#include <map>
#include <algorithm>
#include <memory>
+#include <functional>
#include <sstream>
#include <backends/cxxrtl/cxxrtl_capi.h>
+#ifndef __has_attribute
+# define __has_attribute(x) 0
+#endif
+
// CXXRTL essentially uses the C++ compiler as a hygienic macro engine that feeds an instruction selector.
// It generates a lot of specialized template functions with relatively large bodies that, when inlined
// into the caller and (for those with loops) unrolled, often expose many new optimization opportunities.
// Because of this, most of the CXXRTL runtime must be always inlined for best performance.
-#ifndef __has_attribute
-# define __has_attribute(x) 0
-#endif
#if __has_attribute(always_inline)
#define CXXRTL_ALWAYS_INLINE inline __attribute__((__always_inline__))
#else
#define CXXRTL_ALWAYS_INLINE inline
#endif
+// Conversely, some functions in the generated code are extremely large yet very cold, with both of these
+// properties being extreme enough to confuse C++ compilers into spending pathological amounts of time
+// on a futile (the code becomes worse) attempt to optimize the least important parts of code.
+#if __has_attribute(optnone)
+#define CXXRTL_EXTREMELY_COLD __attribute__((__optnone__))
+#elif __has_attribute(optimize)
+#define CXXRTL_EXTREMELY_COLD __attribute__((__optimize__(0)))
+#else
+#define CXXRTL_EXTREMELY_COLD
+#endif
+
+// CXXRTL uses assert() to check for C++ contract violations (which may result in e.g. undefined behavior
+// of the simulation code itself), and CXXRTL_ASSERT to check for RTL contract violations (which may at
+// most result in undefined simulation results).
+//
+// Though by default, CXXRTL_ASSERT() expands to assert(), it may be overridden e.g. when integrating
+// the simulation into another process that should survive violating RTL contracts.
+#ifndef CXXRTL_ASSERT
+#ifndef CXXRTL_NDEBUG
+#define CXXRTL_ASSERT(x) assert(x)
+#else
+#define CXXRTL_ASSERT(x)
+#endif
+#endif
namespace cxxrtl {
explicit constexpr value(Init ...init) : data{init...} {}
value(const value<Bits> &) = default;
- value(value<Bits> &&) = default;
value<Bits> &operator=(const value<Bits> &) = default;
+ value(value<Bits> &&) = default;
+ value<Bits> &operator=(value<Bits> &&) = default;
+
// A (no-op) helper that forces the cast to value<>.
CXXRTL_ALWAYS_INLINE
const value<Bits> &val() const {
return sext_cast<NewBits>()(*this);
}
+ // Bit replication is far more efficient than the equivalent concatenation.
+ template<size_t Count>
+ CXXRTL_ALWAYS_INLINE
+ value<Bits * Count> repeat() const {
+ static_assert(Bits == 1, "repeat() is implemented only for 1-bit values");
+ return *this ? value<Bits * Count>().bit_not() : value<Bits * Count>();
+ }
+
// Operations with run-time parameters (offsets, amounts, etc).
//
// These operations are used for computations.
bool carry = CarryIn;
for (size_t n = 0; n < result.chunks; n++) {
result.data[n] = data[n] + (Invert ? ~other.data[n] : other.data[n]) + carry;
- if (result.chunks - 1 == n)
+ if (result.chunks - 1 == n)
result.data[result.chunks - 1] &= result.msb_mask;
carry = (result.data[n] < data[n]) ||
(result.data[n] == data[n] && carry);
value<Bits> next;
wire() = default;
- constexpr wire(const value<Bits> &init) : curr(init), next(init) {}
+ explicit constexpr wire(const value<Bits> &init) : curr(init), next(init) {}
template<typename... Init>
explicit constexpr wire(Init ...init) : curr{init...}, next{init...} {}
+ // Copying and copy-assigning values is natural. If, however, a value is replaced with a wire,
+ // e.g. because a module is built with a different optimization level, then existing code could
+ // unintentionally copy a wire instead, which would create a subtle but serious bug. To make sure
+ // this doesn't happen, prohibit copying and copy-assigning wires.
wire(const wire<Bits> &) = delete;
- wire(wire<Bits> &&) = default;
wire<Bits> &operator=(const wire<Bits> &) = delete;
+ wire(wire<Bits> &&) = default;
+ wire<Bits> &operator=(wire<Bits> &&) = default;
+
template<class IntegerT>
CXXRTL_ALWAYS_INLINE
IntegerT get() const {
memory(const memory<Width> &) = delete;
memory<Width> &operator=(const memory<Width> &) = delete;
+ memory(memory<Width> &&) = default;
+ memory<Width> &operator=(memory<Width> &&) = default;
+
// The only way to get the compiler to put the initializer in .rodata and do not copy it on stack is to stuff it
// into a plain array. You'd think an std::initializer_list would work here, but it doesn't, because you can't
// construct an initializer_list in a constexpr (or something) and so if you try to do that the whole thing is
typedef std::map<std::string, metadata> metadata_map;
-// Helper class to disambiguate values/wires and their aliases.
