diff options
Diffstat (limited to 'gcc/go/gofrontend/gogo.cc')
| -rw-r--r-- | gcc/go/gofrontend/gogo.cc | 202 |
1 files changed, 111 insertions, 91 deletions
diff --git a/gcc/go/gofrontend/gogo.cc b/gcc/go/gofrontend/gogo.cc index 67b91fa..9197eef 100644 --- a/gcc/go/gofrontend/gogo.cc +++ b/gcc/go/gofrontend/gogo.cc @@ -1086,8 +1086,8 @@ class Find_vars : public Traverse public: Find_vars() - : Traverse(traverse_expressions), - vars_(), seen_objects_() + : Traverse(traverse_expressions | traverse_statements), + vars_(), seen_objects_(), lhs_is_ref_(false) { } // An iterator through the variables found, after the traversal. @@ -1104,11 +1104,16 @@ class Find_vars : public Traverse int expression(Expression**); + int + statement(Block*, size_t* index, Statement*); + private: // Accumulated variables. Vars vars_; // Objects we have already seen. Seen_objects seen_objects_; + // Whether an assignment to a variable counts as a reference. + bool lhs_is_ref_; }; // Collect global variables referenced by EXPR. Look through function @@ -1164,7 +1169,11 @@ Find_vars::expression(Expression** pexpr) if (ins.second) { // This is the first time we have seen this name. - if (f->func_value()->block()->traverse(this) == TRAVERSE_EXIT) + bool hold = this->lhs_is_ref_; + this->lhs_is_ref_ = true; + int r = f->func_value()->block()->traverse(this); + this->lhs_is_ref_ = hold; + if (r == TRAVERSE_EXIT) return TRAVERSE_EXIT; } } @@ -1192,6 +1201,29 @@ Find_vars::expression(Expression** pexpr) return TRAVERSE_CONTINUE; } +// Check a statement while searching for variables. This is where we +// skip variables on the left hand side of assigments if appropriate. + +int +Find_vars::statement(Block*, size_t*, Statement* s) +{ + if (this->lhs_is_ref_) + return TRAVERSE_CONTINUE; + Assignment_statement* as = s->assignment_statement(); + if (as == NULL) + return TRAVERSE_CONTINUE; + + // Only traverse subexpressions of the LHS. + if (as->lhs()->traverse_subexpressions(this) == TRAVERSE_EXIT) + return TRAVERSE_EXIT; + + Expression* rhs = as->rhs(); + if (Expression::traverse(&rhs, this) == TRAVERSE_EXIT) + return TRAVERSE_EXIT; + + return TRAVERSE_SKIP_COMPONENTS; +} + // Return true if EXPR, PREINIT, or DEP refers to VAR. static bool @@ -1230,11 +1262,11 @@ class Var_init { public: Var_init() - : var_(NULL), init_(NULL), refs_(NULL), dep_count_(0) + : var_(NULL), init_(NULL), dep_count_(0) { } Var_init(Named_object* var, Bstatement* init) - : var_(var), init_(init), refs_(NULL), dep_count_(0) + : var_(var), init_(init), dep_count_(0) { } // Return the variable. @@ -1247,19 +1279,6 @@ class Var_init init() const { return this->init_; } - // Add a reference. - void - add_ref(Named_object* var); - - // The variables which this variable's initializers refer to. - const std::vector<Named_object*>* - refs() - { return this->refs_; } - - // Clear the references, if any. - void - clear_refs(); - // Return the number of remaining dependencies. size_t dep_count() const @@ -1280,36 +1299,12 @@ class Var_init Named_object* var_; // The backend initialization statement. Bstatement* init_; - // Variables this refers to. - std::vector<Named_object*>* refs_; // The number of initializations this is dependent on. A variable // initialization should not be emitted if any of its dependencies // have not yet been resolved. size_t dep_count_; }; -// Add a reference. - -void -Var_init::add_ref(Named_object* var) -{ - if (this->refs_ == NULL) - this->refs_ = new std::vector<Named_object*>; - this->refs_->push_back(var); -} - -// Clear the references, if any. - -void -Var_init::clear_refs() -{ - if (this->refs_ != NULL) - { - delete this->refs_; - this->refs_ = NULL; - } -} - // For comparing Var_init keys in a map. inline bool @@ -1324,7 +1319,7 @@ typedef std::list<Var_init> Var_inits; // variable V2 then we initialize V1 after V2. static void -sort_var_inits(Gogo* gogo, Var_inits* var_inits) +sort_var_inits(Var_inits* var_inits) { if (var_inits->empty()) return; @@ -1337,33 +1332,13 @@ sort_var_inits(Gogo* gogo, Var_inits* var_inits) Init_deps init_deps; bool init_loop = false; - // Compute all variable references. + // Map from variable to Var_init. for (Var_inits::iterator pvar = var_inits->begin(); pvar != var_inits->end(); ++pvar) { Named_object* var = pvar->var(); var_to_init[var] = &*pvar; - - Find_vars find_vars; - Expression* init = var->var_value()->init(); - if (init != NULL) - Expression::traverse(&init, &find_vars); - if (var->var_value()->has_pre_init()) - var->var_value()->preinit()->traverse(&find_vars); - Named_object* dep = gogo->var_depends_on(var->var_value()); - if (dep != NULL) - { - Expression* dinit = dep->var_value()->init(); - if (dinit != NULL) - Expression::traverse(&dinit, &find_vars); - if (dep->var_value()->has_pre_init()) - dep->var_value()->preinit()->traverse(&find_vars); - } - for (Find_vars::const_iterator p = find_vars.begin(); - p != find_vars.end(); - ++p) - pvar->add_ref(*p); } // Add dependencies to init_deps, and check for cycles. @@ -1373,7 +1348,8 @@ sort_var_inits(Gogo* gogo, Var_inits* var_inits) { Named_object* var = pvar->var(); - const std::vector<Named_object*>* refs = pvar->refs(); + const std::vector<Named_object*>* refs = + pvar->var()->var_value()->init_refs(); if (refs == NULL) continue; for (std::vector<Named_object*>::const_iterator pdep = refs->begin(); @@ -1383,19 +1359,11 @@ sort_var_inits(Gogo* gogo, Var_inits* var_inits) Named_object* dep = *pdep; if (var == dep) { - // This is a reference from a variable to itself, which - // may indicate a loop. We only report an error if - // there is an initializer and there is no dependency. - // When there is no initializer, it means that the - // preinitializer sets the variable, which will appear - // to be a loop here. - if (var->var_value()->init() != NULL - && gogo->var_depends_on(var->var_value()) == NULL) - go_error_at(var->location(), - ("initialization expression for %qs " - "depends upon itself"), - var->message_name().c_str()); - + // This is a reference from a variable to itself. + go_error_at(var->location(), + ("initialization expression for %qs " + "depends upon itself"), + var->message_name().c_str()); continue; } @@ -1412,7 +1380,8 @@ sort_var_inits(Gogo* gogo, Var_inits* var_inits) pvar->add_dependency(); // Check for cycles. - const std::vector<Named_object*>* deprefs = dep_init->refs(); + const std::vector<Named_object*>* deprefs = + dep_init->var()->var_value()->init_refs(); if (deprefs == NULL) continue; for (std::vector<Named_object*>::const_iterator pdepdep = @@ -1437,10 +1406,6 @@ sort_var_inits(Gogo* gogo, Var_inits* var_inits) } var_to_init.clear(); - for (Var_inits::iterator pvar = var_inits->begin(); - pvar != var_inits->end(); - ++pvar) - pvar->clear_refs(); // If there are no dependencies then the declaration order is sorted. if (!init_deps.empty() && !init_loop) @@ -1748,7 +1713,7 @@ Gogo::write_globals() // workable order. if (!var_inits.empty()) { - sort_var_inits(this, &var_inits); + sort_var_inits(&var_inits); for (Var_inits::const_iterator p = var_inits.begin(); p != var_inits.end(); ++p) @@ -3840,6 +3805,51 @@ Gogo::check_types_in_block(Block* block) block->traverse(&traverse); } +// For each global variable defined in the current package, record the +// set of variables that its initializer depends on. We do this after +// lowering so that all unknown names are resolved to their final +// locations. We do this before write barrier insertion because that +// makes it harder to distinguish references from assignments in +// preinit blocks. + +void +Gogo::record_global_init_refs() +{ + Bindings* bindings = this->package_->bindings(); + for (Bindings::const_definitions_iterator pb = bindings->begin_definitions(); + pb != bindings->end_definitions(); + pb++) + { + Named_object* no = *pb; + if (!no->is_variable()) + continue; + + Variable* var = no->var_value(); + go_assert(var->is_global()); + + Find_vars find_vars; + Expression* init = var->init(); + if (init != NULL) + Expression::traverse(&init, &find_vars); + if (var->has_pre_init()) + var->preinit()->traverse(&find_vars); + Named_object* dep = this->var_depends_on(var); + if (dep != NULL) + { + Expression* dinit = dep->var_value()->init(); + if (dinit != NULL) + Expression::traverse(&dinit, &find_vars); + if (dep->var_value()->has_pre_init()) + dep->var_value()->preinit()->traverse(&find_vars); + } + + for (Find_vars::const_iterator pv = find_vars.begin(); + pv != find_vars.end(); + ++pv) + var->add_init_ref(*pv); + } +} + // A traversal class which finds all the expressions which must be // evaluated in order within a statement or larger expression. This // is used to implement the rules about order of evaluation. @@ -7422,16 +7432,16 @@ Variable::Variable(Type* type, Expression* init, bool is_global, bool is_parameter, bool is_receiver, Location location) : type_(type), init_(init), preinit_(NULL), location_(location), - embeds_(NULL), backend_(NULL), is_global_(is_global), - is_parameter_(is_parameter), is_closure_(false), is_receiver_(is_receiver), - is_varargs_parameter_(false), is_global_sink_(false), is_used_(false), - is_address_taken_(false), is_non_escaping_address_taken_(false), - seen_(false), init_is_lowered_(false), init_is_flattened_(false), + toplevel_decl_(NULL), init_refs_(NULL), embeds_(NULL), backend_(NULL), + is_global_(is_global), is_parameter_(is_parameter), is_closure_(false), + is_receiver_(is_receiver), is_varargs_parameter_(false), + is_global_sink_(false), is_used_(false), is_address_taken_(false), + is_non_escaping_address_taken_(false), seen_(false), + init_is_lowered_(false), init_is_flattened_(false), type_from_init_tuple_(false), type_from_range_index_(false), type_from_range_value_(false), type_from_chan_element_(false), is_type_switch_var_(false), determined_type_(false), - in_unique_section_(false), is_referenced_by_inline_(false), - toplevel_decl_(NULL) + in_unique_section_(false), is_referenced_by_inline_(false) { go_assert(type != NULL || init != NULL); go_assert(!is_parameter || init == NULL); @@ -7921,6 +7931,16 @@ Variable::get_init_block(Gogo* gogo, Named_object* function, return block_stmt; } +// Add an initializer reference. + +void +Variable::add_init_ref(Named_object* var) +{ + if (this->init_refs_ == NULL) + this->init_refs_ = new std::vector<Named_object*>; + this->init_refs_->push_back(var); +} + // Export the variable void |