/* LTO symbol table.
- Copyright 2009 Free Software Foundation, Inc.
+ Copyright 2009, 2010 Free Software Foundation, Inc.
Contributed by CodeSourcery, Inc.
This file is part of GCC.
#include "config.h"
#include "system.h"
#include "coretypes.h"
-#include "toplev.h"
+#include "diagnostic-core.h"
#include "tree.h"
#include "gimple.h"
-#include "ggc.h" /* lambda.h needs this */
-#include "lambda.h" /* gcd */
+#include "ggc.h"
#include "hashtab.h"
#include "plugin-api.h"
#include "lto-streamer.h"
tree id;
/* The symbol table entry, a DECL. */
tree decl;
+ /* The cgraph node if decl is a function decl. Filled in during the
+ merging process. */
+ struct cgraph_node *node;
+ /* The varpool node if decl is a variable decl. Filled in during the
+ merging process. */
+ struct varpool_node *vnode;
/* LTO file-data and symbol resolution for this decl. */
struct lto_file_decl_data * GTY((skip (""))) file_data;
enum ld_plugin_symbol_resolution resolution;
+ /* True when resolution was guessed and not read from the file. */
+ bool guessed;
/* Pointer to the next entry with the same key. Before decl merging
this links all symbols from the different TUs. After decl merging
this links merged but incompatible decls, thus all prevailing ones
param_is (struct lto_symtab_entry_def)))
htab_t lto_symtab_identifiers;
+/* Free symtab hashtable. */
+
+void
+lto_symtab_free (void)
+{
+ htab_delete (lto_symtab_identifiers);
+ lto_symtab_identifiers = NULL;
+}
+
/* Return the hash value of an lto_symtab_entry_t object pointed to by P. */
static hashval_t
{
const struct lto_symtab_entry_def *base =
(const struct lto_symtab_entry_def *) p;
- return htab_hash_string (IDENTIFIER_POINTER (base->id));
+ return IDENTIFIER_HASH_VALUE (base->id);
}
/* Return non-zero if P1 and P2 points to lto_symtab_entry_def structs
}
/* Returns non-zero if P points to an lto_symtab_entry_def struct that needs
- to be marked for GC. */
+ to be marked for GC. */
static int
lto_symtab_entry_marked_p (const void *p)
const struct lto_symtab_entry_def *base =
(const struct lto_symtab_entry_def *) p;
- /* Keep this only if the decl or the chain is marked. */
- return (ggc_marked_p (base->decl)
- || (base->next && ggc_marked_p (base->next)));
+ /* Keep this only if the common IDENTIFIER_NODE of the symtab chain
+ is marked which it will be if at least one of the DECLs in the
+ chain is marked. */
+ return ggc_marked_p (base->id);
}
/* Lazily initialize resolution hash tables. */
lto_symtab_entry_eq, NULL);
}
-static bool maybe_merge_incomplete_and_complete_type (tree, tree);
-
-/* Try to merge an incomplete type INCOMPLETE with a complete type
- COMPLETE of same kinds.
- Return true if they were merged, false otherwise. */
-
-static bool
-merge_incomplete_and_complete_type (tree incomplete, tree complete)
-{
- /* For merging array types do some extra sanity checking. */
- if (TREE_CODE (incomplete) == ARRAY_TYPE
- && !maybe_merge_incomplete_and_complete_type (TREE_TYPE (incomplete),
- TREE_TYPE (complete))
- && !gimple_types_compatible_p (TREE_TYPE (incomplete),
- TREE_TYPE (complete)))
- return false;
-
- /* ??? Ideally we would do this by means of a common canonical type, but
- that's difficult as we do not have links from the canonical type
- back to all its children. */
- gimple_force_type_merge (incomplete, complete);
-
- return true;
-}
-
-/* Try to merge a maybe complete / incomplete type pair TYPE1 and TYPE2.
- Return true if they were merged, false otherwise. */
-
-static bool
-maybe_merge_incomplete_and_complete_type (tree type1, tree type2)
-{
- bool res = false;
-
- if (TREE_CODE (type1) != TREE_CODE (type2))
- return false;
-
- if (!COMPLETE_TYPE_P (type1) && COMPLETE_TYPE_P (type2))
- res = merge_incomplete_and_complete_type (type1, type2);
- else if (COMPLETE_TYPE_P (type1) && !COMPLETE_TYPE_P (type2))
- res = merge_incomplete_and_complete_type (type2, type1);
-
- /* Recurse on pointer targets. */
- if (!res
- && POINTER_TYPE_P (type1)
- && POINTER_TYPE_P (type2))
- res = maybe_merge_incomplete_and_complete_type (TREE_TYPE (type1),
- TREE_TYPE (type2));
-
- return res;
-}
-
-/* Check if OLD_DECL and NEW_DECL are compatible. */
-
-static bool
-lto_symtab_compatible (tree old_decl, tree new_decl)
-{
- tree old_type, new_type;
-
- if (TREE_CODE (old_decl) != TREE_CODE (new_decl))
- {
- switch (TREE_CODE (new_decl))
- {
- case VAR_DECL:
- gcc_assert (TREE_CODE (old_decl) == FUNCTION_DECL);
- error_at (DECL_SOURCE_LOCATION (new_decl),
- "function %qD redeclared as variable", new_decl);
- inform (DECL_SOURCE_LOCATION (old_decl),
- "previously declared here");
- return false;
-
- case FUNCTION_DECL:
- gcc_assert (TREE_CODE (old_decl) == VAR_DECL);
- error_at (DECL_SOURCE_LOCATION (new_decl),
- "variable %qD redeclared as function", new_decl);
- inform (DECL_SOURCE_LOCATION (old_decl),
- "previously declared here");
- return false;
-
- default:
- gcc_unreachable ();
- }
- }
-
- if (TREE_CODE (new_decl) == FUNCTION_DECL)
- {
- if (!gimple_types_compatible_p (TREE_TYPE (old_decl),
- TREE_TYPE (new_decl)))
- /* If we don't have a merged type yet...sigh. The linker
- wouldn't complain if the types were mismatched, so we
- probably shouldn't either. Just use the type from
- whichever decl appears to be associated with the
- definition. If for some odd reason neither decl is, the
- older one wins. */
- (void) 0;
-
- return true;
- }
-
- /* Now we exclusively deal with VAR_DECLs. */
-
- /* Handle external declarations with incomplete type or pointed-to
- incomplete types by forcefully merging the types.
