C++ TREE_ASM_WRITTEN函数代码示例

/* Output one variable, if necessary.  Return whether we output it.  */
bool
varpool_assemble_decl (struct varpool_node *node)
{
  tree decl = node->decl;

  if (!TREE_ASM_WRITTEN (decl)
      && !node->alias
      && !node->in_other_partition
      && !DECL_EXTERNAL (decl)
      && (TREE_CODE (decl) != VAR_DECL || !DECL_HAS_VALUE_EXPR_P (decl)))
    {
      assemble_variable (decl, 0, 1, 0);
      if (TREE_ASM_WRITTEN (decl))
	{
	  node->next_needed = varpool_assembled_nodes_queue;
	  node->prev_needed = NULL;
	  if (varpool_assembled_nodes_queue)
	    varpool_assembled_nodes_queue->prev_needed = node;
	  varpool_assembled_nodes_queue = node;
	  node->finalized = 1;
	  assemble_aliases (node);
	  return true;
	}
    }

  return false;
}

/* Output one variable, if necessary.  Return whether we output it.  */
bool
varpool_assemble_decl (struct varpool_node *node)
{
  tree decl = node->decl;

  if (!TREE_ASM_WRITTEN (decl)
      && !node->alias
      && !DECL_EXTERNAL (decl)
      && (TREE_CODE (decl) != VAR_DECL || !DECL_HAS_VALUE_EXPR_P (decl)))
    {
      assemble_variable (decl, 0, 1, 0);
      if (TREE_ASM_WRITTEN (decl))
	{
	  struct varpool_node *alias;

	  node->next_needed = varpool_assembled_nodes_queue;
	  varpool_assembled_nodes_queue = node;
	  node->finalized = 1;

	  /* Also emit any extra name aliases.  */
	  for (alias = node->extra_name; alias; alias = alias->next)
	    {
	      /* Update linkage fields in case they've changed.  */
	      DECL_WEAK (alias->decl) = DECL_WEAK (decl);
	      TREE_PUBLIC (alias->decl) = TREE_PUBLIC (decl);
	      DECL_VISIBILITY (alias->decl) = DECL_VISIBILITY (decl);
	      assemble_alias (alias->decl, DECL_ASSEMBLER_NAME (decl));
	    }

	  return true;
	}
    }

  return false;
}

static void
lower_gimple_bind (gimple_stmt_iterator *gsi, struct lower_data *data)
{
  tree old_block = data->block;
  gimple stmt = gsi_stmt (*gsi);
  tree new_block = gimple_bind_block (stmt);

  if (new_block)
    {
      if (new_block == old_block)
	{
	  /* The outermost block of the original function may not be the
	     outermost statement chain of the gimplified function.  So we
	     may see the outermost block just inside the function.  */
	  gcc_assert (new_block == DECL_INITIAL (current_function_decl));
	  new_block = NULL;
	}
      else
	{
	  /* We do not expect to handle duplicate blocks.  */
	  gcc_assert (!TREE_ASM_WRITTEN (new_block));
	  TREE_ASM_WRITTEN (new_block) = 1;

	  /* Block tree may get clobbered by inlining.  Normally this would
	     be fixed in rest_of_decl_compilation using block notes, but
	     since we are not going to emit them, it is up to us.  */
	  BLOCK_CHAIN (new_block) = BLOCK_SUBBLOCKS (old_block);
	  BLOCK_SUBBLOCKS (old_block) = new_block;
	  BLOCK_SUBBLOCKS (new_block) = NULL_TREE;
	  BLOCK_SUPERCONTEXT (new_block) = old_block;

	  data->block = new_block;
	}
    }

  record_vars (gimple_bind_vars (stmt));
  lower_sequence (gimple_bind_body_ptr (stmt), data);

  if (new_block)
    {
      gcc_assert (data->block == new_block);

      BLOCK_SUBBLOCKS (new_block)
	= blocks_nreverse (BLOCK_SUBBLOCKS (new_block));
      data->block = old_block;
    }

