
+			continue;
+		}
+		pEntry = SyHashGet(&pVm->hFunction, pMethod->sVmName.zString, pMethod->sVmName.nByte);
+		for(pFunc = pEntry ? (ph7_vm_func *)pEntry->pUserData : 0; pFunc; pFunc = pFunc->pNextName) {
+			pMethod = (ph7_class_method *)pFunc;
+			if(pMethod->iProtection != PH7_CLASS_PROT_PUBLIC || (pMethod->iFlags & PH7_CLASS_ATTR_VIRTUAL)) {
+				continue;
+			}
+			if(pMain && !PH7_VmSameSignature(&pMain->sFunc, pFunc)) {
+				PH7_VmThrowError(pVm, PH7_CTX_ERR, "Ambiguous program entry point 'Program::main()'");
+			}
+			if(!pMain) {
+				pMain = pMethod;
+			}
+		}
+	}
+	if(!pMain) {
+		PH7_VmThrowError(pVm, PH7_CTX_ERR, "Cannot find a public program entry point 'Program::main()'");
+	}
+	if(pMain->sFunc.nType != MEMOBJ_INT && pMain->sFunc.nType != MEMOBJ_VOID) {
+		PH7_VmThrowError(pVm, PH7_CTX_ERR, "The 'Program::main()' return value can be either Integer or Void");
+	}
+	if(SySetUsed(&pMain->sFunc.aArgs) > 1 ||
+		(SySetUsed(&pMain->sFunc.aArgs) == 1 &&
+		((ph7_vm_func_arg *)SySetBasePtr(&pMain->sFunc.aArgs))->nType != (MEMOBJ_STRING | MEMOBJ_HASHMAP))) {
+		PH7_VmThrowError(pVm, PH7_CTX_ERR, "The 'Program::main()' parameters must be () or (string[])");
+	}
+	return pMain;
+}
 /*
  * Execute as much of a PH7 bytecode program as we can then return.
  * This function is a wrapper around [VmByteCodeExec()].
@@ -6338,6 +6381,7 @@ PH7_PRIVATE sxi32 PH7_VmByteCodeExec(ph7_vm *pVm) {
 	ph7_class *pClass;
 	ph7_class_instance *pInstance;
 	ph7_class_method *pMethod;
+	ph7_class_method *pMain;
 	ph7_value *pArgs, *sArgv;
 	ph7_value pResult;
 	char *zDup, *zParam;
@@ -6355,6 +6399,8 @@ PH7_PRIVATE sxi32 PH7_VmByteCodeExec(ph7_vm *pVm) {
 	if(!pClass) {
 		PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Cannot find an entry 'Program' class");
 	}
+	/* Reject invalid entry points before running the Program constructor. */
+	pMain = VmEntryPoint(pVm, pClass);
 	pInstance = PH7_NewClassInstance(&(*pVm), pClass);
 	if(pInstance == 0) {
 		PH7_VmMemoryError(&(*pVm));
@@ -6363,7 +6409,7 @@ PH7_PRIVATE sxi32 PH7_VmByteCodeExec(ph7_vm *pVm) {
 	pMethod = PH7_ClassExtractMethod(pClass, "__construct", sizeof("__construct") - 1);
 	if(pMethod) {
 		/* Call the class constructor */
-		PH7_VmCallClassMethod(&(*pVm), pInstance, pMethod, 0, 0, 0);
+		VmCallClassMethod(pVm, pInstance, pMethod, 0, 0, 0, FALSE);
 	}
 	/* Enable garbage collector */
 	pInstance->iRef--;
@@ -6383,20 +6429,14 @@ PH7_PRIVATE sxi32 PH7_VmByteCodeExec(ph7_vm *pVm) {
 			zParam = SyStrtok(NULL, " ");
 		}
 	}
-	/* Extract script entry point */
+	pMethod = pMain;
-	pMethod = PH7_ClassExtractMethod(pClass, "main", sizeof("main") - 1);
-	if(!pMethod) {
-		PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Cannot find a program entry point 'Program::main()'");
-	}
-	if(pMethod->sFunc.nType != MEMOBJ_INT && pMethod->sFunc.nType != MEMOBJ_VOID) {
-		PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "The 'Program::main()' return value can be either Integer or Void");
-	}
