diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ipa-modref.c | 244 |
1 files changed, 224 insertions, 20 deletions
diff --git a/gcc/ipa-modref.c b/gcc/ipa-modref.c index db071d2..5209fbd 100644 --- a/gcc/ipa-modref.c +++ b/gcc/ipa-modref.c @@ -752,8 +752,9 @@ record_access (modref_records *tt, ao_ref *ref) modref_access_node a = get_access (ref); if (dump_file) { - fprintf (dump_file, " - Recording base_set=%i ref_set=%i parm=%i\n", - base_set, ref_set, a.parm_index); + fprintf (dump_file, " - Recording base_set=%i ref_set=%i ", + base_set, ref_set); + dump_access (&a, dump_file); } tt->insert (base_set, ref_set, a, false); } @@ -816,9 +817,9 @@ record_access_lto (modref_records_lto *tt, ao_ref *ref) fprintf (dump_file, " (alias set %i) ref type:", base_type ? get_alias_set (base_type) : 0); print_generic_expr (dump_file, ref_type); - fprintf (dump_file, " (alias set %i) parm:%i\n", - ref_type ? get_alias_set (ref_type) : 0, - a.parm_index); + fprintf (dump_file, " (alias set %i) ", + ref_type ? get_alias_set (ref_type) : 0); + dump_access (&a, dump_file); } tt->insert (base_type, ref_type, a, false); @@ -1456,14 +1457,32 @@ class modref_lattice public: /* EAF flags of the SSA name. */ eaf_flags_t flags; - /* DFS bookkkeeping: we don't do real dataflow yet. */ + /* Used during DFS walk to mark names where final value was determined + without need for dataflow. */ bool known; + /* Used during DFS walk to mark open vertices (for cycle detection). */ bool open; + /* Set during DFS walk for names that needs dataflow propagation. */ + bool do_dataflow; + /* Used during the iterative dataflow. */ + bool changed; /* When doing IPA analysis we can not merge in callee escape points; Only remember them and do the merging at IPA propagation time. */ vec <escape_point, va_heap, vl_ptr> escape_points; + /* Representation of a graph for dataaflow. This graph is built on-demand + using modref_eaf_analysis::analyze_ssa and later solved by + modref_eaf_analysis::propagate. + Each edge represents the fact that flags of current lattice should be + propagated to lattice of SSA_NAME. */ + struct propagate_edge + { + int ssa_name; + bool deref; + }; + vec <propagate_edge, va_heap, vl_ptr> propagate_to; + void init (); void release (); bool merge (const modref_lattice &with); @@ -1495,6 +1514,7 @@ void modref_lattice::release () { escape_points.release (); + propagate_to.release (); } /* Dump lattice to OUT; indent with INDENT spaces. */ @@ -1587,7 +1607,7 @@ bool modref_lattice::merge (const modref_lattice &with) { if (!with.known) - return merge (0); + do_dataflow = true; bool changed = merge (with.flags); @@ -1608,7 +1628,7 @@ bool modref_lattice::merge_deref (const modref_lattice &with, bool ignore_stores) { if (!with.known) - return merge (0); + do_dataflow = true; bool changed = merge (deref_flags (with.flags, ignore_stores)); @@ -1646,13 +1666,24 @@ modref_lattice::merge_direct_store () return merge (~(EAF_UNUSED | EAF_NOCLOBBER)); } -/* Analyzer of EAF flags. */ +/* Analyzer of EAF flags. + This is genrally dataflow problem over the SSA graph, however we only + care about flags of few selected ssa names (arguments, return slot and + static chain). So we first call analyze_ssa_name on all relevant names + and perform a DFS walk to discover SSA names where flags needs to be + determined. For acyclic graphs we try to determine final flags during + this walk. Once cycles or recursin depth is met we enlist SSA names + for dataflow which is done by propagate call. + + After propagation the flags can be obtained using get_ssa_name_flags. */ class modref_eaf_analysis { public: - /* Compute flags for NAME. */ + /* Mark NAME as relevant for analysis. */ void analyze_ssa_name (tree name); + /* Dataflow slover. */ + void propagate (); /* Return