  /* The GIMPLE_BIND no longer carries any useful information -- kill it.  */
  gsi_insert_seq_before (gsi, gimple_bind_body (stmt), GSI_SAME_STMT);
  gsi_remove (gsi, false);
}

static inline void
unpack_ts_base_value_fields (struct bitpack_d *bp, tree expr)
{
  /* Note that the code for EXPR has already been unpacked to create EXPR in
     streamer_alloc_tree.  */
  if (!TYPE_P (expr))
    {
      TREE_SIDE_EFFECTS (expr) = (unsigned) bp_unpack_value (bp, 1);
      TREE_CONSTANT (expr) = (unsigned) bp_unpack_value (bp, 1);
      TREE_READONLY (expr) = (unsigned) bp_unpack_value (bp, 1);

      /* TREE_PUBLIC is used on types to indicate that the type
	 has a TYPE_CACHED_VALUES vector.  This is not streamed out,
	 so we skip it here.  */
      TREE_PUBLIC (expr) = (unsigned) bp_unpack_value (bp, 1);
    }
  else
    bp_unpack_value (bp, 4);
  TREE_ADDRESSABLE (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_THIS_VOLATILE (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (DECL_P (expr))
    DECL_UNSIGNED (expr) = (unsigned) bp_unpack_value (bp, 1);
  else if (TYPE_P (expr))
    TYPE_UNSIGNED (expr) = (unsigned) bp_unpack_value (bp, 1);
  else
    bp_unpack_value (bp, 1);
  TREE_ASM_WRITTEN (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (TYPE_P (expr))
    TYPE_ARTIFICIAL (expr) = (unsigned) bp_unpack_value (bp, 1);
  else
    TREE_NO_WARNING (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_NOTHROW (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_STATIC (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (TREE_CODE (expr) != TREE_BINFO)
    TREE_PRIVATE (expr) = (unsigned) bp_unpack_value (bp, 1);
  else
    bp_unpack_value (bp, 1);
  TREE_PROTECTED (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_DEPRECATED (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (TYPE_P (expr))
    {
      if (AGGREGATE_TYPE_P (expr))
	TYPE_REVERSE_STORAGE_ORDER (expr) = (unsigned) bp_unpack_value (bp, 1);
      else
	TYPE_SATURATING (expr) = (unsigned) bp_unpack_value (bp, 1);
      TYPE_ADDR_SPACE (expr) = (unsigned) bp_unpack_value (bp, 8);
    }
  else if (TREE_CODE (expr) == BIT_FIELD_REF || TREE_CODE (expr) == MEM_REF)
    {
      REF_REVERSE_STORAGE_ORDER (expr) = (unsigned) bp_unpack_value (bp, 1);
      bp_unpack_value (bp, 8);
    }
  else if (TREE_CODE (expr) == SSA_NAME)
    {
      SSA_NAME_IS_DEFAULT_DEF (expr) = (unsigned) bp_unpack_value (bp, 1);
      bp_unpack_value (bp, 8);
    }
  else
    bp_unpack_value (bp, 9);
}

// llvm_emit_code_for_current_function - Top level interface for emitting a
// function to the .s file.
void llvm_emit_code_for_current_function(tree fndecl) {
  if (cfun->nonlocal_goto_save_area)
    sorry("%Jnon-local gotos not supported by LLVM", fndecl);

  if (errorcount || sorrycount) {
    TREE_ASM_WRITTEN(fndecl) = 1;
    return;  // Do not process broken code.
  }
  timevar_push(TV_LLVM_FUNCS);

  // Convert the AST to raw/ugly LLVM code.
  Function *Fn;
  {
    TreeToLLVM Emitter(fndecl);

    // Set up parameters and prepare for return, for the function.
    Emitter.StartFunctionBody();
    
    // Emit the body of the function.
    Emitter.Emit(DECL_SAVED_TREE(fndecl), 0);
  
    // Wrap things up.
    Fn = Emitter.FinishFunctionBody();
  }

#if 0
  if (dump_file) {
    fprintf (dump_file,
             "\n\n;;\n;; Full LLVM generated for this function:\n;;\n");
    Fn->dump();
  }
#endif
  
  if (PerFunctionPasses)
    PerFunctionPasses->run(*Fn);
  
  // TODO: Nuke the .ll code for the function at -O[01] if we don't want to
  // inline it or something else.
  
