#if defined(LLVM_BACKEND_SUPPORT)
#if defined(GB_SYSTEM_WINDOWS)
#include "llvm-c/Core.h"
#include "llvm-c/ExecutionEngine.h"
#include "llvm-c/Target.h"
#include "llvm-c/Analysis.h"
#include "llvm-c/Object.h"
#include "llvm-c/BitWriter.h"
#include "llvm-c/DebugInfo.h"
#include "llvm-c/Transforms/AggressiveInstCombine.h"
#include "llvm-c/Transforms/InstCombine.h"
#include "llvm-c/Transforms/IPO.h"
#include "llvm-c/Transforms/PassManagerBuilder.h"
#include "llvm-c/Transforms/Scalar.h"
#include "llvm-c/Transforms/Utils.h"
#include "llvm-c/Transforms/Vectorize.h"
#else
#include <llvm-c/Core.h>
#include <llvm-c/ExecutionEngine.h>
#include <llvm-c/Target.h>
#include <llvm-c/Analysis.h>
#include <llvm-c/Object.h>
#include <llvm-c/BitWriter.h>
#include <llvm-c/DebugInfo.h>
#include <llvm-c/Transforms/AggressiveInstCombine.h>
#include <llvm-c/Transforms/InstCombine.h>
#include <llvm-c/Transforms/IPO.h>
#include <llvm-c/Transforms/PassManagerBuilder.h>
#include <llvm-c/Transforms/Scalar.h>
#include <llvm-c/Transforms/Utils.h>
#include <llvm-c/Transforms/Vectorize.h>
#endif
#endif

struct lbProcedure;

struct lbValue {
	LLVMValueRef value;
	Type *type;
};


enum lbAddrKind {
	lbAddr_Default,
	lbAddr_Map,
	lbAddr_Context,
	lbAddr_SoaVariable,

	lbAddr_RelativePointer,
	lbAddr_RelativeSlice,

	lbAddr_AtomOp_index_set,
};

struct lbAddr {
	lbAddrKind kind;
	lbValue addr;
	union {
		struct {
			lbValue key;
			Type *type;
			Type *result;
		} map;
		struct {
			Selection sel;
		} ctx;
		struct {
			lbValue index;
			Ast *index_expr;
		} soa;
		struct {
			lbValue index;
			Ast *node;
		} index_set;
		struct {
			bool deref;
		} relative;
	};
};

struct lbIncompleteDebugType {
	Type *type;
	LLVMMetadataRef metadata;
};

struct lbModule {
	LLVMModuleRef mod;
	LLVMContextRef ctx;

	u64 state_flags;

	CheckerInfo *info;

	gbMutex mutex;

	Map<LLVMTypeRef> types; // Key: Type *
	Map<Type *> llvm_types; // Key: LLVMTypeRef
	i32 internal_type_level;

	Map<lbValue>  values;           // Key: Entity *
	Map<lbAddr>   soa_values;       // Key: Entity *
	StringMap<lbValue>  members;
	StringMap<lbProcedure *> procedures;
	Map<Entity *> procedure_values; // Key: LLVMValueRef

	StringMap<LLVMValueRef> const_strings;

	Map<lbProcedure *> anonymous_proc_lits; // Key: Ast *
	Map<struct lbFunctionType *> function_type_map; // Key: Type *

	Map<lbProcedure *> equal_procs; // Key: Type *
	Map<lbProcedure *> hasher_procs; // Key: Type *

	u32 global_array_index;
	u32 global_generated_index;
	u32 nested_type_name_guid;

	Array<lbProcedure *> procedures_to_generate;
	Array<String> foreign_library_paths;

	lbProcedure *curr_procedure;

	LLVMDIBuilderRef debug_builder;
	LLVMMetadataRef debug_compile_unit;
	Map<LLVMMetadataRef> debug_values; // Key: Pointer

	Array<lbIncompleteDebugType> debug_incomplete_types;
};

struct lbGenerator {
	lbModule module;
	CheckerInfo *info;

	Array<String> output_object_paths;
	String   output_base;
	String   output_name;
};


struct lbBlock {
	LLVMBasicBlockRef block;
	Scope *scope;
	isize scope_index;
	bool appended;

