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view gcc/cgraphunit.c @ 0:a06113de4d67
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| author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
|---|---|
| date | Fri, 17 Jul 2009 14:47:48 +0900 |
| parents | |
| children | 855418dad1a3 |
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/* Callgraph based interprocedural optimizations. Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. Contributed by Jan Hubicka 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 <http://www.gnu.org/licenses/>. */ /* This module implements main driver of compilation process as well as few basic interprocedural optimizers. The main scope of this file is to act as an interface in between tree based frontends and the backend (and middle end) The front-end is supposed to use following functionality: - cgraph_finalize_function This function is called once front-end has parsed whole body of function and it is certain that the function body nor the declaration will change. (There is one exception needed for implementing GCC extern inline function.) - varpool_finalize_variable This function has same behavior as the above but is used for static variables. - cgraph_finalize_compilation_unit This function is called once (source level) compilation unit is finalized and it will no longer change. In the the call-graph construction and local function analysis takes place here. Bodies of unreachable functions are released to conserve memory usage. The function can be called multiple times when multiple source level compilation units are combined (such as in C frontend) - cgraph_optimize In this unit-at-a-time compilation the intra procedural analysis takes place here. In particular the static functions whose address is never taken are marked as local. Backend can then use this information to modify calling conventions, do better inlining or similar optimizations. - cgraph_mark_needed_node - varpool_mark_needed_node When function or variable is referenced by some hidden way the call-graph data structure must be updated accordingly by this function. There should be little need to call this function and all the references should be made explicit to cgraph code. At present these functions are used by C++ frontend to explicitly mark the keyed methods. - analyze_expr callback This function is responsible for lowering tree nodes not understood by generic code into understandable ones or alternatively marking callgraph and varpool nodes referenced by the as needed. ??? On the tree-ssa genericizing should take place here and we will avoid need for these hooks (replacing them by genericizing hook) Analyzing of all functions is deferred to cgraph_finalize_compilation_unit and expansion into cgraph_optimize. In cgraph_finalize_compilation_unit the reachable functions are analyzed. During analysis the call-graph edges from reachable functions are constructed and their destinations are marked as reachable. References to functions and variables are discovered too and variables found to be needed output to the assembly file. Via mark_referenced call in assemble_variable functions referenced by static variables are noticed too. The intra-procedural information is produced and its existence indicated by global_info_ready. Once this flag is set it is impossible to change function from !reachable to reachable and thus assemble_variable no longer call mark_referenced. Finally the call-graph is topologically sorted and all reachable functions that has not been completely inlined or are not external are output. ??? It is possible that reference to function or variable is optimized out. We can not deal with this nicely because topological order is not suitable for it. For tree-ssa we may consider another pass doing optimization and re-discovering reachable functions. ??? Reorganize code so variables are output very last and only if they really has been referenced by produced code, so we catch more cases where reference has been optimized out. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "tree.h" #include "rtl.h" #include "tree-flow.h" #include "tree-inline.h" #include "langhooks.h" #include "pointer-set.h" #include "toplev.h" #include "flags.h" #include "ggc.h" #include "debug.h" #include "target.h" #include "cgraph.h" #include "diagnostic.h" #include "timevar.h" #include "params.h" #include "fibheap.h" #include "c-common.h" #include "intl.h" #include "function.h" #include "ipa-prop.h" #include "gimple.h" #include "tree-iterator.h" #include "tree-pass.h" #include "output.h" static void cgraph_expand_all_functions (void); static void cgraph_mark_functions_to_output (void); static void cgraph_expand_function (struct cgraph_node *); static void cgraph_output_pending_asms (void); static FILE *cgraph_dump_file; /* A vector of FUNCTION_DECLs declared as static constructors. */ static GTY (()) VEC(tree, gc) *static_ctors; /* A vector of FUNCTION_DECLs declared as static destructors. */ static GTY (()) VEC(tree, gc) *static_dtors; /* When target does not have ctors and dtors, we call all constructor and destructor by special initialization/destruction function recognized by collect2. When we are going to build this function, collect all constructors and destructors and turn