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* Copyright (c) 2025 Sanko Robinson
*
* This source code is dual-licensed under the Artistic License 2.0 or the MIT License.
* You may choose to use this code under the terms of either license.
*
* SPDX-License-Identifier: (Artistic-2.0 OR MIT)
*
* The documentation blocks within this file are licensed under the
* Creative Commons Attribution 4.0 International License (CC BY 4.0).
*
* SPDX-License-Identifier: CC-BY-4.0
*/
/**
* @file infix_internals.h
* @brief Internal data structures, function prototypes, and constants.
* @ingroup internal_common
*
* @details This is the primary internal header for the `infix` library. It defines the
* complete layout of all opaque public structs (like `infix_forward_t`) and
* declares internal-only functions (`_infix_*`) that are shared between modules.
*
* Its most important role is to define the core ABI abstraction layer through v-tables
* (`infix_forward_abi_spec`, `infix_reverse_abi_spec`). These structures form the
* contract between the platform-agnostic JIT engine (`trampoline.c`) and the
* platform-specific ABI implementations (`arch/...`), making them key to the
* library's portability and architectural design.
*
* This header also brings together all other internal type definitions, creating a
* single source of truth for the library's internal data model.
* @internal
*/
#pragma once
#include "common/infix_config.h"
#include "common/platform.h"
#include <infix/infix.h>
/**
* @struct infix_executable_t
* @brief Internal representation of an executable memory block for JIT code.
*
* @details This struct encapsulates the platform-specific details of allocating and
* managing executable memory in a way that is compliant with modern OS security
* features like W^X (Write XOR Execute). It supports two primary strategies:
*
* 1. **Single-Mapping W^X (Windows/macOS/Android):** A single memory region is
* allocated as Read-Write (`rw_ptr`). After the JIT compiler writes the
* machine code to this region, its permissions are changed to Read-Execute.
* In this model, `rx_ptr` and `rw_ptr` point to the same address.
*
* 2. **Dual-Mapping W^X (Linux/BSD):** A single underlying shared memory object
* is mapped into the process's address space twice: once as Read-Write
* (`rw_ptr`) and once as Read-Execute (`rx_ptr`). The pointers have different
* virtual addresses but point to the same physical memory. This is required
* on systems with stricter W^X enforcement.
*/
typedef struct {
#if defined(INFIX_OS_WINDOWS)
HANDLE handle; /**< The handle from `VirtualAlloc`, needed for `VirtualFree`. */
void * seh_registration; /**< (Windows x64) Opaque handle from `RtlAddFunctionTable`. */
#else
int shm_fd; /**< The file descriptor for shared memory on dual-mapping POSIX systems. -1 otherwise. */
void * eh_frame_ptr; /**< (POSIX) Pointer to the registered .eh_frame data. */
#endif
void * rx_ptr; /**< The read-execute memory address. This is the callable function pointer. */
void * rw_ptr; /**< The read-write memory address. The JIT compiler writes machine code here. */
size_t size; /**< The size of the allocated memory region in bytes. */
} infix_executable_t;
/**
* @struct infix_protected_t
* @brief Internal representation of a memory block that will be made read-only.
*
* @details This is used to harden the `infix_reverse_t` context against runtime
* memory corruption. The context is allocated in a standard read-write memory
* region, fully populated, and then its permissions are changed to read-only
* using this handle.
*/
typedef struct {
void * rw_ptr; /**< The read-write pointer before being made read-only. */
size_t size; /**< The size of the allocated memory region in bytes. */
} infix_protected_t;
/**
* @struct infix_forward_t
* @brief Internal definition of a forward trampoline handle.
* @details This is the concrete implementation of the opaque `infix_forward_t` pointer
* returned to the user. It is a self-contained object that owns all memory and
* metadata required for its operation. The type information (`return_type`,
* `arg_types`) is a deep copy stored in the trampoline's private `arena`,
* ensuring its lifetime is independent of the types used to create it.
*/
struct infix_forward_t {
infix_arena_t * arena; /**< Private or shared arena holding all type metadata for this trampoline. */
bool is_external_arena; /**< True if the arena is user-provided and should not be freed by `infix_forward_destroy`.