	Array<lbBlock *> preds;
	Array<lbBlock *> succs;
};

struct lbBranchBlocks {
	Ast *label;
	lbBlock *break_;
	lbBlock *continue_;
};


struct lbContextData {
	lbAddr ctx;
	isize scope_index;
	isize uses;
};

enum lbParamPasskind {
	lbParamPass_Value,    // Pass by value
	lbParamPass_Pointer,  // Pass as a pointer rather than by value
	lbParamPass_Integer,  // Pass as an integer of the same size
	lbParamPass_ConstRef, // Pass as a pointer but the value is immutable
	lbParamPass_BitCast,  // Pass by value and bit cast to the correct type
	lbParamPass_Tuple,    // Pass across multiple parameters (System V AMD64, up to 2)
};

enum lbDeferExitKind {
	lbDeferExit_Default,
	lbDeferExit_Return,
	lbDeferExit_Branch,
};

enum lbDeferKind {
	lbDefer_Node,
	lbDefer_Instr,
	lbDefer_Proc,
};

struct lbDefer {
	lbDeferKind kind;
	isize       scope_index;
	isize       context_stack_count;
	lbBlock *   block;
	union {
		Ast *stmt;
		// NOTE(bill): 'instr' will be copied every time to create a new one
		lbValue instr;
		struct {
			lbValue deferred;
			Array<lbValue> result_as_args;
		} proc;
	};
};

struct lbTargetList {
	lbTargetList *prev;
	bool          is_block;
	lbBlock *     break_;
	lbBlock *     continue_;
	lbBlock *     fallthrough_;
};


enum lbProcedureFlag : u32 {
	lbProcedureFlag_WithoutMemcpyPass = 1<<0,
};

struct lbProcedure {
	u32 flags;

	lbProcedure *parent;
	Array<lbProcedure *> children;

	Entity *     entity;
	lbModule *   module;
	String       name;
	Type *       type;
	Ast *        type_expr;
	Ast *        body;
	u64          tags;
	ProcInlining inlining;
	bool         is_foreign;
	bool         is_export;
	bool         is_entry_point;
	bool         is_startup;

	lbFunctionType *abi_function_type;

	LLVMValueRef    value;
	LLVMBuilderRef  builder;
	bool            is_done;

	lbAddr           return_ptr;
	Array<lbValue>   params;
	Array<lbDefer>   defer_stmts;
	Array<lbBlock *> blocks;
	Array<lbBranchBlocks> branch_blocks;
	Scope *          curr_scope;
	i32              scope_index;
	lbBlock *        decl_block;
	lbBlock *        entry_block;
	lbBlock *        curr_block;
	lbTargetList *   target_list;

	Ast *curr_stmt;

	Array<Scope *>       scope_stack;
	Array<lbContextData> context_stack;

	LLVMMetadataRef debug_info;

	lbValue  return_ptr_hint_value;
	Ast *    return_ptr_hint_ast;
	bool     return_ptr_hint_used;
};





bool lb_init_generator(lbGenerator *gen, Checker *c);
void lb_generate_module(lbGenerator *gen);

String lb_mangle_name(lbModule *m, Entity *e);
String lb_get_entity_name(lbModule *m, Entity *e, String name = {});

LLVMAttributeRef lb_create_enum_attribute(LLVMContextRef ctx, char const *name, u64 value=0);
void lb_add_proc_attribute_at_index(lbProcedure *p, isize index, char const *name, u64 value);
void lb_add_proc_attribute_at_index(lbProcedure *p, isize index, char const *name);
lbProcedure *lb_create_procedure(lbModule *module, Entity *entity);
void lb_end_procedure(lbProcedure *p);


LLVMTypeRef  lb_type(lbModule *m, Type *type);

lbBlock *lb_create_block(lbProcedure *p, char const *name, bool append=false);

lbValue lb_const_nil(lbModule *m, Type *type);
lbValue lb_const_undef(lbModule *m, Type *type);
lbValue lb_const_value(lbModule *m, Type *type, ExactValue value, bool allow_local=true);
lbValue lb_const_bool(lbModule *m, Type *type, bool value);
lbValue lb_const_int(lbModule *m, Type *type, u64 value);


lbAddr lb_addr(lbValue addr);
Type *lb_addr_type(lbAddr const &addr);
LLVMTypeRef lb_addr_lb_type(lbAddr const &addr);
void lb_addr_store(lbProcedure *p, lbAddr addr, lbValue value);
lbValue lb_addr_load(lbProcedure *p, lbAddr const &addr);
lbValue lb_emit_load(lbProcedure *p, lbValue v);
void lb_emit_store(lbProcedure *p, lbValue ptr, lbValue value);


