compiler: inline call expressions and function references

Scan inlinable methods for references to global variables and
    functions (forgot to do that earlier).
    
    Track all packages mentioned by exports (that should have been done
    earlier too).
    
    Record assembler name in export data, so that we can inline calls to
    non-Go functions.  Modify gccgoimporter code to skip assembler name.
    
    This increases the number of inlinable functions in the standard
    library from 215 to 439.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/180677

From-SVN: r271976

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-949c3b7aa603bc09e650d62e82c600b3463802f0
+2609f9b8420e2341fbbe40d7cf6af42b0fba7293
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/export.cc

@@ -133,6 +133,11 @@ Collect_references_from_inline::expression(Expression** pexpr)
   if (fe != NULL)
     {
       Named_object* no = fe->named_object();
+
+      if (no->is_function_declaration()
+	  && no->func_declaration_value()->type()->is_builtin())
+	return TRAVERSE_CONTINUE;
+
       std::pair<Unordered_set(Named_object*)::iterator, bool> ins =
 	this->exports_->insert(no);
 
@@ -247,6 +252,22 @@ Export::export_globals(const std::string& package_name,
 	  if ((*p)->is_function()
 	      && (*p)->func_value()->export_for_inlining())
 	    check_inline_refs.push_back(*p);
+	  else if ((*p)->is_type())
+	    {
+	      const Bindings* methods = (*p)->type_value()->local_methods();
+	      if (methods != NULL)
+		{
+		  for (Bindings::const_definitions_iterator pm =
+			 methods->begin_definitions();
+		       pm != methods->end_definitions();
+		       ++pm)
+		    {
+		      Function* fn = (*pm)->func_value();
+		      if (fn->export_for_inlining())
+			check_inline_refs.push_back(*pm);
+		    }
+		}
+	    }
 	}
     }
 
@@ -282,6 +303,9 @@ Export::export_globals(const std::string& package_name,
 	}
     }
 
+  // Track all imported packages mentioned in export data.
+  Unordered_set(const Package*) all_imports;
+
   // Export the symbols in sorted order.  That will reduce cases where
   // irrelevant changes to the source code affect the exported
   // interface.
@@ -291,15 +315,20 @@ Export::export_globals(const std::string& package_name,
   for (Unordered_set(Named_object*)::const_iterator p = exports.begin();
        p != exports.end();
        ++p)
-    sorted_exports.push_back(*p);
+    {
+      sorted_exports.push_back(*p);
+
+      const Package* pkg = (*p)->package();
+      if (pkg != NULL)
+	all_imports.insert(pkg);
+    }
 
   std::sort(sorted_exports.begin(), sorted_exports.end(), Sort_bindings());
 
   // Assign indexes to all exported types and types referenced by
   // exported types, and collect all packages mentioned.
-  Unordered_set(const Package*) type_imports;
   int unexported_type_index = this->prepare_types(&sorted_exports,
-						  &type_imports);
+						  &all_imports);
 
   // Although the export data is readable, at least this version is,
   // it is conceptually a binary format.  Start with a four byte
@@ -327,7 +356,7 @@ Export::export_globals(const std::string& package_name,
 
   this->write_packages(packages);
 
-  this->write_imports(imports, type_imports);
+  this->write_imports(imports, all_imports);
 
   this->write_imported_init_fns(package_name, import_init_fn,
 				imported_init_fns);
@@ -693,7 +722,7 @@ import_compare(const std::pair<std::string, Package*>& a,
 
 void
 Export::write_imports(const std::map<std::string, Package*>& imports,
-		      const Unordered_set(const Package*)& type_imports)
+		      const Unordered_set(const Package*)& all_imports)
 {
   // Sort the imports for more consistent output.
   Unordered_set(const Package*) seen;
@@ -729,8 +758,8 @@ Export::write_imports(const std::map<std::string, Package*>& imports,
   // Write out a separate list of indirectly imported packages.
   std::vector<const Package*> indirect_imports;
   for (Unordered_set(const Package*)::const_iterator p =
-	 type_imports.begin();
+	 all_imports.begin();
-       p != type_imports.end();
+       p != all_imports.end();
        ++p)
     {
       if (seen.find(*p) == seen.end())

gcc/go/gofrontend/expressions.cc

@@ -1356,6 +1356,29 @@ Func_expression::do_get_backend(Translate_context* context)
   return gogo->backend()->convert_expression(btype, bexpr, this->location());
 }
 
