247 lines
12 KiB
Ada
247 lines
12 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- I N L I N E --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2020, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING3. If not, go to --
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-- http://www.gnu.org/licenses for a complete copy of the license. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This module handles four kinds of inlining activity:
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-- a) Instantiation of generic bodies. This is done unconditionally, after
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-- analysis and expansion of the main unit.
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-- b) Compilation of unit bodies that contain the bodies of inlined sub-
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-- programs. This is done only if inlining is enabled (-gnatn). Full inlining
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-- requires that a) and b) be mutually recursive, because each step may
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-- generate another generic expansion and further inlined calls.
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-- c) Front-end inlining for Inline_Always subprograms. This is primarily an
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-- expansion activity that is performed for performance reasons, and when the
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-- target does not use the GCC back end.
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-- d) Front-end inlining for GNATprove, to perform source transformations
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-- to simplify formal verification. The machinery used is the same as for
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-- Inline_Always subprograms, but there are fewer restrictions on the source
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-- of subprograms.
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with Opt; use Opt;
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with Sem; use Sem;
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with Types; use Types;
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with Warnsw; use Warnsw;
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package Inline is
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--------------------------------
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-- Generic Body Instantiation --
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--------------------------------
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-- The bodies of generic instantiations are built after semantic analysis
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-- of the main unit is complete. Generic instantiations are saved in a
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-- global data structure, and the bodies constructed by means of a separate
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-- analysis and expansion step.
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-- See full description in body of Sem_Ch12 for more details
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type Pending_Body_Info is record
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Act_Decl : Node_Id;
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-- Declaration for package or subprogram spec for instantiation
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Config_Switches : Config_Switches_Type;
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-- Capture the values of configuration switches
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Current_Sem_Unit : Unit_Number_Type;
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-- The semantic unit within which the instantiation is found. Must be
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-- restored when compiling the body, to insure that internal entities
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-- use the same counter and are unique over spec and body.
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Expander_Status : Boolean;
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-- If the body is instantiated only for semantic checking, expansion
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-- must be inhibited.
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Inst_Node : Node_Id;
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-- Node for instantiation that requires the body
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Scope_Suppress : Suppress_Record;
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Local_Suppress_Stack_Top : Suppress_Stack_Entry_Ptr;
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-- Save suppress information at the point of instantiation. Used to
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-- properly inherit check status active at this point (see RM 11.5
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-- (7.2/2), AI95-00224-01):
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--
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-- "If a checking pragma applies to a generic instantiation, then the
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-- checking pragma also applies to the instance. If a checking pragma
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-- applies to a call to a subprogram that has a pragma Inline applied
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-- to it, then the checking pragma also applies to the inlined
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-- subprogram body".
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--
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-- This means we have to capture this information from the current scope
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-- at the point of instantiation.
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Warnings : Warning_Record;
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-- Capture values of warning flags
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end record;
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-----------------
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-- Subprograms --
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-----------------
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procedure Initialize;
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-- Initialize internal tables
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procedure Lock;
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-- Lock internal tables before calling backend
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procedure Instantiate_Bodies;
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-- This procedure is called after semantic analysis is complete, to
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-- instantiate the bodies of generic instantiations that appear in the
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-- compilation unit.
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procedure Add_Inlined_Body (E : Entity_Id; N : Node_Id);
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-- E is an inlined subprogram appearing in a call, either explicitly or in
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-- a discriminant check for which gigi builds a call or an at-end handler.
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-- Add E's enclosing unit to Inlined_Bodies so that E can be subsequently
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-- retrieved and analyzed. N is the node giving rise to the call to E.
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procedure Add_Pending_Instantiation (Inst : Node_Id; Act_Decl : Node_Id);
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-- Add an entry in the table of generic bodies to be instantiated.
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procedure Analyze_Inlined_Bodies;
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-- At end of compilation, analyze the bodies of all units that contain
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-- inlined subprograms that are actually called.
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procedure Build_Body_To_Inline (N : Node_Id; Spec_Id : Entity_Id);
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-- If a subprogram has pragma Inline and inlining is active, use generic
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-- machinery to build an unexpanded body for the subprogram. This body is
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-- subsequently used for inline expansions at call sites. If subprogram can
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-- be inlined (depending on size and nature of local declarations) the
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-- template body is created. Otherwise subprogram body is treated normally
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-- and calls are not inlined in the frontend. If proper warnings are
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-- enabled and the subprogram contains a construct that cannot be inlined,
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-- the problematic construct is flagged accordingly.
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function Call_Can_Be_Inlined_In_GNATprove_Mode
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(N : Node_Id;
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Subp : Entity_Id) return Boolean;
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-- Returns False if the call in node N to subprogram Subp cannot be inlined
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-- in GNATprove mode, because it may lead to missing a check on type
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-- conversion of input parameters otherwise. Returns True otherwise.
