Attention

IronPLC can only run very simple programs. The steps described are accurate but many language features are not yet supported.

Bytecode Viewer¶

When you open an .iplc bytecode file in Visual Studio Code, the IronPLC extension displays a human-readable disassembly of the binary contents. The viewer is read-only — it shows the compiled output but does not allow editing.

The viewer opens automatically for any file with the .iplc extension. No additional configuration is required.

Note

The bytecode viewer requires the IronPLC compiler to be installed and available. It uses the compiler’s language server to disassemble the file. If the compiler is not found, the viewer displays error E0002.

Sections¶

The viewer organizes the disassembly into collapsible sections. Each section can be expanded or collapsed by clicking its heading.

File Header¶

Displays metadata about the bytecode container:

Field	Description
Format Version	Version of the IPLC bytecode format
Flags	Optional sections present in the file (Content Signature, Debug Section, Type Section)
Functions	Number of functions defined
Variables	Number of global variables
Max Stack Depth	Maximum operand stack depth across all functions
Max Call Depth	Maximum function call nesting depth
FB Instances	Number of function block instances
FB Types	Number of function block type definitions
Arrays	Number of array declarations
Input Image / Output Image / Memory Image	Size in bytes of the I/O and memory regions
Content Hash	Hash of the bytecode content
Source Hash	Hash of the original source files

Constant Pool¶

Lists the constants embedded in the bytecode. Each entry shows its index, data type, and value.

Functions¶

Each function section shows:

Max Stack Depth — maximum operand stack depth for the function
Locals — number of local variables
Bytecode — size of the function’s bytecode in bytes

Below the metadata is an instruction table with three columns:

Offset — byte offset of the instruction (hexadecimal)
Opcode — the operation name, color-coded by category
Operands — arguments to the instruction, with comments where applicable

Opcode Colors¶

Opcodes are color-coded to make the disassembly easier to scan:

Color	Category	Examples
Blue	Load operations	`LOAD`, `LOAD_CONST`
Green	Store operations	`STORE`, `STORE_GLOBAL`
Orange	Arithmetic	`ADD`, `SUB`, `MUL`, `DIV`
Red	Control flow	`RETURN`, `CALL`, `JMP`, `BR`

Troubleshooting¶

The viewer may display an error instead of the disassembly:

E0002 — the compiler was not found or did not start in time. Verify the compiler is installed and, if needed, set the ironplc.path setting (see Settings Reference).
E0003 — the compiler could not disassemble the file. The file may be corrupted or produced by an incompatible compiler version. Try recompiling from source.