compiler: turn on escape analysis by default

    
    The escape analysis now runs by default. It can be disabled with
    the negative flag, -fno-go-optimize-allocs.
    
    Reviewed-on: https://go-review.googlesource.com/86247

	* lang.opt (fgo-optimize): Remove RejectNegative.
	* go-c.h (go_enable_optimize): Update declaration to take value
	argument.
	* go-lang.c (go_langhook_handle_option): Pass value to
	go_enable_optimize.
	* gccgo.texi (Invoking gccgo): Update -fgo-optimize-allocs doc.

From-SVN: r257319

gcc/go/ChangeLog

+2018-02-01  Cherry Zhang  <cherryyz@google.com>
+
+	* lang.opt (fgo-optimize): Remove RejectNegative.
+	* go-c.h (go_enable_optimize): Update declaration to take value
+	argument.
+	* go-lang.c (go_langhook_handle_option): Pass value to
+	go_enable_optimize.
+	* gccgo.texi (Invoking gccgo): Update -fgo-optimize-allocs doc.
+
 2018-01-30  Ian Lance Taylor  <iant@golang.org>
 
 	* go-gcc.cc (Gcc_backend::convert_tree): New private method.

gcc/go/gccgo.texi

@@ -229,10 +229,10 @@ may be used.  Or the checks may be removed via
 by default, but in the future may be off by default on systems that do
 not require it.
 
-@item -fgo-optimize-allocs
-@cindex @option{-fgo-optimize-allocs}
-Use escape analysis to allocate objects on the stack rather than the
-heap when possible.  In the future this may be the default.
+@item -fno-go-optimize-allocs
+@cindex @option{-fno-go-optimize-allocs}
+Disable escape analysis, which tries to allocate objects on the stack
+rather than the heap.
 
 @item -fgo-debug-escape@var{n}
 @cindex @option{-fgo-debug-escape}

gcc/go/go-c.h

@@ -29,7 +29,7 @@ class Backend;
    interface.  */
 
 extern int go_enable_dump (const char*);
-extern int go_enable_optimize (const char*);
+extern int go_enable_optimize (const char*, int);
 
 extern void go_add_search_path (const char*);
 

gcc/go/go-lang.c

@@ -194,7 +194,7 @@ static bool
 go_langhook_handle_option (
     size_t scode,
     const char *arg,
-    int value ATTRIBUTE_UNUSED,
+    int value,
     int kind ATTRIBUTE_UNUSED,
     location_t loc ATTRIBUTE_UNUSED,
     const struct cl_option_handlers *handlers ATTRIBUTE_UNUSED)
@@ -251,7 +251,7 @@ go_langhook_handle_option (
       break;
 
     case OPT_fgo_optimize_:
-      ret = go_enable_optimize (arg) ? true : false;
+      ret = go_enable_optimize (arg, value) ? true : false;
       break;
 
     case OPT_fgo_pkgpath_:

gcc/go/gofrontend/MERGE

-023c3d4358d101c71ac1436065690eaec2ce138e
+e148068360699f24118950b728f23a5c98e1f85e
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/escape.cc

@@ -825,7 +825,7 @@ Escape_note::parse_tag(std::string* tag)
 
 // The -fgo-optimize-alloc flag activates this escape analysis.
 
-Go_optimize optimize_allocation_flag("allocs");
+Go_optimize optimize_allocation_flag("allocs", true);
 
 // A helper function to compute whether a function name has a
 // matching hash value.

gcc/go/gofrontend/go-optimize.cc

@@ -19,8 +19,8 @@ Go_optimize* optimizations;
 
 // Create a new optimization.
 
-Go_optimize::Go_optimize(const char* name)
-  : next_(optimizations), name_(name), is_enabled_(false)
+Go_optimize::Go_optimize(const char* name, bool enabled)
+  : next_(optimizations), name_(name), is_enabled_(enabled)
 {
   optimizations = this;
 }
@@ -28,7 +28,7 @@ Go_optimize::Go_optimize(const char* name)
 // Enable an optimization by name.
 
 bool
-Go_optimize::enable_by_name(const char* name)
+Go_optimize::enable_by_name(const char* name, bool value)
 {
   bool is_all = strcmp(name, "all") == 0;
   bool found = false;
@@ -36,18 +36,18 @@ Go_optimize::enable_by_name(const char* name)
     {
       if (is_all || strcmp(name, p->name_) == 0)
 	{
-	  p->is_enabled_ = true;
+	  p->is_enabled_ = value;
 	  found = true;
 	}
     }
   return found;
 }
 
-// Enable an optimization.  Return 1 if this is a real name, 0 if not.
+// Enable/disable an optimization.  Return 1 if this is a real name, 0 if not.
 
 GO_EXTERN_C
 int
-go_enable_optimize(const char* name)
+go_enable_optimize(const char* name, int value)
 {
-  return Go_optimize::enable_by_name(name) ? 1 : 0;
+  return Go_optimize::enable_by_name(name, (bool)value) ? 1 : 0;
 }

gcc/go/gofrontend/go-optimize.h

@@ -15,16 +15,16 @@
 class Go_optimize
 {
  public:
-  Go_optimize(const char* name);
+  Go_optimize(const char*, bool);
 
   // Whether this optimizaiton was enabled.
   bool
   is_enabled() const
   { return this->is_enabled_; }
 
-  // Enable an optimization by name.  Return true if found.
+  // Enable/disable an optimization by name.  Return true if found.
   static bool
-  enable_by_name(const char*);
+  enable_by_name(const char*, bool);
 
  private:
   // The next optimize flag.  These are not in any order.

gcc/go/lang.opt

@@ -58,7 +58,7 @@ Go Joined RejectNegative
 -fgo-dump-<type>	Dump Go frontend internal information.
 
 fgo-optimize-
-Go Joined RejectNegative
+Go Joined
 -fgo-optimize-<type>	Turn on optimization passes in the frontend.
 
 fgo-pkgpath=