*/
infix_executable_t exec; /**< The executable memory containing the JIT-compiled code. */
infix_type * return_type; /**< A deep copy of the function's return type. */
infix_type ** arg_types; /**< A deep copy of the function's argument types. */
size_t num_args; /**< The total number of arguments. */
size_t num_fixed_args; /**< The number of non-variadic arguments. */
void * target_fn; /**< The target C function pointer (for bound trampolines), or `nullptr` for unbound. */
bool is_direct_trampoline; /**< If true, this is a high-performance direct marshalling trampoline. */
bool is_safe; /**< If true, the trampoline wraps the call in an exception handler. */
size_t ref_count; /**< Reference count for deduplication and shared ownership. */
char * signature; /**< The normalized signature string used to create this trampoline. */
};
/**
* @brief A function pointer to the universal C dispatcher for reverse calls.
* @details This is the C function that the JIT-compiled reverse trampoline stub calls
* after marshalling all arguments into a standard C format.
*/
typedef void (*infix_internal_dispatch_callback_fn)(infix_reverse_t *, void *, void **);
/**
* @struct infix_reverse_t
* @brief Internal definition of a reverse trampoline (callback/closure) handle.
* @details This is the concrete implementation of the opaque `infix_reverse_t` pointer.
* The entire struct is allocated in a page-aligned memory region that is made read-only
* after initialization to prevent memory corruption vulnerabilities. Like the forward
* trampoline, it is self-contained and owns deep copies of all its type metadata.
*/
struct infix_reverse_t {
infix_arena_t * arena; /**< Private arena for type metadata. */
infix_executable_t exec; /**< Executable memory for the JIT stub. */
infix_protected_t protected_ctx; /**< The read-only memory region holding this struct. */
infix/src/common/infix_internals.h view on Meta::CPAN
* @def INFIX_MAX_STACK_ALLOC
* @brief A safety limit (4MB) for the total stack space a trampoline can allocate.
* This prevents stack exhaustion from malformed or malicious type layouts.
*/
#define INFIX_MAX_STACK_ALLOC (1024 * 1024 * 4)
/**
* @def INFIX_MAX_ARG_SIZE
* @brief A safety limit (64KB) for the size of a single argument.
*/
#define INFIX_MAX_ARG_SIZE (1024 * 64)
/**
* @enum infix_arg_location_type
* @brief Describes the physical location where a function argument is passed according to the ABI.
*
* This enumeration abstracts away the differences in how various ABIs use
* registers and the stack to pass data. It is the primary output of the ABI
* classification process.
*/
typedef enum {
/** @brief Argument is passed in a general-purpose integer register (e.g., `RCX`, `RDI`, `X0`). */
ARG_LOCATION_GPR,
#if defined(INFIX_ABI_AAPCS64)
/** @brief (AArch64) Argument is passed in a vector/floating-point register (e.g., `V0`). */
ARG_LOCATION_VPR,
/** @brief (AArch64) A struct <= 16 bytes passed in a pair of GPRs (e.g., `X0`, `X1`). */
ARG_LOCATION_GPR_PAIR,
/** @brief (AArch64) A large struct (> 16 bytes) passed by reference; the pointer is in a GPR. */
ARG_LOCATION_GPR_REFERENCE,
/** @brief (AArch64) A Homogeneous Floating-point Aggregate passed in consecutive VPRs. */
ARG_LOCATION_VPR_HFA,
#else // x64 ABIs
/** @brief (x64) Argument is passed in an SSE/XMM register (e.g., `XMM0`). */
ARG_LOCATION_XMM,
/** @brief (SysV x64) A struct passed in two GPRs (e.g., `RDI`, `RSI`). */
ARG_LOCATION_GPR_PAIR,
/** @brief (SysV x64) A struct passed in two SSE registers (e.g., `XMM0`, `XMM1`). */
ARG_LOCATION_SSE_SSE_PAIR,
/** @brief (SysV x64) A struct split between a GPR and an SSE register. */
ARG_LOCATION_INTEGER_SSE_PAIR,
/** @brief (SysV x64) A struct split between an SSE and a GPR register. */
ARG_LOCATION_SSE_INTEGER_PAIR,
#endif
/** @brief Argument is passed on the stack. */
ARG_LOCATION_STACK
} infix_arg_location_type;
/**
* @struct infix_arg_location
* @brief Detailed location information for a single function argument.
* @details This struct is the result of the ABI classification process for one
* argument. It provides all the information the code emitters need to generate
* the correct move/load/store instructions.
*/
typedef struct {
infix_arg_location_type type; /**< The classification of the argument's location. */
uint8_t reg_index; /**< The index of the primary register used. */
uint8_t reg_index2; /**< The index of the second register (for pairs). */
uint32_t num_regs; /**< Number of regs OR scratch buffer offset. */
uint32_t stack_offset; /**< The byte offset from the stack pointer. */
} infix_arg_location;
/**
* @struct infix_call_frame_layout
* @brief A complete layout blueprint for a forward call frame.
