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Diffstat (limited to 'gcc-4.9/gcc/cgraphunit.c')
-rw-r--r-- | gcc-4.9/gcc/cgraphunit.c | 2335 |
1 files changed, 2335 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/cgraphunit.c b/gcc-4.9/gcc/cgraphunit.c new file mode 100644 index 000000000..06283fc3f --- /dev/null +++ b/gcc-4.9/gcc/cgraphunit.c @@ -0,0 +1,2335 @@ +/* Driver of optimization process + Copyright (C) 2003-2014 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. + + The main scope of this file is to act as an interface in between + tree based frontends and the backend. + + 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_decl + + This function has same behavior as the above but is used for static + variables. + + - add_asm_node + + Insert new toplevel ASM statement + + - finalize_compilation_unit + + This function is called once (source level) compilation unit is finalized + and it will no longer change. + + The symbol table is constructed starting from the trivially needed + symbols finalized by the frontend. Functions are lowered into + GIMPLE representation and callgraph/reference lists are constructed. + Those are used to discover other necessary functions and variables. + + At the end the bodies of unreachable functions are removed. + + The function can be called multiple times when multiple source level + compilation units are combined. + + - compile + + This passes control to the back-end. Optimizations are performed and + final assembler is generated. This is done in the following way. Note + that with link time optimization the process is split into three + stages (compile time, linktime analysis and parallel linktime as + indicated bellow). + + Compile time: + + 1) Inter-procedural optimization. + (ipa_passes) + + This part is further split into: + + a) early optimizations. These are local passes executed in + the topological order on the callgraph. + + The purpose of early optimiations is to optimize away simple + things that may otherwise confuse IP analysis. Very simple + propagation across the callgraph is done i.e. to discover + functions without side effects and simple inlining is performed. + + b) early small interprocedural passes. + + Those are interprocedural passes executed only at compilation + time. These include, for example, transational memory lowering, + unreachable code removal and other simple transformations. + + c) IP analysis stage. All interprocedural passes do their + analysis. + + Interprocedural passes differ from small interprocedural + passes by their ability to operate across whole program + at linktime. Their analysis stage is performed early to + both reduce linking times and linktime memory usage by + not having to represent whole program in memory. + + d) LTO sreaming. When doing LTO, everything important gets + streamed into the object file. + + Compile time and or linktime analysis stage (WPA): + + At linktime units gets streamed back and symbol table is + merged. Function bodies are not streamed in and not + available. + e) IP propagation stage. All IP passes execute their + IP propagation. This is done based on the earlier analysis + without having function bodies at hand. + f) Ltrans streaming. When doing WHOPR LTO, the program + is partitioned and streamed into multple object files. + + Compile time and/or parallel linktime stage (ltrans) + + Each of the object files is streamed back and compiled + separately. Now the function bodies becomes available + again. + + 2) Virtual clone materialization + (cgraph_materialize_clone) + + IP passes can produce copies of existing functoins (such + as versioned clones or inline clones) without actually + manipulating their bodies by creating virtual clones in + the callgraph. At this time the virtual clones are + turned into real functions + 3) IP transformation + + All IP passes transform function bodies based on earlier + decision of the IP propagation. + + 4) late small IP passes + + Simple IP passes working within single program partition. + + 5) Expansion + (expand_all_functions) + + At this stage functions that needs to be output into + assembler are identified and compiled in topological order + 6) Output of variables and aliases + Now it is known what variable references was not optimized + out and thus all variables are output to the file. + + Note that with -fno-toplevel-reorder passes 5 and 6 + are combined together in cgraph_output_in_order. + + Finally there are functions to manipulate the callgraph from + backend. + - cgraph_add_new_function is used to add backend produced + functions introduced after the unit is finalized. + The functions are enqueue for later processing and inserted + into callgraph with cgraph_process_new_functions. + + - cgraph_function_versioning + + produces a copy of function into new one (a version) + and apply simple transformations +*/ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "tree.h" +#include "varasm.h" +#include "stor-layout.h" +#include "stringpool.h" +#include "output.h" +#include "rtl.h" +#include "basic-block.h" +#include "tree-ssa-alias.h" +#include "internal-fn.h" +#include "gimple-fold.h" +#include "gimple-expr.h" +#include "is-a.h" +#include "gimple.h" +#include "gimplify.h" +#include "gimple-iterator.h" +#include "gimplify-me.h" +#include "gimple-ssa.h" +#include "tree-cfg.h" +#include "tree-into-ssa.h" +#include "tree-ssa.h" +#include "tree-inline.h" +#include "langhooks.h" +#include "toplev.h" +#include "flags.h" +#include "debug.h" +#include "target.h" +#include "diagnostic.h" +#include "params.h" +#include "fibheap.h" +#include "intl.h" +#include "function.h" +#include "ipa-prop.h" +#include "tree-iterator.h" +#include "tree-pass.h" +#include "tree-dump.h" +#include "gimple-pretty-print.h" +#include "output.h" +#include "coverage.h" +#include "plugin.h" +#include "ipa-inline.h" +#include "ipa-utils.h" +#include "lto-streamer.h" +#include "except.h" +#include "cfgloop.h" +#include "regset.h" /* FIXME: For reg_obstack. */ +#include "context.h" +#include "pass_manager.h" +#include "tree-nested.h" +#include "gimplify.h" + +/* Queue of cgraph nodes scheduled to be added into cgraph. This is a + secondary queue used during optimization to accommodate passes that + may generate new functions that need to be optimized and expanded. */ +cgraph_node_set cgraph_new_nodes; + +static void expand_all_functions (void); +static void mark_functions_to_output (void); +static void expand_function (struct cgraph_node *); +static void analyze_function (struct cgraph_node *); +static void handle_alias_pairs (void); + +FILE *cgraph_dump_file; + +/* Linked list of cgraph asm nodes. */ +struct asm_node *asm_nodes; + +/* Last node in cgraph_asm_nodes. */ +static GTY(()) struct asm_node *asm_last_node; + +/* Used for vtable lookup in thunk adjusting. */ +static GTY (()) tree vtable_entry_type; + +/* Determine if symbol DECL is needed. That is, visible to something + either outside this translation unit, something magic in the system + configury */ +bool +decide_is_symbol_needed (symtab_node *node) +{ + tree decl = node->decl; + + /* Double check that no one output the function into assembly file + early. */ + gcc_checking_assert (!DECL_ASSEMBLER_NAME_SET_P (decl) + || !TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl))); + + if (!node->definition) + return false; + + if (DECL_EXTERNAL (decl)) + return false; + + /* If the user told us it is used, then it must be so. */ + if (node->force_output) + return true; + + /* ABI forced symbols are needed when they are external. */ + if (node->forced_by_abi && TREE_PUBLIC (decl)) + return