c++: Static init guard generation
The guard generation for a static var init was overly verbose. We can use a bit of RAII and avoid some rechecking. Also in the !cxa_atexit case, the only difference is whether can become whether to use post-inc or pre-dec. gcc/cp/ * decl2.cc (fix_temporary_vars_context_r): Use data argument for new context. (one_static_initialization_or_destruction): Adjust tree walk call. Refactor guard generation.
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Nathan Sidwell
parent
c4d702fb3c
commit
289f860fe6
1 changed files with 42 additions and 69 deletions
111
gcc/cp/decl2.cc
111
gcc/cp/decl2.cc
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@ -4085,34 +4085,25 @@ get_priority_info (int priority)
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|| DECL_ONE_ONLY (decl) \
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|| DECL_WEAK (decl)))
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/* Called from one_static_initialization_or_destruction(),
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via walk_tree.
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Walks the initializer list of a global variable and looks for
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/* Walks the initializer list of a global variable and looks for
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temporary variables (DECL_NAME() == NULL and DECL_ARTIFICIAL != 0)
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and that have their DECL_CONTEXT() == NULL.
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For each such temporary variable, set their DECL_CONTEXT() to
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the current function. This is necessary because otherwise
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some optimizers (enabled by -O2 -fprofile-arcs) might crash
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when trying to refer to a temporary variable that does not have
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it's DECL_CONTECT() properly set. */
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and that have their DECL_CONTEXT() == NULL. For each such
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temporary variable, set their DECL_CONTEXT() to CTX -- the
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initializing function. This is necessary because otherwise some
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optimizers (enabled by -O2 -fprofile-arcs) might crash when trying
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to refer to a temporary variable that does not have its
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DECL_CONTEXT() properly set. */
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static tree
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fix_temporary_vars_context_r (tree *node,
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int * /*unused*/,
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void * /*unused1*/)
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void *ctx)
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{
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gcc_assert (current_function_decl);
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if (TREE_CODE (*node) == BIND_EXPR)
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{
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tree var;
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for (var = BIND_EXPR_VARS (*node); var; var = DECL_CHAIN (var))
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if (VAR_P (var)
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&& !DECL_NAME (var)
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&& DECL_ARTIFICIAL (var)
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&& !DECL_CONTEXT (var))
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DECL_CONTEXT (var) = current_function_decl;
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}
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for (tree var = BIND_EXPR_VARS (*node); var; var = DECL_CHAIN (var))
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if (VAR_P (var) && !DECL_NAME (var)
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&& DECL_ARTIFICIAL (var) && !DECL_CONTEXT (var))
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DECL_CONTEXT (var) = tree (ctx);
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return NULL_TREE;
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}
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@ -4124,9 +4115,6 @@ fix_temporary_vars_context_r (tree *node,
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static void
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one_static_initialization_or_destruction (bool initp, tree decl, tree init)
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{
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tree guard_if_stmt = NULL_TREE;
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tree guard;
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/* If we are supposed to destruct and there's a trivial destructor,
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nothing has to be done. */
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if (!initp
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@ -4150,7 +4138,7 @@ one_static_initialization_or_destruction (bool initp, tree decl, tree init)
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of the temporaries are set to the current function decl. */
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cp_walk_tree_without_duplicates (&init,
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fix_temporary_vars_context_r,
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NULL);
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current_function_decl);
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/* Because of:
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@ -4171,62 +4159,50 @@ one_static_initialization_or_destruction (bool initp, tree decl, tree init)
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}
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/* Assume we don't need a guard. */
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guard = NULL_TREE;
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tree guard_if_stmt = NULL_TREE;
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/* We need a guard if this is an object with external linkage that
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might be initialized in more than one place. (For example, a
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static data member of a template, when the data member requires
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construction.) */
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if (NEEDS_GUARD_P (decl))
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{
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tree guard = get_guard (decl);
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tree guard_cond;
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guard = get_guard (decl);
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/* When using __cxa_atexit, we just check the GUARD as we would
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for a local static. */
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if (flag_use_cxa_atexit)
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{
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/* When using __cxa_atexit, we never try to destroy
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/* When using __cxa_atexit, we just check the GUARD as we
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would for a local static. We never try to destroy
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anything from a static destructor. */
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gcc_assert (initp);
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guard_cond = get_guard_cond (guard, false);
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}
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/* If we don't have __cxa_atexit, then we will be running
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destructors from .fini sections, or their equivalents. So,
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we need to know how many times we've tried to initialize this
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object. We do initializations only if the GUARD is zero,
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i.e., if we are the first to initialize the variable. We do
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destructions only if the GUARD is one, i.e., if we are the
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last to destroy the variable. */
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else if (initp)
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guard_cond
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= cp_build_binary_op (input_location,
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EQ_EXPR,
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cp_build_unary_op (PREINCREMENT_EXPR,
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guard,
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/*noconvert=*/true,
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tf_warning_or_error),
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integer_one_node,
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tf_warning_or_error);
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else
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guard_cond
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= cp_build_binary_op (input_location,
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EQ_EXPR,
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cp_build_unary_op (PREDECREMENT_EXPR,
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guard,
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/*noconvert=*/true,
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tf_warning_or_error),
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integer_zero_node,
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tf_warning_or_error);
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{
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/* If we don't have __cxa_atexit, then we will be running
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destructors from .fini sections, or their equivalents.
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So, we need to know how many times we've tried to
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initialize this object. We do initializations only if
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the GUARD was or becomes zero (initp vs !initp
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respectively). */
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guard_cond = cp_build_unary_op (initp ? POSTINCREMENT_EXPR
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: PREDECREMENT_EXPR,
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guard,
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/*noconvert=*/true,
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tf_warning_or_error);
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guard_cond = cp_build_binary_op (input_location, EQ_EXPR, guard_cond,
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integer_zero_node,
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tf_warning_or_error);
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}
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guard_if_stmt = begin_if_stmt ();
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finish_if_stmt_cond (guard_cond, guard_if_stmt);
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}
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/* If we're using __cxa_atexit, we have not already set the GUARD,
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so we must do so now. */
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if (guard && initp && flag_use_cxa_atexit)
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finish_expr_stmt (set_guard (guard));
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if (flag_use_cxa_atexit)
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/* Set the GUARD now. */
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finish_expr_stmt (set_guard (guard));
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}
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/* Perform the initialization or destruction. */
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if (initp)
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@ -4235,11 +4211,8 @@ one_static_initialization_or_destruction (bool initp, tree decl, tree init)
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{
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finish_expr_stmt (init);
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if (sanitize_flags_p (SANITIZE_ADDRESS, decl))
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{
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varpool_node *vnode = varpool_node::get (decl);
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if (vnode)
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vnode->dynamically_initialized = 1;
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}
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if (varpool_node *vnode = varpool_node::get (decl))
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vnode->dynamically_initialized = 1;
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}
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/* If we're using __cxa_atexit, register a function that calls the
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@ -4251,7 +4224,7 @@ one_static_initialization_or_destruction (bool initp, tree decl, tree init)
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finish_expr_stmt (build_cleanup (decl));
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/* Finish the guard if-stmt, if necessary. */
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if (guard)
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if (guard_if_stmt)
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{
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finish_then_clause (guard_if_stmt);
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finish_if_stmt (guard_if_stmt);
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