The code generation monad, a combined reader-state-exception monad.

An error message produced by a code generation operation.

Kind of relocation, for example PC-relative

Relocation entry

Label

Kind of a fixup entry. When a label is emitted with defineLabel, all prior references to this label must be fixed up. This data type tells how to perform the fixup operation.

Configuration of the code generator. There are currently two configuration options. The first is the number fo bytes to use for allocating code buffers (the first as well as additional buffers created in calls to ensureBufferSize. The second allows to pass in a pre-allocated code buffer and its size. When this option is used, Harpy does not perform any code buffer resizing (calls to ensureBufferSize will be equivalent to calls to checkBufferSize).

Default code generation configuration. The code buffer size is set to 4KB, and code buffer management is automatic. This value is intended to be used with record update syntax, for example:

 runCodeGenWithConfig ... defaultCodeGenConfig{codeBufferSize = 128} ...

Abort code generation with the given error message.

Return a pointer to the beginning of the first code buffer, which is normally the entry point to the generated code.

Return the current offset in the code buffer, e.g. the offset at which the next instruction will be emitted.

Return the pointer to the start of the code buffer.

Return a list of all code buffers and their respective size (i.e., actually used space for code, not allocated size).

Set the user state to the given value.

Return the current user state.

Return the current user environment.

Set the environment to the given value and execute the given code generation in this environment.

Generate a new label to be used with the label operations emitFixup and defineLabel.

Generate a new label to be used with the label operations emitFixup and defineLabel. The given name is used for diagnostic purposes, and will appear in the disassembly.

Generate a new label and define it at once

Emit a label at the current offset in the code buffer. All references to the label will be relocated to this offset.

This operator gives neat syntax for defining labels. When l is a label, the code

l @@ mov eax ebx

associates the label l with the following mov instruction.

Emit a fixup entry for the given label at the current offset in the code buffer (unless the label is already defined). The instruction at this offset will be patched to target the address associated with this label when it is defined later.

Return the address of a label, fail if the label is not yet defined.

Emit a relocation entry for the given offset, relocation kind and target address.

Emit a byte value to the code buffer.

Store a byte value at the given offset into the code buffer.

Return the byte value at the given offset in the code buffer.

Like emit8, but for a 32-bit value.

Like emit8At, but for a 32-bit value.

Check whether the code buffer has room for at least the given number of bytes. This should be called by code generators whenever it cannot be guaranteed that the code buffer is large enough to hold all the generated code. Lets the code generation monad fail when the buffer overflows.

Note: Starting with version 0.4, Harpy automatically checks for buffer overflow, so you do not need to call this function anymore.

Make sure that the code buffer has room for at least the given number of bytes. This should be called by code generators whenever it cannot be guaranteed that the code buffer is large enough to hold all the generated code. Creates a new buffer and places a jump to the new buffer when there is not sufficient space available. When code generation was invoked with a pre-defined code buffer, code generation is aborted on overflow.

Note: Starting with version 0.4, Harpy automatically checks for buffer overflow, so you do not need to call this function anymore.

Execute code generation, given a user environment and state. The result is a tuple of the resulting user state and either an error message (when code generation failed) or the result of the code generation. This function runs runCodeGenWithConfig with a sensible default configuration.

Like runCodeGen, but allows more control over the code generation process. In addition to a code generator and a user environment and state, a code generation configuration must be provided. A code generation configuration allows control over the allocation of code buffers, for example.

Disassemble all code buffers. The result is a list of disassembled instructions which can be converted to strings using the showIntel or showAtt functions from module Harpy.X86Disassembler.