+// The cost of inlining a function reference.
+
+int
+Func_expression::do_inlining_cost() const
+{
+  // FIXME: We don't inline references to nested functions.
+  if (this->closure_ != NULL)
+    return 0x100000;
+  if (this->function_->is_function()
+      && this->function_->func_value()->enclosing() != NULL)
+    return 0x100000;
+
+  return 1;
+}
+
+// Export a reference to a function.
+
+void
+Func_expression::do_export(Export_function_body* efb) const
+{
+  Expression::export_name(efb, this->function_);
+}
+
 // Ast dump for function.
 
 void
@@ -10088,38 +10111,82 @@ void
 Builtin_call_expression::do_export(Export_function_body* efb) const
 {
   Numeric_constant nc;
-  if (!this->numeric_constant_value(&nc))
+  if (this->numeric_constant_value(&nc))
     {
-      go_error_at(this->location(), "value is not constant");
+      if (nc.is_int())
-      return;
+	{
-    }
+	  mpz_t val;
+	  nc.get_int(&val);
+	  Integer_expression::export_integer(efb, val);
+	  mpz_clear(val);
+	}
+      else if (nc.is_float())
+	{
+	  mpfr_t fval;
+	  nc.get_float(&fval);
+	  Float_expression::export_float(efb, fval);
+	  mpfr_clear(fval);
+	}
+      else if (nc.is_complex())
+	{
+	  mpc_t cval;
+	  nc.get_complex(&cval);
+	  Complex_expression::export_complex(efb, cval);
+	  mpc_clear(cval);
+	}
+      else
+	go_unreachable();
 
-  if (nc.is_int())
+      // A trailing space lets us reliably identify the end of the number.
-    {
+      efb->write_c_string(" ");
-      mpz_t val;
-      nc.get_int(&val);
-      Integer_expression::export_integer(efb, val);
-      mpz_clear(val);
-    }
-  else if (nc.is_float())
-    {
-      mpfr_t fval;
-      nc.get_float(&fval);
-      Float_expression::export_float(efb, fval);
-      mpfr_clear(fval);
-    }
-  else if (nc.is_complex())
-    {
-      mpc_t cval;
-      nc.get_complex(&cval);
-      Complex_expression::export_complex(efb, cval);
-      mpc_clear(cval);
     }
   else
-    go_unreachable();
+    {
-
+      const char *s = NULL;
-  // A trailing space lets us reliably identify the end of the number.
+      switch (this->code_)
-  efb->write_c_string(" ");
+	{
+	default:
+	  go_unreachable();
+	case BUILTIN_APPEND:
+	  s = "append";
+	  break;
+	case BUILTIN_COPY:
+	  s = "copy";
+	  break;
+	case BUILTIN_LEN:
+	  s = "len";
+	  break;
+	case BUILTIN_CAP:
+	  s = "cap";
+	  break;
+	case BUILTIN_PRINT:
+	  s = "print";
+	  break;
+	case BUILTIN_PRINTLN:
+	  s = "println";
+	  break;
+	case BUILTIN_PANIC:
+	  s = "panic";
+	  break;
+	case BUILTIN_RECOVER:
+	  s = "recover";
+	  break;
+	case BUILTIN_CLOSE:
+	  s = "close";
+	  break;
+	case BUILTIN_REAL:
+	  s = "real";
+	  break;
+	case BUILTIN_IMAG:
+	  s = "imag";
+	  break;
+	case BUILTIN_COMPLEX:
+	  s = "complex";
+	  break;
+	}
+      efb->write_c_string(s);
+      this->export_arguments(efb);
+    }
 }
 
 // Class Call_expression.
@@ -11637,7 +11704,55 @@ Call_expression::do_get_backend(Translate_context* context)
   return this->call_;
 }
 
