compiler: better abstraction layer for diagnostics.

    
    Introduce an abstraction layer for reporting diagnostics, so as to avoid
    directly using the native GCC interfaces such as "error_at",
    "warning_at", "open_quote", "close_quote", etc.  The new interfaces have
    the same look and feel as the GCC equivalents, but make calls into
    back-end functions to allow the back end to select the proper final
    reporting routine.
    
    Reviewed-on: https://go-review.googlesource.com/29191

	* go-gcc-diagnostics.cc: New file.
	* go-location.h (Location): Remove operator source_location.  Add
	operator==.
	* go-system.h: #include <sstream>.
	* Make-lang.in (GO_OBJS): Add go/go-diagnostics.o and
	go/go-gcc-diagnostics.o.
	(CFLAGS-go/go-gcc-diagnostics.o): New variable.

From-SVN: r240453

gcc/go/ChangeLog

+2016-09-23  Than McIntosh  <thanm@google.com>
+
+	* go-gcc-diagnostics.cc: New file.
+	* go-location.h (Location): Remove operator source_location.  Add
+	operator==.
+	* go-system.h: #include <sstream>.
+	* Make-lang.in (GO_OBJS): Add go/go-diagnostics.o and
+	go/go-gcc-diagnostics.o.
+	(CFLAGS-go/go-gcc-diagnostics.o): New variable.
+
 2016-09-23  Chris Manghane  <cmang@google.com>
 
 	PR go/77701

gcc/go/Make-lang.in

@@ -54,8 +54,10 @@ GO_OBJS = \
 	go/export.o \
 	go/expressions.o \
 	go/go-backend.o \
+	go/go-diagnostics.o \
 	go/go-dump.o \
 	go/go-gcc.o \
+	go/go-gcc-diagnostics.o \
 	go/go-lang.o \
 	go/go-linemap.o \
 	go/go-optimize.o \
@@ -227,6 +229,7 @@ GOINCLUDES = -I $(srcdir)/go -I $(srcdir)/go/gofrontend
 CFLAGS-go/go-gcc.o += $(GOINCLUDES)
 CFLAGS-go/go-linemap.o += $(GOINCLUDES)
 CFLAGS-go/go-sha1.o += $(GOINCLUDES)
+CFLAGS-go/go-gcc-diagnostics.o += $(GOINCLUDES)
 
 go/%.o: go/gofrontend/%.cc
 	$(COMPILE) $(GOINCLUDES) $<

gcc/go/go-gcc-diagnostics.cc

+// go-gcc-diagnostics.cc -- GCC implementation of go diagnostics interface.
+// Copyright (C) 2016 Free Software Foundation, Inc.
+// Contributed by Than McIntosh, Google.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "go-system.h"
+#include "go-diagnostics.h"
+
+void
+go_be_error_at(const Location location, const std::string& errmsg)
+{
+  source_location gcc_loc = location.gcc_location();
+  error_at(gcc_loc, "%s", errmsg.c_str());
+}
+
+
+void
+go_be_warning_at(const Location location,
+                 int opt, const std::string& warningmsg)
+{
+  source_location gcc_loc = location.gcc_location();
+  warning_at(gcc_loc, opt, "%s", warningmsg.c_str());
+}
+
+void
+go_be_fatal_error(const Location location,
+                  const std::string& fatalmsg)
+{
+  source_location gcc_loc = location.gcc_location();
+  fatal_error(gcc_loc, "%s", fatalmsg.c_str());
+}
+
+void
+go_be_inform(const Location location,
+             const std::string& infomsg)
+{
+  source_location gcc_loc = location.gcc_location();
+  inform(gcc_loc, "%s", infomsg.c_str());
+}
+
+void
+go_be_get_quotechars(const char** open_qu, const char** close_qu)
+{
+  *open_qu = open_quote;
+  *close_qu = close_quote;
+}

gcc/go/go-location.h

@@ -26,10 +26,6 @@ class Location
   gcc_location() const
   { return this->gcc_loc_; }
 
-  // Temporary hack till error_at and warning_at can deal with a Location.
-  operator source_location() const
-  { return this->gcc_loc_; }
-
  private:
   source_location gcc_loc_;
 };
@@ -42,4 +38,10 @@ operator<(Location loca, Location locb)
   return loca.gcc_location() < locb.gcc_location();
 }
 
+inline bool
+operator==(Location loca, Location locb)
+{
+  return loca.gcc_location() == locb.gcc_location();
+}
+
 #endif // !defined(GO_LOCATION_H)

gcc/go/go-system.h

@@ -30,6 +30,7 @@
 #include <map>
 #include <set>
 #include <vector>
+#include <sstream>
 
 #if defined(HAVE_UNORDERED_MAP)
 

gcc/go/gofrontend/MERGE

-4f84c5e0210e674163f3f6462da6f5be9e5b0a36
+57bf3f21005c4508003f65207282c057e3526ec0
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/ast-dump.cc

@@ -16,6 +16,7 @@
 #include "ast-dump.h"
 #include "go-c.h"
 #include "go-dump.h"
+#include "go-diagnostics.h"
 
 // The -fgo-dump-ast flag to activate AST dumps.
 
