From 85f59a299815815c970904aad689852556f191f0 Mon Sep 17 00:00:00 2001
From: Rafal Kupiec <belliash@codingworkshop.eu.org>
Date: Sun, 25 Oct 2026 19:57:49 +0100
Subject: [PATCH] Evaluate local constants once per declaration and invocation

---
 engine/vm.c | 52 ++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 42 insertions(+), 10 deletions(-)

diff --git a/engine/vm.c b/engine/vm.c
index 75b6b32..686509c 100644
--- a/engine/vm.c
+++ b/engine/vm.c
@@ -492,6 +492,17 @@ static void VmScopeSync(ph7_vm *pVm, VmScopeInfo *pTarget, void *pExec) {
 	}
 	VmScopeEnter(pVm, pTarget, pExec);
 }
+/* Stable, invocation-owned storage: neither bytecode nor moving VM arrays own
+ * local constant values. Scope exit removes only their visible bindings. */
+typedef struct VmLocalConstant VmLocalConstant;
+struct VmLocalConstant {
+	ph7_constant_info *pDecl;
+	ph7_value sValue;
+};
+static void VmExpandLocalConstant(ph7_value *pVal, void *pUserData) {
+	VmLocalConstant *pConst = (VmLocalConstant *)pUserData;
+	PH7_MemObjLoad(&pConst->sValue, pVal);
+}
 /*
  * Allocate a new virtual machine frame.
  */
@@ -517,7 +528,7 @@ static VmFrame *VmNewFrame(
 	SySetInit(&pFrame->sArg, &pVm->sAllocator, sizeof(VmSlot));
 	SySetInit(&pFrame->sLocal, &pVm->sAllocator, sizeof(VmSlot));
 	SySetInit(&pFrame->sRef, &pVm->sAllocator, sizeof(VmSlot));
-	SySetInit(&pFrame->sConstDecl, &pVm->sAllocator, sizeof(void *));
+	SySetInit(&pFrame->sConstDecl, &pVm->sAllocator, sizeof(VmLocalConstant *));
 	return pFrame;
 }
 /*
@@ -576,6 +587,14 @@ static void VmLeaveFrame(ph7_vm *pVm) {
 		SySetRelease(&pFrame->sArg);
 		SySetRelease(&pFrame->sLocal);
 		SySetRelease(&pFrame->sRef);
+		{
+			VmLocalConstant **apConst = (VmLocalConstant **)SySetBasePtr(&pFrame->sConstDecl);
+			sxu32 n;
+			for(n = 0; n < SySetUsed(&pFrame->sConstDecl); n++) {
+				PH7_MemObjRelease(&apConst[n]->sValue);
+				SyMemBackendPoolFree(&pVm->sAllocator, apConst[n]);
+			}
+		}
 		SySetRelease(&pFrame->sConstDecl);
 		/* Release the whole structure */
 		SyMemBackendPoolFree(&pVm->sAllocator, pFrame);
@@ -3071,25 +3090,39 @@ Resume:
 						/* Constant declaration */
 						ph7_constant_info *pConstInfo = (ph7_constant_info *) pInstr->p3;
 						VmFrame *pOwner = pVm->pFrame;
-						void **apDecl;
+						VmLocalConstant **apDecl, *pConst;
 						sxu32 n;
 						while(pOwner->pParent && (pOwner->iFlags & VM_FRAME_ACTIVE) == 0) {
 							pOwner = pOwner->pParent;
 						}
-						apDecl = (void **)SySetBasePtr(&pOwner->sConstDecl);
+						apDecl = (VmLocalConstant **)SySetBasePtr(&pOwner->sConstDecl);
 						for(n = 0; n < SySetUsed(&pOwner->sConstDecl); n++) {
-							if(apDecl[n] == pConstInfo) {
+							if(apDecl[n]->pDecl == pConstInfo) {
 								PH7_VmThrowError(pVm, PH7_CTX_ERR, "Redeclaration of ‘%z’ constant", &pConstInfo->pName);
 							}
 						}
-						if(SySetPut(&pOwner->sConstDecl, &pConstInfo) != SXRET_OK) {
+						pConst = (VmLocalConstant *)SyMemBackendPoolAlloc(&pVm->sAllocator, sizeof(VmLocalConstant));
+						if(pConst == 0) {
 							PH7_VmMemoryError(pVm);
 						}
-						rc = PH7_VmRegisterConstant(&(*pVm), &pConstInfo->pName, PH7_VmExpandConstantValue, pConstInfo->pConsCode, FALSE);
+						pConst->pDecl = pConstInfo;
+						PH7_MemObjInit(pVm, &pConst->sValue);
+						if(SySetPut(&pOwner->sConstDecl, &pConst) != SXRET_OK) {
+							PH7_VmMemoryError(pVm);
+						}
+						rc = PH7_VmRegisterConstant(&(*pVm), &pConstInfo->pName, VmExpandLocalConstant, pConst, FALSE);
 						if(rc == SXERR_EXISTS) {
 							PH7_VmThrowError(&(*pVm), PH7_CTX_ERR,
 											"Redeclaration of ‘%z’ constant", &pConstInfo->pName);
 						}
+						rc = VmLocalExec(pVm, pConstInfo->pConsCode, &pConst->sValue);
+						if(rc == SXERR_MEM) {
+							PH7_VmMemoryError(pVm);
+						} else if(rc == PH7_ABORT) {
+							goto Abort;
+						} else if(rc == PH7_EXCEPTION) {
+							goto Exception;
+						}
 					} else {
 						/* Variable declaration */
 						ph7_value *pObj;
@@ -6123,10 +6156,9 @@ PH7_PRIVATE sxi32 PH7_VmOutputConsumeAp(
 	return rc;
 }
 /*
- * Default constant expansion callback used by the 'const' statement if used
- * outside a class body [i.e: global or function scope].
- * Refer to the implementation of [PH7_CompileConstant()] defined
- * in 'compile.c' for additional information.
+ * Constant expansion callback used by global constants declared with 'define'.
+ * Refer to the implementation of [PH7_CompileDefine()] defined
+ * in 'compiler.c' for additional information.
  */
 PH7_PRIVATE void PH7_VmExpandConstantValue(ph7_value *pVal, void *pUserData) {
 	SySet *pByteCode = (SySet *)pUserData;