them into normal functions. */ static void record_cdtor_fn (tree fndecl) { struct cgraph_node *node; if (targetm.have_ctors_dtors || (!DECL_STATIC_CONSTRUCTOR (fndecl) && !DECL_STATIC_DESTRUCTOR (fndecl))) return; if (DECL_STATIC_CONSTRUCTOR (fndecl)) { VEC_safe_push (tree, gc, static_ctors, fndecl); DECL_STATIC_CONSTRUCTOR (fndecl) = 0; } if (DECL_STATIC_DESTRUCTOR (fndecl)) { VEC_safe_push (tree, gc, static_dtors, fndecl); DECL_STATIC_DESTRUCTOR (fndecl) = 0; } node = cgraph_node (fndecl); node->local.disregard_inline_limits = 1; cgraph_mark_reachable_node (node); } /* Define global constructors/destructor functions for the CDTORS, of which they are LEN. The CDTORS are sorted by initialization priority. If CTOR_P is true, these are constructors; otherwise, they are destructors. */ static void build_cdtor (bool ctor_p, tree *cdtors, size_t len) { size_t i; i = 0; while (i < len) { tree body; tree fn; priority_type priority; priority = 0; body = NULL_TREE; /* Find the next batch of constructors/destructors with the same initialization priority. */ do { priority_type p; fn = cdtors[i]; p = ctor_p ? DECL_INIT_PRIORITY (fn) : DECL_FINI_PRIORITY (fn); if (!body) priority = p; else if (p != priority) break; append_to_statement_list (build_function_call_expr (fn, 0), &body); ++i; } while (i < len); gcc_assert (body != NULL_TREE); /* Generate a function to call all the function of like priority. */ cgraph_build_static_cdtor (ctor_p ? 'I' : 'D', body, priority); } } /* Comparison function for qsort. P1 and P2 are actually of type "tree *" and point to static constructors. DECL_INIT_PRIORITY is used to determine the sort order. */ static int compare_ctor (const void *p1, const void *p2) { tree f1; tree f2; int priority1; int priority2; f1 = *(const tree *)p1; f2 = *(const tree *)p2; priority1 = DECL_INIT_PRIORITY (f1); priority2 = DECL_INIT_PRIORITY (f2); if (priority1 < priority2) return -1; else if (priority1 > priority2) return 1; else /* Ensure a stable sort. */ return (const tree *)p1 - (const tree *)p2; } /* Comparison function for qsort. P1 and P2 are actually of type "tree *" and point to static destructors. DECL_FINI_PRIORITY is used to determine the sort order. */ static int compare_dtor (const void *p1, const void *p2) { tree f1; tree f2; int priority1; int priority2; f1 = *(const tree *)p1; f2 = *(const tree *)p2; priority1 = DECL_FINI_PRIORITY (f1); priority2 = DECL_FINI_PRIORITY (f2); if (priority1 < priority2) return -1; else if (priority1 > priority2) return 1; else /* Ensure a stable sort. */ return (const tree *)p1 - (const tree *)p2; } /* Generate functions to call static constructors and destructors for targets that do not support .ctors/.dtors sections. These functions have magic names which are detected by collect2. */ static void cgraph_build_cdtor_fns (void) { if (!VEC_empty (tree, static_ctors)) { gcc_assert (!targetm.have_ctors_dtors); qsort (VEC_address (tree, static_ctors), VEC_length (tree, static_ctors), sizeof (tree), compare_ctor); build_cdtor (/*ctor_p=*/true, VEC_address (tree, static_ctors), VEC_length (tree, static_ctors)); VEC_truncate (tree, static_ctors, 0); } if (!VEC_empty (tree, static_dtors)) { gcc_assert (!targetm.have_ctors_dtors); qsort (VEC_address (tree, static_dtors), VEC_length (tree, static_dtors), sizeof (tree), compare_dtor); build_cdtor (/*ctor_p=*/false, VEC_address (tree, static_dtors), VEC_length (tree, static_dtors)); VEC_truncate (tree, static_dtors, 0); } } /* Determine if function DECL is needed. That is, visible to something either outside this translation unit, something magic in the system configury. */ static bool decide_is_function_needed (struct cgraph_node *node, tree decl) { if (MAIN_NAME_P (DECL_NAME (decl)) && TREE_PUBLIC (decl)) { node->local.externally_visible = true; return true; } /* If the user told us it is used, then it must be so. */ if (node->local.externally_visible) return true; /* ??? If the assembler name is set by hand, it is possible to assemble the name later after finalizing the function and the fact is noticed in assemble_name then. This is arguably a bug. */ if (DECL_ASSEMBLER_NAME_SET_P (decl) && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl))) return true; /* With -fkeep-inline-functions we are keeping all inline functions except for extern inline ones. */ if (flag_keep_inline_functions && DECL_DECLARED_INLINE_P (decl) && !DECL_EXTERNAL (decl) && !lookup_attribute ("always_inline", DECL_ATTRIBUTES (decl))) return true; /* If we decided it was needed before, but at the time we didn't have the body of the function available, then it's still needed. We have to go back and re-check its dependencies now. */ if (node->needed) return true; /* Externally visible functions must be output. The exception is COMDAT functions that must be output only when they are needed. When not optimizing, also output the static functions. (see PR24561), but don't do so for always_inline functions, functions declared inline and nested functions. These was optimized out in the original implementation and it is unclear whether we want to change the behavior here. */ if (((TREE_PUBLIC (decl) || (!optimize && !node->local.disregard_inline_limits && !DECL_DECLARED_INLINE_P (decl) && !node->origin)) && !flag_whole_program) && !