- ??? In principle all types involved in the two decls should
- be merged forcefully, for example without considering type or
- field names. */
- old_type = TREE_TYPE (old_decl);
- new_type = TREE_TYPE (new_decl);
-
- if (DECL_EXTERNAL (old_decl) || DECL_EXTERNAL (new_decl))
- maybe_merge_incomplete_and_complete_type (old_type, new_type);
- else if (POINTER_TYPE_P (old_type)
- && POINTER_TYPE_P (new_type))
- maybe_merge_incomplete_and_complete_type (TREE_TYPE (old_type),
- TREE_TYPE (new_type));
-
- /* For array types we have to accept external declarations with
- different sizes than the actual definition (164.gzip).
- ??? We could emit a warning here. */
- if (TREE_CODE (old_type) == TREE_CODE (new_type)
- && TREE_CODE (old_type) == ARRAY_TYPE
- && COMPLETE_TYPE_P (old_type)
- && COMPLETE_TYPE_P (new_type)
- && tree_int_cst_compare (TYPE_SIZE (old_type),
- TYPE_SIZE (new_type)) != 0
- && gimple_types_compatible_p (TREE_TYPE (old_type),
- TREE_TYPE (new_type)))
- {
- /* If only one is external use the type of the non-external decl.
- Else use the larger one and also adjust the decl size.
- ??? Directional merging would allow us to simply pick the
- larger one instead of rewriting it. */
- if (DECL_EXTERNAL (old_decl) ^ DECL_EXTERNAL (new_decl))
- {
- if (DECL_EXTERNAL (old_decl))
- TREE_TYPE (old_decl) = new_type;
- else if (DECL_EXTERNAL (new_decl))
- TREE_TYPE (new_decl) = old_type;
- }
- else
- {
- if (tree_int_cst_compare (TYPE_SIZE (old_type),
- TYPE_SIZE (new_type)) < 0)
- {
- TREE_TYPE (old_decl) = new_type;
- DECL_SIZE (old_decl) = DECL_SIZE (new_decl);
- DECL_SIZE_UNIT (old_decl) = DECL_SIZE_UNIT (new_decl);
- }
- else
- {
- TREE_TYPE (new_decl) = old_type;
- DECL_SIZE (new_decl) = DECL_SIZE (old_decl);
- DECL_SIZE_UNIT (new_decl) = DECL_SIZE_UNIT (old_decl);
- }
- }
- }
-
- /* We can tolerate differences in type qualification, the
- qualification of the prevailing definition will prevail. */
- old_type = TYPE_MAIN_VARIANT (TREE_TYPE (old_decl));
- new_type = TYPE_MAIN_VARIANT (TREE_TYPE (new_decl));
- if (!gimple_types_compatible_p (old_type, new_type))
- {
- if (warning_at (DECL_SOURCE_LOCATION (new_decl), 0,
- "type of %qD does not match original declaration",
- new_decl))
- inform (DECL_SOURCE_LOCATION (old_decl),
- "previously declared here");
- return false;
- }
-
- /* ??? We might want to emit a warning here if type qualification
- differences were spotted. Do not do this unconditionally though. */
-
- /* There is no point in comparing too many details of the decls here.
