/* Gimple ranger SSA cache implementation. Copyright (C) 2017-2021 Free Software Foundation, Inc. Contributed by Andrew MacLeod . 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 . */ #include "config.h" #include "system.h" #include "coretypes.h" #include "backend.h" #include "insn-codes.h" #include "tree.h" #include "gimple.h" #include "ssa.h" #include "gimple-pretty-print.h" #include "gimple-range.h" #include "tree-cfg.h" #define DEBUG_RANGE_CACHE (dump_file && (param_evrp_mode & EVRP_MODE_CACHE) \ == EVRP_MODE_CACHE) // During contructor, allocate the vector of ssa_names. non_null_ref::non_null_ref () { m_nn.create (num_ssa_names); m_nn.quick_grow_cleared (num_ssa_names); bitmap_obstack_initialize (&m_bitmaps); } // Free any bitmaps which were allocated,a swell as the vector itself. non_null_ref::~non_null_ref () { bitmap_obstack_release (&m_bitmaps); m_nn.release (); } // Return true if NAME has a non-null dereference in block bb. If this is the // first query for NAME, calculate the summary first. // If SEARCH_DOM is true, the search the dominator tree as well. bool non_null_ref::non_null_deref_p (tree name, basic_block bb, bool search_dom) { if (!POINTER_TYPE_P (TREE_TYPE (name))) return false; unsigned v = SSA_NAME_VERSION (name); if (v >= m_nn.length ()) m_nn.safe_grow_cleared (num_ssa_names + 1); if (!m_nn[v]) process_name (name); if (bitmap_bit_p (m_nn[v], bb->index)) return true; // See if any dominator has set non-zero. if (search_dom && dom_info_available_p (CDI_DOMINATORS)) { // Search back to the Def block, or the top, whichever is closer. basic_block def_bb = gimple_bb (SSA_NAME_DEF_STMT (name)); basic_block def_dom = def_bb ? get_immediate_dominator (CDI_DOMINATORS, def_bb) : NULL; for ( ; bb && bb != def_dom; bb = get_immediate_dominator (CDI_DOMINATORS, bb)) if (bitmap_bit_p (m_nn[v], bb->index)) return true; } return false; } // If NAME has a non-null dereference in block BB, adjust R with the // non-zero information from non_null_deref_p, and return TRUE. If // SEARCH_DOM is true, non_null_deref_p should search the dominator tree. bool non_null_ref::adjust_range (irange &r, tree name, basic_block bb, bool search_dom) { // Non-call exceptions mean we could throw in the middle of the // block, so just punt on those for now. if (cfun->can_throw_non_call_exceptions) return false; // We only care about the null / non-null property of pointers. if (!POINTER_TYPE_P (TREE_TYPE (name))) return false; if (r.undefined_p () || r.lower_bound () != 0 || r.upper_bound () == 0) return false; // Check if pointers have any non-null dereferences. if (non_null_deref_p (name, bb, search_dom)) { // Remove zero from the range. unsigned prec = TYPE_PRECISION (TREE_TYPE (name)); r.intersect (wi::one (prec), wi::max_value (prec, UNSIGNED)); return true; } return false; } // Allocate an populate the bitmap for NAME. An ON bit for a block // index indicates there is a non-null reference in that block. In // order to populate the bitmap, a quick run of all the immediate uses // are made and the statement checked to see if a non-null dereference // is made on that statement. void non_null_ref::process_name (tree name) { unsigned v = SSA_NAME_VERSION (name); use_operand_p use_p; imm_use_iterator iter; bitmap b; // Only tracked for pointers. if (!POINTER_TYPE_P (TREE_TYPE (name))) return; // Already processed if a bitmap has been allocated. if (m_nn[v]) return; b = BITMAP_ALLOC (&m_bitmaps); // Loop over each immediate use and see if it implies a non-null value. FOR_EACH_IMM_USE_FAST (use_p, iter, name) { gimple *s = USE_STMT (use_p); unsigned index = gimple_bb (s)->index; // If bit is already set for this block, dont bother looking again. if (bitmap_bit_p (b, index)) continue; // If we can infer a nonnull range, then set the bit for this BB if (!SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name) && infer_nonnull_range (s, name)) bitmap_set_bit (b, index); } m_nn[v] = b; } // ------------------------------------------------------------------------- // This