* @details This structure is the primary output of `prepare_forward_call_frame`. It serves
* as a complete plan for the JIT engine, detailing every register and stack slot
* that needs to be populated before making the `call` instruction.
*/
typedef struct {
size_t total_stack_alloc; /**< Total bytes to allocate on the stack for arguments and ABI-required space. */
uint8_t num_gpr_args; /**< The number of GPRs used for arguments. */
#if defined(INFIX_ABI_AAPCS64)
uint8_t num_vpr_args; /**< The number of VPRs used for arguments. */
#else
uint8_t num_xmm_args; /**< The number of XMMs used for arguments. */
#endif
infix_arg_location * arg_locations; /**< An array of location info for each argument. */
bool return_value_in_memory; /**< `true` if the return value uses a hidden pointer argument (struct return). */
bool is_variadic; /**< `true` if the function is variadic. */
size_t num_stack_args; /**< The number of arguments passed on the stack. */
size_t num_args; /**< The total number of arguments. */
void * target_fn; /**< The target function address. */
uint32_t max_align; /**< Maximum required alignment for any argument or the stack. */
uint32_t prologue_size; /**< Size of the generated prologue in bytes. */
uint32_t epilogue_offset; /**< Offset from the start of the JIT block to the epilogue. */
} infix_call_frame_layout;
/**
* @struct infix_reverse_call_frame_layout
* @brief A complete layout blueprint for a reverse call frame.
* @details This structure serves as a plan for the JIT-compiled reverse call stub.
* It contains the offsets for all data structures that the stub needs to create
* on its stack frame before calling the universal C dispatcher.
*/
typedef struct {
size_t total_stack_alloc; /**< Total bytes of local stack space needed. */
int32_t return_buffer_offset; /**< Stack offset for the buffer to store the return value. */
int32_t args_array_offset; /**< Stack offset for the `void**` array passed to the C dispatcher. */
int32_t saved_args_offset; /**< Stack offset for the area where argument data is stored/marshalled. */
int32_t gpr_save_area_offset; /**< (Win x64) Stack offset for saving non-volatile GPRs. */
int32_t xmm_save_area_offset; /**< (Win x64) Stack offset for saving non-volatile XMMs. */
uint32_t max_align; /**< Maximum required alignment for any argument or the stack. */
uint32_t prologue_size; /**< Size of the generated prologue in bytes. */
} infix_reverse_call_frame_layout;
/**
* @brief Defines the ABI-specific implementation interface for forward trampolines.
*
* @details This structure is a virtual function table (v-table) that decouples the
* platform-agnostic JIT engine (`trampoline.c`) from the platform-specific
* code generation logic (`arch/...`). Each supported ABI (e.g., SysV x64,
* Win x64, AArch64) provides a concrete implementation of this interface.
*
* The JIT pipeline for a forward call proceeds in a well-defined order:
* 1. `prepare_forward_call_frame` is called first to analyze the function
* signature and produce a complete `infix_call_frame_layout` blueprint.
* 2. The `generate_*` functions are then called in sequence, consuming the layout
* blueprint to emit the corresponding machine code into a `code_buffer`.
*/
typedef struct {
/**
* @brief Analyzes a function signature to create a complete call frame layout.
* @details This is the "classification" stage. It determines where each argument
* and the return value will be placed (in which registers or on what
* stack offset) according to the target ABI's rules. The resulting
* layout is a complete plan for the code emitters.
* @param[in] arena A temporary arena for allocating the layout struct.
* @param[out] out_layout Receives the newly created layout blueprint.
* @param[in] ret_type The function's return type.
* @param[in] arg_types Array of argument types.
* @param[in] num_args Total number of arguments.
* @param[in] num_fixed_args Number of non-variadic arguments.
* @param[in] target_fn The target function address.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*prepare_forward_call_frame)(infix_arena_t * arena,
infix_call_frame_layout ** out_layout,
infix_type * ret_type,
infix_type ** arg_types,
size_t num_args,
size_t num_fixed_args,
void * target_fn);
/**
* @brief Generates the function prologue (stack setup, saving registers).
* @param[in,out] buf The code buffer to append machine code to.
* @param[in] layout The layout blueprint from the previous step.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*generate_forward_prologue)(code_buffer * buf, infix_call_frame_layout * layout);
/**
* @brief Generates code to move arguments from the `void**` array into registers and/or the stack.
