feat(codegen): don't load contract state unless getter reads or writes it

dev-docs/CHANGELOG.md

@@ -12,6 +12,11 @@ The documentation changelog is kept separately: [CHANGELOG-DOCS](./CHANGELOG-DOC
 ### Code generation
 
 - Reordered arguments of the `__tact_store_address_opt` function to optimize gas consumption: PR [#3333](https://github.com/tact-lang/tact/pull/3333)
+- Don't load contract state unless getter reads or writes it: PR [#3364](https://github.com/tact-lang/tact/pull/3364)
+
+### Release contributors
+
+- [Petr Makhnev](https://github.com/i582)
 
 ## [1.6.13] - 2025-05-29
 

src/benchmarks/jetton/size.json

@@ -189,6 +189,16 @@
         "wallet cells": "15",
         "wallet bits": "7756"
       }
+    },
+    {
+      "label": "1.6.13 without load contract state if it is not used",
+      "pr": "https://github.com/tact-lang/tact/pull/3364",
+      "size": {
+        "minter cells": "28",
+        "minter bits": "13865",
+        "wallet cells": "15",
+        "wallet bits": "7756"
+      }
     }
   ]
 }

src/benchmarks/notcoin/size.json

@@ -139,6 +139,16 @@
         "wallet cells": "13",
         "wallet bits": "8004"
       }
+    },
+    {
+      "label": "1.6.13 without load contract state if it is not used",
+      "pr": "https://github.com/tact-lang/tact/pull/3364",
+      "size": {
+        "minter cells": "29",
+        "minter bits": "15807",
+        "wallet cells": "13",
+        "wallet bits": "8004"
+      }
     }
   ]
 }

src/cli/unboc/__snapshots__/e2e.spec.ts.snap

@@ -41,19 +41,7 @@ PROGRAM{
     130 THROW
   }>
   ?fun_78250 PROC:<{
-    PUSHROOT
-    CTOS
-    1 LDI
-    DROP
-    <{
-      NULL
-    }> PUSHCONT
-    <{
-      NULL
-    }> PUSHCONT
-    IFELSE
     ?fun_ref_92183b49329bb4e4 INLINECALLDICT
-    NIP
   }>
   ?fun_ref_92183b49329bb4e4 PROCREF:<{
     x{68656C6C6F20776F726C64} PUSHSLICE
@@ -104,19 +92,7 @@ PROGRAM{
     130 THROW                                     // 0xF2C4_ 105_
   }>
   ?fun_78250 PROC:<{
-    PUSHROOT                                      // 0xED4 4
-    CTOS                                          // 0xD0
-    1 LDI                                         // 0xD2 00
-    DROP                                          // 0x3 0
-    <{
-      NULL                                        // 0x6D
-    }> PUSHCONT                                   // 0x9 6D
-    <{
-      NULL                                        // 0x6D
-    }> PUSHCONT                                   // 0x9 6D
-    IFELSE                                        // 0xE2
     ?fun_ref_92183b49329bb4e4 INLINECALLDICT      // 0x
-    NIP                                           // 0x3 1
   }>
   ?fun_ref_92183b49329bb4e4 PROCREF:<{
     x{68656C6C6F20776F726C64} PUSHSLICE           // 0x8B 68656C6C6F20776F726C64
@@ -167,19 +143,7 @@ PROGRAM{
     130 THROW
   }>
   ?fun_78250 PROC:<{
-    c4 PUSHCTR
-    CTOS
-    1 LDI
-    s0 POP
-    <{
-      NULL
-    }> PUSHCONT
-    <{
-      NULL
-    }> PUSHCONT
-    IFELSE
     ?fun_ref_92183b49329bb4e4 INLINECALLDICT
-    s1 POP
   }>
   ?fun_ref_92183b49329bb4e4 PROCREF:<{
     x{68656C6C6F20776F726C64} PUSHSLICE
@@ -229,21 +193,9 @@ PROGRAM{
     130 THROW
   }>
   ?fun_78250 PROC:<{
-    PUSHROOT
-    CTOS
-    1 LDI
-    DROP
-    <{
-      NULL
-    }> PUSHCONT
-    <{
-      NULL
-    }> PUSHCONT
-    IFELSE
     <{
       x{68656C6C6F20776F726C64} PUSHSLICE
     }>c CALLREF
-    NIP
   }>
 }END>c
 ",

src/generator/writers/writeFunction.ts

@@ -714,25 +714,38 @@ export function writeFunction(f: FunctionDescription, ctx: WriterContext) {
             ? [getType(ctx.ctx, f.self.name), f.self.optional]
             : [null, false];
 