void    lb_build_stmt(lbProcedure *p, Ast *stmt);
lbValue lb_build_expr(lbProcedure *p, Ast *expr);
lbAddr  lb_build_addr(lbProcedure *p, Ast *expr);
void lb_build_stmt_list(lbProcedure *p, Array<Ast *> const &stmts);

lbValue lb_build_gep(lbProcedure *p, lbValue const &value, i32 index) ;

lbValue lb_emit_struct_ep(lbProcedure *p, lbValue s, i32 index);
lbValue lb_emit_struct_ev(lbProcedure *p, lbValue s, i32 index);
lbValue lb_emit_array_epi(lbProcedure *p, lbValue value, isize index);
lbValue lb_emit_array_ep(lbProcedure *p, lbValue s, lbValue index);
lbValue lb_emit_deep_field_gep(lbProcedure *p, lbValue e, Selection sel);
lbValue lb_emit_deep_field_ev(lbProcedure *p, lbValue e, Selection sel);

lbValue lb_emit_arith(lbProcedure *p, TokenKind op, lbValue lhs, lbValue rhs, Type *type);
lbValue lb_emit_byte_swap(lbProcedure *p, lbValue value, Type *end_type);
void lb_emit_defer_stmts(lbProcedure *p, lbDeferExitKind kind, lbBlock *block);
lbValue lb_emit_transmute(lbProcedure *p, lbValue value, Type *t);
lbValue lb_emit_comp(lbProcedure *p, TokenKind op_kind, lbValue left, lbValue right);
lbValue lb_emit_call(lbProcedure *p, lbValue value, Array<lbValue> const &args, ProcInlining inlining = ProcInlining_none, bool use_return_ptr_hint = false);
lbValue lb_emit_conv(lbProcedure *p, lbValue value, Type *t);
lbValue lb_emit_comp_against_nil(lbProcedure *p, TokenKind op_kind, lbValue x);

void lb_emit_jump(lbProcedure *p, lbBlock *target_block);
void lb_emit_if(lbProcedure *p, lbValue cond, lbBlock *true_block, lbBlock *false_block);
void lb_start_block(lbProcedure *p, lbBlock *b);

lbValue lb_build_call_expr(lbProcedure *p, Ast *expr);


lbAddr lb_find_or_generate_context_ptr(lbProcedure *p);
lbContextData *lb_push_context_onto_stack(lbProcedure *p, lbAddr ctx);
lbContextData *lb_push_context_onto_stack_from_implicit_parameter(lbProcedure *p);


lbAddr lb_add_global_generated(lbModule *m, Type *type, lbValue value={});
lbAddr lb_add_local(lbProcedure *p, Type *type, Entity *e=nullptr, bool zero_init=true, i32 param_index=0);

void lb_add_foreign_library_path(lbModule *m, Entity *e);

lbValue lb_typeid(lbModule *m, Type *type);

lbValue lb_address_from_load_or_generate_local(lbProcedure *p, lbValue value);
lbValue lb_address_from_load(lbProcedure *p, lbValue value);
void    lb_add_defer_node(lbProcedure *p, isize scope_index, Ast *stmt);
lbAddr lb_add_local_generated(lbProcedure *p, Type *type, bool zero_init);

lbValue lb_emit_runtime_call(lbProcedure *p, char const *c_name, Array<lbValue> const &args);


lbValue lb_emit_ptr_offset(lbProcedure *p, lbValue ptr, lbValue index);
lbValue lb_string_elem(lbProcedure *p, lbValue string);
lbValue lb_string_len(lbProcedure *p, lbValue string);
lbValue lb_cstring_len(lbProcedure *p, lbValue value);
lbValue lb_array_elem(lbProcedure *p, lbValue array_ptr);
lbValue lb_slice_elem(lbProcedure *p, lbValue slice);
lbValue lb_slice_len(lbProcedure *p, lbValue slice);
lbValue lb_dynamic_array_elem(lbProcedure *p, lbValue da);
lbValue lb_dynamic_array_len(lbProcedure *p, lbValue da);
lbValue lb_dynamic_array_cap(lbProcedure *p, lbValue da);
lbValue lb_dynamic_array_allocator(lbProcedure *p, lbValue da);
lbValue lb_map_entries(lbProcedure *p, lbValue value);
lbValue lb_map_entries_ptr(lbProcedure *p, lbValue value);
lbValue lb_map_len(lbProcedure *p, lbValue value);
lbValue lb_map_cap(lbProcedure *p, lbValue value);
lbValue lb_soa_struct_len(lbProcedure *p, lbValue value);
void lb_emit_increment(lbProcedure *p, lbValue addr);
lbValue lb_emit_select(lbProcedure *p, lbValue cond, lbValue x, lbValue y);