* @param[in,out] buf The code buffer.
* @param[in] layout The layout blueprint.
* @param[in] arg_types The array of argument types.
* @param[in] num_args Total number of arguments.
* @param[in] num_fixed_args Number of fixed arguments.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*generate_forward_argument_moves)(code_buffer * buf,
infix_call_frame_layout * layout,
infix_type ** arg_types,
size_t num_args,
size_t num_fixed_args);
/**
* @brief Generates the `call` instruction to the target function.
* @param[in,out] buf The code buffer.
* @param[in] layout The layout blueprint.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*generate_forward_call_instruction)(code_buffer * buf, infix_call_frame_layout * layout);
/**
* @brief Generates the function epilogue (handling return value, restoring stack, returning).
* @param[in,out] buf The code buffer.
* @param[in] layout The layout blueprint.
* @param[in] ret_type The function's return type.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*generate_forward_epilogue)(code_buffer * buf,
infix_call_frame_layout * layout,
infix_type * ret_type);
} infix_forward_abi_spec;
/**
* @brief Defines the ABI-specific implementation interface for reverse trampolines.
* @details This v-table defines the contract for generating the JIT stub for a
* reverse call (callback). The stub's primary job is to receive arguments in
* native ABI format, marshal them into a generic `void**` array, and call the
* universal C dispatcher.
*/
typedef struct {
/**
* @brief Analyzes a function signature to create a layout for the reverse call stub's stack frame.
* @param[in] arena The temporary arena for allocations.
* @param[out] out_layout Receives the newly created layout blueprint.
* @param[in] context The reverse trampoline context, containing all type info.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*prepare_reverse_call_frame)(infix_arena_t * arena,
infix_reverse_call_frame_layout ** out_layout,
infix_reverse_t * context);
/**
* @brief Generates the reverse stub's prologue (stack setup).
* @param[in,out] buf The code buffer.
* @param[in] layout The layout blueprint.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*generate_reverse_prologue)(code_buffer * buf, infix_reverse_call_frame_layout * layout);
/**
* @brief Generates code to marshal arguments from their native locations (registers/stack) into a `void**` array.
* @param[in,out] buf The code buffer.
* @param[in] layout The layout blueprint.
* @param[in] context The reverse context.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*generate_reverse_argument_marshalling)(code_buffer * buf,
infix_reverse_call_frame_layout * layout,
infix_reverse_t * context);
/**
* @brief Generates the call to the universal C dispatcher (`infix_internal_dispatch_callback_fn_impl`).
* @param[in,out] buf The code buffer.
* @param[in] layout The layout blueprint.
* @param[in] context The reverse context.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*generate_reverse_dispatcher_call)(code_buffer * buf,
infix_reverse_call_frame_layout * layout,
infix_reverse_t * context);
/**
* @brief Generates the reverse stub's epilogue (handling return value, restoring stack, returning).
* @param[in,out] buf The code buffer.
* @param[in] layout The layout blueprint.
* @param[in] context The reverse context.
* @return `INFIX_SUCCESS` on success.
*/
infix_status (*generate_reverse_epilogue)(code_buffer * buf,
infix_reverse_call_frame_layout * layout,
infix_reverse_t * context);
} infix_reverse_abi_spec;
/**
* @struct infix_direct_arg_layout
* @brief Internal layout information for a single argument in a direct marshalling trampoline.
*
* This struct combines the ABI location information with pointers to the type and
* handler information needed by the JIT emitters.
*/
typedef struct {
infix_arg_location location; ///< The physical location (register/stack) of the argument.
const infix_type * type; ///< The `infix_type` of this argument.
const infix_direct_arg_handler_t * handler; ///< Pointer to the user-provided handler struct for this argument.
} infix_direct_arg_layout;
/**
* @struct infix_direct_call_frame_layout
* @brief A complete layout blueprint for a direct marshalling forward call frame.
*
* This structure serves as the plan for the JIT engine, detailing every register,
* stack slot, and marshaller/write-back call needed to execute a direct FFI call.
*/
typedef struct {
size_t total_stack_alloc; ///< Total bytes to allocate on the stack for arguments and ABI-required space.
size_t num_args; ///< The total number of arguments.
void * target_fn; ///< The target C function address.
bool return_value_in_memory; ///< `true` if the return value uses a hidden pointer argument.
infix_direct_arg_layout * args; ///< An array of layout info for each argument.
uint32_t prologue_size; ///< Size of the generated prologue in bytes.
uint32_t epilogue_offset; ///< Offset from the start of the JIT block to the epilogue.