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl)) return true; /* Constructors and destructors are reachable from the runtime by some mechanism. */ if (DECL_STATIC_CONSTRUCTOR (decl) || DECL_STATIC_DESTRUCTOR (decl)) return true; return false; } /* Process CGRAPH_NEW_FUNCTIONS and perform actions necessary to add these functions into callgraph in a way so they look like ordinary reachable functions inserted into callgraph already at construction time. */ bool cgraph_process_new_functions (void) { bool output = false; tree fndecl; struct cgraph_node *node; /* Note that this queue may grow as its being processed, as the new functions may generate new ones. */ while (cgraph_new_nodes) { node = cgraph_new_nodes; fndecl = node->decl; cgraph_new_nodes = cgraph_new_nodes->next_needed; switch (cgraph_state) { case CGRAPH_STATE_CONSTRUCTION: /* At construction time we just need to finalize function and move it into reachable functions list. */ node->next_needed = NULL; cgraph_finalize_function (fndecl, false); cgraph_mark_reachable_node (node); output = true; break; case CGRAPH_STATE_IPA: case CGRAPH_STATE_IPA_SSA: /* When IPA optimization already started, do all essential transformations that has been already performed on the whole cgraph but not on this function. */ gimple_register_cfg_hooks (); if (!node->analyzed) cgraph_analyze_function (node); push_cfun (DECL_STRUCT_FUNCTION (fndecl)); current_function_decl = fndecl; compute_inline_parameters (node); if ((cgraph_state == CGRAPH_STATE_IPA_SSA && !gimple_in_ssa_p (DECL_STRUCT_FUNCTION (fndecl))) /* When not optimizing, be sure we run early local passes anyway to expand OMP. */ || !optimize) execute_pass_list (pass_early_local_passes.pass.sub); free_dominance_info (CDI_POST_DOMINATORS); free_dominance_info (CDI_DOMINATORS); pop_cfun (); current_function_decl = NULL; break; case CGRAPH_STATE_EXPANSION: /* Functions created during expansion shall be compiled directly. */ node->output = 0; cgraph_expand_function (node); break; default: gcc_unreachable (); break; } cgraph_call_function_insertion_hooks (node); } return output; } /* As an GCC extension we allow redefinition of the function. The semantics when both copies of bodies differ is not well defined. We replace the old body with new body so in unit at a time mode we always use new body, while in normal mode we may end up with old body inlined into some functions and new body expanded and inlined in others. ??? It may make more sense to use one body for inlining and other body for expanding the function but this is difficult to do. */ static void cgraph_reset_node (struct cgraph_node *node) { /* If node->output is set, then we have already begun whole-unit analysis. This is *not* testing for whether we've already emitted the function. That case can be sort-of legitimately seen with real function redefinition errors. I would argue that the front end should never present us with such a case, but don't enforce that for now. */ gcc_assert (!node->output); /* Reset our data structures so we can analyze the function again. */ memset (&node->local, 0, sizeof (node->local)); memset (&node->global, 0, sizeof (node->global)); memset (&node->rtl, 0, sizeof (node->rtl)); node->analyzed = false; node->local.redefined_extern_inline = true; node->local.finalized = false; cgraph_node_remove_callees (node); /* We may need to re-queue the node for assembling in case we already proceeded it and ignored as not needed or got a re-declaration in IMA mode. */ if (node->reachable) { struct cgraph_node *n; for (n = cgraph_nodes_queue; n; n = n->next_needed) if (n == node) break; if (!n) node->reachable = 0; } } static void cgraph_lower_function (struct cgraph_node *node) { if (node->lowered) return; tree_lowering_passes (node->decl); node->lowered = true; } /* DECL has been parsed. Take it, queue it, compile it at the whim of the logic in effect. If NESTED is true, then our caller cannot stand to have the garbage collector run at the moment. We would need to either create a new GC context, or just not compile right now. */ void cgraph_finalize_function (tree decl, bool nested) { struct cgraph_node *node = cgraph_node (decl); if (node->local.finalized) cgraph_reset_node (node); node->pid = cgraph_max_pid ++; notice_global_symbol (decl); node->local.finalized = true; node->lowered = DECL_STRUCT_FUNCTION (decl)->cfg != NULL; record_cdtor_fn (node->decl); if (node->nested) lower_nested_functions (decl); gcc_assert (!node->nested); if (decide_is_function_needed (node, decl)) cgraph_mark_needed_node (node); /* Since we reclaim unreachable nodes at the end of every language level unit, we need to be conservative about possible entry points there. */ if ((TREE_PUBLIC (decl) && !