flags computed earlier for NAME. */ int get_ssa_name_flags (tree name) { @@ -1673,7 +1704,7 @@ public: ~modref_eaf_analysis () { gcc_checking_assert (!m_depth); - if (m_ipa) + if (m_ipa || m_names_to_propagate.length ()) for (unsigned int i = 0; i < num_ssa_names; i++) m_lattice[i].release (); } @@ -1685,6 +1716,8 @@ private: int m_depth; /* Propagation lattice for individual ssa names. */ auto_vec<modref_lattice> m_lattice; + auto_vec<tree> m_deferred_names; + auto_vec<int> m_names_to_propagate; void merge_with_ssa_name (tree dest, tree src, bool deref); void merge_call_lhs_flags (gcall *call, int arg, tree name, bool deref); @@ -1773,26 +1806,27 @@ modref_eaf_analysis::analyze_ssa_name (tree name) int index = SSA_NAME_VERSION (name); /* See if value is already computed. */ - if (m_lattice[index].known) + if (m_lattice[index].known || m_lattice[index].do_dataflow) return; if (m_lattice[index].open) { if (dump_file) fprintf (dump_file, - "%*sGiving up on a cycle in SSA graph\n", + "%*sCycle in SSA graph\n", m_depth * 4, ""); return; } + /* Recursion guard. */ + m_lattice[index].init (); if (m_depth == param_modref_max_depth) { if (dump_file) fprintf (dump_file, - "%*sGiving up on max depth\n", + "%*sMax recursion depth reached; postponing\n", m_depth * 4, ""); + m_deferred_names.safe_push (name); return; } - /* Recursion guard. */ - m_lattice[index].init (); if (dump_file) { @@ -2072,7 +2106,8 @@ modref_eaf_analysis::analyze_ssa_name (tree name) m_lattice[index].dump (dump_file, m_depth * 4 + 2); } m_lattice[index].open = false; - m_lattice[index].known = true; + if (!m_lattice[index].do_dataflow) + m_lattice[index].known = true; } /* Propagate info from SRC to DEST. If DEREF it true, assume that SRC @@ -2084,6 +2119,10 @@ modref_eaf_analysis::merge_with_ssa_name (tree dest, tree src, bool deref) int index = SSA_NAME_VERSION (dest); int src_index = SSA_NAME_VERSION (src); + /* Merging lattice with itself is a no-op. */ + if (!deref && src == dest) + return; + m_depth++; analyze_ssa_name (src); m_depth--; @@ -2091,6 +2130,157 @@ modref_eaf_analysis::merge_with_ssa_name (tree dest, tree src, bool deref) m_lattice[index].merge_deref (m_lattice[src_index], false); else m_lattice[index].merge (m_lattice[src_index]); + + /* If we failed to produce final solution add an edge to the dataflow + graph. */ + if (!m_lattice[src_index].known) + { + modref_lattice::propagate_edge e = {index, deref}; + + if (!m_lattice[src_index].propagate_to.length ()) + m_names_to_propagate.safe_push (src_index); + m_lattice[src_index].propagate_to.safe_push (e); + m_lattice[src_index].changed = true; + m_lattice[src_index].do_dataflow = true; + if (dump_file) + fprintf (dump_file, + "%*sWill propgate from ssa_name %i to %i%s\n", + m_depth * 4 + 4, + "", src_index, index, deref ? " (deref)" : ""); + } +} + +/* In the case we deferred some SSA names, reprocess them. In the case some + dataflow edges were introduced, do the actual iterative dataflow. */ + +void +modref_eaf_analysis::propagate () +{ + int iterations = 0; + size_t i; + int index; + bool changed = true; + + while (m_deferred_names.length ()) + { + tree name = m_deferred_names.pop (); + m_lattice[SSA_NAME_VERSION (name)].open = false; + if (dump_file) + fprintf (dump_file, "Analyzing deferred SSA name\n"); + analyze_ssa_name (name); + } + + if (!m_names_to_propagate.length ()) + return; + if (dump_file) + fprintf (dump_file, "Propagating EAF flags\n"); + + /* Compute reverse postorder. */ + auto_vec <int> rpo; + struct stack_entry + { + int name; + unsigned pos; + }; + auto_vec <struct stack_entry> stack; + int pos = m_names_to_propagate.length () - 1; + + rpo.safe_grow (m_names_to_propagate.length (), true); + stack.reserve_exact (m_names_to_propagate.length ()); + + /* We reuse known