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function Can_Be_Inlined_In_GNATprove_Mode
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(Spec_Id : Entity_Id;
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Body_Id : Entity_Id) return Boolean;
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-- Returns True if the subprogram identified by Spec_Id and Body_Id can
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-- be inlined in GNATprove mode. One but not both of Spec_Id and Body_Id
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-- can be Empty. Body_Id is Empty when doing a partial check on a call
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-- to a subprogram whose body has not been seen yet, to know whether this
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-- subprogram could possibly be inlined. GNATprove relies on this to adapt
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-- its treatment of the subprogram.
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procedure Cannot_Inline
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(Msg : String;
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N : Node_Id;
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Subp : Entity_Id;
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Is_Serious : Boolean := False;
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Suppress_Info : Boolean := False);
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-- This procedure is called if the node N, an instance of a call to
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-- subprogram Subp, cannot be inlined. Msg is the message to be issued,
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-- which ends with ? (it does not end with ?p?, this routine takes care of
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-- the need to change ? to ?p?). Suppress_Info is set to True to prevent
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-- issuing an info message in GNATprove mode. The behavior of this routine
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-- depends on the value of Back_End_Inlining:
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--
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-- * If Back_End_Inlining is not set (ie. legacy frontend inlining model)
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-- then if Subp has a pragma Always_Inlined, then an error message is
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-- issued (by removing the last character of Msg). If Subp is not
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-- Always_Inlined, then a warning is issued if the flag Ineffective_
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-- Inline_Warnings is set, adding ?p to the msg, and if not, the call
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-- has no effect.
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--
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-- * If Back_End_Inlining is set then:
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-- - If Is_Serious is true, then an error is reported (by removing the
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-- last character of Msg);
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--
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-- - otherwise:
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--
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-- * Compiling without optimizations if Subp has a pragma
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-- Always_Inlined, then an error message is issued; if Subp is
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-- not Always_Inlined, then a warning is issued if the flag
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-- Ineffective_Inline_Warnings is set (adding p?), and if not,
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-- the call has no effect.
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--
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-- * Compiling with optimizations then a warning is issued if the
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-- flag Ineffective_Inline_Warnings is set (adding p?); otherwise
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-- no effect since inlining may be performed by the backend.
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procedure Check_And_Split_Unconstrained_Function
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(N : Node_Id;
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Spec_Id : Entity_Id;
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Body_Id : Entity_Id);
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-- Spec_Id and Body_Id are the entities of the specification and body of
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-- the subprogram body N. If N can be inlined by the frontend (supported
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-- cases documented in Check_Body_To_Inline) then build the body-to-inline
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-- associated with N and attach it to the declaration node of Spec_Id.
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procedure Check_Package_Body_For_Inlining (N : Node_Id; P : Entity_Id);
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-- If front-end inlining is enabled and a package declaration contains
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-- inlined subprograms, load and compile the package body to collect the
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-- bodies of these subprograms, so they are available to inline calls.
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-- N is the compilation unit for the package.
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procedure Expand_Inlined_Call
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(N : Node_Id;
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Subp : Entity_Id;
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Orig_Subp : Entity_Id);
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-- If called subprogram can be inlined by the front-end, retrieve the
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-- analyzed body, replace formals with actuals and expand call in place.
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-- Generate thunks for actuals that are expressions, and insert the
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-- corresponding constant declarations before the call. If the original
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-- call is to a derived operation, the return type is the one of the
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-- derived operation, but the body is that of the original, so return
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-- expressions in the body must be converted to the desired type (which
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-- is simply not noted in the tree without inline expansion).
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function Has_Excluded_Declaration
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(Subp : Entity_Id;
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Decls : List_Id) return Boolean;
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-- Check a list of declarations, Decls, that make the inlining of Subp not
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-- worthwhile
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function Has_Excluded_Statement
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(Subp : Entity_Id;
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Stats : List_Id) return Boolean;
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-- Check a list of statements, Stats, that make inlining of Subp not
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-- worthwhile, including any tasking statement, nested at any level.
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procedure Inline_Static_Function_Call
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(N : Node_Id; Subp : Entity_Id);
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-- Evaluate static call to a static function Subp, substituting actuals in
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-- place of references to their corresponding formals and rewriting the
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-- call N as a fully folded and static result expression.
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procedure List_Inlining_Info;
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-- Generate listing of calls inlined by the frontend plus listing of
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-- calls to inline subprograms passed to the backend.
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procedure Remove_Dead_Instance (N : Node_Id);
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-- If an instantiation appears in unreachable code, delete the pending
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-- body instance.
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end Inline;
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