@@ -173,7 +174,8 @@ Ast_dump_context::dump(Gogo* gogo, const char* basename)
 
   if (out.fail())
     {
-      error("cannot open %s:%m, -fgo-dump-ast ignored", dumpname.c_str());
+      go_error_at(Linemap::unknown_location(),
+		  "cannot open %s:%m, -fgo-dump-ast ignored", dumpname.c_str());
       return;
     }
 

gcc/go/gofrontend/backend.h

@@ -55,7 +55,7 @@ class Backend
     Location location;
 
     Btyped_identifier()
-      : name(), btype(NULL), location(UNKNOWN_LOCATION)
+        : name(), btype(NULL), location(Linemap::unknown_location())
     { }
 
     Btyped_identifier(const std::string& a_name, Btype* a_btype,

gcc/go/gofrontend/go-diagnostics.cc

+// go-diagnostics.cc -- Go error/warning diagnostics utilities.
+
+// Copyright 2016 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 "go-diagnostics.h"
+
+static std::string
+mformat_value()
+{
+  return std::string(xstrerror(errno));
+}
+
+// Rewrite a format string to expand any extensions not
+// supported by sprintf(). See comments in go-diagnostics.h
+// for list of supported format specifiers.
+
+static std::string
+expand_format(const char* fmt)
+{
+  std::stringstream ss;
+  for (const char* c = fmt; *c; ++c)
+    {
+      if (*c != '%')
+        {
+          ss << *c;
+          continue;
+        }
+      c++;
+      switch (*c)
+        {
+          case '\0':
+            {
+              // malformed format string
+              go_unreachable();
+            }
+          case '%':
+            {
+              ss << "%";
+              break;
+            }
+          case 'm':
+            {
+              ss << mformat_value();
+              break;
+            }
+          case '<':
+            {
+              ss << go_open_quote();
+              break;
+            }
+          case '>':
+            {
+              ss << go_close_quote();
+              break;
+            }
+          case 'q':
+            {
+              ss << go_open_quote();
+              c++;
+              if (*c == 'm')
+                {
+                  ss << mformat_value();
+                }
+              else
+                {
+                  ss << "%" << *c;
+                }
+              ss << go_close_quote();
+              break;
+            }
+          default:
+            {
+              ss << "%" << *c;
+            }
+        }
+    }
+  return ss.str();
+}
+
+// Expand message format specifiers, using a combination of
+// expand_format above to handle extensions (ex: %m, %q) and vasprintf()
+// to handle regular printf-style formatting. A pragma is being used here to
+// suppress this warning:
+//
+//   warning: function ‘std::__cxx11::string expand_message(const char*, __va_list_tag*)’ might be a candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
+//
+// What appears to be happening here is that the checker is deciding that
+// because of the call to vasprintf() (which has attribute gnu_printf), the
+// calling function must need to have attribute gnu_printf as well, even
+// though there is already an attribute declaration for it.
+
+static std::string
+expand_message(const char* fmt, va_list ap) GO_ATTRIBUTE_GCC_DIAG(1,0);
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
+
+static std::string
+expand_message(const char* fmt, va_list ap)
+{
+  char* mbuf = 0;
+  std::string expanded_fmt = expand_format(fmt);
+  int nwr = vasprintf(&mbuf, expanded_fmt.c_str(), ap);
+  if (nwr == -1)
+    {
+      // memory allocation failed
+      go_be_error_at(Linemap::unknown_location(),
+                     "memory allocation failed in vasprintf");
+      go_assert(0);
+    }
+  std::string rval = std::string(mbuf);
+  free(mbuf);
+  return rval;
+}
+
+#pragma GCC diagnostic pop
+
+static const char* cached_open_quote = NULL;
+static const char* cached_close_quote = NULL;
+
+const char*
+go_open_quote()
+{
+  if (cached_open_quote == NULL)
+    go_be_get_quotechars(&cached_open_quote, &cached_close_quote);
+  return cached_open_quote;
+}
+
+const char*
+go_close_quote()
+{
+  if (cached_close_quote == NULL)
+    go_be_get_quotechars(&cached_open_quote, &cached_close_quote);
+  return cached_close_quote;
+}
+
+void
+go_error_at(const Location location, const char* fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  go_be_error_at(location, expand_message(fmt, ap));
+  va_end(ap);
+}
+
+void
+go_warning_at(const Location location, int opt, const char* fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  go_be_warning_at(location, opt, expand_message(fmt, ap));
+  va_end(ap);
+}
+
+void
+go_fatal_error(const Location location, const char* fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  go_be_fatal_error(location, expand_message(fmt, ap));
+  va_end(ap);
+}
+
+void
+go_inform(const Location location, const char* fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  go_be_inform(location, expand_message(fmt, ap));
+  va_end(ap);
+}

