yosys/frontends/ast/ast.h

/* -*- c++ -*-
 *  yosys -- Yosys Open SYnthesis Suite
 *
 *  Copyright (C) 2012  Claire Xenia Wolf <claire@yosyshq.com>
 *
 *  Permission to use, copy, modify, and/or distribute this software for any
 *  purpose with or without fee is hereby granted, provided that the above
 *  copyright notice and this permission notice appear in all copies.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 *  ---
 *
 *  The AST frontend library is not a frontend on its own but provides an
 *  abstract syntax tree (AST) abstraction for the open source Verilog frontend
 *  at frontends/verilog.
 *
 */

#ifndef AST_H
#define AST_H

#include "kernel/rtlil.h"
#include "kernel/fmt.h"
#include "frontends/verilog/verilog_location.h"
#include <stdint.h>
#include <set>

YOSYS_NAMESPACE_BEGIN

namespace AST
{
	// all node types, type2str() must be extended
	// whenever a new node type is added here
	enum AstNodeType
	{
		AST_NONE,
		AST_DESIGN,
		AST_MODULE,
		AST_TASK,
		AST_FUNCTION,
		AST_DPI_FUNCTION,

		AST_WIRE,
		AST_MEMORY,
		AST_AUTOWIRE,
		AST_PARAMETER,
		AST_LOCALPARAM,
		AST_DEFPARAM,
		AST_PARASET,
		AST_ARGUMENT,
		AST_RANGE,
		AST_MULTIRANGE,
		AST_CONSTANT,
		AST_REALVALUE,
		AST_CELLTYPE,
		AST_IDENTIFIER,
		AST_PREFIX,
		AST_ASSERT,
		AST_ASSUME,
		AST_LIVE,
		AST_FAIR,
		AST_COVER,
		AST_ENUM,
		AST_ENUM_ITEM,

		AST_FCALL,
		AST_TO_BITS,
		AST_TO_SIGNED,
		AST_TO_UNSIGNED,
		AST_SELFSZ,
		AST_CAST_SIZE,
		AST_CONCAT,
		AST_REPLICATE,
		AST_BIT_NOT,
		AST_BIT_AND,
		AST_BIT_OR,
		AST_BIT_XOR,
		AST_BIT_XNOR,
		AST_REDUCE_AND,
		AST_REDUCE_OR,
		AST_REDUCE_XOR,
		AST_REDUCE_XNOR,
		AST_REDUCE_BOOL,
		AST_SHIFT_LEFT,
		AST_SHIFT_RIGHT,
		AST_SHIFT_SLEFT,
		AST_SHIFT_SRIGHT,
		AST_SHIFTX,
		AST_SHIFT,
		AST_LT,
		AST_LE,
		AST_EQ,
		AST_NE,
		AST_EQX,
		AST_NEX,
		AST_GE,
		AST_GT,
		AST_ADD,
		AST_SUB,
		AST_MUL,
		AST_DIV,
		AST_MOD,
		AST_POW,
		AST_POS,
		AST_NEG,
		AST_LOGIC_AND,
		AST_LOGIC_OR,
		AST_LOGIC_NOT,
		AST_TERNARY,
		AST_MEMRD,
		AST_MEMWR,
		AST_MEMINIT,

		AST_TCALL,
		AST_ASSIGN,
		AST_CELL,
		AST_PRIMITIVE,
		AST_CELLARRAY,
		AST_ALWAYS,
		AST_INITIAL,
		AST_BLOCK,
		AST_ASSIGN_EQ,
		AST_ASSIGN_LE,
		AST_CASE,
		AST_COND,
		AST_CONDX,
		AST_CONDZ,
		AST_DEFAULT,
		AST_FOR,
		AST_WHILE,
		AST_REPEAT,

		AST_GENVAR,
		AST_GENFOR,
		AST_GENIF,
		AST_GENCASE,
		AST_GENBLOCK,
		AST_TECALL,

		AST_POSEDGE,
		AST_NEGEDGE,
		AST_EDGE,

		AST_INTERFACE,
		AST_INTERFACEPORT,
		AST_INTERFACEPORTTYPE,
		AST_MODPORT,
		AST_MODPORTMEMBER,
		AST_PACKAGE,
		AST_IMPORT,