+// Tag class to disambiguate values/wires and their aliases.
struct debug_alias {};
+// Tag declaration to disambiguate values and debug outlines.
+using debug_outline = ::_cxxrtl_outline;
+
// This structure is intended for consumption via foreign function interfaces, like Python's ctypes.
// Because of this it uses a C-style layout that is easy to parse rather than more idiomatic C++.
//
// To avoid violating strict aliasing rules, this structure has to be a subclass of the one used
// in the C API, or it would not be possible to cast between the pointers to these.
struct debug_item : ::cxxrtl_object {
+ // Object types.
+ enum : uint32_t {
+ VALUE = CXXRTL_VALUE,
+ WIRE = CXXRTL_WIRE,
+ MEMORY = CXXRTL_MEMORY,
+ ALIAS = CXXRTL_ALIAS,
+ OUTLINE = CXXRTL_OUTLINE,
+ };
+
+ // Object flags.
enum : uint32_t {
- VALUE = CXXRTL_VALUE,
- WIRE = CXXRTL_WIRE,
- MEMORY = CXXRTL_MEMORY,
- ALIAS = CXXRTL_ALIAS,
+ INPUT = CXXRTL_INPUT,
+ OUTPUT = CXXRTL_OUTPUT,
+ INOUT = CXXRTL_INOUT,
+ DRIVEN_SYNC = CXXRTL_DRIVEN_SYNC,
+ DRIVEN_COMB = CXXRTL_DRIVEN_COMB,
+ UNDRIVEN = CXXRTL_UNDRIVEN,
};
debug_item(const ::cxxrtl_object &object) : cxxrtl_object(object) {}
template<size_t Bits>
- debug_item(value<Bits> &item, size_t lsb_offset = 0) {
+ debug_item(value<Bits> &item, size_t lsb_offset = 0, uint32_t flags_ = 0) {
static_assert(sizeof(item) == value<Bits>::chunks * sizeof(chunk_t),
"value<Bits> is not compatible with C layout");
type = VALUE;
+ flags = flags_;
width = Bits;
lsb_at = lsb_offset;
depth = 1;
zero_at = 0;
curr = item.data;
next = item.data;
+ outline = nullptr;
}
template<size_t Bits>
static_assert(sizeof(item) == value<Bits>::chunks * sizeof(chunk_t),
"value<Bits> is not compatible with C layout");
type = VALUE;
+ flags = DRIVEN_COMB;
width = Bits;
lsb_at = lsb_offset;
depth = 1;
zero_at = 0;
curr = const_cast<chunk_t*>(item.data);
next = nullptr;
+ outline = nullptr;
}
template<size_t Bits>
- debug_item(wire<Bits> &item, size_t lsb_offset = 0) {
+ debug_item(wire<Bits> &item, size_t lsb_offset = 0, uint32_t flags_ = 0) {
static_assert(sizeof(item.curr) == value<Bits>::chunks * sizeof(chunk_t) &&
sizeof(item.next) == value<Bits>::chunks * sizeof(chunk_t),
"wire<Bits> is not compatible with C layout");
type = WIRE;
+ flags = flags_;
width = Bits;
lsb_at = lsb_offset;
depth = 1;
zero_at = 0;
curr = item.curr.data;
next = item.next.data;
+ outline = nullptr;
}
template<size_t Width>
static_assert(sizeof(item.data[0]) == value<Width>::chunks * sizeof(chunk_t),
"memory<Width> is not compatible with C layout");
type = MEMORY;
+ flags = 0;
width = Width;
lsb_at = 0;
depth = item.data.size();
zero_at = zero_offset;
curr = item.data.empty() ? nullptr : item.data[0].data;
next = nullptr;
+ outline = nullptr;
}
template<size_t Bits>
static_assert(sizeof(item) == value<Bits>::chunks * sizeof(chunk_t),
"value<Bits> is not compatible with C layout");
type = ALIAS;
+ flags = DRIVEN_COMB;
width = Bits;
lsb_at = lsb_offset;
depth = 1;
zero_at = 0;
curr = const_cast<chunk_t*>(item.data);
next = nullptr;
+ outline = nullptr;
}
template<size_t Bits>
sizeof(item.next) == value<Bits>::chunks * sizeof(chunk_t),
"wire<Bits> is not compatible with C layout");
type = ALIAS;
+ flags = DRIVEN_COMB;
width = Bits;
lsb_at = lsb_offset;
depth = 1;
zero_at = 0;
curr = const_cast<chunk_t*>(item.curr.data);
next = nullptr;
+ outline = nullptr;
+ }
+
+ template<size_t Bits>
+ debug_item(debug_outline &group, const value<Bits> &item, size_t lsb_offset = 0) {
+ static_assert(sizeof(item) == value<Bits>::chunks * sizeof(chunk_t),
+ "value<Bits> is not compatible with C layout");