class represents the API into a cache of ranges for an SSA_NAME. // Routines must be implemented to set, get, and query if a value is set. class ssa_block_ranges { public: virtual bool set_bb_range (const_basic_block bb, const irange &r) = 0; virtual bool get_bb_range (irange &r, const_basic_block bb) = 0; virtual bool bb_range_p (const_basic_block bb) = 0; void dump(FILE *f); }; // Print the list of known ranges for file F in a nice format. void ssa_block_ranges::dump (FILE *f) { basic_block bb; int_range_max r; FOR_EACH_BB_FN (bb, cfun) if (get_bb_range (r, bb)) { fprintf (f, "BB%d -> ", bb->index); r.dump (f); fprintf (f, "\n"); } } // This class implements the range cache as a linear vector, indexed by BB. // It caches a varying and undefined range which are used instead of // allocating new ones each time. class sbr_vector : public ssa_block_ranges { public: sbr_vector (tree t, irange_allocator *allocator); virtual bool set_bb_range (const_basic_block bb, const irange &r) OVERRIDE; virtual bool get_bb_range (irange &r, const_basic_block bb) OVERRIDE; virtual bool bb_range_p (const_basic_block bb) OVERRIDE; protected: irange **m_tab; // Non growing vector. int m_tab_size; int_range<2> m_varying; int_range<2> m_undefined; tree m_type; irange_allocator *m_irange_allocator; }; // Initialize a block cache for an ssa_name of type T. sbr_vector::sbr_vector (tree t, irange_allocator *allocator) { gcc_checking_assert (TYPE_P (t)); m_type = t; m_irange_allocator = allocator; m_tab_size = last_basic_block_for_fn (cfun) + 1; m_tab = (irange **)allocator->get_memory (m_tab_size * sizeof (irange *)); memset (m_tab, 0, m_tab_size * sizeof (irange *)); // Create the cached type range. m_varying.set_varying (t); m_undefined.set_undefined (); } // Set the range for block BB to be R. bool sbr_vector::set_bb_range (const_basic_block bb, const irange &r) { irange *m; gcc_checking_assert (bb->index < m_tab_size); if (r.varying_p ()) m = &m_varying; else if (r.undefined_p ()) m = &m_undefined; else m = m_irange_allocator->allocate (r); m_tab[bb->index] = m; return true; } // Return the range associated with block BB in R. Return false if // there is no range. bool sbr_vector::get_bb_range (irange &r, const_basic_block bb) { gcc_checking_assert (bb->index < m_tab_size); irange *m = m_tab[bb->index]; if (m) { r = *m; return true; } return false; } // Return true if a range is present. bool sbr_vector::bb_range_p (const_basic_block bb) { gcc_checking_assert (bb->index < m_tab_size); return m_tab[bb->index] != NULL; } // This class implements the on entry cache via a sparse bitmap. // It uses the quad bit routines to access 4 bits at a time. // A value of 0 (the default) means there is no entry, and a value of // 1 thru SBR_NUM represents an element in the m_range vector. // Varying is given the first value (1) and pre-cached. // SBR_NUM + 1 represents the value of UNDEFINED, and is never stored. // SBR_NUM is the number of values that can be cached. // Indexes are 1..SBR_NUM and are stored locally at m_range[0..SBR_NUM-1] #define SBR_NUM 14 #define SBR_UNDEF SBR_NUM + 1 #define SBR_VARYING 1 class sbr_sparse_bitmap : public ssa_block_ranges { public: sbr_sparse_bitmap (tree t, irange_allocator *allocator, bitmap_obstack *bm); virtual bool set_bb_range (const_basic_block bb, const irange &r) OVERRIDE; virtual bool get_bb_range (irange &r, const_basic_block bb) OVERRIDE; virtual bool bb_range_p (const_basic_block bb) OVERRIDE; private: void bitmap_set_quad (bitmap head, int quad, int quad_value); int bitmap_get_quad (const_bitmap head, int quad); irange_allocator *m_irange_allocator; irange *m_range[SBR_NUM]; bitmap bitvec; tree m_type; }; // Initialize a block cache for an ssa_name of type T. sbr_sparse_bitmap::sbr_sparse_bitmap (tree t, irange_allocator *allocator, bitmap_obstack *bm) { gcc_checking_assert (TYPE_P (t)); m_type = t; bitvec = BITMAP_ALLOC (bm); m_irange_allocator = allocator; // Pre-cache varying. m_range[0] = m_irange_allocator->allocate (2); m_range[0]->set_varying (t); // Pre-cache zero and non-zero values for pointers. if (POINTER_TYPE_P (t)) { m_range[1] = m_irange_allocator->allocate (2); m_range[1]->set_nonzero (t); m_range[2] = m_irange_allocator->allocate (2); m_range[2]->set_zero (t); } else m_range[1] = m_range[2] = NULL; // Clear SBR_NUM entries. for (int x = 3; x < SBR_NUM; x++) m_range[x] = 0; } // Set 4 bit values in a sparse bitmap. This allows a bitmap to // function as a sparse array of 4 bit values. // QUAD is the index, QUAD_VALUE is the 4 bit value to set. inline void sbr_sparse_bitmap::bitmap_set_quad (bitmap head, int quad, int quad_value) { bitmap_set_aligned_chunk (head, quad, 4, (BITMAP_WORD) quad_value); } // Get a 4 bit value from a sparse bitmap. This allows a bitmap to // function as a sparse array of 4 bit values. // QUAD is the index. inline int sbr_sparse_bitmap::bitmap_get_quad (const_bitmap head, int quad) { return (int) bitmap_get_aligned_chunk (head, quad, 4); } // Set the range on entry to basic block BB to R. bool sbr_sparse_bitmap::set_bb_range (const_basic_block bb, const irange &r) { if (r.undefined_p ()) { bitmap_set_quad (bitvec, bb->index, SBR_UNDEF); return true; } // Loop thru the values to see if R is already present. for (int x = 0; x < SBR_NUM; x++) if (!m_range[x] || r == *(m_range[x])) { if (!m_range[x]) m_range[x] = m_irange_allocator->allocate (r); bitmap_set_quad (bitvec, bb->index, x + 1); return true; } // All values are taken, default to VARYING. bitmap_set_quad (bitvec, bb->index, SBR_VARYING); return false; } // Return the range associated with block BB in R. Return false if // there is no range. bool sbr_sparse_bitmap::get_bb_range (irange &r, const_basic_block bb) { int value = bitmap_get_quad (bitvec, bb->index); if (!value) return false; gcc_checking_assert (value <= SBR_UNDEF); if (value == SBR_UNDEF) r.set_undefined (); else r = *(m_range[value - 1]); return true; } // Return true if a range is present. bool sbr_sparse_bitmap::bb_range_p (const_basic_block bb) { return (bitmap_get_quad (bitvec, bb->index) != 0); } // ------------------------------------------------------------------------- // Initialize the block cache. block_range_cache::block_range_cache () { bitmap_obstack_initialize (&m_bitmaps); m_ssa_ranges.create (0); m_ssa_ranges.safe_grow_cleared (num_ssa_names); m_irange_allocator = new irange_allocator; } // Remove any m_block_caches which have been created. block_range_cache::~block_range_cache () { delete m_irange_allocator; // Release the vector itself. m_ssa_ranges.release (); bitmap_obstack_release (&m_bitmaps); } // Set the range for NAME on entry to block BB to R. // If it has not been accessed yet, allocate it first. bool block_range_cache::set_bb_range (tree name, const_basic_block bb, const irange &r) { unsigned v = SSA_NAME_VERSION (name); if (v >= m_ssa_ranges.length ()) m_ssa_ranges.safe_grow_cleared (num_ssa_names + 1); if (!m_ssa_ranges[v]) { // Use sparse representation if there are too many basic blocks. if (last_basic_block_for_fn (cfun) > param_evrp_sparse_threshold) { void *r = m_irange_allocator->get_memory (sizeof (sbr_sparse_bitmap)); m_ssa_ranges[v] = new (r) sbr_sparse_bitmap (TREE_TYPE (name), m_irange_allocator, &m_bitmaps); } else { // Otherwise use the default vector implemntation. void *r = m_irange_allocator->get_memory (sizeof (sbr_vector)); m_ssa_ranges[v] = new (r) sbr_vector (TREE_TYPE (name), m_irange_allocator); } } return m_ssa_ranges[v]->set_bb_range (bb, r); } // Return a pointer to the ssa_block_cache for NAME. If it has not been // accessed yet, return NULL. inline ssa_block_ranges * block_range_cache::query_block_ranges (tree name) { unsigned v = SSA_NAME_VERSION (name); if (v >= m_ssa_ranges.length () || !m_ssa_ranges[v]) return NULL; return m_ssa_ranges[v]; } // Return the range for NAME on entry to BB in R. Return true if there // is one. bool block_range_cache::get_bb_range (irange &r, tree name, const_basic_block bb) { ssa_block_ranges *ptr = query_block_ranges (name); if (ptr) return ptr->get_bb_range (r, bb); return false; } // Return true if NAME has a range set in block BB. bool block_range_cache::bb_range_p (tree name, const_basic_block bb) { ssa_block_ranges *ptr = query_block_ranges (name); if (ptr) return ptr->bb_range_p (bb); return false; } // Print all known block caches to file F. void block_range_cache::dump (FILE *f) { unsigned x; for (x = 0; x < m_ssa_ranges.length (); ++x) { if (m_ssa_ranges[x]) { fprintf (f, " Ranges for "); print_generic_expr (f, ssa_name (x), TDF_NONE); fprintf (f, ":\n"); m_ssa_ranges[x]->dump (f); fprintf (f, "\n"); } } } // Print all known ranges on entry to blobk BB to file F. void block_range_cache::dump (FILE *f, basic_block bb, bool print_varying) { unsigned x; int_range_max r; bool summarize_varying = false; for (x = 1; x < m_ssa_ranges.length (); ++x) { if (!gimple_range_ssa_p (ssa_name (x))) continue; if (m_ssa_ranges[x] && m_ssa_ranges[x]->get_bb_range (r, bb)) { if (!print_varying && r.varying_p ()) { summarize_varying = true; continue; } print_generic_expr (f, ssa_name (x), TDF_NONE); fprintf (f, "\t"); r.dump(f); fprintf (f, "\n"); } } // If there were any varying entries, lump them all together. if (summarize_varying) { fprintf (f, "VARYING_P on entry : "); for (x = 1; x < num_ssa_names; ++x) { if (!gimple_range_ssa_p (ssa_name (x))) continue; if (m_ssa_ranges[x] && m_ssa_ranges[x]->get_bb_range (r, bb)) { if (r.varying_p ()) { print_generic_expr (f, ssa_name (x), TDF_NONE); fprintf (f, " "); } } } fprintf (f, "\n"); } } // ------------------------------------------------------------------------- // Initialize a global cache. ssa_global_cache::ssa_global_cache () { m_tab.create (0); m_irange_allocator = new irange_allocator; } // Deconstruct a global cache. ssa_global_cache::~ssa_global_cache () { m_tab.release (); delete m_irange_allocator; } // Retrieve the global range of NAME from cache memory if it exists. // Return the value in R. bool ssa_global_cache::get_global_range (irange &r, tree name) const { unsigned v = SSA_NAME_VERSION (name); if (v >= m_tab.length ()) return false; irange *stow = m_tab[v]; if (!stow) return false; r = *stow; return true; } // Set the range for NAME to R in the global cache. // Return TRUE if there was already a range set, otherwise false. bool ssa_global_cache::set_global_range (tree name, const irange &r) { unsigned v = SSA_NAME_VERSION (name); if (v >= m_tab.length ()) m_tab.safe_grow_cleared (num_ssa_names + 1); irange *m = m_tab[v]; if (m && m->fits_p (r)) *m = r; else m_tab[v] = m_irange_allocator->allocate (r); return m != NULL; } // Set the range for NAME to R in the glonbal cache. void ssa_global_cache::clear_global_range (tree name) { unsigned v = SSA_NAME_VERSION (name); if (v >= m_tab.length ()) m_tab.safe_grow_cleared (num_ssa_names + 1); m_tab[v] = NULL; } // Clear the global cache. void ssa_global_cache::clear () { memset (m_tab.address(), 0, m_tab.length () * sizeof (irange *)); } // Dump the contents of the global cache to F. void ssa_global_cache::dump (FILE *f) { /* Cleared after the table header has been printed. */ bool print_header = true; for (unsigned x = 1; x < num_ssa_names; x++) { int_range_max r; if (gimple_range_ssa_p (ssa_name (x)) && get_global_range (r, ssa_name (x)) && !r.varying_p ()) { if (print_header) { /* Print the header only when there's something else to print below. */ fprintf (f, "Non-varying global ranges:\n"); fprintf (f, "=========================:\n"); print_header = false; } print_generic_expr (f, ssa_name (x), TDF_NONE); fprintf (f, " : "); r.dump (f); fprintf (f, "\n"); } } if (!print_header) fputc ('\n', f); } // -------------------------------------------------------------------------- // This class will manage the timestamps for each ssa_name. // When a value is calculated, the timestamp is set to the current time. // Current time is then incremented. Any dependencies will already have // been calculated, and will thus have older timestamps. // If one of those values is