		AST_WIRETYPE,
		AST_TYPEDEF,
		AST_STRUCT,
		AST_UNION,
		AST_STRUCT_ITEM,
		AST_BIND
	};

	using AstSrcLocType = Location;

	// convert an node type to a string (e.g. for debug output)
	std::string type2str(AstNodeType type);

	// The AST is built using instances of this struct
	struct AstNode
	{
		// for dict<> and pool<>
		unsigned int hashidx_;
		[[nodiscard]] Hasher hash_into(Hasher h) const { h.eat(hashidx_); return h; }

		// this nodes type
		AstNodeType type;

		// the list of child nodes for this node
		std::vector<std::unique_ptr<AstNode>> children;

		// the list of attributes assigned to this node
		std::map<RTLIL::IdString, std::unique_ptr<AstNode>> attributes;
		bool get_bool_attribute(RTLIL::IdString id);

		// node content - most of it is unused in most node types
		std::string str;
		std::vector<RTLIL::State> bits;
		bool is_input, is_output, is_reg, is_logic, is_signed, is_string, is_wand, is_wor, range_valid, range_swapped, was_checked, is_unsized, is_custom_type;
		int port_id, range_left, range_right;
		uint32_t integer;
		double realvalue;
		// set for IDs typed to an enumeration, not used
		bool is_enum;

		// Declared range for array dimension.
		struct dimension_t {
			int range_right;     // lsb in [msb:lsb]
			int range_width;     // msb - lsb + 1
			bool range_swapped;  // if the declared msb < lsb, msb and lsb above are swapped
		};
		// Packed and unpacked dimensions for arrays.
		// Unpacked dimensions go first, to follow the order of indexing.
		std::vector<dimension_t> dimensions;
		// Number of unpacked dimensions.
		int unpacked_dimensions;

		// this is set by simplify and used during RTLIL generation
		AstNode* id2ast;

		// this is used by simplify to detect if basic analysis has been performed already on the node
		bool basic_prep;

		// this is used for ID references in RHS expressions that should use the "new" value for non-blocking assignments
		bool lookahead;

		// this is the original sourcecode location that resulted in this AST node
		// it is automatically set by the constructor using AST::current_filename and
		// the AST::get_line_num() callback function.
		AstSrcLocType location;

		// are we embedded in an lvalue, param?
		// (see fixup_hierarchy_flags)
		bool in_lvalue;
		bool in_param;
		bool in_lvalue_from_above;
		bool in_param_from_above;

		// creating and deleting nodes
		AstNode(AstSrcLocType loc, AstNodeType type = AST_NONE, std::unique_ptr<AstNode> child1 = nullptr, std::unique_ptr<AstNode> child2 = nullptr, std::unique_ptr<AstNode> child3 = nullptr, std::unique_ptr<AstNode> child4 = nullptr);
		std::unique_ptr<AstNode> clone() const;
		void cloneInto(AstNode &other) const;
		void delete_children();
		~AstNode();

		enum mem2reg_flags
		{
			/* status flags */
			MEM2REG_FL_ALL       = 0x00000001,
			MEM2REG_FL_ASYNC     = 0x00000002,
			MEM2REG_FL_INIT      = 0x00000004,

			/* candidate flags */
			MEM2REG_FL_FORCED    = 0x00000100,
			MEM2REG_FL_SET_INIT  = 0x00000200,
			MEM2REG_FL_SET_ELSE  = 0x00000400,
			MEM2REG_FL_SET_ASYNC = 0x00000800,
			MEM2REG_FL_EQ2       = 0x00001000,
			MEM2REG_FL_CMPLX_LHS = 0x00002000,
			MEM2REG_FL_CONST_LHS = 0x00004000,
			MEM2REG_FL_VAR_LHS   = 0x00008000,

