//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Mangler.cpp --
//
// Author           : Richard C. Bilson
// Created On       : Sun May 17 21:40:29 2015
// Last Modified By : Andrew Beach
// Last Modified On : Fri Oct 21 16:18:00 2022
// Update Count     : 75
//
#include "Mangler.hpp"

#include <algorithm>                     // for copy, transform
#include <cassert>                       // for assert, assertf
#include <functional>                    // for const_mem_fun_t, mem_fun
#include <iterator>                      // for ostream_iterator, back_insert_ite...
#include <list>                          // for _List_iterator, list, _List_const...
#include <string>                        // for string, char_traits, operator<<

#include "AST/Pass.hpp"
#include "CodeGen/OperatorTable.hpp"     // for OperatorInfo, operatorLookup
#include "Common/ToString.hpp"           // for toCString
#include "Common/SemanticError.hpp"      // for SemanticError

namespace Mangle {

namespace {

/// Mangles names to a unique C identifier.
struct Mangler : public ast::WithShortCircuiting, public ast::WithVisitorRef<Mangler>, public ast::WithGuards {
	Mangler( Mangle::Mode mode );
	Mangler( const Mangler & ) = delete;

	void previsit( const ast::Node * ) { visit_children = false; }

	void postvisit( const ast::ObjectDecl * declaration );
	void postvisit( const ast::FunctionDecl * declaration );
	void postvisit( const ast::TypeDecl * declaration );

	void postvisit( const ast::VoidType * voidType );
	void postvisit( const ast::BasicType * basicType );
	void postvisit( const ast::PointerType * pointerType );
	void postvisit( const ast::ArrayType * arrayType );
	void postvisit( const ast::ReferenceType * refType );
	void postvisit( const ast::FunctionType * functionType );
	void postvisit( const ast::StructInstType * aggregateUseType );
	void postvisit( const ast::UnionInstType * aggregateUseType );
	void postvisit( const ast::EnumInstType * aggregateUseType );
	void postvisit( const ast::TypeInstType * aggregateUseType );
	void postvisit( const ast::TraitInstType * inst );
	void postvisit( const ast::TupleType * tupleType );
	void postvisit( const ast::VarArgsType * varArgsType );
	void postvisit( const ast::ZeroType * zeroType );
	void postvisit( const ast::OneType * oneType );
	void postvisit( const ast::QualifiedType * qualType );

	/// The result is the current constructed mangled name.
	std::string result() const { return mangleName; }
private:
	std::string mangleName;         ///< Mangled name being constructed
	typedef std::map< std::string, std::pair< int, int > > VarMapType;
	VarMapType varNums;             ///< Map of type variables to indices
	int nextVarNum;                 ///< Next type variable index
	bool isTopLevel;                ///< Is the Mangler at the top level
	bool mangleOverridable;         ///< Specially mangle overridable built-in methods
	bool typeMode;                  ///< Produce a unique mangled name for a type
	bool mangleGenericParams;       ///< Include generic parameters in name mangling if true
	bool inFunctionType = false;    ///< Include type qualifiers if false.
	bool inQualifiedType = false;   ///< Add start/end delimiters around qualified type

private:
	Mangler( bool mangleOverridable, bool typeMode, bool mangleGenericParams,
		int nextVarNum, const VarMapType& varNums );
	friend class ast::Pass<Mangler>;

private:
	void mangleDecl( const ast::DeclWithType *declaration );
	void mangleRef( const ast::BaseInstType *refType, const std::string & prefix );

	void printQualifiers( const ast::Type *type );
}; // Mangler

Mangler::Mangler( Mangle::Mode mode )
	: nextVarNum( 0 ), isTopLevel( true ),
	mangleOverridable  ( ! mode.no_overrideable   ),
	typeMode           (   mode.type              ),
	mangleGenericParams( ! mode.no_generic_params ) {}

Mangler::Mangler( bool mangleOverridable, bool typeMode, bool mangleGenericParams,
	int nextVarNum, const VarMapType& varNums )
	: varNums( varNums ), nextVarNum( nextVarNum ), isTopLevel( false ),
	mangleOverridable( mangleOverridable ), typeMode( typeMode ),
	mangleGenericParams( mangleGenericParams ) {}

void Mangler::mangleDecl( const ast::DeclWithType * decl ) {
	bool wasTopLevel = isTopLevel;
	if ( isTopLevel ) {
		varNums.clear();
		nextVarNum = 0;
		isTopLevel = false;
	}
	mangleName += Encoding::manglePrefix;
	if ( auto opInfo = CodeGen::operatorLookup( decl->name ) ) {
		mangleName += std::to_string( opInfo->outputName.size() ) + opInfo->outputName;
	} else {
		mangleName += std::to_string( decl->name.size() ) + decl->name;
	}
	decl->get_type()->accept( *visitor );
	if ( mangleOverridable && decl->linkage.is_overrideable ) {
		// want to be able to override autogenerated and intrinsic routines,
		// so they need a different name mangling
		if ( decl->linkage == ast::Linkage::AutoGen ) {
			mangleName += Encoding::autogen;
		} else if ( decl->linkage == ast::Linkage::Intrinsic ) {
			mangleName += Encoding::intrinsic;
		} else {
			// if we add another kind of overridable function, this has to change
			assert( false && "unknown overrideable linkage" );
		}
	}
	isTopLevel = wasTopLevel;
}