- The type compatibility checks or the completing of types has properly
- dealt with most issues. */
-
- /* The following should all not invoke fatal errors as in non-LTO
- mode the linker wouldn't complain either. Just emit warnings. */
-
- /* Report a warning if user-specified alignments do not match. */
- if ((DECL_USER_ALIGN (old_decl) && DECL_USER_ALIGN (new_decl))
- && DECL_ALIGN (old_decl) != DECL_ALIGN (new_decl))
- {
- warning_at (DECL_SOURCE_LOCATION (new_decl), 0,
- "alignment of %qD does not match original declaration",
- new_decl);
- inform (DECL_SOURCE_LOCATION (old_decl), "previously declared here");
- return false;
- }
-
- return true;
-}
-
/* Registers DECL with the LTO symbol table as having resolution RESOLUTION
and read from FILE_DATA. */
&& (TREE_CODE (decl) == VAR_DECL
|| TREE_CODE (decl) == FUNCTION_DECL)
&& DECL_ASSEMBLER_NAME_SET_P (decl));
- if (TREE_CODE (decl) == VAR_DECL)
- gcc_assert (!(DECL_EXTERNAL (decl) && DECL_INITIAL (decl)));
+ if (TREE_CODE (decl) == VAR_DECL
+ && DECL_INITIAL (decl))
+ gcc_assert (!DECL_EXTERNAL (decl)
+ || (TREE_STATIC (decl) && TREE_READONLY (decl)));
if (TREE_CODE (decl) == FUNCTION_DECL)
gcc_assert (!DECL_ABSTRACT (decl));
- new_entry = GGC_CNEW (struct lto_symtab_entry_def);
- new_entry->id = DECL_ASSEMBLER_NAME (decl);
+ new_entry = ggc_alloc_cleared_lto_symtab_entry_def ();
+ new_entry->id = (*targetm.asm_out.mangle_assembler_name)
+ (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)));
new_entry->decl = decl;
new_entry->resolution = resolution;
new_entry->file_data = file_data;
-
+
lto_symtab_maybe_init_hash_table ();
slot = htab_find_slot (lto_symtab_identifiers, new_entry, INSERT);
new_entry->next = (lto_symtab_entry_t) *slot;
gcc_assert (DECL_ASSEMBLER_NAME_SET_P (decl));
- e = lto_symtab_get (DECL_ASSEMBLER_NAME (decl));
+ e = lto_symtab_get ((*targetm.asm_out.mangle_assembler_name)
+ (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl))));
while (e && e->decl != decl)
e = e->next;
if (!e)
return e->resolution;
}
-/* Replace the cgraph node OLD_NODE with NEW_NODE in the cgraph, merging
+
+/* Replace the cgraph node NODE with PREVAILING_NODE in the cgraph, merging
all edges and removing the old node. */
static void
-lto_cgraph_replace_node (struct cgraph_node *old_node,
- struct cgraph_node *new_node)
+lto_cgraph_replace_node (struct cgraph_node *node,
+ struct cgraph_node *prevailing_node)
{
struct cgraph_edge *e, *next;
+ bool compatible_p;
+
+ if (cgraph_dump_file)
+ {
+ fprintf (cgraph_dump_file, "Replacing cgraph node %s/%i by %s/%i"
+ " for symbol %s\n",
+ cgraph_node_name (node), node->uid,
+ cgraph_node_name (prevailing_node),
+ prevailing_node->uid,
+ IDENTIFIER_POINTER ((*targetm.asm_out.mangle_assembler_name)
+ (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)))));
+ }
/* Merge node flags. */
- if (old_node->needed)
- cgraph_mark_needed_node (new_node);
- if (old_node->reachable)
- cgraph_mark_reachable_node (new_node);
- if (old_node->address_taken)
- cgraph_mark_address_taken_node (new_node);
+ if (node->needed)
+ cgraph_mark_needed_node (prevailing_node);
+ if (node->reachable)
+ cgraph_mark_reachable_node (prevailing_node);
+ if (node->address_taken)
+ {
+ gcc_assert (!prevailing_node->global.inlined_to);
+ cgraph_mark_address_taken_node (prevailing_node);
+ }
/* Redirect all incoming edges. */
- for (e = old_node->callers; e; e = next)
+ compatible_p
+ = types_compatible_p (TREE_TYPE (TREE_TYPE (prevailing_node->decl)),
+ TREE_TYPE (TREE_TYPE (node->decl)));
+ for (e = node->callers; e; e = next)
{
next = e->next_caller;
- cgraph_redirect_edge_callee (e, new_node);
+ cgraph_redirect_edge_callee (e, prevailing_node);
+ /* If there is a mismatch between the supposed callee return type and
+ the real one do not attempt to inline this function.
+ ??? We really need a way to match function signatures for ABI
+ compatibility and perform related promotions at inlining time. */
+ if (!compatible_p)
+ e->call_stmt_cannot_inline_p = 1;
}
+ /* Redirect incomming references. */
+ ipa_clone_refering (prevailing_node, NULL, &node->ref_list);
- /* There are not supposed to be any outgoing edges from a node we
- replace. Still this can happen for multiple instances of weak
- functions.
- ??? For now do what the old code did. Do not create edges for them. */
- for (e = old_node->callees; e; e = next)
+ /* Finally remove the replaced node. */
+ cgraph_remove_node (node);
+}
+
+/* Replace the cgraph node NODE with PREVAILING_NODE in the cgraph, merging
+ all edges and removing the old node. */
+
+static void
+lto_varpool_replace_node (struct varpool_node *vnode,
+ struct varpool_node *prevailing_node)
+{
+ /* Merge node flags. */
+ if (vnode->needed)
{
- next = e->next_callee;
- cgraph_remove_edge (e);
+ gcc_assert (!vnode->analyzed || prevailing_node->analyzed);
+ varpool_mark_needed_node (prevailing_node);
}
+ gcc_assert (!vnode->finalized || prevailing_node->finalized);
+ gcc_assert (!vnode->analyzed || prevailing_node->analyzed);
+ ipa_clone_refering (NULL, prevailing_node, &vnode->ref_list);
+
+ /* Be sure we can garbage collect the initializer. */
+ if (DECL_INITIAL (vnode->decl))
+ DECL_INITIAL (vnode->decl) = error_mark_node;
/* Finally remove the replaced node. */
- cgraph_remove_node (old_node);
+ varpool_remove_node (vnode);
}
-/* Merge two variable or function symbol table entries ENTRY1 and ENTRY2.
- Return the prevailing one or NULL if a merge is not possible. */
+/* Merge two variable or function symbol table entries PREVAILING and ENTRY.
