Add support for per-location warning groups.

gcc/ChangeLog:

	* Makefile.in (OBJS-libcommon): Add diagnostic-spec.o.
	* gengtype.c (open_base_files): Add diagnostic-spec.h.
	* diagnostic-spec.c: New file.
	* diagnostic-spec.h: New file.
	* tree.h (no_warning, all_warnings, suppress_warning_at): New
	declarations.
	* warning-control.cc: New file.

1 files changed, 141 insertions, 0 deletions

diff --git a/gcc/diagnostic-spec.h b/gcc/diagnostic-spec.h
new file mode 100644
index 0000000..4e4d260
--- /dev/null
+++ b/gcc/diagnostic-spec.h
@@ -0,0 +1,141 @@
+/* Language-independent APIs to enable/disable per-location warnings.
+
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   Contributed by Martin Sebor <msebor@redhat.com>
+
+   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/>.  */
+
+#ifndef DIAGNOSTIC_SPEC_H_INCLUDED
+#define DIAGNOSTIC_SPEC_H_INCLUDED
+
+#include "hash-map.h"
+
+/* A "bitset" of warning groups.  */
+
+class nowarn_spec_t
+{
+public:
+  enum
+    {
+     /* Middle end warnings about invalid accesses.  */
+     NW_ACCESS = 1 << 0,
+     /* Front end/lexical warnings.  */
+     NW_LEXICAL = 1 << 1,
+     /* Warnings about null pointers.  */
+     NW_NONNULL = 1 << 2,
+     /* Warnings about uninitialized reads.  */
+     NW_UNINIT = 1 << 3,
+     /* Warnings about arithmetic overflow.  */
+     NW_VFLOW = 1 << 4,
+     /* All other unclassified warnings.  */
+     NW_OTHER = 1 << 5,
+     /* All groups of warnings.  */
+     NW_ALL = (NW_ACCESS | NW_LEXICAL | NW_NONNULL
+	       | NW_UNINIT | NW_VFLOW | NW_OTHER)
+   };
+
+  nowarn_spec_t (): m_bits () { }
+
+  nowarn_spec_t (opt_code);
+
+  /* Return the raw bitset.  */
+  operator unsigned() const
+  {
+    return m_bits;
+  }
+
+  /* Return true if the bitset is clear.  */
+  bool operator!() const
+  {
+    return !m_bits;
+  }
+
+  /* Return the inverse of the bitset.  */
+  nowarn_spec_t operator~() const
+  {
+    nowarn_spec_t res (*this);
+    res.m_bits &= ~NW_ALL;
+    return res;
+  }
+
+  /* Set *THIS to the bitwise OR of *THIS and RHS.  */
+  nowarn_spec_t& operator|= (const nowarn_spec_t &rhs)
+  {
+    m_bits |= rhs.m_bits;
+    return *this;
+  }
+
+  /* Set *THIS to the bitwise AND of *THIS and RHS.  */
+  nowarn_spec_t& operator&= (const nowarn_spec_t &rhs)
+  {
+    m_bits &= rhs.m_bits;
+    return *this;
+  }
+
+  /* Set *THIS to the bitwise exclusive OR of *THIS and RHS.  */
+  nowarn_spec_t& operator^= (const nowarn_spec_t &rhs)
+  {
+    m_bits ^= rhs.m_bits;
+    return *this;
+  }
+
+private:
+  /* Bitset of warning groups.  */
+  unsigned m_bits;
+};
+
+/* Return the bitwise OR of LHS and RHS.  */
+
+inline nowarn_spec_t
+operator| (const nowarn_spec_t &lhs, const nowarn_spec_t &rhs)
+{
+  return nowarn_spec_t (lhs) |= rhs;
+}
+
+/* Return the bitwise AND of LHS and RHS.  */
+
+inline nowarn_spec_t
+operator& (const nowarn_spec_t &lhs, const nowarn_spec_t &rhs)
+{
+  return nowarn_spec_t (lhs) &= rhs;
+}
+
+/* Return true if LHS is equal RHS.  */
+
+inline bool
+operator== (const nowarn_spec_t &lhs, const nowarn_spec_t &rhs)
+{
+  return static_cast<unsigned>(lhs) == static_cast<unsigned>(rhs);
+}
+
+/* Return true if LHS is not equal RHS.  */
+
+inline bool
+operator!= (const nowarn_spec_t &lhs, const nowarn_spec_t &rhs)
+{
+  return !(lhs == rhs);
+}
+
+typedef location_t key_type_t;
+typedef int_hash <key_type_t, 0, UINT_MAX> xint_hash_t;
+typedef hash_map<xint_hash_t, nowarn_spec_t> xint_hash_map_t;
+
+/* A mapping from the location of an expression to the warning spec
+   set for it.  */
+extern GTY(()) xint_hash_map_t *nowarn_map;
+
+#endif // DIAGNOSTIC_SPEC_H_INCLUDED