void Mangler::postvisit( const ast::ObjectDecl * decl ) {
	mangleDecl( decl );
}

void Mangler::postvisit( const ast::FunctionDecl * decl ) {
	mangleDecl( decl );
}

void Mangler::postvisit( const ast::VoidType * voidType ) {
	printQualifiers( voidType );
	mangleName += Encoding::void_t;
}

void Mangler::postvisit( const ast::BasicType * basicType ) {
	printQualifiers( basicType );
	assertf( basicType->kind < ast::BasicKind::NUMBER_OF_BASIC_TYPES, "Unhandled basic type: %d", basicType->kind );
	mangleName += Encoding::basicTypes[ basicType->kind ];
}

void Mangler::postvisit( const ast::PointerType * pointerType ) {
	printQualifiers( pointerType );
	// Mangle void (*f)() and void f() to the same name to prevent overloading on functions and function pointers.
	if ( !pointerType->base.as<ast::FunctionType>() ) mangleName += Encoding::pointer;
	maybe_accept( pointerType->base.get(), *visitor );
}

void Mangler::postvisit( const ast::ArrayType * arrayType ) {
	// TODO: encode dimension
	printQualifiers( arrayType );
	mangleName += Encoding::array + "0";
	arrayType->base->accept( *visitor );
}

void Mangler::postvisit( const ast::ReferenceType * refType ) {
	// Don't print prefix (e.g. 'R') for reference types so that references and non-references do not overload.
	// Further, do not print the qualifiers for a reference type (but do run printQualifers because of TypeDecls, etc.),
	// by pretending every reference type is a function parameter.
	GuardValue( inFunctionType ) = true;
	printQualifiers( refType );
	refType->base->accept( *visitor );
}

void Mangler::postvisit( const ast::FunctionType * functionType ) {
	printQualifiers( functionType );
	mangleName += Encoding::function;
	// Turn on inFunctionType so that printQualifiers does not print most qualifiers for function parameters,
	// since qualifiers on outermost parameter type do not differentiate function types, e.g.,
	// void (*)(const int) and void (*)(int) are the same type, but void (*)(const int *) and void (*)(int *) are different.
	GuardValue( inFunctionType ) = true;
	if (functionType->returns.empty()) mangleName += Encoding::void_t;
	else accept_each( functionType->returns, *visitor );
	mangleName += "_";
	accept_each( functionType->params, *visitor );
	mangleName += "_";
}

void Mangler::mangleRef(
		const ast::BaseInstType * refType, const std::string & prefix ) {
	printQualifiers( refType );

	mangleName += prefix + std::to_string( refType->name.length() ) + refType->name;

	if ( mangleGenericParams && ! refType->params.empty() ) {
		mangleName += "_";
		for ( const ast::Expr * param : refType->params ) {
			auto paramType = dynamic_cast< const ast::TypeExpr * >( param );
			assertf(paramType, "Aggregate parameters should be type expressions: %s", toCString(param));
			paramType->type->accept( *visitor );
		}
		mangleName += "_";
	}
}

void Mangler::postvisit( const ast::StructInstType * aggregateUseType ) {
	mangleRef( aggregateUseType, Encoding::struct_t );
}

void Mangler::postvisit( const ast::UnionInstType * aggregateUseType ) {
	mangleRef( aggregateUseType, Encoding::union_t );
}

void Mangler::postvisit( const ast::EnumInstType * aggregateUseType ) {
	mangleRef( aggregateUseType, Encoding::enum_t );
}

void Mangler::postvisit( const ast::TypeInstType * typeInst ) {
	VarMapType::iterator varNum = varNums.find( typeInst->name );
	if ( varNum == varNums.end() ) {
		mangleRef( typeInst, Encoding::type );
	} else {
		printQualifiers( typeInst );
		// Note: Can't use name here, since type variable names do not actually disambiguate a function, e.g.
		//   forall(dtype T) void f(T);
		//   forall(dtype S) void f(S);
		// are equivalent and should mangle the same way. This is accomplished by numbering the type variables when they
		// are first found and prefixing with the appropriate encoding for the type class.
		assertf( varNum->second.second < ast::TypeDecl::NUMBER_OF_KINDS, "Unhandled type variable kind: %d", varNum->second.second );
		mangleName += Encoding::typeVariables[varNum->second.second] + std::to_string( varNum->second.first );
	}
}

void Mangler::postvisit( const ast::TraitInstType * inst ) {
	printQualifiers( inst );
	mangleName += std::to_string( inst->name.size() ) + inst->name;
}