ever calculated again, it will get a newer // timestamp, and the "current_p" check will fail. class temporal_cache { public: temporal_cache (); ~temporal_cache (); bool current_p (tree name, tree dep1, tree dep2) const; void set_timestamp (tree name); void set_always_current (tree name); private: unsigned temporal_value (unsigned ssa) const; unsigned m_current_time; vec m_timestamp; }; inline temporal_cache::temporal_cache () { m_current_time = 1; m_timestamp.create (0); m_timestamp.safe_grow_cleared (num_ssa_names); } inline temporal_cache::~temporal_cache () { m_timestamp.release (); } // Return the timestamp value for SSA, or 0 if there isnt one. inline unsigned temporal_cache::temporal_value (unsigned ssa) const { if (ssa >= m_timestamp.length ()) return 0; return m_timestamp[ssa]; } // Return TRUE if the timestampe for NAME is newer than any of its dependents. // Up to 2 dependencies can be checked. bool temporal_cache::current_p (tree name, tree dep1, tree dep2) const { unsigned ts = temporal_value (SSA_NAME_VERSION (name)); if (ts == 0) return true; // Any non-registered dependencies will have a value of 0 and thus be older. // Return true if time is newer than either dependent. if (dep1 && ts < temporal_value (SSA_NAME_VERSION (dep1))) return false; if (dep2 && ts < temporal_value (SSA_NAME_VERSION (dep2))) return false; return true; } // This increments the global timer and sets the timestamp for NAME. inline void temporal_cache::set_timestamp (tree name) { unsigned v = SSA_NAME_VERSION (name); if (v >= m_timestamp.length ()) m_timestamp.safe_grow_cleared (num_ssa_names + 20); m_timestamp[v] = ++m_current_time; } // Set the timestamp to 0, marking it as "always up to date". inline void temporal_cache::set_always_current (tree name) { unsigned v = SSA_NAME_VERSION (name); if (v >= m_timestamp.length ()) m_timestamp.safe_grow_cleared (num_ssa_names + 20); m_timestamp[v] = 0; } // -------------------------------------------------------------------------- ranger_cache::ranger_cache (int not_executable_flag) : m_gori (not_executable_flag) { m_workback.create (0); m_workback.safe_grow_cleared (last_basic_block_for_fn (cfun)); m_update_list.create (0); m_update_list.safe_grow_cleared (last_basic_block_for_fn (cfun)); m_update_list.truncate (0); m_temporal = new temporal_cache; // If DOM info is available, spawn an oracle as well. if (dom_info_available_p (CDI_DOMINATORS)) m_oracle = new dom_oracle (); else m_oracle = NULL; unsigned x, lim = last_basic_block_for_fn (cfun); // Calculate outgoing range info upfront. This will fully populate the // m_maybe_variant bitmap which will help eliminate processing of names // which never have their ranges adjusted. for (x = 0; x < lim ; x++) { basic_block bb = BASIC_BLOCK_FOR_FN (cfun, x); if (bb) m_gori.exports (bb); } m_propfail = BITMAP_ALLOC (NULL); } ranger_cache::~ranger_cache () { BITMAP_FREE (m_propfail); if (m_oracle) delete m_oracle; delete m_temporal; m_workback.release (); m_update_list.release (); } // Dump the global caches to file F. if GORI_DUMP is true, dump the // gori map as well. void ranger_cache::dump (FILE *f) { m_globals.dump (f); fprintf (f, "\n"); } // Dump the caches for basic block BB to file F. void ranger_cache::dump_bb (FILE *f, basic_block bb) { m_gori.gori_map::dump (f, bb, false); m_on_entry.dump (f, bb); if (m_oracle) m_oracle->dump (f, bb); } // Get the global range for NAME, and return in R. Return false if the // global range is not set. bool ranger_cache::get_global_range (irange &r, tree name) const { return m_globals.get_global_range (r, name); } // Get the global range for NAME, and return in R if the value is not stale. // If the range is set, but is stale, mark it current and return false. // If it is not set pick up the legacy global value, mark it current, and // return false. // Note there is always a value returned in R. The return value indicates // whether that value is an up-to-date calculated value or not.. bool ranger_cache::get_non_stale_global_range (irange &r, tree name) { if (m_globals.get_global_range (r, name)) { // Use this value if the range is constant or current. if (r.singleton_p () || m_temporal->current_p (name, m_gori.depend1 (name), m_gori.depend2 (name))) return true; } else { // Global has never been accessed, so pickup the legacy global value. r = gimple_range_global (name); m_globals.set_global_range (name, r); } // After a stale check failure, mark the value as always current until a // new one is set. m_temporal->set_always_current (name); return false; } // Set the global range of NAME to R. void ranger_cache::set_global_range (tree name, const irange &r) { if (m_globals.set_global_range (name, r)) { // If there was already a range set, propagate the new value. basic_block bb = gimple_bb (SSA_NAME_DEF_STMT (name)); if (!bb) bb = ENTRY_BLOCK_PTR_FOR_FN (cfun); if (DEBUG_RANGE_CACHE) fprintf (dump_file, " GLOBAL :"); propagate_updated_value (name, bb); } // Constants no longer need to tracked. Any further refinement has to be // undefined. Propagation works better with constants. PR 100512. // Pointers which resolve to non-zero also do not need // tracking in the cache as they will never change. See PR 98866. // Timestamp must always be updated, or dependent calculations may // not include this latest value. PR 100774. if (r.singleton_p () || (POINTER_TYPE_P (TREE_TYPE (name)) && r.nonzero_p ())) m_gori.set_range_invariant (name); m_temporal->set_timestamp (name); } // Provide lookup for the gori-computes class to access the best known range // of an ssa_name in any given basic block. Note, this does no additonal // lookups, just accesses the data that is already known. // Get the range of NAME when the def occurs in block BB. If BB is NULL // get the best global value available. void ranger_cache::range_of_def (irange &r, tree name, basic_block bb) { gcc_checking_assert (gimple_range_ssa_p (name)); gcc_checking_assert (!bb || bb == gimple_bb (SSA_NAME_DEF_STMT (name))); // Pick up the best global range available. if (!m_globals.get_global_range (r, name)) { // If that fails, try to calculate the range using just global values. gimple *s = SSA_NAME_DEF_STMT (name); if (gimple_get_lhs (s) == name) fold_range (r, s, get_global_range_query ()); else r = gimple_range_global (name); } if (bb) m_non_null.adjust_range (r, name, bb, false); } // Get the range of NAME as it occurs on entry to block BB. void ranger_cache::entry_range (irange &r, tree name, basic_block bb) { if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)) { r = gimple_range_global (name); return; } // Look for the on-entry value of name in BB from the cache. // Otherwise pick up the best available global value. if (!m_on_entry.get_bb_range (r, name, bb)) range_of_def (r, name); m_non_null.adjust_range (r, name, bb, false); } // Get the range of NAME as it occurs on exit from block BB. void ranger_cache::exit_range (irange &r, tree name, basic_block bb) { if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)) { r = gimple_range_global (name); return; } gimple *s = SSA_NAME_DEF_STMT (name); basic_block def_bb = gimple_bb (s); if (def_bb == bb) range_of_def (r, name, bb); else entry_range (r, name, bb); } // Implement range_of_expr. bool ranger_cache::range_of_expr (irange &r, tree name, gimple *stmt) { if (!gimple_range_ssa_p (name)) { get_tree_range (r, name, stmt); return true; } basic_block bb = gimple_bb (stmt); gimple *def_stmt = SSA_NAME_DEF_STMT (name); basic_block def_bb = gimple_bb (def_stmt); if (bb == def_bb) range_of_def (r, name, bb); else entry_range (r, name, bb); return true; } // Implement range_on_edge. Always return the best available range. bool ranger_cache::range_on_edge (irange &r, edge e, tree expr) { if (gimple_range_ssa_p (expr)) { exit_range (r, expr, e->src); int_range_max edge_range; if (m_gori.outgoing_edge_range_p (edge_range, e, expr, *this)) r.intersect (edge_range); return true; } return get_tree_range (r, expr, NULL); } // Return a static range for NAME on entry to basic block