// Basic-block-related classes for RTL SSA -*- C++ -*-
// Copyright (C) 2020-2022 Free Software Foundation, Inc.
//
// This file is part of GCC.
//
// GCC is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 3, or (at your option) any later
// version.
//
// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License
// along with GCC; see the file COPYING3. If not see
// .
namespace rtl_ssa {
// SSA-related information about a basic block. Each block contains
// the following, which are conceptually executed in order:
//
// - an artificial "head" insn_info that holds artificial uses and definitions
// for the start of the block.
//
// - one insn_info for each "real" instruction in the block
// (i.e. those that have an RTL pattern).
//
// - an artificial "end" insn_info that holds artificial uses and definitions
// for the end of the block.
//
// Blocks are grouped together into extended basic blocks. In cases where
// multiple EBBs exist (such as in a full diamond), we try to pick the one
// that's most frequently executed.
//
// Blocks are chained together in reverse postorder. (Rather than use a
// list, we could instead have stored the index of the block in the overall
// postorder. However, using lists should make it cheaper to update the
// information after trivial CFG manipulations.)
class bb_info
{
// Size: 6 LP64 words.
friend class function_info;
public:
// Return the previous basic block in reverse postorder, or null if this
// is the entry block.
bb_info *prev_bb () const { return m_prev_bb; }
// Return the next basic block in reverse postorder, or null if this
// is the exit block.
bb_info *next_bb () const { return m_next_bb; }
// Return true if this block is the function's entry block.
bool is_entry_block () const { return !m_prev_bb; }
// Return true if this block is the function's exit block.
bool is_exit_block () const { return !m_next_bb; }
// Return the underlying basic_block structure.
basic_block cfg_bb () const { return m_cfg_bb; }
// Return the unique identifier of the underlying basic_block. These uids
// do not follow any particular order.
unsigned int index () const { return m_cfg_bb->index; }
// Return the EBB that contains this block.
ebb_info *ebb () const { return m_ebb; }
// Return a list of all the instructions in the block, in execution order.
// The list includes the head and end instructions described above.
//
// Iterations over the list will pick up any new instructions that are
// inserted after the iterator's current instruction.
iterator_range all_insns () const;
// Like all_insns (), except that the instructions are in reverse order.
//
// Iterations over the list will pick up any new instructions that are
// inserted before the iterator's current instruction.
iterator_range reverse_all_insns () const;
// Like all_insns (), but without the debug instructions.
iterator_range nondebug_insns () const;
// Like reverse_all_insns (), but without the debug instructions.
iterator_range
reverse_nondebug_insns () const;
// Like all_insns (), but without the artificial instructions.
iterator_range real_insns () const;
// Like reverse_all_insns (), but without the artificial instructions.
iterator_range reverse_real_insns () const;
// Like real_insns (), but without the debug instructions.
iterator_range real_nondebug_insns () const;
// Like reverse_real_insns (), but without the debug instructions.
iterator_range
reverse_real_nondebug_insns () const;
// Return the instruction that holds the artificial uses and
// definitions at the head of the block. The associated RTL insn
// is the block head note.
//
// This instruction always exists, even if it has no uses and definitions.
insn_info *head_insn () const { return m_head_insn; }
// Return the instruction that holds the artificial uses and definitions
// at the end of the block. There is no associated RTL insn.
//
// This instruction always exists, even if it has no uses and definitions.
insn_info *end_insn () const { return m_end_insn; }
// Print "bb" + index () to PP.
void print_identifier (pretty_printer *pp) const;
// Print a full description of the block to PP.
void print_full (pretty_printer *) const;
private:
bb_info (basic_block);
void set_prev_bb (bb_info *bb) { m_prev_bb = bb; }
void set_next_bb (bb_info *bb) { m_next_bb = bb; }
void set_cfg_bb (basic_block cfg_bb) { m_cfg_bb = cfg_bb; }
void set_ebb (ebb_info *ebb) { m_ebb = ebb; }
void set_head_insn (insn_info *insn) { m_head_insn = insn; }
void set_end_insn (insn_info *insn) { m_end_insn = insn; }
// The values returned by the functions above.
bb_info *m_prev_bb;
bb_info *m_next_bb;
basic_block m_cfg_bb;
ebb_info *m_ebb;
insn_info *m_head_insn;
insn_info *m_end_insn;
};
// Iterators for lists of basic blocks.
using bb_iterator = list_iterator;
using reverse_bb_iterator = list_iterator;
// This class collects together instructions for which has_call_clobbers ()
// is true, storing them in a splay tree that follows reverse postorder.