gcc/go/gofrontend/go-diagnostics.h

+// go-diagnostics.h -- interface to diagnostic reporting   -*- C++ -*-
+
+// Copyright 2016 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.
+
+#ifndef GO_DIAGNOSTICS_H
+#define GO_DIAGNOSTICS_H
+
+#include "go-linemap.h"
+
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)
+#define GO_ATTRIBUTE_GCC_DIAG(m, n) __attribute__ ((__format__ (__gcc_tdiag__, m, n))) __attribute__ ((__nonnull__ (m)))
+#else
+#define GO_ATTRIBUTE_GCC_DIAG(m,  n)
+#endif
+
+// These declarations define the interface through which the frontend
+// reports errors and warnings. These functions accept printf-like
+// format specifiers (e.g. %d, %f, %s, etc), with the following additional
+// extensions:
+//
+//  1.  'q' qualifier may be applied to a specifier to add quoting, e.g.
+//      %qd produces a quoted decimal output, %qs a quoted string output.
+//      [This extension is supported only with single-character format
+//      specifiers].
+//
+//  2.  %m specifier outputs value of "strerror(errno)" at time of call.
+//
+//  3.  %< outputs an opening quote, %> a closing quote.
+//
+// All other format specifiers are as defined by 'sprintf'. The final resulting
+// message is then sent to the back end via go_be_error_at/go_be_warning_at.
+
+extern void go_error_at(const Location, const char* fmt, ...)
+    GO_ATTRIBUTE_GCC_DIAG(2,3);
+extern void go_warning_at(const Location, int opt, const char* fmt, ...)
+    GO_ATTRIBUTE_GCC_DIAG(3,4);
+extern void go_fatal_error(const Location, const char* fmt, ...)
+    GO_ATTRIBUTE_GCC_DIAG(2,3);
+extern void go_inform(const Location, const char* fmt, ...)
+    GO_ATTRIBUTE_GCC_DIAG(2,3);
+
+// These interfaces provide a way for the front end to ask for
+// the open/close quote characters it should use when formatting
+// diagnostics (warnings, errors).
+extern const char* go_open_quote();
+extern const char* go_close_quote();
+
+// These interfaces are used by utilities above to pass warnings and
+// errors (once format specifiers have been expanded) to the back end,
+// and to determine quoting style. Avoid calling these routines directly;
+// instead use the equivalent routines above. The back end is required to
+// implement these routines.
+
+extern void go_be_error_at(const Location, const std::string& errmsg);
+extern void go_be_warning_at(const Location, int opt,
+                             const std::string& warningmsg);
+extern void go_be_fatal_error(const Location, const std::string& errmsg);
+extern void go_be_inform(const Location, const std::string& infomsg);
+extern void go_be_get_quotechars(const char** open_quote,
+                                 const char** close_quote);
+
+#endif // !defined(GO_DIAGNOSTICS_H)

gcc/go/gofrontend/go.cc

@@ -7,6 +7,7 @@
 #include "go-system.h"
 
 #include "go-c.h"
+#include "go-diagnostics.h"
 
 #include "lex.h"
 #include "parse.h"
@@ -68,7 +69,7 @@ go_parse_input_files(const char** filenames, unsigned int filename_count,
 	{
 	  file = fopen(filename, "r");
 	  if (file == NULL)
-	    fatal_error(Linemap::unknown_location(),
+	    go_fatal_error(Linemap::unknown_location(),
 			   "cannot open %s: %m", filename);
 	}
 
@@ -88,7 +89,7 @@ go_parse_input_files(const char** filenames, unsigned int filename_count,
 	      for (Lex::Linknames::const_iterator p = linknames->begin();
 		   p != linknames->end();
 		   ++p)
-		error_at(p->second.loc,
+		go_error_at(p->second.loc,
 			    ("//go:linkname only allowed in Go files that "
 			     "import \"unsafe\""));
 	    }

gcc/go/gofrontend/import-archive.cc

@@ -6,6 +6,7 @@
 
 #include "go-system.h"
 
+#include "go-diagnostics.h"
 #include "import.h"
 