+ type = OUTLINE;
+ flags = DRIVEN_COMB;
+ width = Bits;
+ lsb_at = lsb_offset;
+ depth = 1;
+ zero_at = 0;
+ curr = const_cast<chunk_t*>(item.data);
+ next = nullptr;
+ outline = &group;
}
};
static_assert(std::is_standard_layout<debug_item>::value, "debug_item is not compatible with C layout");
}
};
+// Tag class to disambiguate module move constructor and module constructor that takes black boxes
+// out of another instance of the module.
+struct adopt {};
+
struct module {
module() {}
virtual ~module() {}
+ // Modules with black boxes cannot be copied. Although not all designs include black boxes,
+ // delete the copy constructor and copy assignment operator to make sure that any downstream
+ // code that manipulates modules doesn't accidentally depend on their availability.
module(const module &) = delete;
module &operator=(const module &) = delete;
+ module(module &&) = default;
+ module &operator=(module &&) = default;
+
+ virtual void reset() = 0;
+
virtual bool eval() = 0;
virtual bool commit() = 0;
} // namespace cxxrtl
-// Internal structure used to communicate with the implementation of the C interface.
+// Internal structures used to communicate with the implementation of the C interface.
+
typedef struct _cxxrtl_toplevel {
std::unique_ptr<cxxrtl::module> module;
} *cxxrtl_toplevel;
+typedef struct _cxxrtl_outline {
+ std::function<void()> eval;
+} *cxxrtl_outline;
+
// Definitions of internal Yosys cells. Other than the functions in this namespace, CXXRTL is fully generic
// and indepenent of Yosys implementation details.
//
template<size_t BitsY, size_t BitsA, size_t BitsB>
CXXRTL_ALWAYS_INLINE
value<BitsY> shl_uu(const value<BitsA> &a, const value<BitsB> &b) {
- return a.template zcast<BitsY>().template shl(b);
+ return a.template zcast<BitsY>().shl(b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
CXXRTL_ALWAYS_INLINE
value<BitsY> shl_su(const value<BitsA> &a, const value<BitsB> &b) {
- return a.template scast<BitsY>().template shl(b);
+ return a.template scast<BitsY>().shl(b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
CXXRTL_ALWAYS_INLINE
value<BitsY> sshl_uu(const value<BitsA> &a, const value<BitsB> &b) {
- return a.template zcast<BitsY>().template shl(b);
+ return a.template zcast<BitsY>().shl(b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
CXXRTL_ALWAYS_INLINE
value<BitsY> sshl_su(const value<BitsA> &a, const value<BitsB> &b) {
- return a.template scast<BitsY>().template shl(b);
+ return a.template scast<BitsY>().shl(b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
CXXRTL_ALWAYS_INLINE
value<BitsY> shr_uu(const value<BitsA> &a, const value<BitsB> &b) {
- return a.template shr(b).template zcast<BitsY>();
+ return a.shr(b).template zcast<BitsY>();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
CXXRTL_ALWAYS_INLINE
value<BitsY> shr_su(const value<BitsA> &a, const value<BitsB> &b) {
- return a.template shr(b).template scast<BitsY>();
+ return a.shr(b).template scast<BitsY>();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
CXXRTL_ALWAYS_INLINE
value<BitsY> sshr_uu(const value<BitsA> &a, const value<BitsB> &b) {
- return a.template shr(b).template zcast<BitsY>();
+ return a.shr(b).template zcast<BitsY>();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
CXXRTL_ALWAYS_INLINE
value<BitsY> sshr_su(const value<BitsA> &a, const value<BitsB> &b) {
- return a.template sshr(b).template scast<BitsY>();
+ return a.sshr(b).template scast<BitsY>();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
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