compiler, runtime: Track fields with tag go:"track".

	* go-gcc.cc: Include "output.h".
	(global_variable): Add is_unique_section parameter.
	(global_variable_set_init): Adjust unique section if necessary.
	* Make-lang.in (go/go-gcc.o): Add dependency on output.h.

From-SVN: r193945

4 files changed, 119 insertions, 1 deletions

diff --git a/libgo/Makefile.am b/libgo/Makefile.am
index fc0d991..50a21b8 100644
--- a/libgo/Makefile.am
+++ b/libgo/Makefile.am
@@ -450,6 +450,7 @@ runtime_files = \
 	runtime/go-deferred-recover.c \
 	runtime/go-eface-compare.c \
 	runtime/go-eface-val-compare.c \
+	runtime/go-fieldtrack.c \
 	runtime/go-getgoroot.c \
 	runtime/go-int-array-to-string.c \
 	runtime/go-int-to-string.c \
diff --git a/libgo/Makefile.in b/libgo/Makefile.in
index 147d9c8..38b8ddf 100644
--- a/libgo/Makefile.in
+++ b/libgo/Makefile.in
@@ -196,7 +196,7 @@ am__objects_5 = go-append.lo go-assert.lo go-assert-interface.lo \
 	go-check-interface.lo go-construct-map.lo \
 	go-convert-interface.lo go-copy.lo go-defer.lo \
 	go-deferred-recover.lo go-eface-compare.lo \
-	go-eface-val-compare.lo go-getgoroot.lo \
+	go-eface-val-compare.lo go-fieldtrack.lo go-getgoroot.lo \
 	go-int-array-to-string.lo go-int-to-string.lo \
 	go-interface-compare.lo go-interface-eface-compare.lo \
 	go-interface-val-compare.lo go-make-slice.lo go-map-delete.lo \
@@ -781,6 +781,7 @@ runtime_files = \
 	runtime/go-deferred-recover.c \
 	runtime/go-eface-compare.c \
 	runtime/go-eface-val-compare.c \
+	runtime/go-fieldtrack.c \
 	runtime/go-getgoroot.c \
 	runtime/go-int-array-to-string.c \
 	runtime/go-int-to-string.c \
@@ -2421,6 +2422,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/go-deferred-recover.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/go-eface-compare.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/go-eface-val-compare.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/go-fieldtrack.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/go-getgoroot.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/go-int-array-to-string.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/go-int-to-string.Plo@am__quote@
@@ -2657,6 +2659,13 @@ go-eface-val-compare.lo: runtime/go-eface-val-compare.c
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o go-eface-val-compare.lo `test -f 'runtime/go-eface-val-compare.c' || echo '$(srcdir)/'`runtime/go-eface-val-compare.c
 