true; + + /* Keep constructors, destructors and virtual functions. */ + if (TREE_CODE (decl) == FUNCTION_DECL + && (DECL_STATIC_CONSTRUCTOR (decl) || DECL_STATIC_DESTRUCTOR (decl))) + return true; + + /* Externally visible variables must be output. The exception is + COMDAT variables that must be output only when they are needed. */ + if (TREE_PUBLIC (decl) && !DECL_COMDAT (decl)) + return true; + + return false; +} + +/* Head and terminator of the queue of nodes to be processed while building + callgraph. */ + +static symtab_node symtab_terminator; +static symtab_node *queued_nodes = &symtab_terminator; + +/* Add NODE to queue starting at QUEUED_NODES. + The queue is linked via AUX pointers and terminated by pointer to 1. */ + +static void +enqueue_node (symtab_node *node) +{ + if (node->aux) + return; + gcc_checking_assert (queued_nodes); + node->aux = queued_nodes; + queued_nodes = node; +} + +/* 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. */ + +void +cgraph_process_new_functions (void) +{ + tree fndecl; + struct cgraph_node *node; + cgraph_node_set_iterator csi; + + if (!cgraph_new_nodes) + return; + handle_alias_pairs (); + /* Note that this queue may grow as its being processed, as the new + functions may generate new ones. */ + for (csi = csi_start (cgraph_new_nodes); !csi_end_p (csi); csi_next (&csi)) + { + node = csi_node (csi); + fndecl = node->decl; + switch (cgraph_state) + { + case CGRAPH_STATE_CONSTRUCTION: + /* At construction time we just need to finalize function and move + it into reachable functions list. */ + + cgraph_finalize_function (fndecl, false); + cgraph_call_function_insertion_hooks (node); + enqueue_node (node); + 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) + analyze_function (node); + push_cfun (DECL_STRUCT_FUNCTION (fndecl)); + if (cgraph_state == CGRAPH_STATE_IPA_SSA + && !gimple_in_ssa_p (DECL_STRUCT_FUNCTION (fndecl))) + g->get_passes ()->execute_early_local_passes (); + else if (inline_summary_vec != NULL) + compute_inline_parameters (node, true); + free_dominance_info (CDI_POST_DOMINATORS); + free_dominance_info (CDI_DOMINATORS); + pop_cfun (); + cgraph_call_function_insertion_hooks (node); + break; + + case CGRAPH_STATE_EXPANSION: + /* Functions created during expansion shall be compiled + directly. */ + node->process = 0; + cgraph_call_function_insertion_hooks (node); + expand_function (node); + break; + + default: + gcc_unreachable (); + break; + } + } + free_cgraph_node_set (cgraph_new_nodes); + cgraph_new_nodes = NULL; +} + +/* 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. */ + +void +cgraph_reset_node (struct cgraph_node *node) +{ + /* If node->process 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->process); + + /* 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->definition = false; + node->alias = false; + node->weakref = false; + node->cpp_implicit_alias = false; + + cgraph_node_remove_callees (node); + ipa_remove_all_references (&node->ref_list); +} + +/* Return true when there are references to NODE. */ + +static bool +referred_to_p (symtab_node *node) +{ + struct ipa_ref *ref; + + /* See if there are any references at all. */ + if (ipa_ref_list_referring_iterate (&node->ref_list, 0, ref)) + return true; + /* For functions check also calls. */ + cgraph_node *cn = dyn_cast <cgraph_node> (node); + if (cn && cn->callers) + return true; + return false; +} + +/* DECL has been parsed. Take it, queue it, compile it at the whim of the + logic in effect. If NO_COLLECT 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 no_collect) +{ + struct cgraph_node *node = cgraph_get_create_node (decl); + + if (node->definition) + { + /* Nested functions should only be defined once. */ + gcc_assert (!DECL_CONTEXT (decl) + || TREE_CODE (DECL_CONTEXT (decl)) != FUNCTION_DECL); + cgraph_reset_node (node); + node->local.redefined_extern_inline = true; + } + + notice_global_symbol (decl); + node->definition = true; + node->lowered = DECL_STRUCT_FUNCTION (decl)->cfg != NULL; + + /* 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) + && !DECL_DISREGARD_INLINE_LIMITS (decl)) + node->force_output = 1; + + /* 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 were optimized out + in the original implementation and it is unclear whether we want + to change the behavior here. */ + if ((!optimize + && !node->cpp_implicit_alias + && !DECL_DISREGARD_INLINE_LIMITS (decl) + && !DECL_DECLARED_INLINE_P (decl) + && !(DECL_CONTEXT (decl) + && TREE_CODE (DECL_CONTEXT (decl)) == FUNCTION_DECL)) + && !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl)) + node->force_output = 1; + + /* 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 (!no_collect) + ggc_collect (); + + if (cgraph_state == CGRAPH_STATE_CONSTRUCTION + && (decide_is_symbol_needed (node) + || referred_to_p (node))) + enqueue_node (node); +} + +/* Add the function FNDECL to the call graph. + Unlike cgraph_finalize_function, this function is intended to be used + by middle end and allows insertion of new function at arbitrary point + of compilation. The function can be either in high, low or SSA form + GIMPLE. + + The function is assumed to be reachable and have address taken (so no + API breaking optimizations are performed on it). + + Main work done by this function is to enqueue the function for later + processing to avoid need the passes to be re-entrant. */ + +void +cgraph_add_new_function (tree fndecl, bool lowered) +{ + gcc::pass_manager *passes = g->get_passes (); + struct cgraph_node *node; + switch (cgraph_state) + { + case CGRAPH_STATE_PARSING: + cgraph_finalize_function (fndecl, false); + break; + case CGRAPH_STATE_CONSTRUCTION: + /* Just enqueue function to be processed at nearest occurrence. */ + node = cgraph_create_node (fndecl); + if (lowered) + node->lowered = true; + if (!cgraph_new_nodes) + cgraph_new_nodes = cgraph_node_set_new (); + cgraph_node_set_add (cgraph_new_nodes, node); + break; + + case CGRAPH_STATE_IPA: + case CGRAPH_STATE_IPA_SSA: + case CGRAPH_STATE_EXPANSION: + /* Bring the function into finalized state and enqueue for later + analyzing and compilation. */ + node = cgraph_get_create_node (fndecl); + node->local.local = false; + node->definition = true; + node->force_output = true; + if (!lowered && cgraph_state == CGRAPH_STATE_EXPANSION) + { + push_cfun (DECL_STRUCT_FUNCTION (fndecl)); + gimple_register_cfg_hooks (); + bitmap_obstack_initialize (NULL); + execute_pass_list (passes->all_lowering_passes); + passes->execute_early_local_passes (); + bitmap_obstack_release (NULL); + pop_cfun (); + + lowered = true; + } + if (lowered) + node->lowered = true; + if (!cgraph_new_nodes) + cgraph_new_nodes = cgraph_node_set_new (); + cgraph_node_set_add (cgraph_new_nodes, node); + break; + + case CGRAPH_STATE_FINISHED: + /* At the very end of compilation we have to do all the work up + to expansion. */ + node = cgraph_create_node (fndecl); + if (lowered) + node->lowered = true; + node->definition = true; + analyze_function (node); + push_cfun (DECL_STRUCT_FUNCTION (fndecl)); + gimple_register_cfg_hooks (); + bitmap_obstack_initialize (NULL); + if (!gimple_in_ssa_p (DECL_STRUCT_FUNCTION (fndecl))) + g->get_passes ()->execute_early_local_passes (); + bitmap_obstack_release (NULL); + pop_cfun (); + expand_function (node); + break; + + default: + gcc_unreachable (); + } + + /* Set a personality if required and we already passed EH lowering. */ + if (lowered + && (function_needs_eh_personality (DECL_STRUCT_FUNCTION (fndecl)) + == eh_personality_lang)) + DECL_FUNCTION_PERSONALITY (fndecl) = lang_hooks.eh_personality (); +} + +/* Add a top-level