 #ifndef O_BINARY
@@ -144,7 +145,7 @@ Archive_file::initialize()
   struct stat st;
   if (fstat(this->fd_, &st) < 0)
     {
-      error_at(this->location_, "%s: %m", this->filename_.c_str());
+      go_error_at(this->location_, "%s: %m", this->filename_.c_str());
       return false;
     }
   this->filesize_ = st.st_size;
@@ -153,7 +154,7 @@ Archive_file::initialize()
   if (::lseek(this->fd_, 0, SEEK_SET) < 0
       || ::read(this->fd_, buf, sizeof(armagt)) != sizeof(armagt))
     {
-      error_at(this->location_, "%s: %m", this->filename_.c_str());
+      go_error_at(this->location_, "%s: %m", this->filename_.c_str());
       return false;
     }
   this->is_thin_archive_ = memcmp(buf, armagt, sizeof(armagt)) == 0;
@@ -183,7 +184,7 @@ Archive_file::initialize()
       char* rdbuf = new char[size];
       if (::read(this->fd_, rdbuf, size) != size)
 	{
-	  error_at(this->location_, "%s: could not read extended names",
+	  go_error_at(this->location_, "%s: could not read extended names",
 		   filename.c_str());
 	  delete[] rdbuf;
 	  return false;
@@ -203,7 +204,7 @@ Archive_file::read(off_t offset, off_t size, char* buf)
   if (::lseek(this->fd_, offset, SEEK_SET) < 0
       || ::read(this->fd_, buf, size) != size)
     {
-      error_at(this->location_, "%s: %m", this->filename_.c_str());
+      go_error_at(this->location_, "%s: %m", this->filename_.c_str());
       return false;
     }
   return true;
@@ -219,19 +220,19 @@ Archive_file::read_header(off_t off, std::string* pname, off_t* size,
   Archive_header hdr;
   if (::lseek(this->fd_, off, SEEK_SET) < 0)
     {
-      error_at(this->location_, "%s: %m", this->filename_.c_str());
+      go_error_at(this->location_, "%s: %m", this->filename_.c_str());
       return false;
     }
   ssize_t got = ::read(this->fd_, &hdr, sizeof hdr);
   if (got != sizeof hdr)
     {
       if (got < 0)
-	error_at(this->location_, "%s: %m", this->filename_.c_str());
+	go_error_at(this->location_, "%s: %m", this->filename_.c_str());
       else if (got > 0)
-	error_at(this->location_, "%s: short archive header at %ld",
+	go_error_at(this->location_, "%s: short archive header at %ld",
 		    this->filename_.c_str(), static_cast<long>(off));
       else
-	error_at(this->location_, "%s: unexpected EOF at %ld",
+	go_error_at(this->location_, "%s: unexpected EOF at %ld",
 		    this->filename_.c_str(), static_cast<long>(off));
     }
   off_t local_nested_off;
@@ -252,7 +253,7 @@ Archive_file::interpret_header(const Archive_header* hdr, off_t off,
 {
   if (memcmp(hdr->ar_fmag, arfmag, sizeof arfmag) != 0)
     {
-      error_at(this->location_, "%s: malformed archive header at %lu",
+      go_error_at(this->location_, "%s: malformed archive header at %lu",
 		  this->filename_.c_str(), static_cast<unsigned long>(off));
       return false;
     }
@@ -272,7 +273,7 @@ Archive_file::interpret_header(const Archive_header* hdr, off_t off,
       || *size < 0
       || (*size == LONG_MAX && errno == ERANGE))
     {
-      error_at(this->location_, "%s: malformed archive header size at %lu",
+      go_error_at(this->location_, "%s: malformed archive header size at %lu",
 		  this->filename_.c_str(), static_cast<unsigned long>(off));
       return false;
     }
@@ -284,7 +285,8 @@ Archive_file::interpret_header(const Archive_header* hdr, off_t off,
       if (name_end == NULL
 	  || name_end - hdr->ar_name >= static_cast<int>(sizeof hdr->ar_name))
 	{
-	  error_at(this->location_, "%s: malformed archive header name at %lu",
+	  go_error_at(this->location_,
+		      "%s: malformed archive header name at %lu",
 		      this->filename_.c_str(), static_cast<unsigned long>(off));
 	  return false;
 	}
@@ -321,7 +323,7 @@ Archive_file::interpret_header(const Archive_header* hdr, off_t off,
 	  || (x == LONG_MAX && errno == ERANGE)
 	  || static_cast<size_t>(x) >= this->extended_names_.size())
 	{
-	  error_at(this->location_, "%s: bad extended name index at %lu",
+	  go_error_at(this->location_, "%s: bad extended name index at %lu",
 		      this->filename_.c_str(), static_cast<unsigned long>(off));
 	  return false;
 	}
@@ -331,7 +333,8 @@ Archive_file::interpret_header(const Archive_header* hdr, off_t off,
       if (static_cast<size_t>(name_end - name) > this->extended_names_.size()
 	  || name_end[-1] != '/')
 	{
-	  error_at(this->location_, "%s: bad extended name entry at header %lu",
+	  go_error_at(this->location_,
+		      "%s: bad extended name entry at header %lu",
 		      this->filename_.c_str(), static_cast<unsigned long>(off));
 	  return false;
 	}
@@ -380,7 +383,7 @@ Archive_file::get_file_and_offset(off_t off, const std::string& hdrname,
 	  int nfd = open(filename.c_str(), O_RDONLY | O_BINARY);
 	  if (nfd < 0)
 	    {
-	      error_at(this->location_, "%s: can't open nested archive %s",
+	      go_error_at(this->location_, "%s: can't open nested archive %s",
 			  this->filename_.c_str(), filename.c_str());
 	      return false;
 	    }
@@ -406,7 +409,7 @@ Archive_file::get_file_and_offset(off_t off, const std::string& hdrname,
   *memfd = open(filename.c_str(), O_RDONLY | O_BINARY);
   if (*memfd < 0)
     {
-      error_at(this->location_, "%s: %m", filename.c_str());
+      go_error_at(this->location_, "%s: %m", filename.c_str());
       return false;
     }
   *memoff = 0;
@@ -499,7 +502,7 @@ Archive_iterator::read_next_header()
 	{
 	  if (filesize != this->off_)
 	    {
-	      error_at(this->afile_->location(),
+	      go_error_at(this->afile_->location(),
 			  "%s: short archive header at %lu",
 			  this->afile_->filename().c_str(),
 			  static_cast<unsigned long>(this->off_));

gcc/go/gofrontend/import.cc

@@ -9,6 +9,7 @@
 #include "filenames.h"
 
 #include "go-c.h"
+#include "go-diagnostics.h"
 #include "gogo.h"
 #include "lex.h"
 #include "types.h"
@@ -132,7 +133,7 @@ Import::try_package_in_directory(const std::string& filename,
   if (fd < 0)
     {
       if (errno != ENOENT && errno != EISDIR)
-	warning_at(location, 0, "%s: %m", filename.c_str());
+	go_warning_at(location, 0, "%s: %m", filename.c_str());
 
       fd = Import::try_suffixes(&found_filename);
       if (fd < 0)
@@ -146,7 +147,7 @@ Import::try_package_in_directory(const std::string& filename,
 
   close(fd);
 
-  error_at(location, "%s exists but does not contain any Go export data",
+  go_error_at(location, "%s exists but does not contain any Go export data",
 	      found_filename.c_str());
 
   return NULL;
@@ -211,7 +212,7 @@ Import::find_export_data(const std::string& filename, int fd, Location location)
 
   if (lseek(fd, 0, SEEK_SET) < 0)
     {
-      error_at(location, "lseek %s failed: %m", filename.c_str());
+      go_error_at(location, "lseek %s failed: %m", filename.c_str());
       return NULL;
     }
 