+ Return false if the symbols are not fully compatible and a diagnostic
+ should be emitted. */
-static lto_symtab_entry_t
-lto_symtab_merge (lto_symtab_entry_t entry1, lto_symtab_entry_t entry2)
+static bool
+lto_symtab_merge (lto_symtab_entry_t prevailing, lto_symtab_entry_t entry)
{
- tree old_decl = entry1->decl;
- tree new_decl = entry2->decl;
- ld_plugin_symbol_resolution_t old_resolution = entry1->resolution;
- ld_plugin_symbol_resolution_t new_resolution = entry2->resolution;
- struct cgraph_node *old_node = NULL;
- struct cgraph_node *new_node = NULL;
-
- /* Give ODR violation errors. */
- if (new_resolution == LDPR_PREVAILING_DEF
- || new_resolution == LDPR_PREVAILING_DEF_IRONLY)
+ tree prevailing_decl = prevailing->decl;
+ tree decl = entry->decl;
+ tree prevailing_type, type;
+
+ /* Merge decl state in both directions, we may still end up using
+ the new decl. */
+ TREE_ADDRESSABLE (prevailing_decl) |= TREE_ADDRESSABLE (decl);
+ TREE_ADDRESSABLE (decl) |= TREE_ADDRESSABLE (prevailing_decl);
+
+ /* The linker may ask us to combine two incompatible symbols.
+ Detect this case and notify the caller of required diagnostics. */
+
+ if (TREE_CODE (decl) == FUNCTION_DECL)
{
- if ((old_resolution == LDPR_PREVAILING_DEF
- || old_resolution == LDPR_PREVAILING_DEF_IRONLY)
- && (old_resolution != new_resolution || flag_no_common))
+ if (!types_compatible_p (TREE_TYPE (prevailing_decl),
+ TREE_TYPE (decl)))
+ /* If we don't have a merged type yet...sigh. The linker
+ wouldn't complain if the types were mismatched, so we
+ probably shouldn't either. Just use the type from
+ whichever decl appears to be associated with the
+ definition. If for some odd reason neither decl is, the
+ older one wins. */
+ (void) 0;
+
+ return true;
+ }
+
+ /* Now we exclusively deal with VAR_DECLs. */
+
+ /* Sharing a global symbol is a strong hint that two types are
+ compatible. We could use this information to complete
+ incomplete pointed-to types more aggressively here, ignoring
+ mismatches in both field and tag names. It's difficult though
+ to guarantee that this does not have side-effects on merging
+ more compatible types from other translation units though. */
+
+ /* We can tolerate differences in type qualification, the
+ qualification of the prevailing definition will prevail.
+ ??? In principle we might want to only warn for structurally
+ incompatible types here, but unless we have protective measures
+ for TBAA in place that would hide useful information. */
+ prevailing_type = TYPE_MAIN_VARIANT (TREE_TYPE (prevailing_decl));
+ type = TYPE_MAIN_VARIANT (TREE_TYPE (decl));
+
+ if (!types_compatible_p (prevailing_type, type))
+ {
+ if (COMPLETE_TYPE_P (type))
+ return false;
+
+ /* If type is incomplete then avoid warnings in the cases
+ that TBAA handles just fine. */
+
+ if (TREE_CODE (prevailing_type) != TREE_CODE (type))
+ return false;
+
+ if (TREE_CODE (prevailing_type) == ARRAY_TYPE)
{
- error_at (DECL_SOURCE_LOCATION (new_decl),
- "%qD has already been defined", new_decl);
- inform (DECL_SOURCE_LOCATION (old_decl),
- "previously defined here");
- return NULL;
+ tree tem1 = TREE_TYPE (prevailing_type);
+ tree tem2 = TREE_TYPE (type);
+ while (TREE_CODE (tem1) == ARRAY_TYPE
+ && TREE_CODE (tem2) == ARRAY_TYPE)
+ {
+ tem1 = TREE_TYPE (tem1);
+ tem2 = TREE_TYPE (tem2);
+ }
+
+ if (TREE_CODE (tem1) != TREE_CODE (tem2))
+ return false;
+
+ if (!types_compatible_p (tem1, tem2))
+ return false;
}
+
+ /* Fallthru. Compatible enough. */
}
- /* The linker may ask us to combine two incompatible symbols. */
- if (!lto_symtab_compatible (old_decl, new_decl))
- return NULL;
+ /* ??? We might want to emit a warning here if type qualification
+ differences were spotted. Do not do this unconditionally though. */
- if (TREE_CODE (old_decl) == FUNCTION_DECL)
- old_node = cgraph_get_node (old_decl);
- if (TREE_CODE (new_decl) == FUNCTION_DECL)
- new_node = cgraph_get_node (new_decl);
+ /* There is no point in comparing too many details of the decls here.
+ The type compatibility checks or the completing of types has properly
+ dealt with most issues. */
- /* Merge decl state in both directions, we may still end up using
- the new decl. */
- TREE_ADDRESSABLE (old_decl) |= TREE_ADDRESSABLE (new_decl);
- TREE_ADDRESSABLE (new_decl) |= TREE_ADDRESSABLE (old_decl);
+ /* The following should all not invoke fatal errors as in non-LTO
+ mode the linker wouldn't complain either. Just emit warnings. */
+
+ /* Report a warning if user-specified alignments do not match. */
+ if ((DECL_USER_ALIGN (prevailing_decl) && DECL_USER_ALIGN (decl))
+ && DECL_ALIGN (prevailing_decl) < DECL_ALIGN (decl))
+ return false;
+
+ return true;
+}
- gcc_assert (new_resolution != LDPR_UNKNOWN
- && new_resolution != LDPR_UNDEF
- && old_resolution != LDPR_UNKNOWN
- && old_resolution != LDPR_UNDEF);
+/* Return true if the symtab entry E can be replaced by another symtab
+ entry. */
- if (new_resolution == LDPR_PREVAILING_DEF
- || new_resolution == LDPR_PREVAILING_DEF_IRONLY
- || (!old_node && new_node))
+static bool
+lto_symtab_resolve_replaceable_p (lto_symtab_entry_t e)
+{
+ if (DECL_EXTERNAL (e->decl)
+ || DECL_COMDAT (e->decl)
+ || DECL_ONE_ONLY (e->decl)
+ || DECL_WEAK (e->decl))
+ return true;
+
+ if (TREE_CODE (e->decl) == VAR_DECL)
+ return (DECL_COMMON (e->decl)
+ || (!flag_no_common && !DECL_INITIAL (e->decl)));
+
+ return false;
+}
+
+/* Return true if the symtab entry E can be the prevailing one. */
+
+static bool
+lto_symtab_resolve_can_prevail_p (lto_symtab_entry_t e)
+{
+ /* The C++ frontend ends up neither setting TREE_STATIC nor
+ DECL_EXTERNAL on virtual methods but only TREE_PUBLIC.