asm statement to the list. */ + +struct asm_node * +add_asm_node (tree asm_str) +{ + struct asm_node *node; + + node = ggc_alloc_cleared_asm_node (); + node->asm_str = asm_str; + node->order = symtab_order++; + node->next = NULL; + if (asm_nodes == NULL) + asm_nodes = node; + else + asm_last_node->next = node; + asm_last_node = node; + return node; +} + +/* Output all asm statements we have stored up to be output. */ + +static void +output_asm_statements (void) +{ + struct asm_node *can; + + if (seen_error ()) + return; + + for (can = asm_nodes; can; can = can->next) + assemble_asm (can->asm_str); + asm_nodes = NULL; +} + +/* Analyze the function scheduled to be output. */ +static void +analyze_function (struct cgraph_node *node) +{ + tree decl = node->decl; + location_t saved_loc = input_location; + input_location = DECL_SOURCE_LOCATION (decl); + + if (node->thunk.thunk_p) + { + cgraph_create_edge (node, cgraph_get_node (node->thunk.alias), + NULL, 0, CGRAPH_FREQ_BASE); + if (!expand_thunk (node, false)) + { + node->thunk.alias = NULL; + node->analyzed = true; + return; + } + node->thunk.alias = NULL; + } + if (node->alias) + symtab_resolve_alias + (node, cgraph_get_node (node->alias_target)); + else if (node->dispatcher_function) + { + /* Generate the dispatcher body of multi-versioned functions. */ + struct cgraph_function_version_info *dispatcher_version_info + = get_cgraph_node_version (node); + if (dispatcher_version_info != NULL + && (dispatcher_version_info->dispatcher_resolver + == NULL_TREE)) + { + tree resolver = NULL_TREE; + gcc_assert (targetm.generate_version_dispatcher_body); + resolver = targetm.generate_version_dispatcher_body (node); + gcc_assert (resolver != NULL_TREE); + } + } + else + { + push_cfun (DECL_STRUCT_FUNCTION (decl)); + + assign_assembler_name_if_neeeded (node->decl); + + /* Make sure to gimplify bodies only once. During analyzing a + function we lower it, which will require gimplified nested + functions, so we can end up here with an already gimplified + body. */ + if (!gimple_has_body_p (decl)) + gimplify_function_tree (decl); + dump_function (TDI_generic, decl); + + /* Lower the function. */ + if (!node->lowered) + { + if (node->nested) + lower_nested_functions (node->decl); + gcc_assert (!node->nested); + + gimple_register_cfg_hooks (); + bitmap_obstack_initialize (NULL); + execute_pass_list (g->get_passes ()->all_lowering_passes); + free_dominance_info (CDI_POST_DOMINATORS); + free_dominance_info (CDI_DOMINATORS); + compact_blocks (); + bitmap_obstack_release (NULL); + node->lowered = true; + } + + pop_cfun (); + } + node->analyzed = true; + + input_location = saved_loc; +} + +/* C++ frontend produce same body aliases all over the place, even before PCH + gets streamed out. It relies on us linking the aliases with their function + in order to do the fixups, but ipa-ref is not PCH safe. Consequentely we + first produce aliases without links, but once C++ FE is sure he won't sream + PCH we build the links via this function. */ + +void +cgraph_process_same_body_aliases (void) +{ + symtab_node *node; + FOR_EACH_SYMBOL (node) + if (node->cpp_implicit_alias && !node->analyzed) + symtab_resolve_alias + (node, + TREE_CODE (node->alias_target) == VAR_DECL + ? (symtab_node *)varpool_node_for_decl (node->alias_target) + : (symtab_node *)cgraph_get_create_node (node->alias_target)); + cpp_implicit_aliases_done = true; +} + +/* Process attributes common for vars and functions. */ + +static void +process_common_attributes (tree decl) +{ + tree weakref = lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)); + + if (weakref && !lookup_attribute ("alias", DECL_ATTRIBUTES (decl))) + { + warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wattributes, + "%<weakref%> attribute should be accompanied with" + " an %<alias%> attribute"); + DECL_WEAK (decl) = 0; + DECL_ATTRIBUTES (decl) = remove_attribute ("weakref", + DECL_ATTRIBUTES (decl)); + } +} + +/* 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, + varpool_node *first_var) +{ + struct cgraph_node *node; + varpool_node *vnode; + + for (node = cgraph_first_function (); node != first; + node = cgraph_next_function (node)) + { + tree decl = node->decl; + if (DECL_PRESERVE_P (decl)) + cgraph_mark_force_output_node (node); + else if (lookup_attribute ("externally_visible", DECL_ATTRIBUTES (decl))) + { + if (! TREE_PUBLIC (node->decl)) + warning_at (DECL_SOURCE_LOCATION (node->decl), OPT_Wattributes, + "%<externally_visible%>" + " attribute have effect only on public objects"); + } + if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)) + && (node->definition && !node->alias)) + { + warning_at (DECL_SOURCE_LOCATION (node->decl), OPT_Wattributes, + "%<weakref%> attribute ignored" + " because function is defined"); + DECL_WEAK (decl) = 0; + DECL_ATTRIBUTES (decl) = remove_attribute ("weakref", + DECL_ATTRIBUTES (decl)); + } + + if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (decl)) + && !DECL_DECLARED_INLINE_P (decl) + /* redefining extern inline function makes it DECL_UNINLINABLE. */ + && !DECL_UNINLINABLE (decl)) + warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wattributes, + "always_inline function might not be inlinable"); + + process_common_attributes (decl); + } + for (vnode = varpool_first_variable (); vnode != first_var; + vnode = varpool_next_variable (vnode)) + { + tree decl = vnode->decl; + if (DECL_EXTERNAL (decl) + && DECL_INITIAL (decl)) + varpool_finalize_decl (decl); + if (DECL_PRESERVE_P (decl)) + vnode->force_output = true; + else if (lookup_attribute ("externally_visible", DECL_ATTRIBUTES (decl))) + { + if (! TREE_PUBLIC (vnode->decl)) + warning_at (DECL_SOURCE_LOCATION (vnode->decl), OPT_Wattributes, + "%<externally_visible%>" + " attribute have effect only on public objects"); + } + if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)) + && vnode->definition + && DECL_INITIAL (decl)) + { + warning_at (DECL_SOURCE_LOCATION (vnode->decl), OPT_Wattributes, + "%<weakref%> attribute ignored" + " because variable is initialized"); + DECL_WEAK (decl) = 0; + DECL_ATTRIBUTES (decl) = remove_attribute ("weakref", + DECL_ATTRIBUTES (decl)); + } + process_common_attributes (decl); + } +} + +/* Mark DECL as finalized. By finalizing the declaration, frontend instruct the + middle end to output the variable to asm file, if needed or externally + visible. */ + +void +varpool_finalize_decl (tree decl) +{ + varpool_node *node = varpool_node_for_decl (decl); + + gcc_assert (TREE_STATIC (decl) || DECL_EXTERNAL (decl)); + + if (node->definition) + return; + notice_global_symbol (decl); + node->definition = true; + if (TREE_THIS_VOLATILE (decl) || DECL_PRESERVE_P (decl) + /* Traditionally we do not eliminate static variables when not + optimizing and when not doing toplevel reoder. */ + || (!flag_toplevel_reorder && !DECL_COMDAT (node->decl) + && !DECL_ARTIFICIAL (node->decl))) + node->force_output = true; + + if (cgraph_state == CGRAPH_STATE_CONSTRUCTION + && (decide_is_symbol_needed (node) + || referred_to_p (node))) + enqueue_node (node); + if (cgraph_state >= CGRAPH_STATE_IPA_SSA) + varpool_analyze_node (node); + /* Some frontends produce various interface variables after compilation + finished. */ + if (cgraph_state == CGRAPH_STATE_FINISHED + || (!flag_toplevel_reorder && cgraph_state == CGRAPH_STATE_EXPANSION)) + varpool_assemble_decl (node); +} + +/* EDGE is an polymorphic call. Mark all possible targets as reachable + and if there is only one target, perform trivial devirtualization. + REACHABLE_CALL_TARGETS collects target lists we already walked to + avoid udplicate work. */ + +static void +walk_polymorphic_call_targets (pointer_set_t *reachable_call_targets, + struct cgraph_edge *edge) +{ + unsigned int i; + void *cache_token; + bool final; + vec <cgraph_node *>targets + = possible_polymorphic_call_targets + (edge, &final, &cache_token); + + if (!pointer_set_insert (reachable_call_targets, + cache_token)) + { + if (cgraph_dump_file) + dump_possible_polymorphic_call_targets + (cgraph_dump_file, edge); + + for (i = 0; i < targets.length (); i++) + { + /* Do not bother to mark virtual methods in anonymous namespace; + either we will find use of virtual table defining it, or it is + unused. */ + if (targets[i]->definition + && TREE_CODE + (TREE_TYPE (targets[i]->decl)) + == METHOD_TYPE + && !type_in_anonymous_namespace_p + (method_class_type + (TREE_TYPE (targets[i]->decl)))) + enqueue_node (targets[i]); + } + } + + /* Very trivial devirtualization; when the type is + final or anonymous (so we know all its derivation) + and there is only one possible virtual call target, + make the edge direct. */ + if (final) + { + if (targets.length () <= 1) + { + cgraph_node *target; + if (targets.length () == 1) + target = targets[0]; + else + target = cgraph_get_create_node + (builtin_decl_implicit (BUILT_IN_UNREACHABLE)); + + if (cgraph_dump_file) + { + fprintf (cgraph_dump_file, + "Devirtualizing call: "); + print_gimple_stmt (cgraph_dump_file, + edge->call_stmt, 0, + TDF_SLIM); + } + cgraph_make_edge_direct (edge, target); + cgraph_redirect_edge_call_stmt_to_callee (edge); + if (cgraph_dump_file) + { + fprintf (cgraph_dump_file, + "Devirtualized as: "); + print_gimple_stmt (cgraph_dump_file, + edge->call_stmt, 0, + TDF_SLIM); + } + } + } +} + + +/* Discover all functions and variables that are trivially needed, analyze + them as well as all functions and variables referred by them */ + +static void +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_handled = first_analyzed; + static varpool_node *first_analyzed_var; + varpool_node *first_handled_var = first_analyzed_var; + struct pointer_set_t *reachable_call_targets = pointer_set_create (); + + symtab_node *node; + symtab_node *next; + int i; + struct ipa_ref *ref; + bool changed = true; + location_t saved_loc = input_location; + + bitmap_obstack_initialize (NULL); + cgraph_state = CGRAPH_STATE_CONSTRUCTION; + input_location = UNKNOWN_LOCATION; + + /* Ugly, but the fixup can not happen at a time same body alias is created; + C++ FE is confused about the COMDAT groups being right. */ + if (cpp_implicit_aliases_done) + FOR_EACH_SYMBOL (node) + if (node->cpp_implicit_alias) + fixup_same_cpp_alias_visibility (node, symtab_alias_target (node)); + if (optimize && flag_devirtualize) + build_type_inheritance_graph (); + + /* Analysis adds static variables that in turn adds references to new functions. + So we need to iterate the process until it stabilize. */ + while (changed) + { + changed = false; + process_function_and_variable_attributes (first_analyzed, + first_analyzed_var); + + /* First identify the trivially needed symbols. */ + for (node = symtab_nodes; + node != first_analyzed + && node != first_analyzed_var; node = node->next) + { + if (decide_is_symbol_needed (node)) + { + enqueue_node (node); + if (!changed && cgraph_dump_file) + fprintf (cgraph_dump_file, "Trivially needed symbols:"); + changed = true; + if (cgraph_dump_file) + fprintf (cgraph_dump_file, " %s", node->asm_name ()); + if (!changed && cgraph_dump_file) + fprintf (cgraph_dump_file, "\n"); + } + if (node == first_analyzed + || node == first_analyzed_var) + break; + } + cgraph_process_new_functions (); + first_analyzed_var = varpool_first_variable (); + first_analyzed = cgraph_first_function (); + + if (changed && dump_file) + fprintf (cgraph_dump_file, "\n"); + + /* Lower representation, build callgraph edges and references for all trivially + needed symbols and all symbols referred by them. */ + while (queued_nodes != &symtab_terminator) + { + changed = true; + node = queued_nodes; + queued_nodes = (symtab_node *)queued_nodes->aux; + cgraph_node *cnode = dyn_cast <cgraph_node> (node); + if (cnode && cnode->definition) + { + struct cgraph_edge *edge; + tree decl = cnode->decl; + + /* ??? 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) + && !cnode->alias + && !cnode->thunk.thunk_p + && !cnode->dispatcher_function) + { + cgraph_reset_node (cnode); + cnode->local.redefined_extern_inline = true; + continue; + } + + if (!cnode->analyzed) + analyze_function (cnode); + + for (edge = cnode->callees; edge; edge = edge->next_callee) + if (edge->callee->definition) + enqueue_node (edge->callee); + if (optimize && flag_devirtualize) + { + struct cgraph_edge *next; + + for (edge = cnode->indirect_calls; edge; edge = next) + { + next = edge->next_callee; + if (edge->indirect_info->polymorphic) + walk_polymorphic_call_targets (reachable_call_targets, + edge); + } + } + + /* 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_get_node (DECL_ABSTRACT_ORIGIN (decl)); + origin_node->used_as_abstract_origin = true; + } + } + else + { + varpool_node *vnode = dyn_cast <varpool_node> (node); + if (vnode && vnode->definition && !vnode->analyzed) + varpool_analyze_node (vnode); + } + + if (node->same_comdat_group) + { + symtab_node *next; + for (next = node->same_comdat_group; + next != node; + next = next->same_comdat_group) + enqueue_node (next); + } + for (i = 0; ipa_ref_list_reference_iterate (&node->ref_list, i, ref); i++) + if (ref->referred->definition) + enqueue_node (ref->referred); + cgraph_process_new_functions (); + } + } + if (optimize && flag_devirtualize) + update_type_inheritance_graph (); + + /* Collect entry points to the unit. */ + if (cgraph_dump_file) + { + fprintf (cgraph_dump_file, "\n\nInitial "); + dump_symtab (cgraph_dump_file); + } + + if (cgraph_dump_file) + fprintf (cgraph_dump_file, "\nRemoving unused symbols:"); + + for (node = symtab_nodes; + node != first_handled + && node != first_handled_var; node = next) + { + next = node->next; + if (!node->aux && !referred_to_p (node)) + { + if (cgraph_dump_file) + fprintf (cgraph_dump_file, " %s", node->name ()); + symtab_remove_node (node); + continue; + } + if (cgraph_node *cnode = dyn_cast <cgraph_node> (node)) + { + tree decl = node->decl; + + if (cnode->definition && !gimple_has_body_p (decl) + && !cnode->alias + && !cnode->thunk.thunk_p) + cgraph_reset_node (cnode); + + gcc_assert (!cnode->definition || cnode->thunk.thunk_p + || cnode->alias + || gimple_has_body_p (decl)); + gcc_assert (cnode->analyzed == cnode->definition); + } + node->aux = NULL; + } + for (;node; node = node->next) + node->aux = NULL; + first_analyzed = cgraph_first_function (); + first_analyzed_var = varpool_first_variable (); + if (cgraph_dump_file) + { + fprintf (cgraph_dump_file, "\n\nReclaimed "); + dump_symtab (cgraph_dump_file); + } + bitmap_obstack_release (NULL); + pointer_set_destroy (reachable_call_targets); + ggc_collect (); + /* Initialize assembler name hash, in particular we want to trigger C++ + mangling and same body alias creation before we free DECL_ARGUMENTS + used by it. */ + if (!seen_error ()) + symtab_initialize_asm_name_hash (); + + input_location = saved_loc; +} + +/* Translate the ugly representation of aliases as alias pairs into nice + representation in callgraph. We don't handle all cases yet, + unfortunately. */ + +static void +handle_alias_pairs (void) +{ + alias_pair *p; + unsigned i; + + for (i = 0; alias_pairs && alias_pairs->iterate (i, &p);) + { + symtab_node *target_node = symtab_node_for_asm (p->target); + + /* Weakrefs with target not defined in current unit are easy to handle: + they behave just as external variables except we need to note the + alias flag to later output the weakref pseudo op into asm file. */ + if (!target_node + && lookup_attribute ("weakref", DECL_ATTRIBUTES (p->decl)) != NULL) + { + symtab_node *node = symtab_get_node (p->decl); + if (node) + { + node->alias_target = p->target; + node->weakref = true; + node->alias = true; + } + alias_pairs->unordered_remove (i); + continue; + } + else if (!target_node) + { + error ("%q+D aliased to undefined symbol %qE", p->decl, p->target); + symtab_node *node = symtab_get_node (p->decl); + if (node) + node->alias = false; + alias_pairs->unordered_remove (i); + continue; + } + + if (DECL_EXTERNAL (target_node->decl) + /* We use local aliases for C++ thunks to force the tailcall + to bind locally. This is a hack - to keep it working do + the following (which is not strictly correct). */ + && (! TREE_CODE (target_node->decl) == FUNCTION_DECL + || ! DECL_VIRTUAL_P (target_node->decl)) + && ! lookup_attribute ("weakref", DECL_ATTRIBUTES (p->decl))) + { + error ("%q+D aliased to external symbol %qE", + p->decl, p->target); + } + + if (TREE_CODE (p->decl) == FUNCTION_DECL + && target_node && is_a <cgraph_node> (target_node)) + { + struct cgraph_node *src_node = cgraph_get_node (p->decl); + if (src_node && src_node->definition) + cgraph_reset_node (src_node); + cgraph_create_function_alias (p->decl, target_node->decl); + alias_pairs->unordered_remove (i); + } + else if (TREE_CODE (p->decl) == VAR_DECL + && target_node && is_a <varpool_node> (target_node)) + { + varpool_create_variable_alias (p->decl, target_node->decl); + alias_pairs->unordered_remove (i); + } + else + { + error ("%q+D alias in between function and variable is not supported", + p->decl); + warning (0, "%q+D aliased declaration", + target_node->decl); + alias_pairs->unordered_remove (i); + } + } + vec_free (alias_pairs); +} + + +/* Figure out what functions we want to assemble. */ + +static void +mark_functions_to_output (void) +{ + struct cgraph_node *node; +#ifdef ENABLE_CHECKING + bool check_same_comdat_groups = false; + + FOR_EACH_FUNCTION (node) + gcc_assert (!node->process); +#endif + + FOR_EACH_FUNCTION (node) + { + tree decl = node->decl; + + gcc_assert (!node->process || node->same_comdat_group); + if (node->process) + continue; + + /* 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->thunk.thunk_p + && !node->alias + && !node->global.inlined_to + && !TREE_ASM_WRITTEN (decl) + && !DECL_EXTERNAL (decl)) + { + node->process = 1; + if (node->same_comdat_group) + { + struct cgraph_node *next; + for (next = cgraph (node->same_comdat_group); + next != node; + next = cgraph (next->same_comdat_group)) + if (!next->thunk.thunk_p && !next->alias + && !symtab_comdat_local_p (next)) + next->process = 1; + } + } + else if (node->same_comdat_group) + { +#ifdef ENABLE_CHECKING + check_same_comdat_groups = true; +#endif + } + else + { + /* We should've reclaimed all functions that are not needed. */ +#ifdef ENABLE_CHECKING + if (!node->global.inlined_to + && gimple_has_body_p (decl) + /* FIXME: in ltrans unit when offline copy is outside partition but inline copies + are inside partition, we can end up not removing the body since we no longer + have analyzed node pointing to it. */ + && !node->in_other_partition + && !node->alias + && !node->clones + && !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) + || node->in_other_partition + || node->clones + || DECL_ARTIFICIAL (decl) + || DECL_EXTERNAL (decl)); + + } + + } +#ifdef ENABLE_CHECKING + if (check_same_comdat_groups) + FOR_EACH_FUNCTION (node) + if (node->same_comdat_group && !node->process) + { + tree decl = node->decl; + if (!node->global.inlined_to + && gimple_has_body_p (decl) + /* FIXME: in an ltrans unit when the offline copy is outside a + partition but inline copies are inside a partition, we can + end up not removing the body since we no longer have an + analyzed node pointing to it. */ + && !node->in_other_partition + && !node->clones + && !DECL_EXTERNAL (decl)) + { + dump_cgraph_node (stderr, node); + internal_error ("failed to reclaim unneeded function in same " + "comdat group"); + } + } +#endif +} + +/* DECL is FUNCTION_DECL. Initialize datastructures so DECL is a function + in lowered gimple form. IN_SSA is true if the gimple is in SSA. + + Set current_function_decl and cfun to newly constructed empty function body. + return basic block in the function body. */ + +basic_block +init_lowered_empty_function (tree decl, bool in_ssa) +{ + basic_block bb; + + current_function_decl = decl; + allocate_struct_function (decl, false); + gimple_register_cfg_hooks (); + init_empty_tree_cfg (); + + if (in_ssa) + { + init_tree_ssa (cfun); + init_ssa_operands (cfun); + cfun->gimple_df->in_ssa_p = true; + cfun->curr_properties |= PROP_ssa; + } + + DECL_INITIAL (decl) = make_node (BLOCK); + + DECL_SAVED_TREE (decl) = error_mark_node; + cfun->curr_properties |= (PROP_gimple_lcf | PROP_gimple_leh | PROP_gimple_any + | PROP_cfg | PROP_loops); + + set_loops_for_fn (cfun, ggc_alloc_cleared_loops ()); + init_loops_structure (cfun, loops_for_fn (cfun), 1); + loops_for_fn (cfun)->state |= LOOPS_MAY_HAVE_MULTIPLE_LATCHES; + + /* Create BB for body of the function and connect it properly. */ + bb = create_basic_block (NULL, (void *) 0, ENTRY_BLOCK_PTR_FOR_FN (cfun)); + make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, EDGE_FALLTHRU); + make_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun), 0); + add_bb_to_loop (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun)->loop_father); + + return bb; +} + +/* Adjust PTR by the constant FIXED_OFFSET, and by the vtable + offset indicated by VIRTUAL_OFFSET, if that is + non-null. THIS_ADJUSTING is nonzero for a this adjusting thunk and + zero for a result adjusting thunk. */ + +static tree +thunk_adjust (gimple_stmt_iterator * bsi, + tree ptr, bool this_adjusting, + HOST_WIDE_INT fixed_offset, tree virtual_offset) +{ + gimple stmt; + tree ret; + + if (this_adjusting + && fixed_offset != 0) + { + stmt = gimple_build_assign + (ptr, fold_build_pointer_plus_hwi_loc (input_location, + ptr, + fixed_offset)); + gsi_insert_after (bsi, stmt, GSI_NEW_STMT); + } + + /* If there's a virtual offset, look up that value in the vtable and + adjust the pointer again. */ + if (virtual_offset) + { + tree vtabletmp; + tree vtabletmp2; + tree vtabletmp3; + + if (!vtable_entry_type) + { + tree vfunc_type = make_node (FUNCTION_TYPE); + TREE_TYPE (vfunc_type) = integer_type_node; + TYPE_ARG_TYPES (vfunc_type) = NULL_TREE; + layout_type (vfunc_type); + + vtable_entry_type = build_pointer_type (vfunc_type); + } + + vtabletmp = + create_tmp_reg (build_pointer_type + (build_pointer_type (vtable_entry_type)), "vptr"); + + /* The vptr is always at offset zero in the object. */ + stmt = gimple_build_assign (vtabletmp, + build1 (NOP_EXPR, TREE_TYPE (vtabletmp), + ptr)); + gsi_insert_after (bsi, stmt, GSI_NEW_STMT); + + /* Form the vtable address. */ + vtabletmp2 = create_tmp_reg (TREE_TYPE (TREE_TYPE (vtabletmp)), + "vtableaddr"); + stmt = gimple_build_assign (vtabletmp2, + build_simple_mem_ref (vtabletmp)); + gsi_insert_after (bsi, stmt, GSI_NEW_STMT); + + /* Find the entry with the vcall offset. */ + stmt = gimple_build_assign (vtabletmp2, + fold_build_pointer_plus_loc (input_location, + vtabletmp2, + virtual_offset)); + gsi_insert_after (bsi, stmt, GSI_NEW_STMT); + + /* Get the offset itself. */ + vtabletmp3 = create_tmp_reg (TREE_TYPE (TREE_TYPE (vtabletmp2)), + "vcalloffset"); + stmt = gimple_build_assign (vtabletmp3, + build_simple_mem_ref (vtabletmp2)); + gsi_insert_after (bsi, stmt, GSI_NEW_STMT); + + /* Adjust the `this' pointer. */ + ptr = fold_build_pointer_plus_loc (input_location, ptr, vtabletmp3); + ptr = force_gimple_operand_gsi (bsi, ptr, true, NULL_TREE, false, + GSI_CONTINUE_LINKING); + } + + if (!this_adjusting + && fixed_offset != 0) + /* Adjust the pointer by the constant. */ + { + tree ptrtmp; + + if (TREE_CODE (ptr) == VAR_DECL) + ptrtmp = ptr; + else + { + ptrtmp = create_tmp_reg (TREE_TYPE (ptr), "ptr"); + stmt = gimple_build_assign (ptrtmp, ptr); + gsi_insert_after (bsi, stmt, GSI_NEW_STMT); + } + ptr = fold_build_pointer_plus_hwi_loc (input_location, + ptrtmp, fixed_offset); + } + + /* Emit the statement and gimplify the adjustment expression. */ + ret = create_tmp_reg (TREE_TYPE (ptr), "adjusted_this"); + stmt = gimple_build_assign (ret, ptr); + gsi_insert_after (bsi, stmt, GSI_NEW_STMT); + + return ret; +} + +/* Expand thunk NODE to gimple if possible. + When OUTPUT_ASM_THUNK is true, also produce assembler for + thunks that are not lowered. */ + +bool +expand_thunk (struct cgraph_node *node, bool output_asm_thunks) +{ + bool this_adjusting = node->thunk.this_adjusting; + HOST_WIDE_INT fixed_offset = node->thunk.fixed_offset; + HOST_WIDE_INT virtual_value = node->thunk.virtual_value; + tree virtual_offset = NULL; + tree alias = node->callees->callee->decl; + tree thunk_fndecl = node->decl; + tree a; + + + if (this_adjusting + && targetm.asm_out.can_output_mi_thunk (thunk_fndecl, fixed_offset, + virtual_value, alias)) + { + const char *fnname; + tree fn_block; + tree restype = TREE_TYPE (TREE_TYPE (thunk_fndecl)); + + if (!output_asm_thunks) + return false; + + if (in_lto_p) + cgraph_get_body (node); + a = DECL_ARGUMENTS (thunk_fndecl); + + current_function_decl = thunk_fndecl; + + /* Ensure thunks are emitted in their correct sections. */ + resolve_unique_section (thunk_fndecl, 0, flag_function_sections); + + DECL_RESULT (thunk_fndecl) + = build_decl (DECL_SOURCE_LOCATION (thunk_fndecl), + RESULT_DECL, 0, restype); + DECL_CONTEXT (DECL_RESULT (thunk_fndecl)) = thunk_fndecl; + fnname = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (thunk_fndecl)); + + /* The back end expects DECL_INITIAL to contain a BLOCK, so we + create one. */ + fn_block = make_node (BLOCK); + BLOCK_VARS (fn_block) = a; + DECL_INITIAL (thunk_fndecl) = fn_block; + init_function_start (thunk_fndecl); + cfun->is_thunk = 1; + insn_locations_init (); + set_curr_insn_location (DECL_SOURCE_LOCATION (thunk_fndecl)); + prologue_location = curr_insn_location (); + assemble_start_function (thunk_fndecl, fnname); + + targetm.asm_out.output_mi_thunk (asm_out_file, thunk_fndecl, + fixed_offset, virtual_value, alias); + + assemble_end_function (thunk_fndecl, fnname); + insn_locations_finalize (); + init_insn_lengths (); + free_after_compilation (cfun); + set_cfun (NULL); + TREE_ASM_WRITTEN (thunk_fndecl) = 1; + node->thunk.thunk_p = false; + node->analyzed = false; + } + else + { + tree restype; + basic_block bb, then_bb, else_bb, return_bb; + gimple_stmt_iterator bsi; + int nargs = 0; + tree arg; + int i; + tree resdecl; + tree restmp = NULL; + + gimple call; + gimple ret; + + if (in_lto_p) + cgraph_get_body (node); + a = DECL_ARGUMENTS (thunk_fndecl); + + current_function_decl = thunk_fndecl; + + /* Ensure thunks are emitted in their correct sections. */ + resolve_unique_section (thunk_fndecl, 0, flag_function_sections); + + DECL_IGNORED_P (thunk_fndecl) = 1; + bitmap_obstack_initialize (NULL); + + if (node->thunk.virtual_offset_p) + virtual_offset = size_int (virtual_value); + + /* Build the return declaration for the function. */ + restype = TREE_TYPE (TREE_TYPE (thunk_fndecl)); + if (DECL_RESULT (thunk_fndecl) == NULL_TREE) + { + resdecl = build_decl (input_location, RESULT_DECL, 0, restype); + DECL_ARTIFICIAL (resdecl) = 1; + DECL_IGNORED_P (resdecl) = 1; + DECL_RESULT (thunk_fndecl) = resdecl; + DECL_CONTEXT (DECL_RESULT (thunk_fndecl)) = thunk_fndecl; + } + else + resdecl = DECL_RESULT (thunk_fndecl); + + bb = then_bb = else_bb = return_bb = init_lowered_empty_function (thunk_fndecl, true); + + bsi = gsi_start_bb (bb); + + /* Build call to the function being thunked. */ + if (!VOID_TYPE_P (restype)) + { + if (DECL_BY_REFERENCE (resdecl)) + restmp = gimple_fold_indirect_ref (resdecl); + else if (!is_gimple_reg_type (restype)) + { + restmp = resdecl; + add_local_decl (cfun, restmp); + BLOCK_VARS (DECL_INITIAL (current_function_decl)) = restmp; + } + else + restmp = create_tmp_reg (restype, "retval"); + } + + for (arg = a; arg; arg = DECL_CHAIN (arg)) + nargs++; + auto_vec<tree> vargs (nargs); + if (this_adjusting) + vargs.quick_push (thunk_adjust (&bsi, a, 1, fixed_offset, + virtual_offset)); + else if (nargs) + vargs.quick_push (a); + + if (nargs) + for (i = 1, arg = DECL_CHAIN (a); i < nargs; i++, arg = DECL_CHAIN (arg)) + { + tree tmp = arg; + if (!is_gimple_val (arg)) + { + tmp = create_tmp_reg (TYPE_MAIN_VARIANT + (TREE_TYPE (arg)), "arg"); + gimple stmt = gimple_build_assign (tmp, arg); + gsi_insert_after (&bsi, stmt, GSI_NEW_STMT); + } + vargs.quick_push (tmp); + } + call = gimple_build_call_vec (build_fold_addr_expr_loc (0, alias), vargs); + node->callees->call_stmt = call; + gimple_call_set_from_thunk (call, true); + if (restmp) + { + gimple_call_set_lhs (call, restmp); + gcc_assert (useless_type_conversion_p (TREE_TYPE (restmp), + TREE_TYPE (TREE_TYPE (alias)))); + } + gsi_insert_after (&bsi, call, GSI_NEW_STMT); + if (!(gimple_call_flags (call) & ECF_NORETURN)) + { + if (restmp && !this_adjusting + && (fixed_offset || virtual_offset)) + { + tree true_label = NULL_TREE; + + if (TREE_CODE (TREE_TYPE (restmp)) == POINTER_TYPE) + { + gimple stmt; + /* If the return type is a pointer, we need to + protect against NULL. We know there will be an + adjustment, because that's why we're emitting a + thunk. */ + then_bb = create_basic_block (NULL, (void *) 0, bb); + return_bb = create_basic_block (NULL, (void *) 0, then_bb); + else_bb = create_basic_block (NULL, (void *) 0, else_bb); + add_bb_to_loop (then_bb, bb->loop_father); + add_bb_to_loop (return_bb, bb->loop_father); + add_bb_to_loop (else_bb, bb->loop_father); + remove_edge (single_succ_edge (bb)); + true_label = gimple_block_label (then_bb); + stmt = gimple_build_cond (NE_EXPR, restmp, + build_zero_cst (TREE_TYPE (restmp)), + NULL_TREE, NULL_TREE); + gsi_insert_after (&bsi, stmt, GSI_NEW_STMT); + make_edge (bb, then_bb, EDGE_TRUE_VALUE); + make_edge (bb, else_bb, EDGE_FALSE_VALUE); + make_edge (return_bb, EXIT_BLOCK_PTR_FOR_FN (cfun), 0); + make_edge (then_bb, return_bb, EDGE_FALLTHRU); + make_edge (else_bb, return_bb, EDGE_FALLTHRU); + bsi = gsi_last_bb (then_bb); + } + + restmp = thunk_adjust (&bsi, restmp, /*this_adjusting=*/0, + fixed_offset, virtual_offset); + if (true_label) + { + gimple stmt; + bsi = gsi_last_bb (else_bb); + stmt = gimple_build_assign (restmp, + build_zero_cst (TREE_TYPE (restmp))); + gsi_insert_after (&bsi, stmt, GSI_NEW_STMT); + bsi = gsi_last_bb (return_bb); + } + } + else + gimple_call_set_tail (call, true); + + /* Build return value. */ + ret = gimple_build_return (restmp); + gsi_insert_after (&bsi, ret, GSI_NEW_STMT); + } + else + { + gimple_call_set_tail (call, true); + remove_edge (single_succ_edge (bb)); + } + + cfun->gimple_df->in_ssa_p = true; + /* FIXME: C++ FE should stop setting TREE_ASM_WRITTEN on thunks. */ + TREE_ASM_WRITTEN (thunk_fndecl) = false; + delete_unreachable_blocks (); + update_ssa (TODO_update_ssa); +#ifdef ENABLE_CHECKING + verify_flow_info (); +#endif + + /* Since we want to emit the thunk, we explicitly mark its name as + referenced. */ + node->thunk.thunk_p = false; + node->lowered = true; + bitmap_obstack_release (NULL); + } + current_function_decl = NULL; + set_cfun (NULL); + return true; +} + +/* Assemble thunks and aliases associated to NODE. */ + +static void +assemble_thunks_and_aliases (struct cgraph_node *node) +{ + struct cgraph_edge *e; + int i; + struct ipa_ref *ref; + + for (e = node->callers; e;) + if (e->caller->thunk.thunk_p) + { + struct cgraph_node *thunk = e->caller; + + e = e->next_caller; + assemble_thunks_and_aliases (thunk); + expand_thunk (thunk, true); + } + else + e = e->next_caller; + for (i = 0; ipa_ref_list_referring_iterate (&node->ref_list, + i, ref); i++) + if (ref->use == IPA_REF_ALIAS) + { + struct cgraph_node *alias = ipa_ref_referring_node (ref); + bool saved_written = TREE_ASM_WRITTEN (node->decl); + + /* Force assemble_alias to really output the alias this time instead + of buffering it in same alias pairs. */ + TREE_ASM_WRITTEN (node->decl) = 1; + do_assemble_alias (alias->decl, + DECL_ASSEMBLER_NAME (node->decl)); + assemble_thunks_and_aliases (alias); + TREE_ASM_WRITTEN (node->decl) = saved_written; + } +} + +/* Expand function specified by NODE. */ + +static void +expand_function (struct cgraph_node *node) +{ + tree decl = node->decl; + location_t saved_loc; + + /* We ought to not compile any inline clones. */ + gcc_assert (!node->global.inlined_to); + + announce_function (decl); + node->process = 0; + gcc_assert (node->lowered); + cgraph_get_body (node); + + /* Generate RTL for the body of DECL. */ + + timevar_push (TV_REST_OF_COMPILATION); + + gcc_assert (cgraph_global_info_ready); + + /* Initialize the default bitmap obstack. */ + bitmap_obstack_initialize (NULL); + + /* Initialize the RTL code for the function. */ + current_function_decl = decl; + saved_loc = input_location; + input_location = DECL_SOURCE_LOCATION (decl); + init_function_start (decl); + + gimple_register_cfg_hooks (); + + bitmap_obstack_initialize (®_obstack); /* FIXME, only at RTL generation*/ + + execute_all_ipa_transforms (); + + /* Perform all tree transforms and optimizations. */ + + /* Signal the start of passes. */ + invoke_plugin_callbacks (PLUGIN_ALL_PASSES_START, NULL); + + execute_pass_list (g->get_passes ()->all_passes); + + /* Signal the end of passes. */ + invoke_plugin_callbacks (PLUGIN_ALL_PASSES_END, NULL); + + bitmap_obstack_release (®_obstack); + + /* Release the default bitmap obstack. */ + bitmap_obstack_release (NULL); + + /* If requested, warn about function definitions where the function will + return a value (usually of some struct or union type) which itself will + take up a lot of stack space. */ + if (warn_larger_than && !DECL_EXTERNAL (decl) && TREE_TYPE (decl)) + { + tree ret_type = TREE_TYPE (TREE_TYPE (decl)); + + if (ret_type && TYPE_SIZE_UNIT (ret_type) + && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST + && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type), + larger_than_size)) + { + unsigned int size_as_int + = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type)); + + if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0) + warning (OPT_Wlarger_than_, "size of return value of %q+D is %u bytes", + decl, size_as_int); + else + warning (OPT_Wlarger_than_, "size of return value of %q+D is larger than %wd bytes", + decl, larger_than_size); + } + } + + gimple_set_body (decl, NULL); + if (DECL_STRUCT_FUNCTION (decl) == 0 + && !cgraph_get_node (decl)->origin) + { + /* Stop pointing to the local nodes about to be freed. + But DECL_INITIAL must remain nonzero so we know this + was an actual function definition. + For a nested function, this is done in c_pop_function_context. + If rest_of_compilation set this to 0, leave it 0. */ + if (DECL_INITIAL (decl) != 0) + DECL_INITIAL (decl) = error_mark_node; + } + + input_location = saved_loc; + + ggc_collect (); + timevar_pop (TV_REST_OF_COMPILATION); + + /* Make sure that BE didn't give up on compiling. */ + gcc_assert (TREE_ASM_WRITTEN (decl)); + set_cfun (NULL); + current_function_decl = NULL; + + /* It would make a lot more sense to output thunks before function body to get more + forward and lest backwarding jumps. This however would need solving problem + with comdats. See PR48668. Also aliases must come after function itself to + make one pass assemblers, like one on AIX, happy. See PR 50689. + FIXME: Perhaps thunks should be move before function IFF they are not in comdat + groups. */ + assemble_thunks_and_aliases (node); + 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); + ipa_remove_all_references (&node->ref_list); +} + +/* Node comparer that is responsible for the order that corresponds + to time when a function was launched for the first time. */ + +static int +node_cmp (const void *pa, const void *pb) +{ + const struct cgraph_node *a = *(const struct cgraph_node * const *) pa; + const struct cgraph_node *b = *(const struct cgraph_node * const *) pb; + + /* Functions with time profile must be before these without profile. */ + if (!a->tp_first_run || !b->tp_first_run) + return a->tp_first_run - b->tp_first_run; + + return a->tp_first_run != b->tp_first_run + ? b->tp_first_run - a->tp_first_run + : b->order - a->order; +} + +/* 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 +expand_all_functions (void) +{ + struct cgraph_node *node; + struct cgraph_node **order = XCNEWVEC (struct cgraph_node *, cgraph_n_nodes); + unsigned int expanded_func_count = 0, profiled_func_count = 0; + int order_pos, new_order_pos = 0; + int i; + + order_pos = ipa_reverse_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]->process) + order[new_order_pos++] = order[i]; + + if (flag_profile_reorder_functions) + qsort (order, new_order_pos, sizeof (struct cgraph_node *), node_cmp); + + for (i = new_order_pos - 1; i >= 0; i--) + { + node = order[i]; + + if (node->process) + { + expanded_func_count++; + if(node->tp_first_run) + profiled_func_count++; + + if (cgraph_dump_file) + fprintf (cgraph_dump_file, "Time profile order in expand_all_functions:%s:%d\n", node->asm_name (), node->tp_first_run); + + node->process = 0; + expand_function (node); + } + } + + if (dump_file) + fprintf (dump_file, "Expanded functions with time profile (%s):%u/%u\n", + main_input_filename, profiled_func_count, expanded_func_count); + + if (cgraph_dump_file && flag_profile_reorder_functions) + fprintf (cgraph_dump_file, "Expanded functions with time profile:%u/%u\n", + profiled_func_count, expanded_func_count); + + cgraph_process_new_functions (); + free_gimplify_stack (); + + free (order); +} + +/* This is used to sort the node types by the cgraph order number. */ + +enum cgraph_order_sort_kind +{ + ORDER_UNDEFINED = 0, + ORDER_FUNCTION, + ORDER_VAR, + ORDER_ASM +}; + +struct cgraph_order_sort +{ + enum cgraph_order_sort_kind kind; + union + { + struct cgraph_node *f; + varpool_node *v; + struct 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 +output_in_order (void) +{ + int max; + struct cgraph_order_sort *nodes; + int i; + struct cgraph_node *pf; + varpool_node *pv; + struct asm_node *pa; + + max = symtab_order; + nodes = XCNEWVEC (struct cgraph_order_sort, max); + + FOR_EACH_DEFINED_FUNCTION (pf) + { + if (pf->process && !pf->thunk.thunk_p && !pf->alias) + { + i = pf->order; + gcc_assert (nodes[i].kind == ORDER_UNDEFINED); + nodes[i].kind = ORDER_FUNCTION; + nodes[i].u.f = pf; + } + } + + FOR_EACH_DEFINED_VARIABLE (pv) + if (!DECL_EXTERNAL (pv->decl)) + { + i = pv->order; + gcc_assert (nodes[i].kind == ORDER_UNDEFINED); + nodes[i].kind = ORDER_VAR; + nodes[i].u.v = pv; + } + + for (pa = 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_finalize_named_section_flags (nodes[i].u.v); + + for (i = 0; i < max; ++i) + { + switch (nodes[i].kind) + { + case ORDER_FUNCTION: + nodes[i].u.f->process = 0; + 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 (); + } + } + + asm_nodes = NULL; + free (nodes); +} + +static void +ipa_passes (void) +{ + gcc::pass_manager *passes = g->get_passes (); + + set_cfun (NULL); + current_function_decl = NULL; + gimple_register_cfg_hooks (); + bitmap_obstack_initialize (NULL); + + invoke_plugin_callbacks (PLUGIN_ALL_IPA_PASSES_START, NULL); + + if (!in_lto_p) + { + execute_ipa_pass_list (passes->all_small_ipa_passes); + if (seen_error ()) + return; + } + + /* We never run removal of unreachable nodes after early passes. This is + because TODO is run before the subpasses. It is important to remove + the unreachable functions to save works at IPA level and to get LTO + symbol tables right. */ + symtab_remove_unreachable_nodes (true, cgraph_dump_file); + + /* If pass_all_early_optimizations was not scheduled, the state of + the cgraph will not be properly updated. Update it now. */ + if (cgraph_state < CGRAPH_STATE_IPA_SSA) + cgraph_state = CGRAPH_STATE_IPA_SSA; + + if (!in_lto_p) + { + /* Generate coverage variables and constructors. */ + coverage_finish (); + + /* Process new functions added. */ + set_cfun (NULL); + current_function_decl = NULL; + cgraph_process_new_functions (); + + execute_ipa_summary_passes + ((ipa_opt_pass_d *) passes->all_regular_ipa_passes); + } + + /* Some targets need to handle LTO assembler output specially. */ + if (flag_generate_lto) + targetm.asm_out.lto_start (); + + if (!in_lto_p) + ipa_write_summaries (); + + if (flag_generate_lto) + targetm.asm_out.lto_end (); + + if (!flag_ltrans && (in_lto_p || !flag_lto || flag_fat_lto_objects)) + execute_ipa_pass_list (passes->all_regular_ipa_passes); + invoke_plugin_callbacks (PLUGIN_ALL_IPA_PASSES_END, NULL); + + bitmap_obstack_release (NULL); +} + + +/* Return string alias is alias of. */ + +static tree +get_alias_symbol (tree decl) +{ + tree alias = lookup_attribute ("alias", DECL_ATTRIBUTES (decl)); + return get_identifier (TREE_STRING_POINTER + (TREE_VALUE (TREE_VALUE (alias)))); +} + + +/* Weakrefs may be associated to external decls and thus not output + at expansion time. Emit all necessary aliases. */ + +static void +output_weakrefs (void) +{ + symtab_node *node; + FOR_EACH_SYMBOL (node) + if (node->alias + && !TREE_ASM_WRITTEN (node->decl) + && node->weakref) + { + tree target; + + /* Weakrefs are special by not requiring target definition in current + compilation unit. It is thus bit hard to work out what we want to + alias. + When alias target is defined, we need to fetch it from symtab reference, + otherwise it is pointed to by alias_target. */ + if (node->alias_target) + target = (DECL_P (node->alias_target) + ? DECL_ASSEMBLER_NAME (node->alias_target) + : node->alias_target); + else if (node->analyzed) + target = DECL_ASSEMBLER_NAME (symtab_alias_target (node)->decl); + else + { + gcc_unreachable (); + target = get_alias_symbol (node->decl); + } + do_assemble_alias (node->decl, target); + } +} + +/* Initialize callgraph dump file. */ + +void +init_cgraph (void) +{ + if (!cgraph_dump_file) + cgraph_dump_file = dump_begin (TDI_cgraph, NULL); +} + + +/* Perform simple optimizations based on callgraph. */ + +void +compile (void) +{ + if (seen_error ()) + return; + +#ifdef ENABLE_CHECKING + verify_symtab (); +#endif + + 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; + + /* If LTO is enabled, initialize the streamer hooks needed by GIMPLE. */ + if (flag_lto) + lto_streamer_hooks_init (); + + /* Don't run the IPA passes if there was any error or sorry messages. */ + if (!seen_error ()) + ipa_passes (); + + /* Do nothing else if any IPA pass found errors or if we are just streaming LTO. */ + if (seen_error () + || (!in_lto_p && flag_lto && !flag_fat_lto_objects)) + { + timevar_pop (TV_CGRAPHOPT); + return; + } + + /* This pass remove bodies of extern inline functions we never inlined. + Do this later so other IPA passes see what is really going on. */ + symtab_remove_unreachable_nodes (false, dump_file); + cgraph_global_info_ready = true; + if (cgraph_dump_file) + { + fprintf (cgraph_dump_file, "Optimized "); + dump_symtab (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. */ + (*debug_hooks->assembly_start) (); + if (!quiet_flag) + fprintf (stderr, "Assembling functions:\n"); +#ifdef ENABLE_CHECKING + verify_symtab (); +#endif + + cgraph_materialize_all_clones (); + bitmap_obstack_initialize (NULL); + execute_ipa_pass_list (g->get_passes ()->all_late_ipa_passes); + symtab_remove_unreachable_nodes (true, dump_file); +#ifdef ENABLE_CHECKING + verify_symtab (); +#endif + bitmap_obstack_release (NULL); + mark_functions_to_output (); + + /* When weakref support is missing, we autmatically translate all + references to NODE to references to its ultimate alias target. + The renaming mechanizm uses flag IDENTIFIER_TRANSPARENT_ALIAS and + TREE_CHAIN. + + Set up this mapping before we output any assembler but once we are sure + that all symbol renaming is done. + + FIXME: All this uglyness can go away if we just do renaming at gimple + level by physically rewritting the IL. At the moment we can only redirect + calls, so we need infrastructure for renaming references as well. */ +#ifndef ASM_OUTPUT_WEAKREF + symtab_node *node; + + FOR_EACH_SYMBOL (node) + if (node->alias + && lookup_attribute ("weakref", DECL_ATTRIBUTES (node->decl))) + { + IDENTIFIER_TRANSPARENT_ALIAS + (DECL_ASSEMBLER_NAME (node->decl)) = 1; + TREE_CHAIN (DECL_ASSEMBLER_NAME (node->decl)) + = (node->alias_target ? node->alias_target + : DECL_ASSEMBLER_NAME (symtab_alias_target (node)->decl)); + } +#endif + + cgraph_state = CGRAPH_STATE_EXPANSION; + + if (!flag_toplevel_reorder) + output_in_order (); + else + { + output_asm_statements (); + + expand_all_functions (); + varpool_output_variables (); + } + + cgraph_process_new_functions (); + cgraph_state = CGRAPH_STATE_FINISHED; + output_weakrefs (); + + if (cgraph_dump_file) + { + fprintf (cgraph_dump_file, "\nFinal "); + dump_symtab (cgraph_dump_file); + } +#ifdef ENABLE_CHECKING + verify_symtab (); + /* Double check that all inline clones are gone and that all + function bodies have been released from memory. */ + if (!seen_error ()) + { + struct cgraph_node *node; + bool error_found = false; + + FOR_EACH_DEFINED_FUNCTION (node) + if (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 +} + + +/* Analyze the whole compilation unit once it is parsed completely. */ + +void +finalize_compilation_unit (void) +{ + timevar_push (TV_CGRAPH); + + /* If we're here there's no current function anymore. Some frontends + are lazy in clearing these. */ + current_function_decl = NULL; + set_cfun (NULL); + + /* Do not skip analyzing the functions if there were errors, we + miss diagnostics for following functions otherwise. */ + + /* Emit size functions we didn't inline. */ + finalize_size_functions (); + + /* Mark alias targets necessary and emit diagnostics. */ + handle_alias_pairs (); + + if (!quiet_flag) + { + fprintf (stderr, "\nAnalyzing compilation unit\n"); + fflush (stderr); + } + + if (flag_dump_passes) + dump_passes (); + + /* Gimplify and lower all functions, compute reachability and + remove unreachable nodes. */ + analyze_functions (); + + /* Mark alias targets necessary and emit diagnostics. */ + handle_alias_pairs (); + + /* Gimplify and lower thunks. */ + analyze_functions (); + + /* Finally drive the pass manager. */ + compile (); + + timevar_pop (TV_CGRAPH); +} + + +#include "gt-cgraphunit.h" |