  // There's no need to defer outputting this function any more; we
  // know we want to output it.
  DECL_DEFER_OUTPUT(fndecl) = 0;
  
  // Finally, we have written out this function!
  TREE_ASM_WRITTEN(fndecl) = 1;
  timevar_pop(TV_LLVM_FUNCS);
}

/* Notify finalize_compilation_unit that given node is reachable
   or needed.  */
void
varpool_mark_needed_node (struct varpool_node *node)
{
  if (!node->needed && node->finalized
      && !TREE_ASM_WRITTEN (node->decl))
    varpool_enqueue_needed_node (node);
  node->needed = 1;
}

bool
varpool_assemble_decl (varpool_node *node)
{
  tree decl = node->decl;

  /* Aliases are outout when their target is produced or by
     output_weakrefs.  */
  if (node->alias)
    return false;

  /* Constant pool is output from RTL land when the reference
     survive till this level.  */
  if (DECL_IN_CONSTANT_POOL (decl) && TREE_ASM_WRITTEN (decl))
    return false;

  /* Decls with VALUE_EXPR should not be in the varpool at all.  They
     are not real variables, but just info for debugging and codegen.
     Unfortunately at the moment emutls is not updating varpool correctly
     after turning real vars into value_expr vars.  */
  if (DECL_HAS_VALUE_EXPR_P (decl)
      && !targetm.have_tls)
    return false;

  /* Hard register vars do not need to be output.  */
  if (DECL_HARD_REGISTER (decl))
    return false;

  gcc_checking_assert (!TREE_ASM_WRITTEN (decl)
		       && TREE_CODE (decl) == VAR_DECL
		       && !DECL_HAS_VALUE_EXPR_P (decl));

  if (!node->in_other_partition
      && !DECL_EXTERNAL (decl))
    {
      assemble_variable (decl, 0, 1, 0);
      gcc_assert (TREE_ASM_WRITTEN (decl));
      node->definition = true;
      assemble_aliases (node);
      return true;
    }

  return false;
}

/* For variables in named sections make sure get_variable_section
   is called before we switch to those sections.  Then section
   conflicts between read-only and read-only requiring relocations
   sections can be resolved.  */
void
varpool_finalize_named_section_flags (varpool_node *node)
{
  if (!TREE_ASM_WRITTEN (node->decl)
      && !node->alias
      && !node->in_other_partition
      && !DECL_EXTERNAL (node->decl)
      && TREE_CODE (node->decl) == VAR_DECL
      && !DECL_HAS_VALUE_EXPR_P (node->decl)
      && DECL_SECTION_NAME (node->decl))
    get_variable_section (node->decl, false);
}

static void
pack_ts_base_value_fields (struct bitpack_d *bp, tree expr)
{
  bp_pack_value (bp, TREE_CODE (expr), 16);
  if (!TYPE_P (expr))
    {
      bp_pack_value (bp, TREE_SIDE_EFFECTS (expr), 1);
      bp_pack_value (bp, TREE_CONSTANT (expr), 1);
      bp_pack_value (bp, TREE_READONLY (expr), 1);