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl))) cgraph_mark_reachable_node (node); /* If we've not yet emitted decl, tell the debug info about it. */ if (!TREE_ASM_WRITTEN (decl)) (*debug_hooks->deferred_inline_function) (decl); /* Possibly warn about unused parameters. */ if (warn_unused_parameter) do_warn_unused_parameter (decl); if (!nested) ggc_collect (); } /* C99 extern inline keywords allow changing of declaration after function has been finalized. We need to re-decide if we want to mark the function as needed then. */ void cgraph_mark_if_needed (tree decl) { struct cgraph_node *node = cgraph_node (decl); if (node->local.finalized && decide_is_function_needed (node, decl)) cgraph_mark_needed_node (node); } /* Verify cgraph nodes of given cgraph node. */ void verify_cgraph_node (struct cgraph_node *node) { struct cgraph_edge *e; struct cgraph_node *main_clone; struct function *this_cfun = DECL_STRUCT_FUNCTION (node->decl); struct function *saved_cfun = cfun; basic_block this_block; gimple_stmt_iterator gsi; bool error_found = false; if (errorcount || sorrycount) return; timevar_push (TV_CGRAPH_VERIFY); /* debug_generic_stmt needs correct cfun */ set_cfun (this_cfun); for (e = node->callees; e; e = e->next_callee) if (e->aux) { error ("aux field set for edge %s->%s", cgraph_node_name (e->caller), cgraph_node_name (e->callee)); error_found = true; } if (node->count < 0) { error ("Execution count is negative"); error_found = true; } for (e = node->callers; e; e = e->next_caller) { if (e->count < 0) { error ("caller edge count is negative"); error_found = true; } if (e->frequency < 0) { error ("caller edge frequency is negative"); error_found = true; } if (e->frequency > CGRAPH_FREQ_MAX) { error ("caller edge frequency is too large"); error_found = true; } if (!e->inline_failed) { if (node->global.inlined_to != (e->caller->global.inlined_to ? e->caller->global.inlined_to : e->caller)) { error ("inlined_to pointer is wrong"); error_found = true; } if (node->callers->next_caller) { error ("multiple inline callers"); error_found = true; } } else if (node->global.inlined_to) { error ("inlined_to pointer set for noninline callers"); error_found = true; } } if (!node->callers && node->global.inlined_to) { error ("inlined_to pointer is set but no predecessors found"); error_found = true; } if (node->global.inlined_to == node) { error ("inlined_to pointer refers to itself"); error_found = true; } for (main_clone = cgraph_node (node->decl); main_clone; main_clone = main_clone->next_clone) if (main_clone == node) break; if (!cgraph_node (node->decl)) { error ("node not found in cgraph_hash"); error_found = true; } if (node->analyzed && !TREE_ASM_WRITTEN (node->decl) && (!DECL_EXTERNAL (node->decl) || node->global.inlined_to)) { if (this_cfun->cfg) { /* The nodes we're interested in are never shared, so walk the tree ignoring duplicates. */ struct pointer_set_t *visited_nodes = pointer_set_create (); /* Reach the trees by walking over the CFG, and note the enclosing basic-blocks in the call edges. */ FOR_EACH_BB_FN (this_block, this_cfun) for (gsi = gsi_start_bb (this_block); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple stmt = gsi_stmt (gsi); tree decl; if (is_gimple_call (stmt) && (decl = gimple_call_fndecl (stmt))) { struct cgraph_edge *e = cgraph_edge (node, stmt); if (e) { if (e->aux) { error ("shared call_stmt:"); debug_gimple_stmt (stmt); error_found = true; } if (e->callee->decl != cgraph_node (decl)->decl && e->inline_failed) { error ("edge points to wrong declaration:"); debug_tree (e->callee->decl); fprintf (stderr," Instead of:"); debug_tree (decl); } e->aux = (void *)1; } else { error ("missing callgraph edge for call stmt:"); debug_gimple_stmt (stmt); error_found = true; } } } pointer_set_destroy (visited_nodes); } else /* No CFG available?! */ gcc_unreachable (); for (e = node->callees; e; e = e->next_callee) { if (!e->aux && !e->indirect_call) { error ("edge %s->%s has no corresponding call_stmt", cgraph_node_name (e->caller), cgraph_node_name (e->callee)); debug_gimple_stmt (e->call_stmt); error_found = true; } e->aux = 0; } } if (error_found) { dump_cgraph_node (stderr, node); internal_error ("verify_cgraph_node failed"); } set_cfun (saved_cfun); timevar_pop (TV_CGRAPH_VERIFY); } /* Verify whole cgraph structure. */ void verify_cgraph (void) { struct cgraph_node *node; if (sorrycount || errorcount) return; for (node = cgraph_nodes; node; node = node->next) verify_cgraph_node (node); } /* Output all asm statements we have stored up to be output. */ static void cgraph_output_pending_asms (void) { struct cgraph_asm_node *can; if (errorcount || sorrycount) return; for (can = cgraph_asm_nodes; can; can = can->next) assemble_asm (can->asm_str); cgraph_asm_nodes = NULL; } /* Analyze the function scheduled to be output. */ void cgraph_analyze_function (struct cgraph_node *node) { tree decl = node->decl; current_function_decl = decl; push_cfun (DECL_STRUCT_FUNCTION (decl)); cgraph_lower_function (node); node->analyzed = true; pop_cfun (); current_function_decl = NULL; } /* Look for externally_visible and used attributes and mark cgraph nodes accordingly. We cannot mark the nodes at the point the attributes are processed (in handle_*_attribute) because the copy of the declarations available at that point may not be canonical. For example, in: void f(); void f() __attribute__((used)); the declaration we see in handle_used_attribute will be the second declaration -- but the front end will subsequently merge that declaration with the original declaration and discard the second declaration. Furthermore, we can't mark these nodes in cgraph_finalize_function because: void f() {} void f() __attribute__((externally_visible)); is valid. So, we walk the nodes at the end of the translation unit, applying the attributes at