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[PATCH 8/9] variant: more assertions
From: |
Akim Demaille |
Subject: |
[PATCH 8/9] variant: more assertions |
Date: |
Wed, 19 Dec 2012 11:36:09 +0100 |
Equip variants with more checking code. Provide a means to request
includes.
* data/variant.hh (b4_variant_includes): New.
* data/lalr1.cc: Use it.
* data/variant.hh (variant::built): Define at the end, as a private member.
(variant::tname): New.
Somewhat makes "built" useless, but let's keep both for a start, in
case using "typeinfo" is considered unacceptable in some environments.
Fix some formatting issues.
---
data/lalr1.cc | 1 +
data/variant.hh | 83 ++++++++++++++++++++++++++++++++++++++++-----------------
2 files changed, 59 insertions(+), 25 deletions(-)
diff --git a/data/lalr1.cc b/data/lalr1.cc
index 7b2aef2..0209925 100644
--- a/data/lalr1.cc
+++ b/data/lalr1.cc
@@ -139,6 +139,7 @@ m4_define([b4_shared_declarations],
# include <string>]b4_defines_if([[
# include "stack.hh"
]b4_bison_locations_if([[# include "location.hh"]])])[
+]b4_variant_if([b4_variant_includes])[
]b4_YYDEBUG_define[
diff --git a/data/variant.hh b/data/variant.hh
index 65f0026..684f9e3 100644
--- a/data/variant.hh
+++ b/data/variant.hh
@@ -74,26 +74,37 @@ m4_map([b4_char_sizeof_], address@hidden)dnl
])])
+# b4_variant_includes
+# -------------------
+# The needed includes for variants support.
+m4_define([b4_variant_includes],
+[b4_parse_assert_if([[#include <typeinfo>]])[
+#ifndef YYASSERT
+# include <cassert>
+# define YYASSERT assert
+#endif
+]])
+
# b4_variant_define
# -----------------
# Define "variant".
m4_define([b4_variant_define],
-[[
- /// A char[S] buffer to store and retrieve objects.
+[[ /// A char[S] buffer to store and retrieve objects.
///
/// Sort of a variant, but does not keep track of the nature
/// of the stored data, since that knowledge is available
/// via the current state.
template <size_t S>
struct variant
- {]b4_parse_assert_if([
- /// Whether something is contained.
- bool built;
-])[
+ {
+ /// Type of *this.
+ typedef variant<S> self_type;
+
/// Empty construction.
inline
variant ()]b4_parse_assert_if([
- : built (false)])[
+ : built (false)
+ , tname (YY_NULL)])[
{}
/// Instantiate a \a T in here.
@@ -101,8 +112,11 @@ m4_define([b4_variant_define],
inline T&
build ()
{]b4_parse_assert_if([
- assert (!built);
- built = true;])[
+ YYASSERT (!built);
+ YYASSERT (!tname);
+ YYASSERT (sizeof (T) <= S);
+ built = true;
+ tname = typeid (T).name ();])[
return *new (buffer.raw) T;
}
@@ -111,18 +125,23 @@ m4_define([b4_variant_define],
inline T&
build (const T& t)
{]b4_parse_assert_if([
- assert(!built);
- built = true;])[
- return *new (buffer.raw) T(t);
+ YYASSERT (!built);
+ YYASSERT (!tname);
+ YYASSERT (sizeof (T) <= S);
+ built = true;
+ tname = typeid (T).name ();])[
+ return *new (buffer.raw) T (t);
}
/// Construct and fill.
template <typename T>
inline
variant (const T& t)]b4_parse_assert_if([
- : built (true)])[
+ : built (true)
+ , tname (typeid (T).name ())])[
{
- new (buffer.raw) T(t);
+ YYASSERT (sizeof (T) <= S);
+ new (buffer.raw) T (t);
}
/// Accessor to a built \a T.
@@ -130,8 +149,10 @@ m4_define([b4_variant_define],
inline T&
as ()
{]b4_parse_assert_if([
- assert (built);])[
- return reinterpret_cast<T&>(buffer.raw);
+ YYASSERT (built);
+ YYASSERT (tname == typeid (T).name ());
+ YYASSERT (sizeof (T) <= S);])[
+ return reinterpret_cast<T&> (buffer.raw);
}
/// Const accessor to a built \a T (for %printer).
@@ -139,16 +160,21 @@ m4_define([b4_variant_define],
inline const T&
as () const
{]b4_parse_assert_if([
- assert(built);])[
- return reinterpret_cast<const T&>(buffer.raw);
+ YYASSERT (built);
+ YYASSERT (tname == typeid (T).name ());
+ YYASSERT (sizeof (T) <= S);])[
+ return reinterpret_cast<const T&> (buffer.raw);
}
- /// Swap the content with \a other.
+ /// Swap the content with \a other, of same type.
template <typename T>
inline void
swap (variant<S>& other)
- {
- std::swap (as<T>(), other.as<T>());
+ {]b4_parse_assert_if([
+ YYASSERT (tname == other.tname);])[
+ std::swap (as<T>(), other.as<T>());]b4_parse_assert_if([
+ std::swap (built, other.built);
+ std::swap (tname, other.tname);])[
}
/// Assign the content of \a other to this.
@@ -167,10 +193,12 @@ m4_define([b4_variant_define],
inline void
destroy ()
{
- as<T>().~T();]b4_parse_assert_if([
- built = false;])[
+ as<T> ().~T ();]b4_parse_assert_if([
+ built = false;
+ tname = YY_NULL;])[
}
+ private:
/// A buffer large enough to store any of the semantic values.
/// Long double is chosen as it has the strongest alignment
/// constraints.
@@ -178,7 +206,11 @@ m4_define([b4_variant_define],
{
long double align_me;
char raw[S];
- } buffer;
+ } buffer;]b4_parse_assert_if([
+ /// Whether something is contained.
+ bool built;
+ /// If defined, the name of the stored type.
+ const char* tname;])[
};
]])
@@ -197,7 +229,8 @@ m4_define([b4_semantic_type_declare],
{]b4_type_foreach([b4_char_sizeof])[};
/// Symbol semantic values.
- typedef variant<sizeof(union_type)> semantic_type;])
+ typedef variant<sizeof(union_type)> semantic_type;dnl
+])
# How the semantic value is extracted when using variants.
--
1.8.0.2
- [PATCH 0/9] {master} import improvements from {make-glr-symbol}, Akim Demaille, 2012/12/19
- [PATCH 7/9] gnulib: update, Akim Demaille, 2012/12/19
- [PATCH 4/9] glr.cc: simplifying the handling of parse/lex params, Akim Demaille, 2012/12/19
- [PATCH 6/9] skeletons: fix output directives, Akim Demaille, 2012/12/19
- [PATCH 5/9] yacc.c: style changes, Akim Demaille, 2012/12/19
- [PATCH 1/9] %define variables: backward compatibility, Akim Demaille, 2012/12/19
- [PATCH 2/9] glr.c: move function declaration earlier, Akim Demaille, 2012/12/19
- [PATCH 3/9] glr: rename lex params, Akim Demaille, 2012/12/19
- [PATCH 9/9] variants: prohibit simple copies, Akim Demaille, 2012/12/19
- [PATCH 8/9] variant: more assertions,
Akim Demaille <=