      /* TREE_PUBLIC is used on types to indicate that the type
	 has a TYPE_CACHED_VALUES vector.  This is not streamed out,
	 so we skip it here.  */
      bp_pack_value (bp, TREE_PUBLIC (expr), 1);
    }
  else
    bp_pack_value (bp, 0, 4);
  bp_pack_value (bp, TREE_ADDRESSABLE (expr), 1);
  bp_pack_value (bp, TREE_THIS_VOLATILE (expr), 1);
  if (DECL_P (expr))
    bp_pack_value (bp, DECL_UNSIGNED (expr), 1);
  else if (TYPE_P (expr))
    bp_pack_value (bp, TYPE_UNSIGNED (expr), 1);
  else
    bp_pack_value (bp, 0, 1);
  /* We write debug info two times, do not confuse the second one.
     The only relevant TREE_ASM_WRITTEN use is on SSA names.  */
  bp_pack_value (bp, (TREE_CODE (expr) != SSA_NAME
		      ? 0 : TREE_ASM_WRITTEN (expr)), 1);
  if (TYPE_P (expr))
    bp_pack_value (bp, TYPE_ARTIFICIAL (expr), 1);
  else
    bp_pack_value (bp, TREE_NO_WARNING (expr), 1);
  bp_pack_value (bp, TREE_NOTHROW (expr), 1);
  bp_pack_value (bp, TREE_STATIC (expr), 1);
  if (TREE_CODE (expr) != TREE_BINFO)
    bp_pack_value (bp, TREE_PRIVATE (expr), 1);
  bp_pack_value (bp, TREE_PROTECTED (expr), 1);
  bp_pack_value (bp, TREE_DEPRECATED (expr), 1);
  if (TYPE_P (expr))
    {
      bp_pack_value (bp, TYPE_SATURATING (expr), 1);
      bp_pack_value (bp, TYPE_ADDR_SPACE (expr), 8);
    }
  else if (TREE_CODE (expr) == SSA_NAME)
    bp_pack_value (bp, SSA_NAME_IS_DEFAULT_DEF (expr), 1);
  else
    bp_pack_value (bp, 0, 1);
}

static void
sdbout_dequeue_anonymous_types (void)
{
  tree types, link;

  while (anonymous_types)
    {
      types = nreverse (anonymous_types);
      anonymous_types = NULL_TREE;

      for (link = types; link; link = TREE_CHAIN (link))
	{
	  tree type = TREE_VALUE (link);

	  if (type && ! TREE_ASM_WRITTEN (type))
	    sdbout_one_type (type);
	}
    }
}

static void
expand_one_static_var (tree var)
{
  /* If this is an inlined copy of a static local variable,
     look up the original.  */
  var = DECL_ORIGIN (var);

  /* If we've already processed this variable because of that, do nothing.  */
  if (TREE_ASM_WRITTEN (var))
    return;

  /* Give the front end a chance to do whatever.  In practice, this is
     resolving duplicate names for IMA in C.  */
  if (lang_hooks.expand_decl (var))
    return;

  /* Otherwise, just emit the variable.  */
  rest_of_decl_compilation (var, 0, 0);
}

void
cgraph_finalize_function (tree decl, bool nested)
{
  struct cgraph_node *node = cgraph_node (decl);

  if (node->local.finalized)
    cgraph_reset_node (node);

  node->pid = cgraph_max_pid ++;
  notice_global_symbol (decl);
  node->local.finalized = true;
  node->lowered = DECL_STRUCT_FUNCTION (decl)->cfg != NULL;
  record_cdtor_fn (node->decl);
  if (node->nested)
    lower_nested_functions (decl);
  gcc_assert (!node->nested);

  if (decide_is_function_needed (node, decl))
    cgraph_mark_needed_node (node);

  /* Since we reclaim unreachable nodes at the end of every language
     level unit, we need to be conservative about possible entry points
     there.  */
  if ((TREE_PUBLIC (decl) && !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl)))
    cgraph_mark_reachable_node (node);

  /* If we've not yet emitted decl, tell the debug info about it.  */
  if (!TREE_ASM_WRITTEN (decl))
    (*debug_hooks->deferred_inline_function) (decl);