+ So do not reject !TREE_STATIC here but only DECL_EXTERNAL. */
+ if (DECL_EXTERNAL (e->decl))
+ return false;
+
+ /* For functions we need a non-discarded body. */
+ if (TREE_CODE (e->decl) == FUNCTION_DECL)
+ return (e->node && e->node->analyzed);
+
+ else if (TREE_CODE (e->decl) == VAR_DECL)
{
- gcc_assert ((!old_node && new_node)
- || old_resolution == LDPR_PREEMPTED_IR
- || old_resolution == LDPR_RESOLVED_IR
- || (old_resolution == new_resolution && !flag_no_common));
- if (old_node)
- lto_cgraph_replace_node (old_node, new_node);
- /* Choose new_decl, entry2. */
- return entry2;
+ if (!e->vnode)
+ return false;
+ return e->vnode->finalized;
}
- if (new_resolution == LDPR_PREEMPTED_REG
- || new_resolution == LDPR_RESOLVED_EXEC
- || new_resolution == LDPR_RESOLVED_DYN)
- gcc_assert (old_resolution == LDPR_PREEMPTED_REG
- || old_resolution == LDPR_RESOLVED_EXEC
- || old_resolution == LDPR_RESOLVED_DYN);
-
- if (new_resolution == LDPR_PREEMPTED_IR
- || new_resolution == LDPR_RESOLVED_IR)
- gcc_assert (old_resolution == LDPR_PREVAILING_DEF
- || old_resolution == LDPR_PREVAILING_DEF_IRONLY
- || old_resolution == LDPR_PREEMPTED_IR
- || old_resolution == LDPR_RESOLVED_IR);
-
- if (new_node)
- lto_cgraph_replace_node (new_node, old_node);
-
- /* Choose old_decl, entry1. */
- return entry1;
+ gcc_unreachable ();
}
/* Resolve the symbol with the candidates in the chain *SLOT and store
static void
lto_symtab_resolve_symbols (void **slot)
{
- lto_symtab_entry_t e = (lto_symtab_entry_t) *slot;
+ lto_symtab_entry_t e;
+ lto_symtab_entry_t prevailing = NULL;
- /* If the chain is already resolved there is nothing to do. */
- if (e->resolution != LDPR_UNKNOWN)
+ /* Always set e->node so that edges are updated to reflect decl merging. */
+ for (e = (lto_symtab_entry_t) *slot; e; e = e->next)
+ {
+ if (TREE_CODE (e->decl) == FUNCTION_DECL)
+ e->node = cgraph_get_node (e->decl);
+ else if (TREE_CODE (e->decl) == VAR_DECL)
+ e->vnode = varpool_get_node (e->decl);
+ if (e->resolution == LDPR_PREVAILING_DEF_IRONLY
+ || e->resolution == LDPR_PREVAILING_DEF_IRONLY_EXP
+ || e->resolution == LDPR_PREVAILING_DEF)
+ prevailing = e;
+ }
+
+ /* If the chain is already resolved there is nothing else to do. */
+ if (prevailing)
return;
- /* This is a poor mans resolver. */
- for (; e; e = e->next)
+ /* Find the single non-replaceable prevailing symbol and
+ diagnose ODR violations. */
+ for (e = (lto_symtab_entry_t) *slot; e; e = e->next)
{
- gcc_assert (e->resolution == LDPR_UNKNOWN);
- if (DECL_EXTERNAL (e->decl)
- || (TREE_CODE (e->decl) == FUNCTION_DECL
- && !cgraph_get_node (e->decl)))
- e->resolution = LDPR_RESOLVED_IR;
- else
+ if (!lto_symtab_resolve_can_prevail_p (e))
+ {
+ e->resolution = LDPR_RESOLVED_IR;
+ e->guessed = true;
+ continue;
+ }
+
+ /* Set a default resolution - the final prevailing one will get
+ adjusted later. */
+ e->resolution = LDPR_PREEMPTED_IR;
+ e->guessed = true;
+ if (!lto_symtab_resolve_replaceable_p (e))
{
- if (TREE_READONLY (e->decl))
- e->resolution = LDPR_PREVAILING_DEF_IRONLY;
- else
- e->resolution = LDPR_PREVAILING_DEF;
+ if (prevailing)
+ {
+ error_at (DECL_SOURCE_LOCATION (e->decl),
+ "%qD has already been defined", e->decl);
+ inform (DECL_SOURCE_LOCATION (prevailing->decl),
+ "previously defined here");
+ }
+ prevailing = e;
}
}
-}
+ if (prevailing)
+ goto found;
-/* Merge one symbol table chain to a (set of) prevailing decls. */
+ /* Do a second round choosing one from the replaceable prevailing decls. */
+ for (e = (lto_symtab_entry_t) *slot; e; e = e->next)
+ {
+ if (e->resolution != LDPR_PREEMPTED_IR)
+ continue;
-static void
-lto_symtab_merge_decls_2 (void **slot)
-{
- lto_symtab_entry_t e2, e1;
+ /* Choose the first function that can prevail as prevailing. */
+ if (TREE_CODE (e->decl) == FUNCTION_DECL)
+ {
+ prevailing = e;
+ break;
+ }
- /* Nothing to do for a single entry. */
- e1 = (lto_symtab_entry_t) *slot;
- if (!e1->next)
+ /* From variables that can prevail choose the largest one. */
+ if (!prevailing
+ || tree_int_cst_lt (DECL_SIZE (prevailing->decl),
+ DECL_SIZE (e->decl)))
+ prevailing = e;
+ }
