feat: support any layout BoC (#56)

Author: i582

README.md

@@ -10,7 +10,7 @@ yarn add @tact-lang/opcode
 
 ## Usage
 
-For most cases you will want to disassemble a BoC file generated by the Tact/FunC/Tolk compiler.
+For most cases you will want to disassemble a BoC file generated by the Tact/FunC/Tolk compiler. In this case decompiler will unpack the dictionary to procedures and methods.
 
 ```typescript
 import {AssemblyWriter, disassembleRoot} from "@tact-lang/opcode"
@@ -20,12 +20,12 @@ const program = disassembleRoot(source, {
     computeRefs: false,
 })
 
-// Write the program AST into a TVM bytecode string
+// Write the program AST into a Fift assembly string
 const res = AssemblyWriter.write(program, {})
 console.log(res)
 ```
 
-If you want to decompile BoC file with non-standard root layout (for example, wallet v1), you can do the following:
+If you want to decompile BoC file without unpacking of the dictionary, you can do the following:
 
 ```typescript
 import {AssemblyWriter, disassembleRawRoot} from "@tact-lang/opcode"

src/decompiler/constants.ts

@@ -18,9 +18,8 @@ import {
     ProgramNode,
 } from "../ast/ast"
 import {createBlock, createInstruction} from "../ast/helpers"
-import {RootLayout} from "./constants"
 import {getDisplayNumber, hasHint} from "../spec/helpers"
-import {LayoutError, OperandError, UnknownOperandTypeError} from "./errors"
+import {OperandError, UnknownOperandTypeError} from "./errors"
 
 export interface DisassembleParams {
     /**
@@ -338,45 +337,52 @@ function processRefOrSliceOperand(
     }
 }
 
-/**
- * Checks if the root layout is valid.
- *
- * Valid layout is:
- * - `SETCP`
- * - `DICTPUSHCONST`
- * - `DICTIGETJMPZ`
- * - `THROWARG`
- *
- * This is the only layout that is supported by the decompiler.
- * This layout is generated by the FunC and Tact compilers.
- */
-function checkLayout(opcodes: DecompiledInstruction[]): void {
-    if (opcodes.length !== RootLayout.instructionsCount) {
-        throw new LayoutError(RootLayout.instructionsCount, opcodes.length, {
-            instructions: opcodes.map(op => op.op.definition.mnemonic),
+function findDictOpcode(opcodes: DecompiledInstruction[]): DecompiledInstruction | undefined {
+    return opcodes.find(it => it.op.definition.mnemonic === "DICTPUSHCONST")
+}
+
+function findRootMethods(opcodes: DecompiledInstruction[]): MethodNode[] {
+    const methods: MethodNode[] = []
+
+    if (opcodes[2]?.op.definition.mnemonic === "PUSHCONT") {
+        const cont = opcodes[2].op.operands.at(0)
+        if (!cont || cont.type !== "subslice") {
+            return methods
+        }
+
+        const recvInternal = disassembleRawRoot(cont.value)
+        methods.push({
+            type: "method",
+            hash: recvInternal.hash,
+            offset: recvInternal.offset,
+            body: recvInternal,
+            id: 0,
         })
     }
 
-    const isValidLayout =
-        opcodes[RootLayout.instructions.SETCP].op.definition.mnemonic === "SETCP" &&
-        opcodes[RootLayout.instructions.DICTPUSHCONST].op.definition.mnemonic === "DICTPUSHCONST" &&
-        (opcodes[RootLayout.instructions.DICTIGETJMPZ].op.definition.mnemonic === "DICTIGETJMPZ" ||
-            opcodes[RootLayout.instructions.DICTIGETJMPZ].op.definition.mnemonic ===
-                "DICTIGETJMP") &&
-        opcodes[RootLayout.instructions.THROWARG].op.definition.mnemonic === "THROWARG"
-
-    if (!isValidLayout) {
-        throw new LayoutError(RootLayout.instructionsCount, opcodes.length, {
-            expected: ["SETCP", "DICTPUSHCONST", "DICTIGETJMPZ", "THROWARG"],
-            actual: opcodes.map(op => op.op.definition.mnemonic),
+    if (opcodes[6]?.op.definition.mnemonic === "PUSHCONT") {
+        const cont = opcodes[6].op.operands.at(0)
+        if (!cont || cont.type !== "subslice") {
+            return methods
+        }
+
+        const recvExternal = disassembleRawRoot(cont.value)
+        methods.push({
+            type: "method",
+            hash: recvExternal.hash,
+            offset: recvExternal.offset,
+            body: recvExternal,
+            id: -1,
         })
     }
+
+    return methods
 }
 
 /**
  * Disassembles the root cell into a list of instructions.
  *
- * Use this function if you want to disassemble the whole BoC file.
+ * Use this function if you want to disassemble the whole BoC file with dictionary unpacked.
  */
 export function disassembleRoot(
     cell: Cell,
@@ -388,29 +394,40 @@ export function disassembleRoot(
     },
 ): ProgramNode {
     const opcodes = disassemble({source: cell})
-    checkLayout(opcodes)
-
-    const dictOpcode = opcodes[RootLayout.instructions.DICTPUSHCONST].op
-    const {procedures, methods} = deserializeDict(dictOpcode.operands, options.computeRefs)
 
     const args = {
         source: cell,
         offset: {bits: 0, refs: 9},
         onCellReference: undefined,
     }
+
+    const rootMethods = findRootMethods(opcodes)
+