			/* proc flags */
			MEM2REG_FL_EQ1       = 0x01000000,
		};

		// simplify() creates a simpler AST by unrolling for-loops, expanding generate blocks, etc.
		// it also sets the id2ast pointers so that identifier lookups are fast in genRTLIL()
		bool simplify(bool const_fold, int stage, int width_hint, bool sign_hint);
		void replace_result_wire_name_in_function(const std::string &from, const std::string &to);
		std::unique_ptr<AstNode> readmem(bool is_readmemh, std::string mem_filename, AstNode *memory, int start_addr, int finish_addr, bool unconditional_init);
		void expand_genblock(const std::string &prefix);
		void label_genblks(std::set<std::string>& existing, int &counter);
		void mem2reg_as_needed_pass1(dict<AstNode*, pool<std::string>> &mem2reg_places,
				dict<AstNode*, uint32_t> &mem2reg_flags, dict<AstNode*, uint32_t> &proc_flags, uint32_t &status_flags);
		bool mem2reg_as_needed_pass2(pool<AstNode*> &mem2reg_set, AstNode *mod, AstNode *block, AstNode* async_block);
		bool mem2reg_check(pool<AstNode*> &mem2reg_set);
		void mem2reg_remove(pool<AstNode*> &mem2reg_set);
		void meminfo(int &mem_width, int &mem_size, int &addr_bits);
		bool detect_latch(const std::string &var);
		const RTLIL::Module* lookup_cell_module();

		// additional functionality for evaluating constant functions
		struct varinfo_t {
			RTLIL::Const val;
			int offset;
			bool range_swapped;
			bool is_signed;
			AstNode *arg = nullptr;
			bool explicitly_sized;
		};
		bool has_const_only_constructs();
		bool replace_variables(std::map<std::string, varinfo_t> &variables, AstNode *fcall, bool must_succeed);
		std::unique_ptr<AstNode> eval_const_function(AstNode *fcall, bool must_succeed);
		bool is_simple_const_expr();

		// helper for parsing format strings
		Fmt processFormat(int stage, bool sformat_like, int default_base = 10, size_t first_arg_at = 0, bool may_fail = false);

		bool is_recursive_function() const;
		std::pair<AstNode*, AstNode*> get_tern_choice();

		// create a human-readable text representation of the AST (for debugging)
		void dumpAst(FILE *f, std::string indent) const;
		void dumpVlog(FILE *f, std::string indent) const;

		// Generate RTLIL for a bind construct
		std::vector<RTLIL::Binding *> genBindings() const;

		// used by genRTLIL() for detecting expression width and sign
		void detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *found_real = nullptr);
		void detectSignWidth(int &width_hint, bool &sign_hint, bool *found_real = nullptr);

		// create RTLIL code for this AST node
		// for expressions the resulting signal vector is returned
		// all generated cell instances, etc. are written to the RTLIL::Module pointed to by AST_INTERNAL::current_module
		RTLIL::SigSpec genRTLIL(int width_hint = -1, bool sign_hint = false);
		RTLIL::SigSpec genWidthRTLIL(int width, bool sgn, const dict<RTLIL::SigBit, RTLIL::SigBit> *new_subst_ptr = nullptr);

		// compare AST nodes
		bool operator==(const AstNode &other) const;
		bool operator!=(const AstNode &other) const;
		bool contains(const AstNode *other) const;
		AstNode operator=(AstNode) = delete;

		// helper functions for creating AST nodes for constants
		static std::unique_ptr<AstNode> mkconst_int(AstSrcLocType loc, uint32_t v, bool is_signed, int width = 32);
		static std::unique_ptr<AstNode> mkconst_bits(AstSrcLocType loc, const std::vector<RTLIL::State> &v, bool is_signed, bool is_unsized);
		static std::unique_ptr<AstNode> mkconst_bits(AstSrcLocType loc, const std::vector<RTLIL::State> &v, bool is_signed);
		static std::unique_ptr<AstNode> mkconst_str(AstSrcLocType loc, const std::vector<RTLIL::State> &v);
		static std::unique_ptr<AstNode> mkconst_str(AstSrcLocType loc, const std::string &str);