-// Dump ast representation for a call expressin.
+// The cost of inlining a call expression.
+
+int
+Call_expression::do_inlining_cost() const
+{
+  Func_expression* fn = this->fn_->func_expression();
+
+  // FIXME: We don't yet support all kinds of calls.
+  if (fn != NULL && fn->closure() != NULL)
+    return 0x100000;
+  if (this->fn_->interface_field_reference_expression())
+    return 0x100000;
+  if (this->get_function_type()->is_method())
+    return 0x100000;
+
+  return 5;
+}
+
+// Export a call expression.
+
+void
+Call_expression::do_export(Export_function_body* efb) const
+{
+  this->fn_->export_expression(efb);
+  this->export_arguments(efb);
+}
+
+// Export call expression arguments.
+
+void
+Call_expression::export_arguments(Export_function_body* efb) const
+{
+  efb->write_c_string("(");
+  if (this->args_ != NULL && !this->args_->empty())
+    {
+      Expression_list::const_iterator pa = this->args_->begin();
+      (*pa)->export_expression(efb);
+      for (pa++; pa != this->args_->end(); pa++)
+	{
+	  efb->write_c_string(", ");
+	  (*pa)->export_expression(efb);
+	}
+      if (this->is_varargs_)
+	efb->write_c_string("...");
+    }
+  efb->write_c_string(")");
+}
+
+// Dump ast representation for a call expression.
 
 void
 Call_expression::do_dump_expression(Ast_dump_context* ast_dump_context) const
@@ -17522,6 +17637,47 @@ Expression::make_backend(Bexpression* bexpr, Type* type, Location location)
 
 Expression*
 Expression::import_expression(Import_expression* imp, Location loc)
+{
+  Expression* expr = Expression::import_expression_without_suffix(imp, loc);
+  while (true)
+    {
+      if (imp->match_c_string("("))
+	{
+	  imp->advance(1);
+	  Expression_list* args = new Expression_list();
+	  bool is_varargs = false;
+	  while (!imp->match_c_string(")"))
+	    {
+	      Expression* arg = Expression::import_expression(imp, loc);
+	      if (arg->is_error_expression())
+		return arg;
+	      args->push_back(arg);
+	      if (imp->match_c_string(")"))
+		break;
+	      else if (imp->match_c_string("...)"))
+		{
+		  imp->advance(3);
+		  is_varargs = true;
+		  break;
+		}
+	      imp->require_c_string(", ");
+	    }
+	  imp->require_c_string(")");
+	  expr = Expression::make_call(expr, args, is_varargs, loc);
+	}
+      else
+	break;
+    }
+
+  return expr;
+}
+
+// Import an expression without considering a suffix (function
+// arguments, index operations, etc.).
+
+Expression*
+Expression::import_expression_without_suffix(Import_expression* imp,
+					     Location loc)
 {
   int c = imp->peek_char();
   if (c == '+' || c == '-' || c == '!' || c == '^' || c == '&' || c == '*')
@@ -17608,7 +17764,21 @@ Expression::import_identifier(Import_function_body* ifb, Location loc)
       return Expression::make_error(loc);
     }
 
-  return Expression::make_var_reference(no, loc);
+  if (no->is_variable() || no->is_result_variable())
+    return Expression::make_var_reference(no, loc);
+  else if (no->is_function() || no->is_function_declaration())
+    return Expression::make_func_reference(no, NULL, loc);
+  else
+    {
+      if (!ifb->saw_error())
+	go_error_at(ifb->location(),
+		    ("import error for %qs: "
+		     "unexpected type of identifier %qs (%d)"),
+		    ifb->name().c_str(),
+		    id.c_str(), no->classification());
+      ifb->set_saw_error();
+      return Expression::make_error(loc);
+    }
 }
 
 // Class Expression_list.

gcc/go/gofrontend/expressions.h

@@ -1253,6 +1253,9 @@ class Expression
   static Expression*
   import_identifier(Import_function_body*, Location);
 
+  static Expression*
+  import_expression_without_suffix(Import_expression*, Location);
+
   // The expression classification.
   Expression_classification classification_;
   // The location in the input file.
@@ -2409,6 +2412,12 @@ class Call_expression : public Expression
   virtual Bexpression*
   do_get_backend(Translate_context*);
 
+  int
+  do_inlining_cost() const;
+
+  void
+  do_export(Export_function_body*) const;
+
   virtual bool
   do_is_recover_call() const;
 
@@ -2431,6 +2440,9 @@ class Call_expression : public Expression
   bool
   determining_types();
 
+  void
+  export_arguments(Export_function_body*) const;
+
   void
   do_dump_expression(Ast_dump_context*) const;
 
@@ -2571,6 +2583,10 @@ class Builtin_call_expression : public Call_expression
   Bexpression*
   do_get_backend(Translate_context*);
 
+  int
+  do_inlining_cost() const
+  { return 1; }
+
   void
   do_export(Export_function_body*) const;
 
@@ -2745,6 +2761,12 @@ class Func_expression : public Expression
   Bexpression*
   do_get_backend(Translate_context*);
 
