compiler: add an option to emit optimization diagnostics

    Add a -fgo-debug-optimization option to emit optimization
    diagnostics. This can be used for testing optimizations. Apply
    this to the range clear optimizations of maps and arrays.

    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/170002

gcc/go:

	* lang.opt (-fgo-debug-optimization): New option.
	* go-c.h (struct go_create_gogo_args): Add debug_optimization
	field.
	* go-lang.c (go_langhook_init): Set debug_optimization field.
	* gccgo.texi (Invoking gccgo): Document -fgo-debug-optimization.

gcc/testsuite:

	* go.dg/arrayclear.go: New test.
	* go.dg/mapclear.go: New test.

From-SVN: r270993

diff --git a/gcc/go/ChangeLog b/gcc/go/ChangeLog
index 2c88593b05b5915840125832aa8892c7d4c08c0b..a73072f2546e5892e9f476292ca84cd151b59744 100644 (file)
--- a/gcc/go/ChangeLog
+++ b/gcc/go/ChangeLog
@@ -1,3 +1,11 @@
+2019-05-07  Cherry Zhang  <cherryyz@google.com>
+
+       * lang.opt (-fgo-debug-optimization): New option.
+       * go-c.h (struct go_create_gogo_args): Add debug_optimization
+       field.
+       * go-lang.c (go_langhook_init): Set debug_optimization field.
+       * gccgo.texi (Invoking gccgo): Document -fgo-debug-optimization.
+
 2019-03-06  Ian Lance Taylor  <iant@golang.org>
 
        PR go/89227

diff --git a/gcc/go/gccgo.texi b/gcc/go/gccgo.texi
index 231019541998ca2840abde79db8e8dd983d945f6..92fd74501ec9a5ed9ed02d4592c0195ab28cfc6b 100644 (file)
--- a/gcc/go/gccgo.texi
+++ b/gcc/go/gccgo.texi
@@ -246,6 +246,11 @@ This runs escape analysis only on functions whose names hash to values
 that match the given suffix @var{n}.  This can be used to binary
 search across functions to uncover escape analysis bugs.
 
+@item -fgo-debug-optimization
+@cindex @option{-fgo-debug-optimization}
+@cindex @option{-fno-go-debug-optimization}
+Output optimization diagnostics.
+
 @item -fgo-c-header=@var{file}
 @cindex @option{-fgo-c-header}
 Write top-level named Go struct definitions to @var{file} as C code.

diff --git a/gcc/go/go-c.h b/gcc/go/go-c.h
index 42e86cd335843040485cd0451cf27f4a29dfc205..695484cb84f08eaa2f90ff7119f0d8489b13c206 100644 (file)
--- a/gcc/go/go-c.h
+++ b/gcc/go/go-c.h
@@ -49,6 +49,7 @@ struct go_create_gogo_args
   int debug_escape_level;
   const char* debug_escape_hash;
   int64_t nil_check_size_threshold;
+  bool debug_optimization;
 };
 
 extern void go_create_gogo (const struct go_create_gogo_args*);

diff --git a/gcc/go/go-lang.c b/gcc/go/go-lang.c
index dd22fdab33fe288f3734f439f5ef339fc047d807..94f2cb25df3fdd306749add65fa4b3413d6ccb83 100644 (file)
--- a/gcc/go/go-lang.c
+++ b/gcc/go/go-lang.c
@@ -118,6 +118,7 @@ go_langhook_init (void)
   args.debug_escape_level = go_debug_escape_level;
   args.debug_escape_hash = go_debug_escape_hash;
   args.nil_check_size_threshold = TARGET_AIX ? -1 : 4096;
+  args.debug_optimization = go_debug_optimization;
   args.linemap = go_get_linemap();
   args.backend = go_get_backend();
   go_create_gogo (&args);

diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index 6cb0662957ee28703e8724d0ac0e3fc313fd1536..aafb52c90ad8b4f271e8d4ee4a30ee5d3e607e08 100644 (file)
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-4b3015de639cf22ed11ff96097555700909827c8
+dc9c1b43753f392fdc2045bcb7a4abaa44fe79f1
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

diff --git a/gcc/go/gofrontend/go.cc b/gcc/go/gofrontend/go.cc
index d8da232bbf036ea7a63b88c75b9b6218ed4e2424..183664a56625df6f3e8241c485a34dd961f78506 100644 (file)
--- a/gcc/go/gofrontend/go.cc
+++ b/gcc/go/gofrontend/go.cc
@@ -44,6 +44,8 @@ go_create_gogo(const struct go_create_gogo_args* args)
   if (args->debug_escape_hash != NULL)
     ::gogo->set_debug_escape_hash(args->debug_escape_hash);
   ::gogo->set_nil_check_size_threshold(args->nil_check_size_threshold);
+  if (args->debug_optimization)
+    ::gogo->set_debug_optimization(args->debug_optimization);
 }
 
 // Parse the input files.