flag for RPO DFS walk bookeeping. */ + if (flag_checking) + FOR_EACH_VEC_ELT (m_names_to_propagate, i, index) + gcc_assert (!m_lattice[index].known && m_lattice[index].changed); + + FOR_EACH_VEC_ELT (m_names_to_propagate, i, index) + { + if (!m_lattice[index].known) + { + stack_entry e = {index, 0}; + + stack.quick_push (e); + m_lattice[index].known = true; + } + while (stack.length ()) + { + bool found = false; + int index1 = stack.last ().name; + + while (stack.last ().pos < m_lattice[index1].propagate_to.length ()) + { + int index2 = m_lattice[index1] + .propagate_to[stack.last ().pos].ssa_name; + + stack.last ().pos++; + if (!m_lattice[index2].known + && m_lattice[index2].propagate_to.length ()) + { + stack_entry e = {index2, 0}; + + stack.quick_push (e); + m_lattice[index2].known = true; + found = true; + break; + } + } + if (!found + && stack.last ().pos == m_lattice[index1].propagate_to.length ()) + { + rpo[pos--] = index1; + stack.pop (); + } + } + } + + /* Perform itrative dataflow. */ + while (changed) + { + changed = false; + iterations++; + if (dump_file) + fprintf (dump_file, " iteration %i\n", iterations); + FOR_EACH_VEC_ELT (rpo, i, index) + { + if (m_lattice[index].changed) + { + size_t j; + + m_lattice[index].changed = false; + if (dump_file) + fprintf (dump_file, " Visiting ssa name %i\n", index); + for (j = 0; j < m_lattice[index].propagate_to.length (); j++) + { + bool ch; + int target = m_lattice[index].propagate_to[j].ssa_name; + bool deref = m_lattice[index].propagate_to[j].deref; + + if (dump_file) + fprintf (dump_file, " Propagating flags of ssa name" + " %i to %i%s\n", + index, target, deref ? " (deref)" : ""); + m_lattice[target].known = true; + if (!m_lattice[index].propagate_to[j].deref) + ch = m_lattice[target].merge (m_lattice[index]); + else + ch = m_lattice[target].merge_deref (m_lattice[index], + false); + if (!ch) + continue; + if (dump_file) + { + fprintf (dump_file, " New lattice: "); + m_lattice[target].dump (dump_file); + } + if (target <= (int)i) + changed = true; + m_lattice[target].changed = true; + } + } + } + } + if (dump_file) + fprintf (dump_file, "EAF flags propagated in %i iterations\n", iterations); } /* Record escape points of PARM_INDEX according to LATTICE. */ @@ -2151,6 +2341,23 @@ analyze_parms (modref_summary *summary, modref_summary_lto *summary_lto, modref_eaf_analysis eaf_analysis (ipa); + /* Determine all SSA names we need to know flags for. */ + for (tree parm = DECL_ARGUMENTS (current_function_decl); parm; + parm = TREE_CHAIN (parm)) + { + tree name = ssa_default_def (cfun, parm); + if (name) + eaf_analysis.analyze_ssa_name (name); + } + if (retslot) + eaf_analysis.analyze_ssa_name (retslot); + if (static_chain) + eaf_analysis.analyze_ssa_name (static_chain); + + /* Do the dataflow. */ + eaf_analysis.propagate (); + + /* Store results to summaries. */ for (tree parm = DECL_ARGUMENTS (current_function_decl); parm; parm_index++, parm = TREE_CHAIN (parm)) { @@ -2175,7 +2382,6 @@ analyze_parms (modref_summary *summary, modref_summary_lto *summary_lto, } continue; } - eaf_analysis.analyze_ssa_name (name); int flags = eaf_analysis.get_ssa_name_flags (name); /* Eliminate useless flags so we do not end up storing unnecessary @@ -2204,7 +2410,6 @@ analyze_parms (modref_summary *summary, modref_summary_lto *summary_lto, } if (retslot) { - eaf_analysis.analyze_ssa_name (retslot); int flags = eaf_analysis.get_ssa_name_flags (retslot); flags = remove_useless_eaf_flags (flags, ecf_flags, false); @@ -2220,7 +2425,6 @@ analyze_parms (modref_summary *summary, modref_summary_lto *summary_lto, } if (static_chain) { - eaf_analysis.analyze_ssa_name (static_chain); int flags = eaf_analysis.get_ssa_name_flags (static_chain); flags = remove_useless_eaf_flags (flags, ecf_flags, false); |