void lb_fill_slice(lbProcedure *p, lbAddr const &slice, lbValue base_elem, lbValue len);

lbValue lb_type_info(lbModule *m, Type *type);

lbValue lb_find_or_add_entity_string(lbModule *m, String const &str);
lbValue lb_generate_anonymous_proc_lit(lbModule *m, String const &prefix_name, Ast *expr, lbProcedure *parent = nullptr);

bool lb_is_const(lbValue value);
bool lb_is_const_or_global(lbValue value);
bool lb_is_const_nil(lbValue value);
String lb_get_const_string(lbModule *m, lbValue value);

lbValue lb_generate_local_array(lbProcedure *p, Type *elem_type, i64 count, bool zero_init=true);
lbValue lb_generate_global_array(lbModule *m, Type *elem_type, i64 count, String prefix, i64 id);
lbValue lb_gen_map_header(lbProcedure *p, lbValue map_val_ptr, Type *map_type);
lbValue lb_gen_map_hash(lbProcedure *p, lbValue key, Type *key_type);
void    lb_insert_dynamic_map_key_and_value(lbProcedure *p, lbAddr addr, Type *map_type, lbValue map_key, lbValue map_value, Ast *node);


void lb_store_type_case_implicit(lbProcedure *p, Ast *clause, lbValue value);
lbAddr lb_store_range_stmt_val(lbProcedure *p, Ast *stmt_val, lbValue value);
lbValue lb_emit_source_code_location(lbProcedure *p, String const &procedure, TokenPos const &pos);

lbValue lb_handle_param_value(lbProcedure *p, Type *parameter_type, ParameterValue const &param_value, TokenPos const &pos);

lbValue lb_get_equal_proc_for_type(lbModule *m, Type *type);
lbValue lb_get_hasher_proc_for_type(lbModule *m, Type *type);
lbValue lb_emit_conv(lbProcedure *p, lbValue value, Type *t);

LLVMMetadataRef lb_debug_type(lbModule *m, Type *type);

lbValue lb_emit_count_ones(lbProcedure *p, lbValue x, Type *type);
lbValue lb_emit_trailing_zeros(lbProcedure *p, lbValue x, Type *type);
lbValue lb_emit_reverse_bits(lbProcedure *p, lbValue x, Type *type);

lbValue lb_emit_bit_set_card(lbProcedure *p, lbValue x);



#define LB_STARTUP_RUNTIME_PROC_NAME   "__$startup_runtime"
#define LB_STARTUP_TYPE_INFO_PROC_NAME "__$startup_type_info"
#define LB_TYPE_INFO_DATA_NAME       "__$type_info_data"
#define LB_TYPE_INFO_TYPES_NAME      "__$type_info_types_data"
#define LB_TYPE_INFO_NAMES_NAME      "__$type_info_names_data"
#define LB_TYPE_INFO_OFFSETS_NAME    "__$type_info_offsets_data"
#define LB_TYPE_INFO_USINGS_NAME     "__$type_info_usings_data"
#define LB_TYPE_INFO_TAGS_NAME       "__$type_info_tags_data"



