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compiler: Fix order of initialization bug with global var a, b = f(). 

From-SVN: r187103
This commit is contained in:
Ian Lance Taylor 2012-05-03 16:09:25 +00:00
parent 0fe5522f8b
commit 29f31724ef
4 changed files with 85 additions and 18 deletions
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54
gcc/go/gofrontend/gogo-tree.cc
View File

@ -590,10 +590,11 @@ Find_var::expression(Expression** pexpr)
return TRAVERSE_CONTINUE;
}
// Return true if EXPR refers to VAR.
// Return true if EXPR, PREINIT, or DEP refers to VAR.
static bool
expression_requires(Expression* expr, Block* preinit, Named_object* var)
expression_requires(Expression* expr, Block* preinit, Named_object* dep,
Named_object* var)
{
Find_var::Seen_objects seen_objects;
Find_var find_var(var, &seen_objects);
@ -601,7 +602,15 @@ expression_requires(Expression* expr, Block* preinit, Named_object* var)
Expression::traverse(&expr, &find_var);
if (preinit != NULL)
preinit->traverse(&find_var);
if (dep != NULL)
{
Expression* init = dep->var_value()->init();
if (init != NULL)
Expression::traverse(&init, &find_var);
if (dep->var_value()->has_pre_init())
dep->var_value()->preinit()->traverse(&find_var);
}
return find_var.found();
}
@ -658,7 +667,7 @@ typedef std::list<Var_init> Var_inits;
// variable V2 then we initialize V1 after V2.
static void
sort_var_inits(Var_inits* var_inits)
sort_var_inits(Gogo* gogo, Var_inits* var_inits)
{
Var_inits ready;
while (!var_inits->empty())
@ -667,6 +676,7 @@ sort_var_inits(Var_inits* var_inits)
Named_object* var = p1->var();
Expression* init = var->var_value()->init();
Block* preinit = var->var_value()->preinit();
Named_object* dep = gogo->var_depends_on(var->var_value());
// Start walking through the list to see which variables VAR
// needs to wait for. We can skip P1->WAITING variables--that
@ -678,20 +688,22 @@ sort_var_inits(Var_inits* var_inits)
for (; p2 != var_inits->end(); ++p2)
{
if (expression_requires(init, preinit, p2->var()))
Named_object* p2var = p2->var();
if (expression_requires(init, preinit, dep, p2var))
{
// Check for cycles.
if (expression_requires(p2->var()->var_value()->init(),
p2->var()->var_value()->preinit(),
if (expression_requires(p2var->var_value()->init(),
p2var->var_value()->preinit(),
gogo->var_depends_on(p2var->var_value()),
var))
{
error_at(var->location(),
("initialization expressions for %qs and "
"%qs depend upon each other"),
var->message_name().c_str(),
p2->var()->message_name().c_str());
p2var->message_name().c_str());
inform(p2->var()->location(), "%qs defined here",
p2->var()->message_name().c_str());
p2var->message_name().c_str());
p2 = var_inits->end();
}
else
@ -714,9 +726,11 @@ sort_var_inits(Var_inits* var_inits)
// VAR does not depends upon any other initialization expressions.
// Check for a loop of VAR on itself. We only do this if
// INIT is not NULL; when INIT is NULL, it means that
// PREINIT sets VAR, which we will interpret as a loop.
if (init != NULL && expression_requires(init, preinit, var))
// INIT is not NULL and there is no dependency; when INIT is
// NULL, it means that PREINIT sets VAR, which we will
// interpret as a loop.
if (init != NULL && dep == NULL
&& expression_requires(init, preinit, NULL, var))
error_at(var->location(),
"initialization expression for %qs depends upon itself",
var->message_name().c_str());
@ -783,7 +797,7 @@ Gogo::write_globals()
}
// There is nothing useful we can output for constants which
// have ideal or non-integeral type.
// have ideal or non-integral type.
if (no->is_const())
{
Type* type = no->const_value()->type();
@ -834,7 +848,9 @@ Gogo::write_globals()
;
else if (TREE_CONSTANT(init))
{
if (expression_requires(no->var_value()->init(), NULL, no))
if (expression_requires(no->var_value()->init(), NULL,
this->var_depends_on(no->var_value()),
no))
error_at(no->location(),
"initialization expression for %qs depends "
"upon itself",
@ -879,6 +895,14 @@ Gogo::write_globals()
else
var_inits.push_back(Var_init(no, var_init_tree));
}
else if (this->var_depends_on(no->var_value()) != NULL)
{
// This variable is initialized from something that is
// not in its init or preinit. This variable needs to
// participate in dependency analysis sorting, in case
// some other variable depends on this one.
var_inits.push_back(Var_init(no, integer_zero_node));
}
if (!is_sink && no->var_value()->type()->has_pointer())
var_gc.push_back(no);
@ -896,7 +920,7 @@ Gogo::write_globals()
// workable order.
if (!var_inits.empty())
{
sort_var_inits(&var_inits);
sort_var_inits(this, &var_inits);
for (Var_inits::const_iterator p = var_inits.begin();
p != var_inits.end();
++p)