+go-fieldtrack.lo: runtime/go-fieldtrack.c
+@am__fastdepCC_TRUE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT go-fieldtrack.lo -MD -MP -MF $(DEPDIR)/go-fieldtrack.Tpo -c -o go-fieldtrack.lo `test -f 'runtime/go-fieldtrack.c' || echo '$(srcdir)/'`runtime/go-fieldtrack.c
+@am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/go-fieldtrack.Tpo $(DEPDIR)/go-fieldtrack.Plo
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	source='runtime/go-fieldtrack.c' object='go-fieldtrack.lo' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o go-fieldtrack.lo `test -f 'runtime/go-fieldtrack.c' || echo '$(srcdir)/'`runtime/go-fieldtrack.c
+
 go-getgoroot.lo: runtime/go-getgoroot.c
 @am__fastdepCC_TRUE@	$(LIBTOOL)  --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT go-getgoroot.lo -MD -MP -MF $(DEPDIR)/go-getgoroot.Tpo -c -o go-getgoroot.lo `test -f 'runtime/go-getgoroot.c' || echo '$(srcdir)/'`runtime/go-getgoroot.c
 @am__fastdepCC_TRUE@	$(am__mv) $(DEPDIR)/go-getgoroot.Tpo $(DEPDIR)/go-getgoroot.Plo
diff --git a/libgo/go/runtime/debug.go b/libgo/go/runtime/debug.go
index 0211ce6..9da71a7 100644
--- a/libgo/go/runtime/debug.go
+++ b/libgo/go/runtime/debug.go
@@ -168,3 +168,10 @@ func BlockProfile(p []BlockProfileRecord) (n int, ok bool)
 // If all is true, Stack formats stack traces of all other goroutines
 // into buf after the trace for the current goroutine.
 func Stack(buf []byte, all bool) int
+
+// Get field tracking information.  Only fields with a tag go:"track"
+// are tracked.  This function will add every such field that is
+// referenced to the map.  The keys in the map will be
+// PkgPath.Name.FieldName.  The value will be true for each field
+// added.
+func Fieldtrack(map[string]bool)
diff --git a/libgo/runtime/go-fieldtrack.c b/libgo/runtime/go-fieldtrack.c
new file mode 100644
index 0000000..62b36dc
--- /dev/null
+++ b/libgo/runtime/go-fieldtrack.c
@@ -0,0 +1,101 @@
+/* go-fieldtrack.c -- structure field data analysis.
+
+   Copyright 2012 The Go Authors. All rights reserved.
+   Use of this source code is governed by a BSD-style
+   license that can be found in the LICENSE file.  */
+
+#include "runtime.h"
+#include "go-type.h"
+#include "map.h"
+
+/* The compiler will track fields that have the tag go:"track".  Any
+   function that refers to such a field will call this function with a
+   string
+       fieldtrack "package.type.field"
+
+   This function does not actually do anything.  Instead, we gather
+   the field tracking information by looking for strings of that form
+   in the read-only data section.  This is, of course, a horrible
+   hack, but it's good enough for now.  We can improve it, e.g., by a
+   linker plugin, if this turns out to be useful.  */
+
+void
+__go_fieldtrack (byte *p __attribute__ ((unused)))
+{
+}
+
+/* A runtime function to add all the tracked fields to a
+   map[string]bool.  */
+
+extern const char _etext[] __attribute__ ((weak));
+extern const char __etext[] __attribute__ ((weak));
+extern const char __data_start[] __attribute__ ((weak));
+extern const char _edata[] __attribute__ ((weak));
+extern const char __edata[] __attribute__ ((weak));
+extern const char __bss_start[] __attribute__ ((weak));
+
+void runtime_Fieldtrack (struct __go_map *) __asm__ ("runtime.Fieldtrack");
+
+void
+runtime_Fieldtrack (struct __go_map *m)
+{
+  const char *p;
+  const char *pend;
+  const char *prefix;
+  size_t prefix_len;
+
+  p = __data_start;
+  if (p == NULL)
+    p = __etext;
+  if (p == NULL)
+    p = _etext;
+  if (p == NULL)
+    return;
+
+  pend = __edata;
+  if (pend == NULL)
+    pend = _edata;
+  if (pend == NULL)
+    pend = __bss_start;
+  if (pend == NULL)
+    return;
+
+  prefix = "fieldtrack ";
+  prefix_len = __builtin_strlen (prefix);
+
+  while (p < pend)
+    {
+      const char *q1;
+      const char *q2;
+
+      q1 = __builtin_memchr (p + prefix_len, '"', pend - (p + prefix_len));
+      if (q1 == NULL)
+	break;
+
+      if (__builtin_memcmp (q1 - prefix_len, prefix, prefix_len) != 0)
+	{
+	  p = q1 + 1;
+	  continue;
+	}
+
+      q1++;
+      q2 = __builtin_memchr (q1, '"', pend - q1);
+      if (q2 == NULL)
+	break;
+
+      if (__builtin_memchr (q1, '\0', q2 - q1) == NULL)
+	{
+	  String s;
+	  void *v;
+	  _Bool *pb;
+
+	  s.str = (const byte *) q1;
+	  s.len = q2 - q1;
+	  v = __go_map_index (m, &s, 1);
+	  pb = (_Bool *) v;
+	  *pb = 1;
+	}
+
+      p = q2;
+    }
+}