+
+ if (!prevailing)
return;
- /* Try to merge each entry with each other entry. In case of a
- single prevailing decl this is linear. */
-restart:
- for (; e1; e1 = e1->next)
- for (e2 = e1->next; e2; e2 = e2->next)
- {
- lto_symtab_entry_t prevailing = lto_symtab_merge (e1, e2);
- if (prevailing == e1)
- {
- lto_symtab_entry_t tmp = prevailing;
- while (tmp->next != e2)
- tmp = tmp->next;
- tmp->next = e2->next;
- e2->next = NULL;
- e2 = tmp;
- }
- else if (prevailing == e2)
- {
- lto_symtab_entry_t tmp = (lto_symtab_entry_t) *slot;
- if (tmp == e1)
- {
- *slot = e1->next;
- tmp = e1->next;
- }
- else
- {
- while (tmp->next != e1)
- tmp = tmp->next;
- tmp->next = e1->next;
- }
- e1->next = NULL;
- e1 = tmp;
- goto restart;
- }
- }
+found:
+ /* If current lto files represent the whole program,
+ it is correct to use LDPR_PREVALING_DEF_IRONLY.
+ If current lto files are part of whole program, internal
+ resolver doesn't know if it is LDPR_PREVAILING_DEF
+ or LDPR_PREVAILING_DEF_IRONLY. Use IRONLY conforms to
+ using -fwhole-program. Otherwise, it doesn't
+ matter using either LDPR_PREVAILING_DEF or
+ LDPR_PREVAILING_DEF_IRONLY
+
+ FIXME: above workaround due to gold plugin makes some
+ variables IRONLY, which are indeed PREVAILING_DEF in
+ resolution file. These variables still need manual
+ externally_visible attribute. */
+ prevailing->resolution = LDPR_PREVAILING_DEF_IRONLY;
+ prevailing->guessed = true;
}
-/* Fixup the chain of prevailing variable decls *SLOT that are commonized
- during link-time. */
+/* Merge all decls in the symbol table chain to the prevailing decl and
+ issue diagnostics about type mismatches. If DIAGNOSED_P is true
+ do not issue further diagnostics.*/
static void
-lto_symtab_fixup_var_decls (void **slot)
+lto_symtab_merge_decls_2 (void **slot, bool diagnosed_p)
{
- lto_symtab_entry_t e = (lto_symtab_entry_t) *slot;
- tree size = bitsize_zero_node;
-
- /* Find the largest prevailing decl and move it to the front of the chain.
- This is the decl we will output as representative for the common
- section. */
- size = bitsize_zero_node;
- if (e->resolution == LDPR_PREVAILING_DEF_IRONLY
- || e->resolution == LDPR_PREVAILING_DEF)
- size = DECL_SIZE (e->decl);
- for (; e->next;)
+ lto_symtab_entry_t prevailing, e;
+ VEC(tree, heap) *mismatches = NULL;
+ unsigned i;
+ tree decl;
+
+ /* Nothing to do for a single entry. */
+ prevailing = (lto_symtab_entry_t) *slot;
+ if (!prevailing->next)
+ return;
+
+ /* Try to merge each entry with the prevailing one. */
+ for (e = prevailing->next; e; e = e->next)
{
- lto_symtab_entry_t next = e->next;
- if ((next->resolution == LDPR_PREVAILING_DEF_IRONLY
- || next->resolution == LDPR_PREVAILING_DEF)
- && tree_int_cst_lt (size, DECL_SIZE (next->decl)))
+ if (!lto_symtab_merge (prevailing, e)
+ && !diagnosed_p)
+ VEC_safe_push (tree, heap, mismatches, e->decl);
+ }
+ if (VEC_empty (tree, mismatches))
+ return;
+
+ /* Diagnose all mismatched re-declarations. */
+ FOR_EACH_VEC_ELT (tree, mismatches, i, decl)
+ {
+ if (!types_compatible_p (TREE_TYPE (prevailing->decl), TREE_TYPE (decl)))
+ diagnosed_p |= warning_at (DECL_SOURCE_LOCATION (decl), 0,
+ "type of %qD does not match original "
+ "declaration", decl);
+
+ else if ((DECL_USER_ALIGN (prevailing->decl) && DECL_USER_ALIGN (decl))
+ && DECL_ALIGN (prevailing->decl) < DECL_ALIGN (decl))
{
- size = DECL_SIZE (next->decl);
- e->next = next->next;
- next->next = (lto_symtab_entry_t) *slot;
- *slot = next;
+ diagnosed_p |= warning_at (DECL_SOURCE_LOCATION (decl), 0,
+ "alignment of %qD is bigger than "
+ "original declaration", decl);
}
- else
- e = next;
}
+ if (diagnosed_p)
+ inform (DECL_SOURCE_LOCATION (prevailing->decl),
+ "previously declared here");
- /* Mark everything apart from the first var as written out. */
- e = (lto_symtab_entry_t) *slot;
- for (e = e->next; e; e = e->next)
- TREE_ASM_WRITTEN (e->decl) = true;
+ VEC_free (tree, heap, mismatches);
}
/* Helper to process the decl chain for the symbol table entry *SLOT. */
static int
lto_symtab_merge_decls_1 (void **slot, void *data ATTRIBUTE_UNUSED)
{
- lto_symtab_entry_t e;