		// helper function to create an AST node for a temporary register
		std::unique_ptr<AstNode> mktemp_logic(AstSrcLocType loc, const std::string &name, AstNode *mod, bool nosync, int range_left, int range_right, bool is_signed);

		// helper function for creating sign-extended const objects
		RTLIL::Const bitsAsConst(int width, bool is_signed);
		RTLIL::Const bitsAsConst(int width = -1);
		RTLIL::Const bitsAsUnsizedConst(int width);
		RTLIL::Const asAttrConst() const;
		RTLIL::Const asParaConst() const;
		uint64_t asInt(bool is_signed);
		bool bits_only_01() const;
		bool asBool() const;

		// helper functions for real valued const eval
		int isConst() const; // return '1' for AST_CONSTANT and '2' for AST_REALVALUE
		double asReal(bool is_signed);
		RTLIL::Const realAsConst(int width);

		// helpers for enum
		void allocateDefaultEnumValues();
		void annotateTypedEnums(AstNode *template_node);

		// helpers for locations
		std::string loc_string() const;

		// Helper for looking up identifiers which are prefixed with the current module name
		std::string try_pop_module_prefix() const;

		// helper to clone the node with some of its subexpressions replaced with zero (this is used
		// to evaluate widths of dynamic ranges)
		std::unique_ptr<AstNode> clone_at_zero();

		void set_attribute(RTLIL::IdString key, std::unique_ptr<AstNode> node)
		{
			node->set_in_param_flag(true);
			attributes[key] = std::move(node);
		}

		// helper to set in_lvalue/in_param flags from the hierarchy context (the actual flag
		// can be overridden based on the intrinsic properties of this node, i.e. based on its type)
		void set_in_lvalue_flag(bool flag, bool no_descend = false);
		void set_in_param_flag(bool flag, bool no_descend = false);

		// fix up the hierarchy flags (in_lvalue/in_param) of this node and its children
		//
		// to keep the flags in sync, fixup_hierarchy_flags(true) needs to be called once after
		// parsing the AST to walk the full tree, then plain fixup_hierarchy_flags() performs
		// localized fixups after modifying children/attributes of a particular node
		void fixup_hierarchy_flags(bool force_descend = false);

		// helpers for indexing
		std::unique_ptr<AstNode> make_index_range(AstNode *node, bool unpacked_range = false);
		AstNode *get_struct_member() const;

		// helper to print errors from simplify/genrtlil code
		[[noreturn]] void formatted_input_error(std::string str) const;
		template <typename... Args>
		[[noreturn]] void input_error(FmtString<TypeIdentity<Args>...> fmt, const Args &... args) const
		{
			formatted_input_error(fmt.format(args...));
		}
	};

	// process an AST tree (ast must point to an AST_DESIGN node) and generate RTLIL code
	void process(RTLIL::Design *design, AstNode *ast, bool nodisplay, bool dump_ast1, bool dump_ast2, bool no_dump_ptr, bool dump_vlog1, bool dump_vlog2, bool dump_rtlil, bool nolatches, bool nomeminit,
			bool nomem2reg, bool mem2reg, bool noblackbox, bool lib, bool nowb, bool noopt, bool icells, bool pwires, bool nooverwrite, bool overwrite, bool defer, bool autowire);