  /* Possibly warn about unused parameters.  */
  if (warn_unused_parameter)
    do_warn_unused_parameter (decl);

  if (!nested)
    ggc_collect ();
}

/* Dump given cgraph node.  */
void
dump_varpool_node (FILE *f, struct varpool_node *node)
{
  fprintf (f, "%s:", varpool_node_name (node));
  fprintf (f, " availability:%s",
	   cgraph_function_flags_ready
	   ? cgraph_availability_names[cgraph_variable_initializer_availability (node)]
	   : "not-ready");
  if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
    fprintf (f, " (asm: %s)", IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
  if (DECL_INITIAL (node->decl))
    fprintf (f, " initialized");
  if (TREE_ASM_WRITTEN (node->decl))
    fprintf (f, " (asm written)");
  if (node->needed)
    fprintf (f, " needed");
  if (node->analyzed)
    fprintf (f, " analyzed");
  if (node->finalized)
    fprintf (f, " finalized");
  if (node->output)
    fprintf (f, " output");
  if (node->externally_visible)
    fprintf (f, " externally_visible");
  if (node->resolution != LDPR_UNKNOWN)
    fprintf (f, " %s",
 	     ld_plugin_symbol_resolution_names[(int)node->resolution]);
  if (node->in_other_partition)
    fprintf (f, " in_other_partition");
  else if (node->used_from_other_partition)
    fprintf (f, " used_from_other_partition");
  fprintf (f, "\n");
  fprintf (f, "  References: ");
  ipa_dump_references (f, &node->ref_list);
  fprintf (f, "  Refering this var: ");
  ipa_dump_refering (f, &node->ref_list);
}

/* Verify cgraph nodes of given cgraph node.  */
void
verify_cgraph_node (struct cgraph_node *node)
{
  struct cgraph_edge *e;
  struct cgraph_node *main_clone;
  struct function *this_cfun = DECL_STRUCT_FUNCTION (node->decl);
  struct function *saved_cfun = cfun;
  basic_block this_block;
  gimple_stmt_iterator gsi;
  bool error_found = false;

  if (errorcount || sorrycount)
    return;

  timevar_push (TV_CGRAPH_VERIFY);
  /* debug_generic_stmt needs correct cfun */
  set_cfun (this_cfun);
  for (e = node->callees; e; e = e->next_callee)
    if (e->aux)
      {
	error ("aux field set for edge %s->%s",
	       cgraph_node_name (e->caller), cgraph_node_name (e->callee));
	error_found = true;
      }
  if (node->count < 0)
    {
      error ("Execution count is negative");
      error_found = true;
    }
  for (e = node->callers; e; e = e->next_caller)
    {
      if (e->count < 0)
	{
	  error ("caller edge count is negative");
	  error_found = true;
	}
      if (e->frequency < 0)
	{
	  error ("caller edge frequency is negative");
	  error_found = true;
	}
      if (e->frequency > CGRAPH_FREQ_MAX)
	{
	  error ("caller edge frequency is too large");
	  error_found = true;
	}
      if (!e->inline_failed)
	{
	  if (node->global.inlined_to
	      != (e->caller->global.inlined_to
		  ? e->caller->global.inlined_to : e->caller))
	    {
	      error ("inlined_to pointer is wrong");
	      error_found = true;
	    }
	  if (node->callers->next_caller)
	    {
	      error ("multiple inline callers");
	      error_found = true;
	    }
	}
      else
	if (node->global.inlined_to)
	  {
	    error ("inlined_to pointer set for noninline callers");
	    error_found = true;
	  }
    }
  if (!node->callers && node->global.inlined_to)
    {
      error ("inlined_to pointer is set but no predecessors found");
      error_found = true;
    }
  if (node->global.inlined_to == node)
    {
      error ("inlined_to pointer refers to itself");
      error_found = true;
    }

  for (main_clone = cgraph_node (node->decl); main_clone;
       main_clone = main_clone->next_clone)
    if (main_clone == node)
      break;
  if (!cgraph_node (node->decl))
    {
      error ("node not found in cgraph_hash");
      error_found = true;
    }

  if (node->analyzed
      && !TREE_ASM_WRITTEN (node->decl)
      && (!DECL_EXTERNAL (node->decl) || node->global.inlined_to))
    {
      if (this_cfun->cfg)
	{
	  /* The nodes we're interested in are never shared, so walk
	     the tree ignoring duplicates.  */
	  struct pointer_set_t *visited_nodes = pointer_set_create ();
	  /* Reach the trees by walking over the CFG, and note the
//.........这里部分代码省略.........

