escape: Add basic debugging.

    
    Emit basic debug information when compiling with the flag
    -fgo-debug-escape#.
    
    Reviewed-on: https://go-review.googlesource.com/22376

	2016-08-02  Chris Manghane  <cmang@google.com>

	* lang.opt: Add -fgo-debug-escape option.
	* go-c.h (go_create_gogo): Add debug_escape_level parameter.
	* go-lang.c (go_langhook_init): Pass go_debug_escape_level to
	go_create_gogo.

From-SVN: r239002

gcc/go/ChangeLog

+2016-08-02  Chris Manghane  <cmang@google.com>
+
+	* lang.opt: Add -fgo-debug-escape option.
+	* go-c.h (go_create_gogo): Add debug_escape_level parameter.
+	* go-lang.c (go_langhook_init): Pass go_debug_escape_level to
+	go_create_gogo.
+
 2016-05-06  Chris Manghane  <cmang@google.com>
 
 	* Make-lang.in (GO_OBJS): Add go/escape.o (based on an entirely

gcc/go/go-c.h

@@ -34,7 +34,8 @@ extern void go_add_search_path (const char*);
 extern void go_create_gogo (int int_type_size, int pointer_size,
 			    const char* pkgpath, const char *prefix,
 			    const char *relative_import_path,
-			    bool check_divide_zero, bool check_divide_overflow);
+			    bool check_divide_zero, bool check_divide_overflow,
+			    int debug_escape_level);
 
 extern void go_parse_input_files (const char**, unsigned int,
 				  bool only_check_syntax,

gcc/go/go-lang.c

@@ -101,7 +101,7 @@ go_langhook_init (void)
      go_type_for_size).  */
   go_create_gogo (INT_TYPE_SIZE, POINTER_SIZE, go_pkgpath, go_prefix,
 		  go_relative_import_path, go_check_divide_zero,
-		  go_check_divide_overflow);
+		  go_check_divide_overflow, go_debug_escape_level);
 
   build_common_builtin_nodes ();
 

gcc/go/gofrontend/MERGE

-d4b47fef149fc905ae6b418934f6be8cf6be433e
+89a0b3a04f80df388242166b8835f12e82ceb194
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/escape.h

@@ -193,6 +193,17 @@ class Node
   Location
   location() const;
 
+  // Return this node's AST formatted string.
+  std::string
+  ast_format(Gogo*) const;
+
+  // Return this node's detailed format string.
+  std::string
+  details() const;
+
+  std::string
+  op_format() const;
+
   // Return this node's escape state.
   Escape_state*
   state(Escape_context* context, Named_object* fn);
@@ -343,6 +354,10 @@ class Escape_context
   set_current_function(Named_object* fn)
   { this->current_function_ = fn; }
 
+  // Return the name of the current function.
+  std::string
+  current_function_name() const;
+
   // Return true if this is the context for a mutually recursive set of functions.
   bool
   recursive() const

gcc/go/gofrontend/go.cc

@@ -22,7 +22,8 @@ GO_EXTERN_C
 void
 go_create_gogo(int int_type_size, int pointer_size, const char *pkgpath,
 	       const char *prefix, const char *relative_import_path,
-	       bool check_divide_by_zero, bool check_divide_overflow)
+	       bool check_divide_by_zero, bool check_divide_overflow,
+	       int debug_escape_level)
 {
   go_assert(::gogo == NULL);
   Linemap* linemap = go_get_linemap();
@@ -39,6 +40,7 @@ go_create_gogo(int int_type_size, int pointer_size, const char *pkgpath,
     ::gogo->set_check_divide_by_zero(check_divide_by_zero);
   if (check_divide_overflow)
     ::gogo->set_check_divide_overflow(check_divide_overflow);
+  ::gogo->set_debug_escape_level(debug_escape_level);
 }
 
 // Parse the input files.

gcc/go/gofrontend/gogo.h

@@ -239,6 +239,16 @@ class Gogo
   set_check_divide_overflow(bool b)
   { this->check_divide_overflow_ = b; }
 
+  // Return the level of escape analysis debug information to emit.
+  int
+  debug_escape_level() const
+  { return this->debug_escape_level_; }
+
+  // Set the level of escape analysis debugging from a command line option.
+  void
+  set_debug_escape_level(int level)
+  { this->debug_escape_level_ = level; }
+
   // Return the priority to use for the package we are compiling.
   // This is two more than the largest priority of any package we
   // import.
@@ -786,6 +796,9 @@ class Gogo
   // Whether or not to check for division overflow, from the
   // -fgo-check-divide-overflow option.
   bool check_divide_overflow_;
+  // The level of escape analysis debug information to emit, from the
+  // -fgo-debug-escape option.
+  int debug_escape_level_;
   // A list of types to verify.
   std::vector<Type*> verify_types_;
   // A list of interface types defined while parsing.
@@ -2715,7 +2728,7 @@ class Unnamed_label
 {
  public:
   Unnamed_label(Location location)
-    : location_(location), blabel_(NULL)
+    : location_(location), derived_from_(NULL), blabel_(NULL)
   { }
 
   // Get the location where the label is defined.
@@ -2728,6 +2741,16 @@ class Unnamed_label
   set_location(Location location)
   { this->location_ = location; }
 
+  // Get the top level statement this unnamed label is derived from.
+  Statement*
+  derived_from() const
+  { return this->derived_from_; }
+
+  // Set the top level statement this unnamed label is derived from.
+  void
+  set_derived_from(Statement* s)
+  { this->derived_from_ = s; }
+
   // Return a statement which defines this label.
   Bstatement*
   get_definition(Translate_context*);
@@ -2743,6 +2766,9 @@ class Unnamed_label
 
   // The location where the label is defined.
   Location location_;
+  // The top-level statement this unnamed label was derived/lowered from.
+  // This is NULL is this label is not the top-level of a lowered statement.
+  Statement* derived_from_;
   // The backend representation of this label.
   Blabel* blabel_;
 };

gcc/go/gofrontend/statements.cc

@@ -3058,7 +3058,6 @@ Unnamed_label_statement::do_get_backend(Translate_context* context)
   return this->label_->get_definition(context);
 }
 
-
 // Dump the AST representation for an unnamed label definition statement.
 
 void
@@ -5091,6 +5090,7 @@ For_statement::do_lower(Gogo*, Named_object*, Block* enclosing,
     }
 
   Unnamed_label* top = new Unnamed_label(this->location());
+  top->set_derived_from(this);
   b->add_statement(Statement::make_unnamed_label_statement(top));
 
   s = Statement::make_block_statement(this->statements_,

gcc/go/lang.opt

@@ -69,6 +69,10 @@ frequire-return-statement
 Go Var(go_require_return_statement) Init(1) Warning
 Functions which return values must end with return statements.
 
+fgo-debug-escape
+Go Joined UInteger Var(go_debug_escape_level) Init(0)
+Emit debugging information related to the escape analysis pass when run with -fgo-optimize-allocs.
+
 o
 Go Joined Separate
 ; Documented in common.opt