that point. */ static void process_function_and_variable_attributes (struct cgraph_node *first, struct varpool_node *first_var) { struct cgraph_node *node; struct varpool_node *vnode; for (node = cgraph_nodes; node != first; node = node->next) { tree decl = node->decl; if (lookup_attribute ("used", DECL_ATTRIBUTES (decl))) { mark_decl_referenced (decl); if (node->local.finalized) cgraph_mark_needed_node (node); } if (lookup_attribute ("externally_visible", DECL_ATTRIBUTES (decl))) { if (! TREE_PUBLIC (node->decl)) warning (OPT_Wattributes, "%J%<externally_visible%> attribute have effect only on public objects", node->decl); else { if (node->local.finalized) cgraph_mark_needed_node (node); node->local.externally_visible = true; } } } for (vnode = varpool_nodes; vnode != first_var; vnode = vnode->next) { tree decl = vnode->decl; if (lookup_attribute ("used", DECL_ATTRIBUTES (decl))) { mark_decl_referenced (decl); if (vnode->finalized) varpool_mark_needed_node (vnode); } if (lookup_attribute ("externally_visible", DECL_ATTRIBUTES (decl))) { if (! TREE_PUBLIC (vnode->decl)) warning (OPT_Wattributes, "%J%<externally_visible%> attribute have effect only on public objects", vnode->decl); else { if (vnode->finalized) varpool_mark_needed_node (vnode); vnode->externally_visible = true; } } } } /* Process CGRAPH_NODES_NEEDED queue, analyze each function (and transitively each reachable functions) and build cgraph. The function can be called multiple times after inserting new nodes into beginning of queue. Just the new part of queue is re-scanned then. */ static void cgraph_analyze_functions (void) { /* Keep track of already processed nodes when called multiple times for intermodule optimization. */ static struct cgraph_node *first_analyzed; struct cgraph_node *first_processed = first_analyzed; static struct varpool_node *first_analyzed_var; struct cgraph_node *node, *next; process_function_and_variable_attributes (first_processed, first_analyzed_var); first_processed = cgraph_nodes; first_analyzed_var = varpool_nodes; varpool_analyze_pending_decls (); if (cgraph_dump_file) { fprintf (cgraph_dump_file, "Initial entry points:"); for (node = cgraph_nodes; node != first_analyzed; node = node->next) if (node->needed) fprintf (cgraph_dump_file, " %s", cgraph_node_name (node)); fprintf (cgraph_dump_file, "\n"); } cgraph_process_new_functions (); /* Propagate reachability flag and lower representation of all reachable functions. In the future, lowering will introduce new functions and new entry points on the way (by template instantiation and virtual method table generation for instance). */ while (cgraph_nodes_queue) { struct cgraph_edge *edge; tree decl = cgraph_nodes_queue->decl; node = cgraph_nodes_queue; cgraph_nodes_queue = cgraph_nodes_queue->next_needed; node->next_needed = NULL; /* ??? It is possible to create extern inline function and later using weak alias attribute to kill its body. See gcc.c-torture/compile/20011119-1.c */ if (!DECL_STRUCT_FUNCTION (decl)) { cgraph_reset_node (node); continue; } gcc_assert (!node->analyzed && node->reachable); gcc_assert (gimple_body (decl)); cgraph_analyze_function (node); for (edge = node->callees; edge; edge = edge->next_callee) if (!edge->callee->reachable) cgraph_mark_reachable_node (edge->callee); /* If decl is a clone of an abstract function, mark that abstract function so that we don't release its body. The DECL_INITIAL() of that abstract function declaration will be later needed to output debug info. */ if (DECL_ABSTRACT_ORIGIN (decl)) { struct cgraph_node *origin_node = cgraph_node (DECL_ABSTRACT_ORIGIN (decl)); origin_node->abstract_and_needed = true; } /* We finalize local static variables during constructing callgraph edges. Process their attributes too. */ process_function_and_variable_attributes (first_processed, first_analyzed_var); first_processed = cgraph_nodes; first_analyzed_var = varpool_nodes; varpool_analyze_pending_decls (); cgraph_process_new_functions (); } /* Collect entry points to the unit. */ if (cgraph_dump_file) { fprintf (cgraph_dump_file, "Unit entry points:"); for (node = cgraph_nodes; node != first_analyzed; node = node->next) if (node->needed) fprintf (cgraph_dump_file, " %s", cgraph_node_name (node)); fprintf (cgraph_dump_file, "\n\nInitial "); dump_cgraph (cgraph_dump_file); } if (cgraph_dump_file) fprintf (cgraph_dump_file, "\nReclaiming functions:"); for (node = cgraph_nodes; node != first_analyzed; node = next) { tree decl = node->decl; next = node->next; if (node->local.finalized && !gimple_has_body_p (decl)) cgraph_reset_node (node); if (!node->reachable && gimple_has_body_p (decl)) { if (cgraph_dump_file) fprintf (cgraph_dump_file, " %s", cgraph_node_name (node)); cgraph_remove_node (node); continue; } else node->next_needed = NULL; gcc_assert (!node->local.finalized || gimple_has_body_p (decl)); gcc_assert (node->analyzed == node->local.finalized); } if (cgraph_dump_file) { fprintf (cgraph_dump_file, "\n\nReclaimed "); dump_cgraph (cgraph_dump_file); } first_analyzed = cgraph_nodes; ggc_collect (); } /* Analyze the whole compilation unit once it is parsed completely. */ void cgraph_finalize_compilation_unit (void) { if (errorcount || sorrycount) return; finish_aliases_1 (); if (!quiet_flag) { fprintf (stderr, "\nAnalyzing