enum lbCallingConventionKind {
    lbCallingConvention_C = 0,
    lbCallingConvention_Fast = 8,
    lbCallingConvention_Cold = 9,
    lbCallingConvention_GHC = 10,
    lbCallingConvention_HiPE = 11,
    lbCallingConvention_WebKit_JS = 12,
    lbCallingConvention_AnyReg = 13,
    lbCallingConvention_PreserveMost = 14,
    lbCallingConvention_PreserveAll = 15,
    lbCallingConvention_Swift = 16,
    lbCallingConvention_CXX_FAST_TLS = 17,
    lbCallingConvention_FirstTargetCC = 64,
    lbCallingConvention_X86_StdCall = 64,
    lbCallingConvention_X86_FastCall = 65,
    lbCallingConvention_ARM_APCS = 66,
    lbCallingConvention_ARM_AAPCS = 67,
    lbCallingConvention_ARM_AAPCS_VFP = 68,
    lbCallingConvention_MSP430_INTR = 69,
    lbCallingConvention_X86_ThisCall = 70,
    lbCallingConvention_PTX_Kernel = 71,
    lbCallingConvention_PTX_Device = 72,
    lbCallingConvention_SPIR_FUNC = 75,
    lbCallingConvention_SPIR_KERNEL = 76,
    lbCallingConvention_Intel_OCL_BI = 77,
    lbCallingConvention_X86_64_SysV = 78,
    lbCallingConvention_Win64 = 79,
    lbCallingConvention_X86_VectorCall = 80,
    lbCallingConvention_HHVM = 81,
    lbCallingConvention_HHVM_C = 82,
    lbCallingConvention_X86_INTR = 83,
    lbCallingConvention_AVR_INTR = 84,
    lbCallingConvention_AVR_SIGNAL = 85,
    lbCallingConvention_AVR_BUILTIN = 86,
    lbCallingConvention_AMDGPU_VS = 87,
    lbCallingConvention_AMDGPU_GS = 88,
    lbCallingConvention_AMDGPU_PS = 89,
    lbCallingConvention_AMDGPU_CS = 90,
    lbCallingConvention_AMDGPU_KERNEL = 91,
    lbCallingConvention_X86_RegCall = 92,
    lbCallingConvention_AMDGPU_HS = 93,
    lbCallingConvention_MSP430_BUILTIN = 94,
    lbCallingConvention_AMDGPU_LS = 95,
    lbCallingConvention_AMDGPU_ES = 96,
    lbCallingConvention_AArch64_VectorCall = 97,
    lbCallingConvention_MaxID = 1023,
};

lbCallingConventionKind const lb_calling_convention_map[ProcCC_MAX] = {
	lbCallingConvention_C,            // ProcCC_Invalid,
	lbCallingConvention_C,            // ProcCC_Odin,
	lbCallingConvention_C,            // ProcCC_Contextless,
	lbCallingConvention_C,            // ProcCC_CDecl,
	lbCallingConvention_X86_StdCall,  // ProcCC_StdCall,
	lbCallingConvention_X86_FastCall, // ProcCC_FastCall,

	lbCallingConvention_C,            // ProcCC_None,
	lbCallingConvention_C,            // ProcCC_InlineAsm,
};

enum : LLVMDWARFTypeEncoding {
	LLVMDWARFTypeEncoding_Address = 1,
	LLVMDWARFTypeEncoding_Boolean = 2,
	LLVMDWARFTypeEncoding_ComplexFloat = 3,
	LLVMDWARFTypeEncoding_Float = 4,
	LLVMDWARFTypeEncoding_Signed = 5,
	LLVMDWARFTypeEncoding_SignedChar = 6,
	LLVMDWARFTypeEncoding_Unsigned = 7,
	LLVMDWARFTypeEncoding_UnsignedChar = 8,
	LLVMDWARFTypeEncoding_ImaginaryFloat = 9,
	LLVMDWARFTypeEncoding_PackedDecimal = 10,
	LLVMDWARFTypeEncoding_NumericString = 11,
	LLVMDWARFTypeEncoding_Edited = 12,
	LLVMDWARFTypeEncoding_SignedFixed = 13,
	LLVMDWARFTypeEncoding_UnsignedFixed = 14,
	LLVMDWARFTypeEncoding_DecimalFloat = 15,
	LLVMDWARFTypeEncoding_Utf = 16,
	LLVMDWARFTypeEncoding_LoUser = 128,
	LLVMDWARFTypeEncoding_HiUser = 255
};


enum {
	DW_TAG_array_type       = 1,
	DW_TAG_enumeration_type = 4,
	DW_TAG_structure_type   = 19,
	DW_TAG_union_type       = 23,
	DW_TAG_vector_type      = 259,
	DW_TAG_subroutine_type  = 21,
	DW_TAG_inheritance      = 28,
};


enum : LLVMAttributeIndex {
	LLVMAttributeIndex_ReturnIndex = 0u,
	LLVMAttributeIndex_FunctionIndex = ~0u,
	LLVMAttributeIndex_FirstArgIndex = 1,
};