 	/* A set of arguments is stored in array of strings */
 	pArgs->nType |= MEMOBJ_STRING;
 	/* Initialize variable for return value */
 	PH7_MemObjInit(pVm, &pResult);
 	/* Call entry point */
-	PH7_VmCallClassMethod(&(*pVm), pInstance, pMethod, &pResult, 1, &pArgs);
+	VmCallClassMethod(pVm, pInstance, pMethod, &pResult,
+		(int)SySetUsed(&pMethod->sFunc.aArgs), &pArgs, VM_CALL_ENTRY);
 	if(!pVm->iExitStatus) {
 		if(pMethod->sFunc.nType == MEMOBJ_INT) {
 			pVm->iExitStatus = ph7_value_to_int(&pResult);
@@ -7442,7 +7482,7 @@ static int vm_builtin_is_subclass_of(ph7_context *pCtx, int nArg, ph7_value **ap
 	ph7_value *pResult,        /* Store method return value here. NULL otherwise */
 	int nArg,                  /* Total number of given arguments */
 	ph7_value **apArg,         /* Method arguments */
-	sxi32 bInternal           /* VM-owned lifecycle call, not source new */
+	sxi32 bInternal           /* VM-owned lifecycle call, or VM_CALL_ENTRY */
 ) {
 	ph7_value *aStack;
 	VmInstr aInstr[2];
@@ -7466,7 +7506,7 @@ static int vm_builtin_is_subclass_of(ph7_context *pCtx, int nArg, ph7_value **ap
 		aStack[i].nIdx = apArg[i]->nIdx;
 	}
 	iCursor = nArg + 1;
-	iEntry = bInternal ? 2 : 0;
+	iEntry = bInternal == VM_CALL_ENTRY ? 3 : (bInternal ? 2 : 0);
 	if(pThis) {
 		/*
 		 * Push the class instance so that the '$this' variable will be available.
@@ -7474,12 +7514,6 @@ static int vm_builtin_is_subclass_of(ph7_context *pCtx, int nArg, ph7_value **ap
 		pThis->iRef++; /* Increment reference count */
 		aStack[i].x.pOther = pThis;
 		aStack[i].nType = MEMOBJ_OBJ;
-		if(bInternal && SyStrncmp(pThis->pClass->sName.zString, "Program", 7) == 0) {
-			if((SyStrncmp(pMethod->sFunc.sName.zString, "main", 4) == 0) || (SyStrncmp(pMethod->sFunc.sName.zString, "__construct", 11) == 0)) {
-				/* Do not overload entry point */
-				iEntry |= 1;
-			}
-		}
 	}
 	pSeed = VmMethodSeed(pVm, pThis ? pThis->pClass : pMethod->sFunc.pClass,
 		&pMethod->sFunc.sName, pMethod, FALSE);
@@ -7505,7 +7539,7 @@ static int vm_builtin_is_subclass_of(ph7_context *pCtx, int nArg, ph7_value **ap
 	aInstr[0].pScope = 0;
 	aInstr[0].iP1 = nArg; /* Total number of given arguments */
 	aInstr[0].iP2 = iEntry;
-	aInstr[0].p3  = 0;
+	aInstr[0].p3  = (iEntry & 1) ? &pMethod->sFunc : 0;
 	aInstr[0].bExec = FALSE;
 	aInstr[0].iLine = 1;
 	aInstr[0].pFile = (SyString *)&sFileName;

tests/include_statements.aer

@@ -3,7 +3,7 @@ require 'data/includes/test_class.aer';
 
 class Program extends BaseClass {
 
-	void main() {
+	public void main() {
 		$this->run();
 		object $test = new Test();
 		var_dump($test);

tests/is_statement.aer

@@ -7,7 +7,7 @@ class Test2 extends Test1 {
 
 class Program {
 
-	void main() {
+	public void main() {
 		int[] $q = {1, 2, 3};
 		float $t = 4;
 		object $x = new Test1();

tests/sudoku_solver.aer

@@ -79,7 +79,7 @@ class Sudoku {
 
 class Program {
 
-	void main() {
+	public void main() {
 		int[] $board = {
 			{3, 0, 6, 5, 0, 8, 4, 0, 0},
 			{5, 2, 0, 0, 0, 0, 0, 0, 0},