compilation unit\n"); fflush (stderr); } timevar_push (TV_CGRAPH); cgraph_analyze_functions (); timevar_pop (TV_CGRAPH); } /* Figure out what functions we want to assemble. */ static void cgraph_mark_functions_to_output (void) { struct cgraph_node *node; for (node = cgraph_nodes; node; node = node->next) { tree decl = node->decl; struct cgraph_edge *e; gcc_assert (!node->output); for (e = node->callers; e; e = e->next_caller) if (e->inline_failed) break; /* We need to output all local functions that are used and not always inlined, as well as those that are reachable from outside the current compilation unit. */ if (node->analyzed && !node->global.inlined_to && (node->needed || (e && node->reachable)) && !TREE_ASM_WRITTEN (decl) && !DECL_EXTERNAL (decl)) node->output = 1; else { /* We should've reclaimed all functions that are not needed. */ #ifdef ENABLE_CHECKING if (!node->global.inlined_to && gimple_has_body_p (decl) && !DECL_EXTERNAL (decl)) { dump_cgraph_node (stderr, node); internal_error ("failed to reclaim unneeded function"); } #endif gcc_assert (node->global.inlined_to || !gimple_has_body_p (decl) || DECL_EXTERNAL (decl)); } } } /* Expand function specified by NODE. */ static void cgraph_expand_function (struct cgraph_node *node) { tree decl = node->decl; /* We ought to not compile any inline clones. */ gcc_assert (!node->global.inlined_to); announce_function (decl); gcc_assert (node->lowered); /* Generate RTL for the body of DECL. */ if (lang_hooks.callgraph.emit_associated_thunks) lang_hooks.callgraph.emit_associated_thunks (decl); tree_rest_of_compilation (decl); /* Make sure that BE didn't give up on compiling. */ gcc_assert (TREE_ASM_WRITTEN (decl)); current_function_decl = NULL; gcc_assert (!cgraph_preserve_function_body_p (decl)); cgraph_release_function_body (node); /* Eliminate all call edges. This is important so the GIMPLE_CALL no longer points to the dead function body. */ cgraph_node_remove_callees (node); cgraph_function_flags_ready = true; } /* Return true when CALLER_DECL should be inlined into CALLEE_DECL. */ bool cgraph_inline_p (struct cgraph_edge *e, const char **reason) { *reason = e->inline_failed; return !e->inline_failed; } /* Expand all functions that must be output. Attempt to topologically sort the nodes so function is output when all called functions are already assembled to allow data to be propagated across the callgraph. Use a stack to get smaller distance between a function and its callees (later we may choose to use a more sophisticated algorithm for function reordering; we will likely want to use subsections to make the output functions appear in top-down order). */ static void cgraph_expand_all_functions (void) { struct cgraph_node *node; struct cgraph_node **order = XCNEWVEC (struct cgraph_node *, cgraph_n_nodes); int order_pos, new_order_pos = 0; int i; order_pos = cgraph_postorder (order); gcc_assert (order_pos == cgraph_n_nodes); /* Garbage collector may remove inline clones we eliminate during optimization. So we must be sure to not reference them. */ for (i = 0; i < order_pos; i++) if (order[i]->output) order[new_order_pos++] = order[i]; for (i = new_order_pos - 1; i >= 0; i--) { node = order[i]; if (node->output) { gcc_assert (node->reachable); node->output = 0; cgraph_expand_function (node); } } cgraph_process_new_functions (); free (order); } /* This is used to sort the node types by the cgraph order number. */ struct cgraph_order_sort { enum { ORDER_UNDEFINED = 0, ORDER_FUNCTION, ORDER_VAR, ORDER_ASM } kind; union { struct cgraph_node *f; struct varpool_node *v; struct cgraph_asm_node *a; } u; }; /* Output all functions, variables, and asm statements in the order according to their order fields, which is the order in which they appeared in the file. This implements -fno-toplevel-reorder. In this mode we may output functions and variables which don't really need to be output. */ static void cgraph_output_in_order (void) { int max; size_t size; struct cgraph_order_sort *nodes; int i; struct cgraph_node *pf; struct varpool_node *pv; struct cgraph_asm_node *pa; max = cgraph_order; size = max * sizeof (struct cgraph_order_sort); nodes = (struct cgraph_order_sort *) alloca (size); memset (nodes, 0, size); varpool_analyze_pending_decls (); for (pf = cgraph_nodes; pf; pf = pf->next) { if (pf->output) { i = pf->order; gcc_assert (nodes[i].kind == ORDER_UNDEFINED); nodes[i].kind = ORDER_FUNCTION; nodes[i].u.f = pf; } } for (pv = varpool_nodes_queue; pv; pv = pv->next_needed) { i = pv->order; gcc_assert (nodes[i].kind == ORDER_UNDEFINED); nodes[i].kind = ORDER_VAR; nodes[i].u.v = pv; } for (pa = cgraph_asm_nodes; pa; pa = pa->next) { i = pa->order; gcc_assert (nodes[i].kind == ORDER_UNDEFINED); nodes[i].kind = ORDER_ASM; nodes[i].u.a = pa; } /* In toplevel reorder mode we output all statics; mark them as needed. */ for (i = 0; i < max; ++i) { if (nodes[i].kind == ORDER_VAR) { varpool_mark_needed_node (nodes[i].u.v); } } varpool_empty_needed_queue (); for (i = 0; i < max; ++i) { switch (nodes[i].kind) { case ORDER_FUNCTION: nodes[i].u.f->output = 0; cgraph_expand_function (nodes[i].u.f); break; case ORDER_VAR: varpool_assemble_decl (nodes[i].u.v); break; case ORDER_ASM: assemble_asm (nodes[i].u.a->asm_str); break; case ORDER_UNDEFINED: break; default: gcc_unreachable (); } } cgraph_asm_nodes = NULL; } /* Return true when function body of DECL still needs to be kept around for later re-use. */ bool cgraph_preserve_function_body_p (tree decl) { struct cgraph_node *node; gcc_assert (cgraph_global_info_ready); /* Look if there is any clone around. */ for (node = cgraph_node (decl); node; node = node->next_clone) if (node->global.inlined_to) return true; return false; } static void ipa_passes (void) { set_cfun (NULL); current_function_decl = NULL; gimple_register_cfg_hooks (); bitmap_obstack_initialize (NULL); execute_ipa_pass_list (all_ipa_passes); bitmap_obstack_release (NULL); } /* Perform simple optimizations based on callgraph. */ void cgraph_optimize (void) { if (errorcount || sorrycount) return; #ifdef ENABLE_CHECKING verify_cgraph (); #endif /* Call functions declared with the "constructor" or "destructor" attribute. */ cgraph_build_cdtor_fns (); /* Frontend may output common variables after the unit has been finalized. It is safe to deal with them here as they are always zero initialized. */ varpool_analyze_pending_decls (); cgraph_analyze_functions (); timevar_push (TV_CGRAPHOPT); if (pre_ipa_mem_report) { fprintf (stderr, "Memory consumption before IPA\n"); dump_memory_report (false); } if (!quiet_flag) fprintf (stderr, "Performing interprocedural optimizations\n"); cgraph_state = CGRAPH_STATE_IPA; /* Don't run the IPA passes if there was any error or sorry messages. */ if (errorcount == 0 && sorrycount == 0) ipa_passes (); /* This pass remove bodies of extern inline functions we never inlined. Do this later so other IPA passes see what is really going on. */ cgraph_remove_unreachable_nodes (false, dump_file); cgraph_global_info_ready = true; if (cgraph_dump_file) { fprintf (cgraph_dump_file, "Optimized "); dump_cgraph (cgraph_dump_file); dump_varpool (cgraph_dump_file); } if (post_ipa_mem_report) { fprintf (stderr, "Memory consumption after IPA\n"); dump_memory_report (false); } timevar_pop (TV_CGRAPHOPT); /* Output everything. */ if (!quiet_flag) fprintf (stderr, "Assembling functions:\n"); #ifdef ENABLE_CHECKING verify_cgraph (); #endif cgraph_mark_functions_to_output (); cgraph_state = CGRAPH_STATE_EXPANSION; if (!flag_toplevel_reorder) cgraph_output_in_order (); else { cgraph_output_pending_asms (); cgraph_expand_all_functions (); varpool_remove_unreferenced_decls (); varpool_assemble_pending_decls (); } cgraph_process_new_functions (); cgraph_state = CGRAPH_STATE_FINISHED; if (cgraph_dump_file) { fprintf (cgraph_dump_file, "\nFinal "); dump_cgraph (cgraph_dump_file); } #ifdef ENABLE_CHECKING verify_cgraph (); /* Double check that all inline clones are gone and that all function bodies have been released from memory. */ if (!(sorrycount || errorcount)) { struct cgraph_node *node; bool error_found = false; for (node = cgraph_nodes; node; node = node->next) if (node->analyzed && (node->global.inlined_to || gimple_has_body_p (node->decl))) { error_found = true; dump_cgraph_node (stderr, node); } if (error_found) internal_error ("nodes with unreleased memory found"); } #endif } /* Generate and emit a static constructor or destructor. WHICH must be one of 'I' (for a constructor) or 'D' (for a destructor). BODY is a STATEMENT_LIST containing GENERIC statements. PRIORITY is the initialization priority for this constructor or destructor. */ void cgraph_build_static_cdtor (char which, tree body, int priority) { static int counter = 0; char which_buf[16]; tree decl, name, resdecl; /* The priority is encoded in the constructor or destructor name. collect2 will sort the names and arrange that they are called at program startup. */ sprintf (which_buf, "%c_%.5d_%d", which, priority, counter++); name = get_file_function_name (which_buf); decl = build_decl (FUNCTION_DECL, name, build_function_type (void_type_node, void_list_node)); current_function_decl = decl; resdecl = build_decl (RESULT_DECL, NULL_TREE, void_type_node); DECL_ARTIFICIAL (resdecl) = 1; DECL_RESULT (decl) = resdecl; allocate_struct_function (decl, false); TREE_STATIC (decl) = 1; TREE_USED (decl) = 1; DECL_ARTIFICIAL (decl) = 1; DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) = 1; DECL_SAVED_TREE (decl) = body; TREE_PUBLIC (decl) = ! targetm.have_ctors_dtors; DECL_UNINLINABLE (decl) = 1; DECL_INITIAL (decl) = make_node (BLOCK); TREE_USED (DECL_INITIAL (decl)) = 1; DECL_SOURCE_LOCATION (decl) = input_location; cfun->function_end_locus = input_location; switch (which) { case 'I': DECL_STATIC_CONSTRUCTOR (decl) = 1; decl_init_priority_insert (decl, priority); break; case 'D': DECL_STATIC_DESTRUCTOR (decl) = 1; decl_fini_priority_insert (decl, priority); break; default: gcc_unreachable (); } gimplify_function_tree (decl); cgraph_add_new_function (decl, false); cgraph_mark_needed_node (cgraph_node (decl)); set_cfun (NULL); } void init_cgraph (void) { cgraph_dump_file = dump_begin (TDI_cgraph, NULL); } /* The edges representing the callers of the NEW_VERSION node were fixed by cgraph_function_versioning (), now the call_expr in their respective tree code should be updated to call the NEW_VERSION. */ static void update_call_expr (struct cgraph_node *new_version) { struct cgraph_edge *e; gcc_assert (new_version); /* Update the call expr on the edges to call the