+ lto_symtab_entry_t e, prevailing;
+ bool diagnosed_p = false;
- /* Compute the symbol resolutions. */
+ /* Compute the symbol resolutions. This is a no-op when using the
+ linker plugin. */
lto_symtab_resolve_symbols (slot);
- /* Register and adjust types of the entries. */
- for (e = (lto_symtab_entry_t) *slot; e; e = e->next)
- TREE_TYPE (e->decl) = gimple_register_type (TREE_TYPE (e->decl));
+ /* Find the prevailing decl. */
+ for (prevailing = (lto_symtab_entry_t) *slot;
+ prevailing
+ && prevailing->resolution != LDPR_PREVAILING_DEF_IRONLY
+ && prevailing->resolution != LDPR_PREVAILING_DEF_IRONLY_EXP
+ && prevailing->resolution != LDPR_PREVAILING_DEF;
+ prevailing = prevailing->next)
+ ;
+
+ /* Assert it's the only one. */
+ if (prevailing)
+ for (e = prevailing->next; e; e = e->next)
+ {
+ if (e->resolution == LDPR_PREVAILING_DEF_IRONLY
+ || e->resolution == LDPR_PREVAILING_DEF_IRONLY_EXP
+ || e->resolution == LDPR_PREVAILING_DEF)
+ fatal_error ("multiple prevailing defs for %qE",
+ DECL_NAME (prevailing->decl));
+ }
- /* Merge the chain to a (hopefully) single prevailing decl. */
- lto_symtab_merge_decls_2 (slot);
+ /* If there's not a prevailing symbol yet it's an external reference.
+ Happens a lot during ltrans. Choose the first symbol with a
+ cgraph or a varpool node. */
+ if (!prevailing)
+ {
+ prevailing = (lto_symtab_entry_t) *slot;
+ /* For functions choose one with a cgraph node. */
+ if (TREE_CODE (prevailing->decl) == FUNCTION_DECL)
+ while (!prevailing->node
+ && prevailing->next)
+ prevailing = prevailing->next;
+ /* For variables chose with a priority variant with vnode
+ attached (i.e. from unit where external declaration of
+ variable is actually used).
+ When there are multiple variants, chose one with size.
+ This is needed for C++ typeinfos, for example in
+ lto/20081204-1 there are typeifos in both units, just
+ one of them do have size. */
+ if (TREE_CODE (prevailing->decl) == VAR_DECL)
+ {
+ for (e = prevailing->next; e; e = e->next)
+ if ((!prevailing->vnode && e->vnode)
+ || ((prevailing->vnode != NULL) == (e->vnode != NULL)
+ && !COMPLETE_TYPE_P (TREE_TYPE (prevailing->decl))
+ && COMPLETE_TYPE_P (TREE_TYPE (e->decl))))
+ prevailing = e;
+ }
+ }
- /* ??? Ideally we should delay all diagnostics until this point to
- avoid duplicates. */
+ /* Move it first in the list. */
+ if ((lto_symtab_entry_t) *slot != prevailing)
+ {
+ for (e = (lto_symtab_entry_t) *slot; e->next != prevailing; e = e->next)
+ ;
+ e->next = prevailing->next;
+ prevailing->next = (lto_symtab_entry_t) *slot;
+ *slot = (void *) prevailing;
+ }
- /* All done for FUNCTION_DECLs. */
- e = (lto_symtab_entry_t) *slot;
- if (TREE_CODE (e->decl) == FUNCTION_DECL)
- return 1;
+ /* Record the prevailing variable. */
+ if (TREE_CODE (prevailing->decl) == VAR_DECL)
+ VEC_safe_push (tree, gc, lto_global_var_decls, prevailing->decl);
- /* Fixup variables in case there are multiple prevailing ones. */
- if (e->next)
- lto_symtab_fixup_var_decls (slot);
+ /* Diagnose mismatched objects. */
+ for (e = prevailing->next; e; e = e->next)
+ {
+ if (TREE_CODE (prevailing->decl) == TREE_CODE (e->decl))
+ continue;
- /* Insert all variable decls into the global variable decl vector. */
- for (e = (lto_symtab_entry_t) *slot; e; e = e->next)
- VEC_safe_push (tree, gc, lto_global_var_decls, e->decl);
+ switch (TREE_CODE (prevailing->decl))
+ {
+ case VAR_DECL:
+ gcc_assert (TREE_CODE (e->decl) == FUNCTION_DECL);
+ error_at (DECL_SOURCE_LOCATION (e->decl),
+ "variable %qD redeclared as function", prevailing->decl);
+ break;
+ case FUNCTION_DECL:
+ gcc_assert (TREE_CODE (e->decl) == VAR_DECL);
+ error_at (DECL_SOURCE_LOCATION (e->decl),
+ "function %qD redeclared as variable", prevailing->decl);
+ break;
+
+ default:
+ gcc_unreachable ();
+ }
+
+ diagnosed_p = true;
+ }
+ if (diagnosed_p)
+ inform (DECL_SOURCE_LOCATION (prevailing->decl),
+ "previously declared here");
+
+ /* Merge the chain to the single prevailing decl and diagnose
+ mismatches. */
+ lto_symtab_merge_decls_2 (slot, diagnosed_p);
+
+ /* Store resolution decision into the callgraph.