+  int
+  do_inlining_cost() const;
+
+  void
+  do_export(Export_function_body*) const;
+
   void
   do_dump_expression(Ast_dump_context*) const;
 

gcc/go/gofrontend/gogo.cc

@@ -5059,6 +5059,9 @@ Mark_inline_candidates::type(Type* t)
 void
 Gogo::do_exports()
 {
+  if (saw_errors())
+    return;
+
   // Mark any functions whose body should be exported for inlining by
   // other packages.
   Mark_inline_candidates mic;
@@ -5690,7 +5693,7 @@ Function::export_func(Export* exp, const Named_object* no) const
     block = this->block_;
   Function::export_func_with_type(exp, no, this->type_, this->results_,
 				  this->is_method() && this->nointerface(),
-				  block, this->location_);
+				  this->asm_name(), block, this->location_);
 }
 
 // Export a function with a type.
@@ -5699,7 +5702,8 @@ void
 Function::export_func_with_type(Export* exp, const Named_object* no,
 				const Function_type* fntype,
 				Function::Results* result_vars,
-				bool nointerface, Block* block, Location loc)
+				bool nointerface, const std::string& asm_name,
+				Block* block, Location loc)
 {
   exp->write_c_string("func ");
 
@@ -5709,6 +5713,13 @@ Function::export_func_with_type(Export* exp, const Named_object* no,
       exp->write_c_string("/*nointerface*/ ");
     }
 
+  if (!asm_name.empty())
+    {
+      exp->write_c_string("/*asm ");
+      exp->write_string(asm_name);
+      exp->write_c_string(" */ ");
+    }
+
   if (fntype->is_method())
     {
       exp->write_c_string("(");
@@ -5848,16 +5859,37 @@ Function::import_func(Import* imp, std::string* pname,
 		      Typed_identifier_list** presults,
 		      bool* is_varargs,
 		      bool* nointerface,
+		      std::string* asm_name,
 		      std::string* body)
 {
   imp->require_c_string("func ");
 
   *nointerface = false;
-  if (imp->match_c_string("/*"))
+  while (imp->match_c_string("/*"))
     {
-      imp->require_c_string("/*nointerface*/ ");
+      imp->advance(2);
-      *nointerface = true;
+      if (imp->match_c_string("nointerface"))
+	{
+	  imp->require_c_string("nointerface*/ ");
+	  *nointerface = true;
+	}
+      else if (imp->match_c_string("asm"))
+	{
+	  imp->require_c_string("asm ");
+	  *asm_name = imp->read_identifier();
+	  imp->require_c_string(" */ ");
+	}
+      else
+	{
+	  go_error_at(imp->location(),
+		      "import error at %d: unrecognized function comment",
+		      imp->pos());
+	  return false;
+	}
+    }
 
+  if (*nointerface)
+    {
       // Only a method can be nointerface.
       go_assert(imp->peek_char() == '(');
     }
@@ -7158,6 +7190,8 @@ Function_declaration::import_function_body(Gogo* gogo, Named_object* no)
       Named_type* rtype = fntype->receiver()->type()->deref()->named_type();
       go_assert(rtype != NULL);
       no = rtype->add_method(no->name(), fn);
+      const Package* package = rtype->named_object()->package();
+      package->bindings()->add_method(no);
     }
 
   Import_function_body ifb(gogo, this->imp_, no, body, nl + 1, outer, indent);

gcc/go/gofrontend/gogo.h

@@ -1573,7 +1573,7 @@ class Function
   static void
   export_func_with_type(Export*, const Named_object*,
 			const Function_type*, Results*, bool nointerface,
-			Block* block, Location);
+			const std::string& asm_name, Block* block, Location);
 
   // Import a function.  Reports whether the import succeeded.
   static bool
@@ -1581,7 +1581,7 @@ class Function
 	      bool* is_exported, Typed_identifier** receiver,
 	      Typed_identifier_list** pparameters,
 	      Typed_identifier_list** presults, bool* is_varargs,
-	      bool* nointerface, std::string* body);
+	      bool* nointerface, std::string* asm_name, std::string* body);
 
  private:
   // Type for mapping from label names to Label objects.
@@ -1805,7 +1805,7 @@ class Function_declaration
   {
     Function::export_func_with_type(exp, no, this->fntype_, NULL,
 				    this->is_method() && this->nointerface(),
-				    NULL, this->location_);
+				    this->asm_name_, NULL, this->location_);
   }
 
   // Check that the types used in this declaration's signature are defined.

gcc/go/gofrontend/import.cc

@@ -757,10 +757,11 @@ Import::import_func(Package* package)
   Typed_identifier_list* results;
   bool is_varargs;
   bool nointerface;
+  std::string asm_name;
   std::string body;
   if (!Function::import_func(this, &name, &fpkg, &is_exported, &receiver,
 			     &parameters, &results, &is_varargs, &nointerface,
-			     &body))
+			     &asm_name, &body))
     return;
   if (fpkg == NULL)
     fpkg = package;
@@ -802,12 +803,14 @@ Import::import_func(Package* package)
   else
     {
       no = fpkg->add_function_declaration(name, fntype, loc);
-      if (this->add_to_globals_)
+      if (this->add_to_globals_ && fpkg == package)
 	this->gogo_->add_dot_import_object(no);
     }
 
   if (nointerface)
     no->func_declaration_value()->set_nointerface();
+  if (!asm_name.empty())
+    no->func_declaration_value()->set_asm_name(asm_name);
   if (!body.empty() && !no->func_declaration_value()->has_imported_body())
     no->func_declaration_value()->set_imported_body(this, body);
 }
@@ -1231,6 +1234,12 @@ Import::register_builtin_type(Gogo* gogo, const char* name, Builtin_code code)
   this->builtin_types_[index] = named_object->type_value();
 }
 
+// Characters that stop read_identifier.  We base this on the
+// characters that stop an identifier, without worrying about
+// characters that are permitted in an identifier.  That lets us skip
+// UTF-8 parsing.
+static const char * const identifier_stop = " \n;,()[]";
+
 // Read an identifier from the stream.
 
 std::string
@@ -1242,8 +1251,14 @@ Import::read_identifier()
   while (true)
     {
       c = stream->peek_char();
-      if (c == -1 || c == ' ' || c == '\n' || c == ';' || c == ')')
+      if (c == -1 || strchr(identifier_stop, c) != NULL)
 	break;
+
+      // FIXME: Probably we shouldn't accept '.', but that might break
+      // some existing imports.
+      if (c == '.' && stream->match_c_string("..."))
+	break;
+
       ret += c;
       stream->advance(1);
     }
@@ -1521,7 +1536,18 @@ Import_function_body::read_identifier()
   for (size_t i = start; i < this->body_.length(); i++)
     {
       int c = static_cast<unsigned char>(this->body_[i]);
-      if (c == ' ' || c == '\n' || c == ';' || c == ')')
+      if (strchr(identifier_stop, c) != NULL)
+	{
+	  this->off_ = i;
+	  return this->body_.substr(start, i - start);
+	}
+
+      // FIXME: Probably we shouldn't accept '.', but that might break
+      // some existing imports.
+      if (c == '.'
+	  && i + 2 < this->body_.length()
+	  && this->body_[i + 1] == '.'
+	  && this->body_[i + 2] == '.')
 	{
 	  this->off_ = i;
 	  return this->body_.substr(start, i - start);

libgo/go/go/internal/gccgoimporter/parser.go

@@ -539,10 +539,12 @@ func (p *parser) parseNamedType(nlist []int) types.Type {
 		for p.tok == scanner.Ident {
 			p.expectKeyword("func")
 			if p.tok == '/' {
-				// Skip a /*nointerface*/ comment.
+				// Skip a /*nointerface*/ or /*asm ID */ comment.
 				p.expect('/')
 				p.expect('*')
-				p.expect(scanner.Ident)
+				if p.expect(scanner.Ident) == "asm" {
+					p.parseUnquotedString()
+				}
 				p.expect('*')
 				p.expect('/')
 			}
@@ -727,6 +729,17 @@ func (p *parser) parseFunctionType(pkg *types.Package, nlist []int) *types.Signa
 
 // Func = Name FunctionType [InlineBody] .
 func (p *parser) parseFunc(pkg *types.Package) *types.Func {
+	if p.tok == '/' {
+		// Skip an /*asm ID */ comment.
+		p.expect('/')
+		p.expect('*')
+		if p.expect(scanner.Ident) == "asm" {
+			p.parseUnquotedString()
+		}
+		p.expect('*')
+		p.expect('/')
+	}
+
 	name := p.parseName()
 	if strings.ContainsRune(name, '$') {
 		// This is a Type$equal or Type$hash function, which we don't want to parse,