} infix_direct_call_frame_layout;
/**
* @brief Defines the ABI-specific implementation interface for direct marshalling forward trampolines.
*
* This v-table defines the contract for generating a high-performance, direct-marshalling
* trampoline. It is parallel to `infix_forward_abi_spec`.
*/
typedef struct {
/** @brief Analyzes a function signature to create a complete direct call frame layout. */
infix_status (*prepare_direct_forward_call_frame)(infix_arena_t * arena,
infix_direct_call_frame_layout ** out_layout,
infix_type * ret_type,
infix_type ** arg_types,
size_t num_args,
infix_direct_arg_handler_t * handlers,
void * target_fn);
/** @brief Generates the function prologue (stack setup, saving registers). */
infix_status (*generate_direct_forward_prologue)(code_buffer * buf, infix_direct_call_frame_layout * layout);
/** @brief Generates code to call marshallers and move arguments into their native locations. */
infix_status (*generate_direct_forward_argument_moves)(code_buffer * buf, infix_direct_call_frame_layout * layout);
/** @brief Generates the `call` instruction to the target function. */
infix_status (*generate_direct_forward_call_instruction)(code_buffer * buf,
infix_direct_call_frame_layout * layout);
/** @brief Generates the function epilogue (handling return value, calling write-back handlers, returning). */
infix_status (*generate_direct_forward_epilogue)(code_buffer * buf,
infix_direct_call_frame_layout * layout,
infix_type * ret_type);
} infix_direct_forward_abi_spec;
// Internal Function Prototypes (Shared across modules)
/**
* @brief Sets the thread-local error state with detailed information.
* @details Located in `src/core/error.c`, this function is the primary mechanism
* for reporting errors from within the library. It populates the thread-local
* `g_infix_last_error` struct. For parser errors, it generates a rich diagnostic
* message with a code snippet.
* @param category The general category of the error.
* @param code The specific error code.
* @param position For parser errors, the byte offset into the signature string where the error occurred.
*/
INFIX_INTERNAL void _infix_set_error(infix_error_category_t category, infix_error_code_t code, size_t position);
/**
* @brief Sets the thread-local error state for a system-level error.
* @details Located in `src/core/error.c`, this is used for errors originating from
* the operating system, such as `dlopen` or `mmap` failures.
* @param category The general category of the error.
* @param code The `infix` error code that corresponds to the failure.
* @param system_code The OS-specific error code (e.g., from `errno` or `GetLastError`).
* @param msg An optional custom message from the OS (e.g., from `dlerror`).
*/
INFIX_INTERNAL void _infix_set_system_error(infix_error_category_t category,
infix_error_code_t code,
long system_code,
const char * msg);
/**
* @brief Clears the thread-local error state.
* @details Located in `src/core/error.c`. This is called at the beginning of every public
* API function to ensure that a prior error from an unrelated call is not accidentally returned.
*/
INFIX_INTERNAL void _infix_clear_error(void);
INFIX_INTERNAL void skip_whitespace(parser_state * state);
INFIX_INTERNAL void _infix_set_parser_error(parser_state * state, infix_error_code_t code);
INFIX_INTERNAL infix_type * parse_type(parser_state * state);
INFIX_INTERNAL infix_type * parse_primitive(parser_state * state);
/**
* @brief Recalculates the layout of a fully resolved type graph.
* @details Located in `src/core/types.c`. This is the "Layout" stage of the data pipeline.
* It recursively walks a type graph and computes the final `size`, `alignment`, and
* member `offset` fields for all aggregate types. It must only be called on a fully
* resolved graph.
* @param[in,out] type The root of the type graph to recalculate. The graph is modified in-place.
*/
INFIX_INTERNAL void _infix_type_recalculate_layout(infix_type * type);
/**
* @brief Resolves all named type references in a type graph in-place.
* @details Located in `src/core/type_registry.c`. This is the "Resolve" stage of the
* data pipeline. It traverses a type graph and replaces all `INFIX_TYPE_NAMED_REFERENCE`
* nodes (`@Name`) with direct pointers to the canonical `infix_type` objects from the registry.
* @param[in,out] type_ptr A pointer to the root of the type graph to resolve. The pointer may be changed.
* @param[in] registry The registry to use for lookups.
* @return `INFIX_SUCCESS` on success, or an error if a name cannot be resolved.
*/
INFIX_INTERNAL c23_nodiscard infix_status _infix_resolve_type_graph_inplace(infix_type ** type_ptr,
infix_registry_t * registry);
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