static unsigned int
lower_function_body (void)
{
  struct lower_data data;
  gimple_seq body = gimple_body (current_function_decl);
  gimple_seq lowered_body;
  gimple_stmt_iterator i;
  gimple bind;
  tree t;
  gimple x;

  /* The gimplifier should've left a body of exactly one statement,
     namely a GIMPLE_BIND.  */
  gcc_assert (gimple_seq_first (body) == gimple_seq_last (body)
	      && gimple_code (gimple_seq_first_stmt (body)) == GIMPLE_BIND);

  memset (&data, 0, sizeof (data));
  data.block = DECL_INITIAL (current_function_decl);
  BLOCK_SUBBLOCKS (data.block) = NULL_TREE;
  BLOCK_CHAIN (data.block) = NULL_TREE;
  TREE_ASM_WRITTEN (data.block) = 1;
  data.return_statements.create (8);

  bind = gimple_seq_first_stmt (body);
  lowered_body = NULL;
  gimple_seq_add_stmt (&lowered_body, bind);
  i = gsi_start (lowered_body);
  lower_gimple_bind (&i, &data);

  i = gsi_last (lowered_body);

  /* If the function falls off the end, we need a null return statement.
     If we've already got one in the return_statements vector, we don't
     need to do anything special.  Otherwise build one by hand.  */
  if (gimple_seq_may_fallthru (lowered_body)
      && (data.return_statements.is_empty ()
	  || gimple_return_retval (data.return_statements.last().stmt) != NULL))
    {
      x = gimple_build_return (NULL);
      gimple_set_location (x, cfun->function_end_locus);
      gimple_set_block (x, DECL_INITIAL (current_function_decl));
      gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
    }

  /* If we lowered any return statements, emit the representative
     at the end of the function.  */
  while (!data.return_statements.is_empty ())
    {
      return_statements_t t = data.return_statements.pop ();
      x = gimple_build_label (t.label);
      gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
      gsi_insert_after (&i, t.stmt, GSI_CONTINUE_LINKING);
    }

  /* If the function calls __builtin_setjmp, we need to emit the computed
     goto that will serve as the unique dispatcher for all the receivers.  */
  if (data.calls_builtin_setjmp)
    {
      tree disp_label, disp_var, arg;

      /* Build 'DISP_LABEL:' and insert.  */
      disp_label = create_artificial_label (cfun->function_end_locus);
      /* This mark will create forward edges from every call site.  */
      DECL_NONLOCAL (disp_label) = 1;
      cfun->has_nonlocal_label = 1;
      x = gimple_build_label (disp_label);
      gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);

      /* Build 'DISP_VAR = __builtin_setjmp_dispatcher (DISP_LABEL);'
	 and insert.  */
      disp_var = create_tmp_var (ptr_type_node, "setjmpvar");
      arg = build_addr (disp_label, current_function_decl);
      t = builtin_decl_implicit (BUILT_IN_SETJMP_DISPATCHER);
      x = gimple_build_call (t, 1, arg);
      gimple_call_set_lhs (x, disp_var);

      /* Build 'goto DISP_VAR;' and insert.  */
      gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
      x = gimple_build_goto (disp_var);
      gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
    }

  /* Once the old body has been lowered, replace it with the new
     lowered sequence.  */
  gimple_set_body (current_function_decl, lowered_body);

  gcc_assert (data.block == DECL_INITIAL (current_function_decl));
  BLOCK_SUBBLOCKS (data.block)
    = blocks_nreverse (BLOCK_SUBBLOCKS (data.block));

  clear_block_marks (data.block);
  data.return_statements.release ();
  return 0;
}