+    const dictOpcode = findDictOpcode(opcodes)
+    if (!dictOpcode) {
+        // Likely some non-Tact/FunC produced BoC
+        return {
+            type: "program",
+            topLevelInstructions: opcodes.map(op => processInstruction(op, args)),
+            procedures: [],
+            methods: rootMethods,
+            withRefs: options.computeRefs,
+        }
+    }
+
+    const {procedures, methods} = deserializeDict(dictOpcode.op.operands, options.computeRefs)
+
     return {
         type: "program",
         topLevelInstructions: opcodes.map(op => processInstruction(op, args)),
         procedures,
-        methods,
+        methods: [...rootMethods, ...methods],
         withRefs: options.computeRefs,
     }
 }
 
 /**
- * Disassembles a cell without any additional checks for the layout.
- *
- * Use this function if your contract use non-usual layout.
+ * Disassembles a cell without any additional unpacking of the dictionary.
  */
 export function disassembleRawRoot(cell: Cell): BlockNode {
     return disassembleAndProcess({

src/decompiler/disasm.ts

@@ -31,17 +31,6 @@ export class OperandError extends DisassemblerError {
     }
 }
 
-export class LayoutError extends DisassemblerError {
-    public constructor(expected: number, actual: number, details?: Record<string, unknown>) {
-        super(`Unexpected root layout: expected ${expected} instructions, got ${actual}`, {
-            expected,
-            actual,
-            ...details,
-        })
-        this.name = "LayoutError"
-    }
-}
-
 export class UnknownOperandTypeError extends DisassemblerError {
     public constructor(operand: OperandValue, details?: Record<string, unknown>) {
         super(`Unknown operand type: ${operand.type}`, {

src/decompiler/errors.ts

@@ -12,4 +12,4 @@ export type {AssemblyWriterOptions} from "./printer/assembly-writer"
 export {AssemblyWriter} from "./printer/assembly-writer"
 
 export {debugSymbols} from "./utils/known-methods"
-export {Cell} from "@ton/core"
+export {Cell, Dictionary} from "@ton/core"

src/index.ts

@@ -132,15 +132,21 @@ export class AssemblyWriter {
             }
         }
 
-        // if (node.topLevelInstructions.length > 0) {
-        //     node.topLevelInstructions.forEach(instruction => {
-        //         // if (i === 1) return
-        //         this.writer.write("// ")
-        //         this.writeInstructionNode(instruction)
-        //     })
-        // }
-
         this.writer.writeLine(`"Asm.fif" include`)
+
+        if (node.procedures.length === 0 && node.methods.length === 0) {
+            this.writer.writeLine("<{")
+
+            this.writer.indent(() => {
+                node.topLevelInstructions.forEach(instruction => {
+                    this.writeInstructionNode(instruction)
+                })
+            })
+
+            this.writer.write("}>c")
+            return
+        }
+
         this.writer.writeLine("PROGRAM{")
         this.writer.indent(() => {
             const methods = [...node.methods].sort((a, b) => a.id - b.id)

src/printer/assembly-writer.ts

@@ -1,5 +1,153 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
+exports[`known contracts > should decompile Tact 1.6.0 with other layout 1`] = `
+""Asm.fif" include
+PROGRAM{
+  DECLPROC recv_internal
+  78250 DECLMETHOD ?fun_78250
+  DECLPROC ?fun_ref_92183b49329bb4e4
+  recv_internal PROC:<{
+    DROP
+    DROP
+    CTOS
+    TWO
+    SDSKIPFIRST
+    1 LDI
+    1 LDI
+    LDMSGADDR
+    OVER
+    s3 s4 XCHG
+    s5 s5 XCHG2
+    4 TUPLE
+    1 SETGLOB
+    SWAP
+    2 SETGLOB
+    PUSHROOT
+    CTOS
+    1 LDI
+    DROP
+    <{
+      NULL
+    }> PUSHCONT
+    <{
+      NULL
+    }> PUSHCONT
+    IFELSE
+    DROP
+    IFRET
+    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
+  }>
+}END>c"
+`;
+
+exports[`known contracts > should decompile Tact 1.6.0 with other layout and recv_external 1`] = `
+""Asm.fif" include
+PROGRAM{
+  -1 DECLMETHOD recv_external
+  DECLPROC recv_internal
+  78250 DECLMETHOD ?fun_78250
+  DECLPROC ?fun_ref_92183b49329bb4e4
+  recv_external PROC:<{
+    DROP
+    DROP
+    PUSHROOT
+    CTOS
+    1 LDI
+    DROP
+    <{
+      NULL
+    }> PUSHCONT
+    <{
+      NULL
+    }> PUSHCONT
+    IFELSE
+    1 GETGLOB
+    4 UNTUPLE
+    s2 s3 XCHG
+    3 BLKDROP
+    41351 PUSHINT
+    MYADDR
+    ROT
+    SDEQ
+    THROWANYIFNOT
+    DROP
+    NEWC
+    -1 PUSHINT
+    SWAP
+    1 STI
+    ENDC
+    POPROOT
+  }>
+  recv_internal PROC:<{
+    DROP
+    DROP
+    CTOS
+    TWO
+    SDSKIPFIRST
+    1 LDI
+    1 LDI
+    LDMSGADDR
+    OVER
+    s3 s4 XCHG
+    s5 s5 XCHG2
+    4 TUPLE
+    1 SETGLOB
+    SWAP
+    2 SETGLOB
+    PUSHROOT
+    CTOS
+    1 LDI
+    DROP
+    <{
+      NULL
+    }> PUSHCONT
+    <{
+      NULL
+    }> PUSHCONT
+    IFELSE
+    DROP
+    IFRET
+    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
+  }>
+}END>c"
+`;
+
 exports[`known contracts > should decompile echo 1`] = `
 ""Asm.fif" include
 PROGRAM{