// Instances of the class form a singly-linked list, with one instance
// per predefined_function_abi.
class ebb_call_clobbers_info : public insn_call_clobbers_tree
{
// Size 3 LP64 words.
friend class function_info;
public:
// Return the next group in the list.
ebb_call_clobbers_info *next () const { return m_next; }
// Return the function abi used by all the calls in the group.
const predefined_function_abi *abi () const { return m_abi; }
// Return true if at least one call in the group should conservatively
// be assumed to clobber RESOURCE.
bool clobbers (resource_info) const;
// Print a summary of what the class describes to PP, without printing
// the actual instructions.
void print_summary (pretty_printer *pp) const;
// Print a full description of the object to PP, including the
// instructions it contains.
void print_full (pretty_printer *) const;
private:
ebb_call_clobbers_info (const predefined_function_abi *);
// The values returned by the accessors above.
ebb_call_clobbers_info *m_next;
const predefined_function_abi *m_abi;
};
// A list of ebb_call_clobbers_infos.
using ebb_call_clobbers_iterator
= list_iterator;
// Information about an extended basic block.
//
// Each EBB has a list of phi nodes and starts with an artificial phi
// instruction that conceptually "executes" the phi nodes. The phi
// nodes are independent of one another and so can be executed in any
// order. The order of the phi nodes in the list is not significant.
//
// Each EBB also maintains a list of ebb_call_clobbers_info structures
// that describe all instructions for which has_call_clobbers () is true.
// See the comment above that class for details.
class ebb_info
{
// Size: 5 LP64 words.
friend class function_info;
public:
// Return the previous EBB in reverse postorder, or null if this EBB
// contains the entry block.
ebb_info *prev_ebb () const;
// Return the next EBB in reverse postorder, or null if this EBB contains
// the exit block.
ebb_info *next_ebb () const;
// Return the instruction that holds the EBB's phi nodes (and does
// nothing else). There is no associated RTL insn.
//
// This instruction always exists, even if the EBB does not currently
// need any phi nodes.
insn_info *phi_insn () const { return m_phi_insn; }
// Return the first and last blocks in the EBB.
bb_info *first_bb () const { return m_first_bb; }
bb_info *last_bb () const { return m_last_bb; }
// Return the first of the EBB's phi nodes.
phi_info *first_phi () const { return m_first_phi; }
// Return the head of the list of ebb_call_clobbers_infos.
ebb_call_clobbers_info *first_call_clobbers () const;
// Return the list of ebb_call_clobbers_infos.
iterator_range call_clobbers () const;
// Return a list of the EBB's phi nodes, in arbitrary order.
iterator_range phis () const;
// Return a list of the blocks in the EBB, in execution order.
iterator_range bbs () const;
// Return a list of the blocks in the EBB, in reverse execution order.
iterator_range reverse_bbs () const;
// Return a list of all the instructions in the EBB, in execution order.
// The list includes phi_insn (), the head and end of each block,
// and the real instructions in each block.
//
// Iterations over the list will pick up any new instructions that are
// inserted after the iterator's current instruction.
iterator_range all_insns () const;
// Like all_insns (), except that the instructions are in reverse order.
//
// Iterations over the list will pick up any new instructions that are
// inserted before the iterator's current instruction.
iterator_range reverse_all_insns () const;
// Like all_insns (), but without the debug instructions.
iterator_range nondebug_insns () const;
// Like reverse_all_insns (), but without the debug instructions.
iterator_range
reverse_nondebug_insns () const;
// Return an insn_range that covers the same instructions as all_insns ().
insn_range_info insn_range () const;
// Print "ebb" + first_bb ()->index () to PP.
void print_identifier (pretty_printer *pp) const;
// Print a full description of the EBB to PP.
void print_full (pretty_printer *pp) const;
private:
ebb_info (bb_info *, bb_info *);
void set_first_phi (phi_info *phi) { m_first_phi = phi; }
void set_phi_insn (insn_info *insn) { m_phi_insn = insn; }
void set_first_call_clobbers (ebb_call_clobbers_info *);
// The values returned by the functions above.
phi_info *m_first_phi;
insn_info *m_phi_insn;
bb_info *m_first_bb;
bb_info *m_last_bb;
ebb_call_clobbers_info *m_first_call_clobbers;
};
// Iterators for lists of extended basic blocks.
using ebb_iterator = list_iterator;
using reverse_ebb_iterator = list_iterator;
void pp_bb (pretty_printer *, const bb_info *);
void pp_ebb_call_clobbers (pretty_printer *, const ebb_call_clobbers_info *);
void pp_ebb (pretty_printer *, const ebb_info *);
}
void dump (FILE *, const rtl_ssa::bb_info *);
void dump (FILE *, const rtl_ssa::ebb_call_clobbers_info *);
void dump (FILE *, const rtl_ssa::ebb_info *);
void DEBUG_FUNCTION debug (const rtl_ssa::bb_info *);
void DEBUG_FUNCTION debug (const rtl_ssa::ebb_call_clobbers_info *);
void DEBUG_FUNCTION debug (const rtl_ssa::ebb_info *);