@@ -247,9 +248,9 @@ Import::find_object_export_data(const std::string& filename,
   if (errmsg != NULL)
     {
       if (err == 0)
-	error_at(location, "%s: %s", filename.c_str(), errmsg);
+	go_error_at(location, "%s: %s", filename.c_str(), errmsg);
       else
-	error_at(location, "%s: %s: %s", filename.c_str(), errmsg,
+	go_error_at(location, "%s: %s: %s", filename.c_str(), errmsg,
 		    xstrerror(err));
       return NULL;
     }
@@ -307,7 +308,7 @@ Import::import(Gogo* gogo, const std::string& local_name,
 	}
       else
 	{
-	  error_at(this->location_,
+	  go_error_at(this->location_,
 		      ("error in import data at %d: invalid magic string"),
 		      stream->pos());
 	  return NULL;
@@ -382,7 +383,7 @@ Import::import(Gogo* gogo, const std::string& local_name,
 	    break;
 	  else
 	    {
-	      error_at(this->location_,
+	      go_error_at(this->location_,
 			  ("error in import data at %d: "
 			   "expected %<const%>, %<type%>, %<var%>, "
 			   "%<func%>, or %<checksum%>"),
@@ -664,7 +665,7 @@ Import::read_type()
 	  : (static_cast<size_t>(index) >= this->types_.size()
 	     || this->types_[index] == NULL))
 	{
-	  error_at(this->location_,
+	  go_error_at(this->location_,
 		      "error in import data at %d: bad type index %d",
 		      stream->pos(), index);
 	  stream->set_saw_error();
@@ -677,7 +678,7 @@ Import::read_type()
   if (c != ' ')
     {
       if (!stream->saw_error())
-	error_at(this->location_,
+	go_error_at(this->location_,
 		    "error in import data at %d: expect %< %> or %<>%>'",
 		    stream->pos());
       stream->set_saw_error();
@@ -689,7 +690,7 @@ Import::read_type()
       || (static_cast<size_t>(index) < this->types_.size()
 	  && this->types_[index] != NULL))
     {
-      error_at(this->location_,
+      go_error_at(this->location_,
 		  "error in import data at %d: type index already defined",
 		  stream->pos());
       stream->set_saw_error();
@@ -768,7 +769,7 @@ Import::read_type()
     no = package->add_type_declaration(type_name, this->location_);
   else if (!no->is_type_declaration() && !no->is_type())
     {
-      error_at(this->location_, "imported %<%s.%s%> both type and non-type",
+      go_error_at(this->location_, "imported %<%s.%s%> both type and non-type",
 		  pkgpath.c_str(), Gogo::message_name(type_name).c_str());
       stream->set_saw_error();
       return Type::make_error_type();
@@ -866,8 +867,9 @@ Import::read_escape()
 
       if (c != '>')
 	{
-	  error_at(this->location(),
-		   "error in import data at %d: expect %< %> or %<>%>, got %c",
+	  go_error_at(this->location(),
+		      ("error in import data at %d: "
+		       "expect %< %> or %<>%>, got %c"),
 		      stream->pos(), c);
 	  stream->set_saw_error();
 	  stream->advance(1);
@@ -961,7 +963,7 @@ Import::string_to_int(const std::string &s, bool is_neg_ok, int* ret)
   long prio = strtol(s.c_str(), &end, 10);
   if (*end != '\0' || prio > 0x7fffffff || (prio < 0 && !is_neg_ok))
     {
-      error_at(this->location_, "invalid integer in import data at %d",
+      go_error_at(this->location_, "invalid integer in import data at %d",
 		  this->stream_->pos());
       this->stream_->set_saw_error();
       return false;
@@ -1018,7 +1020,7 @@ Import::Stream::require_bytes(Location location, const char* bytes,
       || memcmp(bytes, read, length) != 0)
     {
       if (!this->saw_error_)
-	error_at(location, "import error at %d: expected %<%.*s%>",
+	go_error_at(location, "import error at %d: expected %<%.*s%>",
 		    this->pos(), static_cast<int>(length), bytes);
       this->saw_error_ = true;
       return;
@@ -1033,7 +1035,7 @@ Stream_from_file::Stream_from_file(int fd)
 {
   if (lseek(fd, 0, SEEK_SET) != 0)
     {
-      error("lseek failed: %m");
+      go_fatal_error(Linemap::unknown_location(), "lseek failed: %m");
       this->set_saw_error();
     }
 }
@@ -1061,7 +1063,7 @@ Stream_from_file::do_peek(size_t length, const char** bytes)
   if (got < 0)
     {
       if (!this->saw_error())
-	error("read failed: %m");
+	go_fatal_error(Linemap::unknown_location(), "read failed: %m");
       this->set_saw_error();
       return false;
     }
@@ -1069,7 +1071,7 @@ Stream_from_file::do_peek(size_t length, const char** bytes)
   if (lseek(this->fd_, - got, SEEK_CUR) != 0)
     {
       if (!this->saw_error())
-	error("lseek failed: %m");
+	go_fatal_error(Linemap::unknown_location(), "lseek failed: %m");
       this->set_saw_error();
       return false;
     }
@@ -1091,7 +1093,7 @@ Stream_from_file::do_advance(size_t skip)
   if (lseek(this->fd_, skip, SEEK_CUR) != 0)
     {
       if (!this->saw_error())
-	error("lseek failed: %m");
+	go_fatal_error(Linemap::unknown_location(), "lseek failed: %m");
       this->set_saw_error();
     }
   if (!this->data_.empty())

gcc/go/gofrontend/lex.cc

@@ -5,6 +5,7 @@
 // license that can be found in the LICENSE file.
 
 #include "go-system.h"
+#include "go-diagnostics.h"
 
 #include "lex.h"
 
@@ -477,7 +478,7 @@ Lex::get_line()
 	{
 	  size_t ns = 2 * size + 1;
 	  if (ns < size || static_cast<ssize_t>(ns) < 0)
-	    error_at(this->location(), "out of memory");
+	    go_error_at(this->location(), "out of memory");
 	  char* nb = new char[ns];
 	  memcpy(nb, buf, cur);
 	  delete[] buf;
@@ -743,7 +744,7 @@ Lex::next_token()
 		  return this->gather_identifier();
 
 		if (!issued_error)
-		  error_at(this->location(),
+		  go_error_at(this->location(),
 			      "invalid character 0x%x in input file",
 			      ci);
 
@@ -834,7 +835,7 @@ Lex::advance_one_utf8_char(const char* p, unsigned int* value,
 
   if (*p == '\0')
     {
-      error_at(this->location(), "invalid NUL byte");
+      go_error_at(this->location(), "invalid NUL byte");
       *issued_error = true;
       *value = 0;
       return p + 1;
@@ -843,7 +844,7 @@ Lex::advance_one_utf8_char(const char* p, unsigned int* value,
   int adv = Lex::fetch_char(p, value);
   if (adv == 0)
     {
-      error_at(this->location(), "invalid UTF-8 encoding");
+      go_error_at(this->location(), "invalid UTF-8 encoding");
       *issued_error = true;
       return p + 1;
     }
@@ -851,7 +852,7 @@ Lex::advance_one_utf8_char(const char* p, unsigned int* value,
   // Warn about byte order mark, except at start of file.
   if (*value == 0xfeff && (this->lineno_ != 1 || this->lineoff_ != 0))
     {
-      error_at(this->location(), "Unicode (UTF-8) BOM in middle of file");
+      go_error_at(this->location(), "Unicode (UTF-8) BOM in middle of file");
       *issued_error = true;
     }
 
@@ -890,7 +891,7 @@ Lex::gather_identifier()
 		break;
 
 	      this->lineoff_ = p - this->linebuf_;
-	      error_at(this->location(),
+	      go_error_at(this->location(),
 			  "invalid character 0x%x in identifier",
 			  cc);
 	      if (!has_non_ascii_char)
@@ -925,7 +926,7 @@ Lex::gather_identifier()
 	      // handling behavior if we swallow this character after
 	      // giving an error.
 	      if (!issued_error)
-		error_at(this->location(),
+		go_error_at(this->location(),
 			    "invalid character 0x%x in identifier",
 			    ci);
 	      is_invalid = true;
@@ -1109,9 +1110,9 @@ Lex::gather_number()
           if (r != 0)
             {
               if (base == 8)
-                error_at(this->location(), "invalid octal literal");
+                go_error_at(this->location(), "invalid octal literal");
               else
-                error_at(this->location(), "invalid hex literal");
+                go_error_at(this->location(), "invalid hex literal");
             }
 
 	  if (neg)
@@ -1225,7 +1226,7 @@ Lex::advance_one_char(const char* p, bool is_single_quote, unsigned int* value,
       if (is_single_quote
 	  && (*value == '\'' || *value == '\n')
 	  && !issued_error)
-	error_at(this->location(), "invalid character literal");
+	go_error_at(this->location(), "invalid character literal");
       return ret;
     }
   else
@@ -1244,12 +1245,12 @@ Lex::advance_one_char(const char* p, bool is_single_quote, unsigned int* value,
 			+ Lex::octal_value(p[2]));
 	      if (*value > 255)
 		{
-		  error_at(this->location(), "invalid octal constant");
+		  go_error_at(this->location(), "invalid octal constant");
 		  *value = 255;
 		}
 	      return p + 3;
 	    }
-	      error_at(this->location(), "invalid octal character");
+	      go_error_at(this->location(), "invalid octal character");
 	  return (p[1] >= '0' && p[1] <= '7'
 		  ? p + 2
 		  : p + 1);
@@ -1261,7 +1262,7 @@ Lex::advance_one_char(const char* p, bool is_single_quote, unsigned int* value,
 	      *value = (Lex::hex_val(p[1]) << 4) + Lex::hex_val(p[2]);
 	      return p + 3;
 	    }
-	  error_at(this->location(), "invalid hex character");
+	  go_error_at(this->location(), "invalid hex character");
 	  return (Lex::is_hex_digit(p[1])
 		  ? p + 2
 		  : p + 1);
@@ -1292,12 +1293,12 @@ Lex::advance_one_char(const char* p, bool is_single_quote, unsigned int* value,
 	  return p + 1;
 	case '\'':
 	  if (!is_single_quote)
-	    error_at(this->location(), "invalid quoted character");
+	    go_error_at(this->location(), "invalid quoted character");
 	  *value = '\'';
 	  return p + 1;
 	case '"':
 	  if (is_single_quote)
-	    error_at(this->location(), "invalid quoted character");
+	    go_error_at(this->location(), "invalid quoted character");
 	  *value = '"';
 	  return p + 1;
 
@@ -1311,7 +1312,7 @@ Lex::advance_one_char(const char* p, bool is_single_quote, unsigned int* value,
 			+ Lex::hex_val(p[4]));
 	      if (*value >= 0xd800 && *value < 0xe000)
 		{
-		  error_at(this->location(),
+		  go_error_at(this->location(),
 			      "invalid unicode code point 0x%x",
 			      *value);
 		  // Use the replacement character.
@@ -1319,7 +1320,7 @@ Lex::advance_one_char(const char* p, bool is_single_quote, unsigned int* value,
 		}
 	      return p + 5;
 	    }
-	  error_at(this->location(), "invalid little unicode code point");
+	  go_error_at(this->location(), "invalid little unicode code point");
 	  return p + 1;
 
 	case 'U':
@@ -1339,18 +1340,19 @@ Lex::advance_one_char(const char* p, bool is_single_quote, unsigned int* value,
 	      if (*value > 0x10ffff
 		  || (*value >= 0xd800 && *value < 0xe000))
 		{
-		  error_at(this->location(), "invalid unicode code point 0x%x",
+		  go_error_at(this->location(),
+			      "invalid unicode code point 0x%x",
 			      *value);
 		  // Use the replacement character.
 		  *value = 0xfffd;
 		}
 	      return p + 9;
 	    }
-	  error_at(this->location(), "invalid big unicode code point");
+	  go_error_at(this->location(), "invalid big unicode code point");
 	  return p + 1;
 
 	default:
-	  error_at(this->location(), "invalid character after %<\\%>");
+	  go_error_at(this->location(), "invalid character after %<\\%>");
 	  *value = *p;
 	  return p + 1;
 	}
@@ -1382,14 +1384,14 @@ Lex::append_char(unsigned int v, bool is_character, std::string* str,
     {
       if (v > 0x10ffff)
 	{
-	  warning_at(location, 0,
+	  go_warning_at(location, 0,
 			"unicode code point 0x%x out of range in string", v);
 	  // Turn it into the "replacement character".
 	  v = 0xfffd;
 	}
       if (v >= 0xd800 && v < 0xe000)
 	{
-	  warning_at(location, 0,
+	  go_warning_at(location, 0,
 			"unicode code point 0x%x is invalid surrogate pair", v);
 	  v = 0xfffd;
 	}
@@ -1427,7 +1429,7 @@ Lex::gather_character()
 
   if (*p != '\'')
     {
-      error_at(this->location(), "unterminated character constant");
+      go_error_at(this->location(), "unterminated character constant");
       this->lineoff_ = p - this->linebuf_;
       return this->make_invalid_token();
     }
@@ -1461,7 +1463,7 @@ Lex::gather_string()
       p = this->advance_one_char(p, false, &c, &is_character);
       if (p >= pend)
 	{
-	  error_at(this->location(), "unterminated string");
+	  go_error_at(this->location(), "unterminated string");
 	  --p;
 	  break;
 	}
@@ -1505,7 +1507,7 @@ Lex::gather_raw_string()
       this->lineoff_ = p - this->linebuf_;
       if (!this->require_line())
 	{
-	  error_at(location, "unterminated raw string");
+	  go_error_at(location, "unterminated raw string");
 	  return Token::make_string_token(value, location);
 	}
       p = this->linebuf_ + this->lineoff_;
@@ -1685,7 +1687,7 @@ Lex::skip_c_comment(bool* found_newline)
     {
       if (!this->require_line())
 	{
-	  error_at(this->location(), "unterminated comment");
+	  go_error_at(this->location(), "unterminated comment");
 	  return false;
 	}
 
@@ -1861,7 +1863,7 @@ Lex::skip_cpp_comment()
 	    }
 	}
       if (go_name.empty() || ext_name.empty())
-	error_at(loc, "usage: //go:linkname localname linkname");
+	go_error_at(loc, "usage: //go:linkname localname linkname");
       else
 	{
 	  if (this->linknames_ == NULL)

gcc/go/gofrontend/parse.h

@@ -81,7 +81,8 @@ class Parse
     Expression* expr;
 
     Type_switch()
-      : found(false), name(), location(UNKNOWN_LOCATION), expr(NULL)
+        : found(false), name(), location(Linemap::unknown_location()),
+          expr(NULL)
     { }
   };
 

gcc/go/gofrontend/statements.cc

@@ -7,6 +7,7 @@
 #include "go-system.h"
 
 #include "go-c.h"
+#include "go-diagnostics.h"
 #include "types.h"
 #include "expressions.h"
 #include "gogo.h"
@@ -163,7 +164,7 @@ Statement::set_is_error()
 void
 Statement::report_error(const char* msg)
 {
-  error_at(this->location_, "%s", msg);
+  go_error_at(this->location_, "%s", msg);
   this->set_is_error();
 }
 
@@ -428,9 +429,9 @@ Temporary_statement::do_check_types(Gogo*)
       if (!Type::are_assignable(this->type_, this->init_->type(), &reason))
 	{
 	  if (reason.empty())
-	    error_at(this->location(), "incompatible types in assignment");
+	    go_error_at(this->location(), "incompatible types in assignment");
 	  else
-	    error_at(this->location(), "incompatible types in assignment (%s)",
+	    go_error_at(this->location(), "incompatible types in assignment (%s)",
 		     reason.c_str());
 	  this->set_is_error();
 	}
@@ -767,9 +768,9 @@ Assignment_statement::do_check_types(Gogo*)
   if (!Type::are_assignable(lhs_type, rhs_type, &reason))
     {
       if (reason.empty())
-	error_at(this->location(), "incompatible types in assignment");
+	go_error_at(this->location(), "incompatible types in assignment");
       else
-	error_at(this->location(), "incompatible types in assignment (%s)",
+	go_error_at(this->location(), "incompatible types in assignment (%s)",
 		    reason.c_str());
       this->set_is_error();
     }
@@ -2669,9 +2670,10 @@ Return_statement::do_lower(Gogo*, Named_object* function, Block* enclosing,
       else
 	{
 	  if (reason.empty())
-	    error_at(e->location(), "incompatible type for return value %d", i);
+	    go_error_at(e->location(),
+			"incompatible type for return value %d", i);
 	  else
-	    error_at(e->location(),
+	    go_error_at(e->location(),
 			"incompatible type for return value %d (%s)",
 			i, reason.c_str());
 	}
@@ -2850,7 +2852,7 @@ Goto_statement::do_check_types(Gogo*)
 {
   if (!this->label_->is_defined())
     {
-      error_at(this->location(), "reference to undefined label %qs",
+      go_error_at(this->location(), "reference to undefined label %qs",
 		  Gogo::message_name(this->label_->name()).c_str());
       this->set_is_error();
     }
@@ -3274,7 +3276,7 @@ Case_clauses::Case_clause::check_types(Type* type)
 	  if (!Type::are_assignable(type, (*p)->type(), NULL)
 	      && !Type::are_assignable((*p)->type(), type, NULL))
 	    {
-	      error_at((*p)->location(),
+	      go_error_at((*p)->location(),
 			  "type mismatch between switch value and case clause");
 	      return false;
 	    }
@@ -3338,7 +3340,7 @@ Case_clauses::Case_clause::get_backend(Translate_context* context,
 	  if (!ins.second)
 	    {
 	      // Value was already present.
-	      error_at(this->location_, "duplicate case in switch");
+	      go_error_at(this->location_, "duplicate case in switch");
 	      e = Expression::make_error(this->location_);
 	    }
 	  cases->push_back(e->get_backend(context));
@@ -3722,7 +3724,7 @@ Switch_statement::do_lower(Gogo*, Named_object*, Block* enclosing,
       && !Type::are_compatible_for_comparison(true, this->val_->type(),
 					      Type::make_nil_type(), NULL))
     {
-      error_at(this->val_->location(),
+      go_error_at(this->val_->location(),
 		  "cannot switch on value whose type that may not be compared");
       return Statement::make_error_statement(loc);
     }
@@ -3857,9 +3859,9 @@ Type_case_clauses::Type_case_clause::lower(Type* switch_val_type,
 								      &reason))
 	{
 	  if (reason.empty())
-	    error_at(this->location_, "impossible type switch case");
+	    go_error_at(this->location_, "impossible type switch case");
 	  else
-	    error_at(this->location_, "impossible type switch case (%s)",
+	    go_error_at(this->location_, "impossible type switch case (%s)",
 			reason.c_str());
 	}
 
@@ -4025,7 +4027,7 @@ Type_case_clauses::check_duplicates() const
 	t = Type::make_nil_type();
       std::pair<Types_seen::iterator, bool> ins = types_seen.insert(t);
       if (!ins.second)
-	error_at(p->location(), "duplicate type in switch");
+	go_error_at(p->location(), "duplicate type in switch");
     }
 }
 
@@ -4255,7 +4257,7 @@ Send_statement::do_check_types(Gogo*)
   Channel_type* channel_type = type->channel_type();
   if (channel_type == NULL)
     {
-      error_at(this->location(), "left operand of %<<-%> must be channel");
+      go_error_at(this->location(), "left operand of %<<-%> must be channel");
       this->set_is_error();
       return;
     }
@@ -4656,14 +4658,14 @@ Select_clauses::Select_clause::check_types()
   Channel_type* ct = this->channel_->type()->channel_type();
   if (ct == NULL)
     {
-      error_at(this->channel_->location(), "expected channel");
+      go_error_at(this->channel_->location(), "expected channel");
       return;
     }
 
   if (this->is_send_ && !ct->may_send())
-    error_at(this->location(), "invalid send on receive-only channel");
+    go_error_at(this->location(), "invalid send on receive-only channel");
   else if (!this->is_send_ && !ct->may_receive())
-    error_at(this->location(), "invalid receive on send-only channel");
+    go_error_at(this->location(), "invalid receive on send-only channel");
 }
 
 // Whether this clause may fall through to the statement which follows

gcc/go/gofrontend/statements.h

@@ -1624,7 +1624,7 @@ class Case_clauses
    public:
     Case_clause()
       : cases_(NULL), statements_(NULL), is_default_(false),
-	is_fallthrough_(false), location_(UNKNOWN_LOCATION)
+	is_fallthrough_(false), location_(Linemap::unknown_location())
     { }
 
     Case_clause(Expression_list* cases, bool is_default, Block* statements,
@@ -1811,7 +1811,7 @@ class Type_case_clauses
    public:
     Type_case_clause()
       : type_(NULL), statements_(NULL), is_default_(false),
-	location_(UNKNOWN_LOCATION)
+	location_(Linemap::unknown_location())
     { }
 
     Type_case_clause(Type* type, bool is_fallthrough, bool is_default,