diff --git a/gcc/go/gofrontend/gogo.cc b/gcc/go/gofrontend/gogo.cc
index f45576ee77dc0ab53d8a6e0140a65e4e3ee20cf3..9f18e14aecd27a9c6621f363a7b91c4c3abae4d3 100644 (file)
--- a/gcc/go/gofrontend/gogo.cc
+++ b/gcc/go/gofrontend/gogo.cc
@@ -55,6 +55,7 @@ Gogo::Gogo(Backend* backend, Linemap* linemap, int, int pointer_size)
     check_divide_overflow_(true),
     compiling_runtime_(false),
     debug_escape_level_(0),
+    debug_optimization_(false),
     nil_check_size_threshold_(4096),
     verify_types_(),
     interface_types_(),

diff --git a/gcc/go/gofrontend/gogo.h b/gcc/go/gofrontend/gogo.h
index 1c9f0de0b366e60b1795e8108182d16df9a7adc6..cfa238ac6e81a1b0580589379495849bb98f4e8d 100644 (file)
--- a/gcc/go/gofrontend/gogo.h
+++ b/gcc/go/gofrontend/gogo.h
@@ -326,6 +326,16 @@ class Gogo
   set_debug_escape_hash(const std::string& s)
   { this->debug_escape_hash_ = s; }
 
+  // Return whether to output optimization diagnostics.
+  bool
+  debug_optimization() const
+  { return this->debug_optimization_; }
+
+  // Set the option to output optimization diagnostics.
+  void
+  set_debug_optimization(bool b)
+  { this->debug_optimization_ = b; }
+
   // Return the size threshold used to determine whether to issue
   // a nil-check for a given pointer dereference. A threshold of -1
   // implies that all potentially faulting dereference ops should
@@ -1075,6 +1085,9 @@ class Gogo
   // -fgo-debug-escape-hash option. The analysis is run only on
   // functions with names that hash to the matching value.
   std::string debug_escape_hash_;
+  // Whether to output optimization diagnostics, from the
+  // -fgo-debug-optimization option.
+  bool debug_optimization_;
   // Nil-check size threshhold.
   int64_t nil_check_size_threshold_;
   // A list of types to verify.

diff --git a/gcc/go/gofrontend/statements.cc b/gcc/go/gofrontend/statements.cc
index 1827f81901bab00927e9383562f9d4286ef7db14..2e2d039afbd99ad68bf31b99898e28bda0f49a93 100644 (file)
--- a/gcc/go/gofrontend/statements.cc
+++ b/gcc/go/gofrontend/statements.cc
@@ -5512,6 +5512,8 @@ For_range_statement::do_lower(Gogo* gogo, Named_object*, Block* enclosing,
                                                      range_temp, loc);
       if (clear != NULL)
         {
+          if (gogo->debug_optimization())
+            go_inform(loc, "map range clear");
           temp_block->add_statement(clear);
           return Statement::make_block_statement(temp_block, loc);
         }
@@ -5527,6 +5529,8 @@ For_range_statement::do_lower(Gogo* gogo, Named_object*, Block* enclosing,
                                                        range_temp, loc);
       if (clear != NULL)
         {
+          if (gogo->debug_optimization())
+            go_inform(loc, "array range clear");
           temp_block->add_statement(clear);
           return Statement::make_block_statement(temp_block, loc);
         }

diff --git a/gcc/go/lang.opt b/gcc/go/lang.opt
index f1a8126653567d46796882fbac53b796231bbf4d..91b8e4631a622f44036cb5a6d882adaef4689c4a 100644 (file)
--- a/gcc/go/lang.opt
+++ b/gcc/go/lang.opt
@@ -85,6 +85,10 @@ fgo-debug-escape-hash=
 Go Joined RejectNegative Var(go_debug_escape_hash) Init(0)
 -fgo-debug-escape-hash=<string>        Hash value to debug escape analysis.
 
+fgo-debug-optimization
+Go Var(go_debug_optimization) Init(0)
+Emit optimization diagnostics.
+
 o
 Go Joined Separate
 ; Documented in common.opt

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a7b40dfc64e0516d7efa539aa9a0d4c6ea620ece..e132b5b8d7f3de2eb8ba74e972c2d12774823471 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-05-07  Cherry Zhang  <cherryyz@google.com>
+
+       * go.dg/arrayclear.go: New test.
+       * go.dg/mapclear.go: New test.
+
 2019-05-07  Kelvin Nilsen  <kelvin@gcc.gnu.org>
 
        PR target/89765

diff --git a/gcc/testsuite/go.dg/arrayclear.go b/gcc/testsuite/go.dg/arrayclear.go
new file mode 100644 (file)
index 0000000..6daebc0
--- /dev/null
+++ b/gcc/testsuite/go.dg/arrayclear.go
@@ -0,0 +1,20 @@
+// { dg-do compile }
+// { dg-options "-fgo-debug-optimization" }
+
+package p
+
+var a [10]int
+
+func arrayClear() {
+       for i := range a { // { dg-error "array range clear" }
+               a[i] = 0
+       }
+}
+
+var s []int
+
+func sliceClear() {
+       for i := range s { // { dg-error "array range clear" }
+               s[i] = 0
+       }
+}

diff --git a/gcc/testsuite/go.dg/mapclear.go b/gcc/testsuite/go.dg/mapclear.go
new file mode 100644 (file)
index 0000000..a3bebe4
--- /dev/null
+++ b/gcc/testsuite/go.dg/mapclear.go
@@ -0,0 +1,10 @@
+// { dg-do compile }
+// { dg-options "-fgo-debug-optimization" }
+
+package p
+
+func clear(m map[int]int) {
+       for k := range m { // { dg-error "map range clear" }
+               delete(m, k)
+       }
+}