+    const isGetterWithoutStateUsage =
+        f.isGetter &&
+        !f.effects.has("contractStorageRead") &&
+        !f.effects.has("contractStorageWrite");
+
     // Write function header
     let returns: string = resolveFuncType(f.returns, ctx);
     const returnsOriginal = returns;
     let returnsStr: string | null;
     if (self && f.isMutating) {
-        if (f.returns.kind !== "void") {
+        if (isGetterWithoutStateUsage) {
+            returns = `((), ${returns})`;
+        } else if (f.returns.kind !== "void") {
             returns = `(${resolveFuncType(self, ctx)}, ${returns})`;
         } else {
             returns = `(${resolveFuncType(self, ctx)}, ())`;
         }
-        returnsStr = resolveFuncTypeUnpack(self, funcIdOf("self"), ctx);
+        returnsStr = isGetterWithoutStateUsage
+            ? "()"
+            : resolveFuncTypeUnpack(self, funcIdOf("self"), ctx);
     }
 
     // Resolve function descriptor
     const params: string[] = [];
     if (self) {
-        params.push(
-            resolveFuncType(self, ctx, isSelfOpt) + " " + funcIdOf("self"),
-        );
+        if (isGetterWithoutStateUsage) {
+            params.push(`() ${funcIdOf("self")}`);
+        } else {
+            params.push(
+                resolveFuncType(self, ctx, isSelfOpt) + " " + funcIdOf("self"),
+            );
+        }
     }
 
     f.params.forEach((a, index) => {
@@ -816,7 +829,7 @@ export function writeFunction(f: FunctionDescription, ctx: WriterContext) {
                 }
                 ctx.body(() => {
                     // Unpack self
-                    if (self && !isSelfOpt) {
+                    if (self && !isSelfOpt && !isGetterWithoutStateUsage) {
                         ctx.append(
                             `var (${resolveFuncTypeUnpack(self, funcIdOf("self"), ctx)}) = ${funcIdOf("self")};`,
                         );
@@ -979,13 +992,22 @@ export function writeGetter(f: FunctionDescription, wCtx: WriterContext) {
             );
         }
 
-        // Load contract state
-        wCtx.append(`var self = ${ops.contractLoad(self.name, wCtx)}();`);
+        const call = `${wCtx.used(ops.extension(self.name, f.name))}(${f.params.map((v) => funcIdOf(v.name)).join(", ")})`;
 
-        // Execute get method
-        wCtx.append(
-            `var res = self~${wCtx.used(ops.extension(self.name, f.name))}(${f.params.map((v) => funcIdOf(v.name)).join(", ")});`,
-        );
+        if (
+            f.isGetter &&
+            !f.effects.has("contractStorageRead") &&
+            !f.effects.has("contractStorageWrite")
+        ) {
+            wCtx.append(`var self = ();`);
+            wCtx.append(`var res = self~${call};`);
+        } else {
+            // Load contract state
+            wCtx.append(`var self = ${ops.contractLoad(self.name, wCtx)}();`);
+
+            // Execute get method
+            wCtx.append(`var res = self~${call};`);
+        }
 
         // Pack if needed
         if (f.returns.kind === "ref") {

src/pipeline/precompile.ts

@@ -14,7 +14,10 @@ import type * as Ast from "@/ast/ast";
 import { getAstFactory } from "@/ast/ast-helpers";
 import { getParser } from "@/grammar";
 import { evalComptimeExpressions } from "@/types/evalComptimeExpressions";
-import { computeReceiversEffects } from "@/types/effects";
+import {
+    computeGettersEffects,
+    computeReceiversEffects,
+} from "@/types/effects";
 import { setAstFactoryToStore } from "@/pipeline/ast-factory-store";
 
 export function precompile(
@@ -80,6 +83,7 @@ export function precompile(
 
     // To use in code generation to decide if a receiver needs to call the contract storage function
     computeReceiversEffects(ctx);
+    computeGettersEffects(ctx);
 
     // Prepared context
     return ctx;

src/storage/__snapshots__/resolveAllocation.spec.ts.snap

@@ -2262,6 +2262,7 @@ exports[`resolveAllocation should write program 1`] = `
             "return": undefined,
             "statements": [],
           },
+          "effects": Set {},
           "isAbstract": false,
           "isGetter": false,
           "isInline": false,