	// parametric modules are supported directly by the AST library
	// therefore we need our own derivate of RTLIL::Module with overloaded virtual functions
	struct AstModule : RTLIL::Module {
		std::unique_ptr<AstNode> ast;
		bool nolatches, nomeminit, nomem2reg, mem2reg, noblackbox, lib, nowb, noopt, icells, pwires, autowire;
		RTLIL::IdString derive(RTLIL::Design *design, const dict<RTLIL::IdString, RTLIL::Const> &parameters, bool mayfail) override;
		RTLIL::IdString derive(RTLIL::Design *design, const dict<RTLIL::IdString, RTLIL::Const> &parameters, const dict<RTLIL::IdString, RTLIL::Module*> &interfaces, const dict<RTLIL::IdString, RTLIL::IdString> &modports, bool mayfail) override;
		std::string derive_common(RTLIL::Design *design, const dict<RTLIL::IdString, RTLIL::Const> &parameters, std::unique_ptr<AstNode>* new_ast_out, bool quiet = false);
		void expand_interfaces(RTLIL::Design *design, const dict<RTLIL::IdString, RTLIL::Module *> &local_interfaces) override;
		bool reprocess_if_necessary(RTLIL::Design *design) override;
		RTLIL::Module *clone() const override;
		void loadconfig() const;
	};

	// this must be set by the language frontend before parsing the sources
	// the AstNode constructor then uses current_filename and get_line_num()
	// to initialize the filename and linenum properties of new nodes
	// extern std::string current_filename;
	// also set by the language frontend to control some AST processing
	extern bool sv_mode_but_global_and_used_for_literally_one_condition;

	// for stats
	unsigned long long astnode_count();

	// set set_line_num and get_line_num to internal dummy functions (done by simplify() and AstModule::derive
	// to control the filename and linenum properties of new nodes not generated by a frontend parser)
	void use_internal_line_num();

	// call a DPI function
	std::unique_ptr<AstNode> dpi_call(AstSrcLocType loc, const std::string &rtype, const std::string &fname, const std::vector<std::string> &argtypes, const std::vector<std::unique_ptr<AstNode>> &args);

	// Helper functions related to handling SystemVerilog interfaces
	std::pair<std::string,std::string> split_modport_from_type(std::string name_type);
	AstNode * find_modport(AstNode *intf, std::string name);
	void explode_interface_port(AstNode *module_ast, RTLIL::Module * intfmodule, std::string intfname, AstNode *modport);

	// Helper for setting the src attribute.
	void set_src_attr(RTLIL::AttrObject *obj, const AstNode *ast);

	// generate standard $paramod... derived module name; parameters should be
	// in the order they are declared in the instantiated module
	std::string derived_module_name(std::string stripped_name, const std::vector<std::pair<RTLIL::IdString, RTLIL::Const>> &parameters);

	// used to provide simplify() access to the current design for looking up
	// modules, ports, wires, etc.
	void set_simplify_design_context(const RTLIL::Design *design);
}

namespace AST_INTERNAL
{
	// internal state variables
	extern bool flag_nodisplay, flag_dump_ast1, flag_dump_ast2, flag_no_dump_ptr, flag_dump_rtlil, flag_nolatches, flag_nomeminit;
	extern bool flag_nomem2reg, flag_mem2reg, flag_lib, flag_noopt, flag_icells, flag_pwires, flag_autowire;
	extern AST::AstNode *current_ast, *current_ast_mod;
	extern std::map<std::string, AST::AstNode*> current_scope;
	extern const dict<RTLIL::SigBit, RTLIL::SigBit> *genRTLIL_subst_ptr;
	extern RTLIL::SigSpec ignoreThisSignalsInInitial;
	extern AST::AstNode *current_always, *current_top_block, *current_block, *current_block_child;
	extern RTLIL::Module *current_module;
	extern bool current_always_clocked;
	extern dict<std::string, int> current_memwr_count;
	extern dict<std::string, pool<int>> current_memwr_visible;
	struct LookaheadRewriter;
	struct ProcessGenerator;

	// Create and add a new AstModule from new_ast, then use it to replace
	// old_module in design, renaming old_module to move it out of the way.
	// Return the new module.
	//
	// If original_ast is not null, it will be used as the AST node for the
	// new module. Otherwise, new_ast will be used.
	RTLIL::Module *
	process_and_replace_module(RTLIL::Design *design,
	                           RTLIL::Module *old_module,
	                           AST::AstNode *new_ast,
	                           std::unique_ptr<AST::AstNode> original_ast = nullptr);
}

YOSYS_NAMESPACE_END

#endif