BB in R. If // calc is true, fill any cache entries required between BB and the // def block for NAME. Otherwise, return false if the cache is empty. bool ranger_cache::block_range (irange &r, basic_block bb, tree name, bool calc) { gcc_checking_assert (gimple_range_ssa_p (name)); // If there are no range calculations anywhere in the IL, global range // applies everywhere, so don't bother caching it. if (!m_gori.has_edge_range_p (name)) return false; if (calc) { gimple *def_stmt = SSA_NAME_DEF_STMT (name); basic_block def_bb = NULL; if (def_stmt) def_bb = gimple_bb (def_stmt);; if (!def_bb) { // If we get to the entry block, this better be a default def // or range_on_entry was called for a block not dominated by // the def. gcc_checking_assert (SSA_NAME_IS_DEFAULT_DEF (name)); def_bb = ENTRY_BLOCK_PTR_FOR_FN (cfun); } // There is no range on entry for the definition block. if (def_bb == bb) return false; // Otherwise, go figure out what is known in predecessor blocks. fill_block_cache (name, bb, def_bb); gcc_checking_assert (m_on_entry.bb_range_p (name, bb)); } return m_on_entry.get_bb_range (r, name, bb); } // Add BB to the list of blocks to update, unless it's already in the list. void ranger_cache::add_to_update (basic_block bb) { // If propagation has failed for BB, or its already in the list, don't // add it again. if (!bitmap_bit_p (m_propfail, bb->index) && !m_update_list.contains (bb)) m_update_list.quick_push (bb); } // If there is anything in the propagation update_list, continue // processing NAME until the list of blocks is empty. void ranger_cache::propagate_cache (tree name) { basic_block bb; edge_iterator ei; edge e; int_range_max new_range; int_range_max current_range; int_range_max e_range; gcc_checking_assert (bitmap_empty_p (m_propfail)); // Process each block by seeing if its calculated range on entry is // the same as its cached value. If there is a difference, update // the cache to reflect the new value, and check to see if any // successors have cache entries which may need to be checked for // updates. while (m_update_list.length () > 0) { bb = m_update_list.pop (); gcc_checking_assert (m_on_entry.bb_range_p (name, bb)); m_on_entry.get_bb_range (current_range, name, bb); if (DEBUG_RANGE_CACHE) { fprintf (dump_file, "FWD visiting block %d for ", bb->index); print_generic_expr (dump_file, name, TDF_SLIM); fprintf (dump_file, " starting range : "); current_range.dump (dump_file); fprintf (dump_file, "\n"); } // Calculate the "new" range on entry by unioning the pred edges. new_range.set_undefined (); FOR_EACH_EDGE (e, ei, bb->preds) { range_on_edge (e_range, e, name); if (DEBUG_RANGE_CACHE) { fprintf (dump_file, " edge %d->%d :", e->src->index, bb->index); e_range.dump (dump_file); fprintf (dump_file, "\n"); } new_range.union_ (e_range); if (new_range.varying_p ()) break; } // If the range on entry has changed, update it. if (new_range != current_range) { bool ok_p = m_on_entry.set_bb_range (name, bb, new_range); // If the cache couldn't set the value, mark it as failed. if (!ok_p) bitmap_set_bit (m_propfail, bb->index); if (DEBUG_RANGE_CACHE) { if (!ok_p) { fprintf (dump_file, " Cache failure to store value:"); print_generic_expr (dump_file, name, TDF_SLIM); fprintf (dump_file, " "); } else { fprintf (dump_file, " Updating range to "); new_range.dump (dump_file); } fprintf (dump_file, "\n Updating blocks :"); } // Mark each successor that has a range to re-check its range FOR_EACH_EDGE (e, ei, bb->succs) if (m_on_entry.bb_range_p (name, e->dest)) { if (DEBUG_RANGE_CACHE) fprintf (dump_file, " bb%d",e->dest->index); add_to_update (e->dest); } if (DEBUG_RANGE_CACHE) fprintf (dump_file, "\n"); } } if (DEBUG_RANGE_CACHE) { fprintf (dump_file, "DONE visiting blocks for "); print_generic_expr (dump_file, name, TDF_SLIM); fprintf (dump_file, "\n"); } bitmap_clear (m_propfail); } // Check to see if an update to the value for NAME in BB has any effect // on values already in the on-entry cache for successor blocks. // If it does, update