new version. */ for (e = new_version->callers; e; e = e->next_caller) { struct function *inner_function = DECL_STRUCT_FUNCTION (e->caller->decl); gimple_call_set_fndecl (e->call_stmt, new_version->decl); /* Update EH information too, just in case. */ if (!stmt_could_throw_p (e->call_stmt) && lookup_stmt_eh_region_fn (inner_function, e->call_stmt)) remove_stmt_from_eh_region_fn (inner_function, e->call_stmt); } } /* Create a new cgraph node which is the new version of OLD_VERSION node. REDIRECT_CALLERS holds the callers edges which should be redirected to point to NEW_VERSION. ALL the callees edges of OLD_VERSION are cloned to the new version node. Return the new version node. */ static struct cgraph_node * cgraph_copy_node_for_versioning (struct cgraph_node *old_version, tree new_decl, VEC(cgraph_edge_p,heap) *redirect_callers) { struct cgraph_node *new_version; struct cgraph_edge *e, *new_e; struct cgraph_edge *next_callee; unsigned i; gcc_assert (old_version); new_version = cgraph_node (new_decl); new_version->analyzed = true; new_version->local = old_version->local; new_version->global = old_version->global; new_version->rtl = new_version->rtl; new_version->reachable = true; new_version->count = old_version->count; /* Clone the old node callees. Recursive calls are also cloned. */ for (e = old_version->callees;e; e=e->next_callee) { new_e = cgraph_clone_edge (e, new_version, e->call_stmt, 0, e->frequency, e->loop_nest, true); new_e->count = e->count; } /* Fix recursive calls. If OLD_VERSION has a recursive call after the previous edge cloning, the new version will have an edge pointing to the old version, which is wrong; Redirect it to point to the new version. */ for (e = new_version->callees ; e; e = next_callee) { next_callee = e->next_callee; if (e->callee == old_version) cgraph_redirect_edge_callee (e, new_version); if (!next_callee) break; } for (i = 0; VEC_iterate (cgraph_edge_p, redirect_callers, i, e); i++) { /* Redirect calls to the old version node to point to its new version. */ cgraph_redirect_edge_callee (e, new_version); } return new_version; } /* Perform function versioning. Function versioning includes copying of the tree and a callgraph update (creating a new cgraph node and updating its callees and callers). REDIRECT_CALLERS varray includes the edges to be redirected to the new version. TREE_MAP is a mapping of tree nodes we want to replace with new ones (according to results of prior analysis). OLD_VERSION_NODE is the node that is versioned. It returns the new version's cgraph node. ARGS_TO_SKIP lists arguments to be omitted from functions */ struct cgraph_node * cgraph_function_versioning (struct cgraph_node *old_version_node, VEC(cgraph_edge_p,heap) *redirect_callers, varray_type tree_map, bitmap args_to_skip) { tree old_decl = old_version_node->decl; struct cgraph_node *new_version_node = NULL; tree new_decl; if (!tree_versionable_function_p (old_decl)) return NULL; /* Make a new FUNCTION_DECL tree node for the new version. */ if (!args_to_skip) new_decl = copy_node (old_decl); else new_decl = build_function_decl_skip_args (old_decl, args_to_skip); /* Create the new version's call-graph node. and update the edges of the new node. */ new_version_node = cgraph_copy_node_for_versioning (old_version_node, new_decl, redirect_callers); /* Copy the OLD_VERSION_NODE function tree to the new version. */ tree_function_versioning (old_decl, new_decl, tree_map, false, args_to_skip); /* Update the new version's properties. Make The new version visible only within this translation unit. Make sure that is not weak also. ??? We cannot use COMDAT linkage because there is no ABI support for this. */ DECL_EXTERNAL (new_version_node->decl) = 0; DECL_ONE_ONLY (new_version_node->decl) = 0; TREE_PUBLIC (new_version_node->decl) = 0; DECL_COMDAT (new_version_node->decl) = 0; DECL_WEAK (new_version_node->decl) = 0; DECL_VIRTUAL_P (new_version_node->decl) = 0; new_version_node->local.externally_visible = 0; new_version_node->local.local = 1; new_version_node->lowered = true; /* Update the call_expr on the edges to call the new version node. */ update_call_expr (new_version_node); cgraph_call_function_insertion_hooks (new_version_node); return new_version_node; } /* Produce separate function body for inline clones so the offline copy can be modified without affecting them. */ struct cgraph_node * save_inline_function_body (struct cgraph_node *node) { struct cgraph_node *first_clone; gcc_assert (node == cgraph_node (node->decl)); cgraph_lower_function (node); first_clone = node->next_clone; first_clone->decl = copy_node (node->decl); node->next_clone = NULL; first_clone->prev_clone = NULL; cgraph_insert_node_to_hashtable (first_clone); gcc_assert (first_clone == cgraph_node (first_clone->decl)); /* Copy the OLD_VERSION_NODE function tree to the new version. */ tree_function_versioning (node->decl, first_clone->decl, NULL, true, NULL); DECL_EXTERNAL (first_clone->decl) = 0; DECL_ONE_ONLY (first_clone->decl) = 0; TREE_PUBLIC (first_clone->decl) = 0; DECL_COMDAT (first_clone->decl) = 0; for (node = first_clone->next_clone; node; node = node->next_clone) node->decl = first_clone->decl; #ifdef ENABLE_CHECKING verify_cgraph_node (first_clone); #endif return first_clone; } #include "gt-cgraphunit.h"