Compiler Options

Porffor provides a wide range of compiler options to control optimization, parsing, memory allocation, and runtime behavior.

Core Options

Debug Mode

-d

flag

Enable debug mode. Includes function names in generated Wasm and enables debug logging.

porf -d script.js

Module Parsing

--module

flag

Parse input as an ES module instead of a script.

porf --module app.js

Secure Mode

--secure

flag

Enable secure mode. Errors on unsafe Porffor features like FFI.

porf --secure untrusted.js

Memory & Allocation

Allocator

--allocator

string

default:"chunk"

Select the memory allocator algorithm.Options:

chunk (default) - Chunk-based allocator with dynamic growth
oneshot - One-shot allocator, faster for short-lived programs (used in Lambda)

porf --allocator=oneshot script.js

The chunk allocator grows memory in configurable chunks (see --allocator-chunks).

--allocator-chunks

number

default:"16"

Number of Wasm pages (64KB each) to allocate per chunk when using the chunk allocator.

porf --allocator-chunks=32 script.js

Source reference: source/compiler/builtins.js:1046

Page Size

--page-size

number

default:"16384"

Internal page size for memory allocation. Default is 16384 (65536 / 4).

porf --page-size=8192 script.js

Source reference: source/compiler/index.js:80

Exception Handling

--exception-mode

string

default:"stack"

Exception handling mode to use.Options:

stack (default) - Stack-based exception handling
lut - Look-up table based exception handling

porf --exception-mode=lut script.js

The lut mode is used by precompile for built-in functions. The stack mode passes exception values on the stack.Source reference: source/compiler/codegen.js:5499

--wasm-exceptions

boolean

default:"true"

Enable or disable Wasm exception handling proposal.

porf --no-wasm-exceptions script.js

Random Number Generation

--prng

string

default:"xorshift128+"

Select the pseudo-random number generator algorithm for Math.random().Options:

xorshift32+
xorshift64+
xorshift128+ (default)
xoroshiro128+
xoshiro128+

porf --prng=xoshiro128+ script.js

Different algorithms offer different trade-offs between speed and randomness quality. The default xorshift128+ provides a good balance.Source reference: source/compiler/builtins.js:617-852

Valtype

--valtype

string

default:"f64"

Primary value type for Wasm operations.Options:

f64 (default) - 64-bit floating point
i32 - 32-bit integer (not well supported)

porf --valtype=i32 script.js

Using i32 is not well supported and may cause issues. The default f64 is recommended.

Source reference: source/runtime/index.js:64

Output & Analysis

Disassembly

-f

flag | string

Print disassembled Wasm generated from user functions.

# Disassemble all functions
porf -f script.js

# Disassemble specific function
porf -f=functionName script.js

Source reference: source/compiler/index.js:18

--opt-funcs

flag

Display function disassembly after optimization.

porf --opt-funcs script.js

Benchmarking

-t

flag

Print timing information for compilation and execution.

porf -t script.js

-b

flag

Print Wasm binary size.

porf -b script.js

--profile-compiler

flag

Log general compiler performance. Enabled by default when compiling to a file.

porf --profile-compiler script.js

Builtin Analysis

--builtin-tree

flag | string

Display tree of builtin function dependencies.

# Show all builtin dependencies
porf --builtin-tree script.js

# Show dependencies for specific builtin
porf --builtin-tree=Array.prototype.map script.js

--compile-alloc-log

flag

Log memory allocation details during compilation.

porf --compile-alloc-log script.js

Source reference: source/compiler/index.js:208

Wasm Import/Export

--treeshake-wasm-imports

boolean

default:"true"

Treeshake (remove) unused Wasm imports.

porf --no-treeshake-wasm-imports script.js

--passive-data

boolean

default:"true"

Use passive Wasm data segments.

porf --no-passive-data script.js

Automatically disabled when compiling to C/native.

Advanced Options

Tail Call Optimization

--tail-call

flag

Enable tail call optimization using Wasm tail call proposal.

porf --tail-call script.js

The tail call proposal is not widely implemented across Wasm runtimes.

Source reference: source/compiler/opt.js:10

Wasm Optimizer

--wasm-opt

flag

Run wasm-opt on generated Wasm binary.

porf --wasm-opt script.js output.wasm

Requires wasm-opt to be installed and available in PATH.Source reference: source/compiler/index.js:215

COCTC

--coctc

boolean

default:"true"

Enable Cross-Object Compile-Time Cache.

porf --no-coctc script.js

Closures

--closures

boolean

default:"true"

Enable closure support.

porf --no-closures script.js

Get Started

Core Concepts

CLI Commands

Configuration

Advanced Features

Guides

Compiler Options

Core Options

Debug Mode

Module Parsing

Secure Mode

Memory & Allocation

Allocator

Page Size

Exception Handling

Random Number Generation

Valtype

Output & Analysis

Disassembly

Benchmarking

Builtin Analysis

Wasm Import/Export

Advanced Options

Tail Call Optimization

Wasm Optimizer

COCTC

Closures

See Also

Build docs developers (and LLMs) love

Get Started

Core Concepts

CLI Commands

Configuration

Advanced Features

Guides

​Core Options

​Debug Mode

​Module Parsing

​Secure Mode

​Memory & Allocation

​Allocator

​Page Size

​Exception Handling

​Random Number Generation

​Valtype

​Output & Analysis

​Disassembly

​Benchmarking

​Builtin Analysis

​Wasm Import/Export

​Advanced Options

​Tail Call Optimization

​Wasm Optimizer

​COCTC

​Closures

​See Also

Build docs developers (and LLMs) love

Core Options

Debug Mode

Module Parsing

Secure Mode

Memory & Allocation

Allocator

Page Size

Exception Handling

Random Number Generation

Valtype

Output & Analysis

Disassembly

Benchmarking

Builtin Analysis

Wasm Import/Export

Advanced Options

Tail Call Optimization

Wasm Optimizer

COCTC

Closures

See Also