+ In LTRANS don't overwrite information we stored into callgraph at
+ WPA stage.
+
+ Do not bother to store guessed decisions. Generic code knows how
+ to handle UNKNOWN relocation well.
+
+ The problem with storing guessed decision is whether to use
+ PREVAILING_DEF, PREVAILING_DEF_IRONLY, PREVAILING_DEF_IRONLY_EXP.
+ First one would disable some whole program optimizations, while
+ ther second would imply to many whole program assumptions. */
+ if (prevailing->node && !flag_ltrans && !prevailing->guessed)
+ prevailing->node->resolution = prevailing->resolution;
+ else if (prevailing->vnode && !flag_ltrans && !prevailing->guessed)
+ prevailing->vnode->resolution = prevailing->resolution;
return 1;
}
htab_traverse (lto_symtab_identifiers, lto_symtab_merge_decls_1, NULL);
}
+/* Helper to process the decl chain for the symbol table entry *SLOT. */
+
+static int
+lto_symtab_merge_cgraph_nodes_1 (void **slot, void *data ATTRIBUTE_UNUSED)
+{
+ lto_symtab_entry_t e, prevailing = (lto_symtab_entry_t) *slot;
+
+ if (!prevailing->next)
+ return 1;
+
+ /* Replace the cgraph node of each entry with the prevailing one. */
+ for (e = prevailing->next; e; e = e->next)
+ {
+ if (e->node != NULL)
+ {
+ /* In case we prevail funcion by an alias, we can run into case
+ that the alias has no cgraph node attached, since it was
+ previously unused. Create the node. */
+ if (!prevailing->node)
+ {
+ prevailing->node = cgraph_create_node (prevailing->decl);
+ prevailing->node->alias = true;
+ }
+ lto_cgraph_replace_node (e->node, prevailing->node);
+ }
+ if (e->vnode != NULL)
+ {
+ if (!prevailing->vnode)
+ {
+ prevailing->vnode = varpool_node (prevailing->decl);
+ prevailing->vnode->alias = true;
+ }
+ lto_varpool_replace_node (e->vnode, prevailing->vnode);
+ }
+ }
+
+ /* Drop all but the prevailing decl from the symtab. */
+ prevailing->next = NULL;
+
+ return 1;
+}
+
+/* Merge cgraph nodes according to the symbol merging done by
+ lto_symtab_merge_decls. */
+
+void
+lto_symtab_merge_cgraph_nodes (void)
+{
+ struct cgraph_node *node;
+ struct varpool_node *vnode;
+ lto_symtab_maybe_init_hash_table ();
+ htab_traverse (lto_symtab_identifiers, lto_symtab_merge_cgraph_nodes_1, NULL);
+
+ for (node = cgraph_nodes; node; node = node->next)
+ if ((node->thunk.thunk_p || node->alias)
+ && node->thunk.alias)
+ node->thunk.alias = lto_symtab_prevailing_decl (node->thunk.alias);
+ for (vnode = varpool_nodes; vnode; vnode = vnode->next)
+ if (vnode->alias_of)
+ vnode->alias_of = lto_symtab_prevailing_decl (vnode->alias_of);
+}
/* Given the decl DECL, return the prevailing decl with the same name. */
gcc_assert (DECL_ASSEMBLER_NAME_SET_P (decl));
/* Walk through the list of candidates and return the one we merged to. */
- ret = lto_symtab_get (DECL_ASSEMBLER_NAME (decl));
+ ret = lto_symtab_get ((*targetm.asm_out.mangle_assembler_name)
+ (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl))));
if (!ret)
return NULL_TREE;
- /* If there is only one candidate return it. */
- if (ret->next == NULL)
- return ret->decl;
-
- /* If there are multiple decls to choose from find the one we merged
- with and return that. */
- while (ret)
- {
- if (gimple_types_compatible_p (TREE_TYPE (decl), TREE_TYPE (ret->decl)))
- return ret->decl;
-
- ret = ret->next;
- }
-
- gcc_unreachable ();
-}
-
-/* Remove any storage used to store resolution of DECL. */
-
-void
-lto_symtab_clear_resolution (tree decl)
-{
- struct lto_symtab_entry_def temp;
- lto_symtab_entry_t head;
- void **slot;
-
- if (!TREE_PUBLIC (decl))
- return;
-
- /* LTO FIXME: There should be no DECL_ABSTRACT in the middle end. */
- if (TREE_CODE (decl) == FUNCTION_DECL && DECL_ABSTRACT (decl))
- return;
-
- gcc_assert (DECL_ASSEMBLER_NAME_SET_P (decl));
-
- lto_symtab_maybe_init_hash_table ();
- temp.id = DECL_ASSEMBLER_NAME (decl);
- slot = htab_find_slot (lto_symtab_identifiers, &temp, NO_INSERT);
- if (!*slot)
- return;
-
- head = (lto_symtab_entry_t) *slot;
- if (head->decl == decl)
- {
- if (head->next)
- {
- *slot = head->next;
- head->next = NULL;
- }
- else
- htab_remove_elt (lto_symtab_identifiers, &temp);
- }
- else
- {
- lto_symtab_entry_t e;
- while (head->next && head->next->decl != decl)
- head = head->next;
- if (head->next)
- {
- e = head->next;
- head->next = e->next;
- e->next = NULL;
- }
- }
+ return ret->decl;
}
#include "gt-lto-symtab.h"
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