void Mangler::postvisit( const ast::TupleType * tupleType ) {
	printQualifiers( tupleType );
	mangleName += Encoding::tuple + std::to_string( tupleType->types.size() );
	accept_each( tupleType->types, *visitor );
}

void Mangler::postvisit( const ast::VarArgsType * varArgsType ) {
	printQualifiers( varArgsType );
	static const std::string vargs = "__builtin_va_list";
	mangleName += Encoding::type + std::to_string( vargs.size() ) + vargs;
}

void Mangler::postvisit( const ast::ZeroType * ) {
	mangleName += Encoding::zero;
}

void Mangler::postvisit( const ast::OneType * ) {
	mangleName += Encoding::one;
}

void Mangler::postvisit( const ast::QualifiedType * qualType ) {
	bool inqual = inQualifiedType;
	if ( !inqual ) {
		// N marks the start of a qualified type.
		inQualifiedType = true;
		mangleName += Encoding::qualifiedTypeStart;
	}
	qualType->parent->accept( *visitor );
	qualType->child->accept( *visitor );
	if ( !inqual ) {
		// E marks the end of a qualified type.
		inQualifiedType = false;
		mangleName += Encoding::qualifiedTypeEnd;
	}
}

void Mangler::postvisit( const ast::TypeDecl * decl ) {
	// TODO: is there any case where mangling a TypeDecl makes sense? If so, this code needs to be
	// fixed to ensure that two TypeDecls mangle to the same name when they are the same type and vice versa.
	// Note: The current scheme may already work correctly for this case, I have not thought about this deeply
	// and the case has not yet come up in practice. Alternatively, if not then this code can be removed
	// aside from the assert false.
	assertf(false, "Mangler should not visit typedecl: %s", toCString(decl));
	assertf( decl->kind < ast::TypeDecl::Kind::NUMBER_OF_KINDS, "Unhandled type variable kind: %d", decl->kind );
	mangleName += Encoding::typeVariables[ decl->kind ] + std::to_string( decl->name.length() ) + decl->name;
}

// For debugging:
__attribute__((unused)) void printVarMap( const std::map< std::string, std::pair< int, int > > &varMap, std::ostream &os ) {
	for ( std::map< std::string, std::pair< int, int > >::const_iterator i = varMap.begin(); i != varMap.end(); ++i ) {
		os << i->first << "(" << i->second.first << "/" << i->second.second << ")" << std::endl;
	}
}

void Mangler::printQualifiers( const ast::Type * type ) {
	// Skip if not including qualifiers:
	if ( typeMode ) return;
	auto funcType = dynamic_cast<const ast::FunctionType *>( type );
	if ( funcType && (!funcType->forall.empty() || !funcType->assertions.empty()) ) {
		std::list< std::string > assertionNames;
		int dcount = 0, fcount = 0, vcount = 0, acount = 0;
		mangleName += Encoding::forall;
		for ( auto & decl : funcType->forall ) {
			switch ( decl->kind ) {
			case ast::TypeDecl::Dtype:
				dcount++;
				break;
			case ast::TypeDecl::Ftype:
				fcount++;
				break;
			case ast::TypeDecl::Ttype:
				vcount++;
				break;
			default:
				assertf( false, "unimplemented kind for type variable %s", Encoding::typeVariables[decl->kind].c_str() );
			}
			varNums[ decl->name ] = std::make_pair( nextVarNum, (int)decl->kind );
		}
		for ( auto & assert : funcType->assertions ) {
			assertionNames.push_back( ast::Pass<Mangler>::read(
				assert->var.get(),
				mangleOverridable, typeMode, mangleGenericParams, nextVarNum, varNums ) );
			acount++;
		}
		mangleName += std::to_string( dcount ) + "_" + std::to_string( fcount ) + "_" + std::to_string( vcount ) + "_" + std::to_string( acount ) + "_";
		for ( const auto & a : assertionNames ) mangleName += a;
		mangleName += "_";
	}
	if ( !inFunctionType ) {
		// These qualifiers do not distinguish the outermost type of a function parameter.
		if ( type->is_const() ) {
			mangleName += Encoding::qualifiers.at( ast::CV::Const );
		}
		if ( type->is_volatile() ) {
			mangleName += Encoding::qualifiers.at( ast::CV::Volatile );
		}
		if ( type->is_atomic() ) {
			mangleName += Encoding::qualifiers.at( ast::CV::Atomic );
		}
	}
	if ( type->is_mutex() ) {
		mangleName += Encoding::qualifiers.at( ast::CV::Mutex );
	}
	if ( inFunctionType ) {
		// Turn off inFunctionType so that types can be differentiated for nested qualifiers.
		GuardValue( inFunctionType ) = false;
	}
}

} // namespace

std::string mangle( const ast::Node * decl, Mangle::Mode mode ) {
	return ast::Pass<Mangler>::read( decl, mode );
}

} // namespace Mangle

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //