gdbsupport: rename source files to .cc

This patch renames the .c source files in gdbsupport to .cc.

In the gdb directory, there is an argument against renaming the source
files, which is that it makes using some git commands more difficult to
do archeology.  Some commands have some kind of "follow" option that
makes git try to follow renames, but it doesn't work in all situations.

Given that we have just moved the gdbsupport directory, that argument
doesn't hold for source files in that directory.  I therefore suggest
renaming them to .cc, so that they are automatically recognized as C++
by various tools and editors.

The original motivation behind this is that when building gdbsupport
with clang, I get:

      CC       agent.o
    clang: error: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Werror,-Wdeprecated]

In the gdb/ directory, we make clang happy by passing "-x c++".  We
could do this in gdbsupport too, but I think that renaming the files is
a better long-term solution.

gdbserver still does its own build of gdbsupport, so a few changes in
its Makefile are necessary.

gdbsupport/ChangeLog:

	* Makefile.am: Rename source files from .c to .cc.
	(CC, CFLAGS): Don't override.
	(AM_CFLAGS): Rename to ...
	(AM_CXXFLAGS): ... this.
	* Makefile.in: Re-generate.
	* %.c: Rename to %.cc.

gdbserver/ChangeLog:

	* Makefile.in: Rename gdbsupport source files from .c to .cc.

1 files changed, 307 insertions, 0 deletions

diff --git a/gdbsupport/rsp-low.cc b/gdbsupport/rsp-low.cc
new file mode 100644
index 00000000000..9bb16605dd4
--- /dev/null
+++ b/gdbsupport/rsp-low.cc
@@ -0,0 +1,307 @@
+/* Low-level RSP routines for GDB, the GNU debugger.
+
+   Copyright (C) 1988-2020 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program 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 of the License, or
+   (at your option) any later version.
+
+   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+#include "rsp-low.h"
+
+/* See rsp-low.h.  */
+
+int
+fromhex (int a)
+{
+  if (a >= '0' && a <= '9')
+    return a - '0';
+  else if (a >= 'a' && a <= 'f')
+    return a - 'a' + 10;
+  else if (a >= 'A' && a <= 'F')
+    return a - 'A' + 10;
+  else
+    error (_("Reply contains invalid hex digit %d"), a);
+}
+
+/* See rsp-low.h.  */
+
+int
+tohex (int nib)
+{
+  if (nib < 10)
+    return '0' + nib;
+  else
+    return 'a' + nib - 10;
+}
+
+/* Encode 64 bits in 16 chars of hex.  */
+
+static const char hexchars[] = "0123456789abcdef";
+
+static int
+ishex (int ch, int *val)
+{
+  if ((ch >= 'a') && (ch <= 'f'))
+    {
+      *val = ch - 'a' + 10;
+      return 1;
+    }
+  if ((ch >= 'A') && (ch <= 'F'))
+    {
+      *val = ch - 'A' + 10;
+      return 1;
+    }
+  if ((ch >= '0') && (ch <= '9'))
+    {
+      *val = ch - '0';
+      return 1;
+    }
+  return 0;
+}
+
+/* See rsp-low.h.  */
+
+char *
+pack_nibble (char *buf, int nibble)
+{
+  *buf++ = hexchars[(nibble & 0x0f)];
+  return buf;
+}
+
+/* See rsp-low.h.  */
+
+char *
+pack_hex_byte (char *pkt, int byte)
+{
+  *pkt++ = hexchars[(byte >> 4) & 0xf];
+  *pkt++ = hexchars[(byte & 0xf)];
+  return pkt;
+}
+
+/* See rsp-low.h.  */
+
+const char *
+unpack_varlen_hex (const char *buff,	/* packet to parse */
+		   ULONGEST *result)
+{
+  int nibble;
+  ULONGEST retval = 0;
+
+  while (ishex (*buff, &nibble))
+    {
+      buff++;
+      retval = retval << 4;
+      retval |= nibble & 0x0f;
+    }
+  *result = retval;
+  return buff;
+}
+
+/* See rsp-low.h.  */
+
+int
+hex2bin (const char *hex, gdb_byte *bin, int count)
+{
+  int i;
+
+  for (i = 0; i < count; i++)
+    {
+      if (hex[0] == 0 || hex[1] == 0)
+	{
+	  /* Hex string is short, or of uneven length.
+	     Return the count that has been converted so far.  */
+	  return i;
+	}
+      *bin++ = fromhex (hex[0]) * 16 + fromhex (hex[1]);
+      hex += 2;
+    }
+  return i;
+}
+
+/* See rsp-low.h.  */
+
+gdb::byte_vector
+hex2bin (const char *hex)
+{
+  size_t bin_len = strlen (hex) / 2;
+  gdb::byte_vector bin (bin_len);
+
+  hex2bin (hex, bin.data (), bin_len);
+
+  return bin;
+}
+
+/* See rsp-low.h.  */
+
+std::string
+hex2str (const char *hex)
+{
+  return hex2str (hex, strlen (hex));
+}
+
+/* See rsp-low.h.  */
+
+std::string
+hex2str (const char *hex, int count)
+{
+  std::string ret;
+
+  ret.reserve (count);
+  for (size_t i = 0; i < count; ++i)
+    {
+      if (hex[0] == '\0' || hex[1] == '\0')
+	{
+	  /* Hex string is short, or of uneven length.  Return what we
+	     have so far.  */
+	  return ret;
+	}
+      ret += fromhex (hex[0]) * 16 + fromhex (hex[1]);
+      hex += 2;
+    }
+
+  return ret;
+}
+
+/* See rsp-low.h.  */
+
+int
+bin2hex (const gdb_byte *bin, char *hex, int count)
+{
+  int i;
+
+  for (i = 0; i < count; i++)
+    {
+      *hex++ = tohex ((*bin >> 4) & 0xf);
+      *hex++ = tohex (*bin++ & 0xf);
+    }
+  *hex = 0;
+  return i;
+}
+
+/* See rsp-low.h.  */
+
+std::string
+bin2hex (const gdb_byte *bin, int count)
+{
+  std::string ret;
+
+  ret.reserve (count * 2);
+  for (int i = 0; i < count; ++i)
+    {
+      ret += tohex ((*bin >> 4) & 0xf);
+      ret += tohex (*bin++ & 0xf);
+    }
+
+  return ret;
+}
+
+/* Return whether byte B needs escaping when sent as part of binary data.  */
+
+static int
+needs_escaping (gdb_byte b)
+{
+  return b == '$' || b == '#' || b == '}' || b == '*';
+}
+
+/* See rsp-low.h.  */
+
+int
+remote_escape_output (const gdb_byte *buffer, int len_units, int unit_size,
+		      gdb_byte *out_buf, int *out_len_units,
+		      int out_maxlen_bytes)
+{
+  int input_unit_index, output_byte_index = 0, byte_index_in_unit;
+  int number_escape_bytes_needed;
+
+  /* Try to copy integral addressable memory units until
+     (1) we run out of space or
+     (2) we copied all of them.  */
+  for (input_unit_index = 0;
+       input_unit_index < len_units;
+       input_unit_index++)
+    {
+      /* Find out how many escape bytes we need for this unit.  */
+      number_escape_bytes_needed = 0;
+      for (byte_index_in_unit = 0;
+	   byte_index_in_unit < unit_size;
+	   byte_index_in_unit++)
+	{
+	  int idx = input_unit_index * unit_size + byte_index_in_unit;
+	  gdb_byte b = buffer[idx];
+	  if (needs_escaping (b))
+	    number_escape_bytes_needed++;
+	}
+
+      /* Check if we have room to fit this escaped unit.  */
+      if (output_byte_index + unit_size + number_escape_bytes_needed >
+	    out_maxlen_bytes)
+	  break;
+
+      /* Copy the unit byte per byte, adding escapes.  */
+      for (byte_index_in_unit = 0;
+	   byte_index_in_unit < unit_size;
+	   byte_index_in_unit++)
+	{
+	  int idx = input_unit_index * unit_size + byte_index_in_unit;
+	  gdb_byte b = buffer[idx];
+	  if (needs_escaping (b))
+	    {
+	      out_buf[output_byte_index++] = '}';
+	      out_buf[output_byte_index++] = b ^ 0x20;
+	    }
+	  else
+	    out_buf[output_byte_index++] = b;
+	}
+    }
+
+  *out_len_units = input_unit_index;
+  return output_byte_index;
+}
+
+/* See rsp-low.h.  */
+
+int
+remote_unescape_input (const gdb_byte *buffer, int len,
+		       gdb_byte *out_buf, int out_maxlen)
+{
+  int input_index, output_index;
+  int escaped;
+
+  output_index = 0;
+  escaped = 0;
+  for (input_index = 0; input_index < len; input_index++)
+    {
+      gdb_byte b = buffer[input_index];
+
+      if (output_index + 1 > out_maxlen)
+	error (_("Received too much data from the target."));
+
+      if (escaped)
+	{
+	  out_buf[output_index++] = b ^ 0x20;
+	  escaped = 0;
+	}
+      else if (b == '}')
+	escaped = 1;
+      else
+	out_buf[output_index++] = b;
+    }
+
+  if (escaped)
+    error (_("Unmatched escape character in target response."));
+
+  return output_index;
+}
+