5
gcc/go/gofrontend/gogo.cc
View File

@ -32,6 +32,7 @@ Gogo::Gogo(Backend* backend, Linemap* linemap, int int_type_size,
imported_unsafe_(false),
packages_(),
init_functions_(),
var_deps_(),
need_init_fn_(false),
init_fn_name_(),
imported_init_fns_(),
@ -3820,6 +3821,10 @@ void
Variable::lower_init_expression(Gogo* gogo, Named_object* function,
Statement_inserter* inserter)
{
Named_object* dep = gogo->var_depends_on(this);
if (dep != NULL && dep->is_variable())
dep->var_value()->lower_init_expression(gogo, function, inserter);
if (this->init_ != NULL && !this->init_is_lowered_)
{
if (this->seen_)

26
gcc/go/gofrontend/gogo.h
View File

@ -384,6 +384,23 @@ class Gogo
void
clear_file_scope();
// Record that VAR1 must be initialized after VAR2. This is used
// when VAR2 does not appear in VAR1's INIT or PREINIT.
void
record_var_depends_on(Variable* var1, Named_object* var2)
{
go_assert(this->var_deps_.find(var1) == this->var_deps_.end());
this->var_deps_[var1] = var2;
}
// Return the variable that VAR depends on, or NULL if none.
Named_object*
var_depends_on(Variable* var) const
{
Var_deps::const_iterator p = this->var_deps_.find(var);
return p != this->var_deps_.end() ? p->second : NULL;
}
// Queue up a type-specific function to be written out. This is
// used when a type-specific function is needed when not at the top
// level.
@ -639,8 +656,9 @@ class Gogo
// Type used to map package names to packages.
typedef std::map<std::string, Package*> Packages;
// Type used to map special names in the sys package.
typedef std::map<std::string, std::string> Sys_names;
// Type used to map variables to the function calls that set them.
// This is used for initialization dependency analysis.
typedef std::map<Variable*, Named_object*> Var_deps;
// Type used to queue writing a type specific function.
struct Specific_type_function
@ -683,6 +701,10 @@ class Gogo
Packages packages_;
// The functions named "init", if there are any.
std::vector<Named_object*> init_functions_;
// A mapping from variables to the function calls that initialize
// them, if it is not stored in the variable's init or preinit.
// This is used for dependency analysis.
Var_deps var_deps_;
// Whether we need a magic initialization function.
bool need_init_fn_;
// The name of the magic initialization function.

18
gcc/go/gofrontend/parse.cc
View File

@ -1667,6 +1667,7 @@ Parse::init_vars_from_call(const Typed_identifier_list* vars, Type* type,
// the right number of values, but it might. Declare the variables,
// and then assign the results of the call to them.
Named_object* first_var = NULL;
unsigned int index = 0;
bool any_new = false;
for (Typed_identifier_list::const_iterator pv = vars->begin();
@ -1674,7 +1675,22 @@ Parse::init_vars_from_call(const Typed_identifier_list* vars, Type* type,
++pv, ++index)
{
Expression* init = Expression::make_call_result(call, index);
this->init_var(*pv, type, init, is_coloneq, false, &any_new);
Named_object* no = this->init_var(*pv, type, init, is_coloneq, false,
&any_new);
if (this->gogo_->in_global_scope() && no->is_variable())
{
if (first_var == NULL)
first_var = no;
else
{
// The subsequent vars have an implicit dependency on
// the first one, so that everything gets initialized in
// the right order and so that we detect cycles
// correctly.
this->gogo_->record_var_depends_on(no->var_value(), first_var);
}
}
}
if (is_coloneq && !any_new)