them. Don't visit any blocks which dont have a cache // entry. void ranger_cache::propagate_updated_value (tree name, basic_block bb) { edge e; edge_iterator ei; // The update work list should be empty at this point. gcc_checking_assert (m_update_list.length () == 0); gcc_checking_assert (bb); if (DEBUG_RANGE_CACHE) { fprintf (dump_file, " UPDATE cache for "); print_generic_expr (dump_file, name, TDF_SLIM); fprintf (dump_file, " in BB %d : successors : ", bb->index); } FOR_EACH_EDGE (e, ei, bb->succs) { // Only update active cache entries. if (m_on_entry.bb_range_p (name, e->dest)) { add_to_update (e->dest); if (DEBUG_RANGE_CACHE) fprintf (dump_file, " UPDATE: bb%d", e->dest->index); } } if (m_update_list.length () != 0) { if (DEBUG_RANGE_CACHE) fprintf (dump_file, "\n"); propagate_cache (name); } else { if (DEBUG_RANGE_CACHE) fprintf (dump_file, " : No updates!\n"); } } // Make sure that the range-on-entry cache for NAME is set for block BB. // Work back through the CFG to DEF_BB ensuring the range is calculated // on the block/edges leading back to that point. void ranger_cache::fill_block_cache (tree name, basic_block bb, basic_block def_bb) { edge_iterator ei; edge e; int_range_max block_result; int_range_max undefined; // At this point we shouldn't be looking at the def, entry or exit block. gcc_checking_assert (bb != def_bb && bb != ENTRY_BLOCK_PTR_FOR_FN (cfun) && bb != EXIT_BLOCK_PTR_FOR_FN (cfun)); // If the block cache is set, then we've already visited this block. if (m_on_entry.bb_range_p (name, bb)) return; // Visit each block back to the DEF. Initialize each one to UNDEFINED. // m_visited at the end will contain all the blocks that we needed to set // the range_on_entry cache for. m_workback.truncate (0); m_workback.quick_push (bb); undefined.set_undefined (); m_on_entry.set_bb_range (name, bb, undefined); gcc_checking_assert (m_update_list.length () == 0); if (DEBUG_RANGE_CACHE) { fprintf (dump_file, "\n"); print_generic_expr (dump_file, name, TDF_SLIM); fprintf (dump_file, " : "); } while (m_workback.length () > 0) { basic_block node = m_workback.pop (); if (DEBUG_RANGE_CACHE) { fprintf (dump_file, "BACK visiting block %d for ", node->index); print_generic_expr (dump_file, name, TDF_SLIM); fprintf (dump_file, "\n"); } FOR_EACH_EDGE (e, ei, node->preds) { basic_block pred = e->src; int_range_max r; if (DEBUG_RANGE_CACHE) fprintf (dump_file, " %d->%d ",e->src->index, e->dest->index); // If the pred block is the def block add this BB to update list. if (pred == def_bb) { add_to_update (node); continue; } // If the pred is entry but NOT def, then it is used before // defined, it'll get set to [] and no need to update it. if (pred == ENTRY_BLOCK_PTR_FOR_FN (cfun)) { if (DEBUG_RANGE_CACHE) fprintf (dump_file, "entry: bail."); continue; } // Regardless of whether we have visited pred or not, if the // pred has a non-null reference, revisit this block. // Don't search the DOM tree. if (m_non_null.non_null_deref_p (name, pred, false)) { if (DEBUG_RANGE_CACHE) fprintf (dump_file, "nonnull: update "); add_to_update (node); } // If the pred block already has a range, or if it can contribute // something new. Ie, the edge generates a range of some sort. if (m_on_entry.get_bb_range (r, name, pred)) { if (DEBUG_RANGE_CACHE) { fprintf (dump_file, "has cache, "); r.dump (dump_file); fprintf (dump_file, ", "); } if (!r.undefined_p () || m_gori.has_edge_range_p (name, e)) { add_to_update (node); if (DEBUG_RANGE_CACHE) fprintf (dump_file, "update. "); } continue; } if (DEBUG_RANGE_CACHE) fprintf (dump_file, "pushing undefined pred block.\n"); // If the pred hasn't been visited (has no range), add it to // the list. gcc_checking_assert (!m_on_entry.bb_range_p (name, pred)); m_on_entry.set_bb_range (name, pred, undefined); m_workback.quick_push (pred); } } if (DEBUG_RANGE_CACHE) fprintf (dump_file, "\n"); // Now fill in the marked blocks with values. propagate_cache (name); if (DEBUG_RANGE_CACHE) fprintf (dump_file, " Propagation update done.\n"); }