Files
concrete/compiler/lib/Dialect/MidLFHE/IR/MidLFHEDialect.cpp
2021-06-23 10:10:31 +02:00

113 lines
3.9 KiB
C++

#include "zamalang/Dialect/MidLFHE/IR/MidLFHEDialect.h"
#include "zamalang/Dialect/MidLFHE/IR/MidLFHEOps.h"
#include "zamalang/Dialect/MidLFHE/IR/MidLFHETypes.h"
#define GET_TYPEDEF_CLASSES
#include "zamalang/Dialect/MidLFHE/IR/MidLFHEOpsTypes.cpp.inc"
using namespace mlir::zamalang::MidLFHE;
void MidLFHEDialect::initialize() {
addOperations<
#define GET_OP_LIST
#include "zamalang/Dialect/MidLFHE/IR/MidLFHEOps.cpp.inc"
>();
addTypes<
#define GET_TYPEDEF_LIST
#include "zamalang/Dialect/MidLFHE/IR/MidLFHEOpsTypes.cpp.inc"
>();
}
::mlir::Type MidLFHEDialect::parseType(::mlir::DialectAsmParser &parser) const {
if (parser.parseOptionalKeyword("glwe").succeeded())
return GLWECipherTextType::parse(this->getContext(), parser);
parser.emitError(parser.getCurrentLocation(), "Unknown MidLFHE type");
return ::mlir::Type();
}
void MidLFHEDialect::printType(::mlir::Type type,
::mlir::DialectAsmPrinter &printer) const {
mlir::zamalang::MidLFHE::GLWECipherTextType glwe =
type.dyn_cast_or_null<mlir::zamalang::MidLFHE::GLWECipherTextType>();
if (glwe != nullptr) {
glwe.print(printer);
return;
}
// TODO - What should be done here?
printer << "unknwontype";
}
/*
* Returns the nubmer of bits from the log2StdDev parameter of a GLWE.
* This is widely inspired by the rust version on concrete:
*
* pub fn nb_bit_from_variance_99(var: f64, torus_bit: usize) -> usize {
* // compute sigma
* let sigma: f64 = f64::sqrt(var);
*
* // the constant to get 99% of the normal distribution
* let z: f64 = 3.;
* let tmp = torus_bit as f64 + f64::log2(sigma * z);
* if tmp < 0. {
* // means no bits are affected by the noise in the integer
* representation (discrete space) 0usize } else { tmp.ceil() as usize
* }
* }
*/
unsigned nbBitsFromLog2StdDev(signed log2StdDev, signed bits) {
long double sigma = std::pow(2, log2StdDev);
long double z = 3;
long double tmp = bits + std::log2(sigma * z);
if (tmp < 0.) {
return 0;
}
return std::ceil(tmp);
}
/**
* Verify that GLWE parameter are consistant, the layout of the ciphertext is
* organized like that.
*
* [0 0 0 0 0 0 0 0 X X X X X X X M M M M M M M X X X X X X X X 0 0 0 0 0 0 0 E
* E E E E E E E E E E E E] ^ paddingBits ^ ^ p ^ ^
* phantomBits ^ ^ nb_bits of log2StdDev ^ ^ scalingFactor We
* verify :
* - The bits parameter is 32 or 64 (we support only this value for now)
* - The message is not overlaped by the error
* - The message is still in the ciphertext
*/
::mlir::LogicalResult GLWECipherTextType::verify(
::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError,
signed dimension, signed polynomialSize, signed bits, signed paddingBits,
signed p, signed phantomBits, signed scalingFactor, signed log2StdDev) {
if (bits != -1 && bits != 32 && bits != 64) {
emitError() << "GLWE bits parameter can only be 32 or 64";
return ::mlir::failure();
}
if (bits != -1 && log2StdDev != -1 && scalingFactor != -1 &&
phantomBits != -1) {
unsigned errBits = nbBitsFromLog2StdDev(log2StdDev, bits);
if (errBits > scalingFactor + phantomBits) {
emitError() << "GLWE error overlap message, errBits(" << errBits
<< ") > scalingFactor(" << scalingFactor << ") + phantomBits("
<< phantomBits << ")";
return ::mlir::failure();
}
}
if (bits != -1 && paddingBits != -1 && p != -1 && phantomBits != -1 &&
scalingFactor != -1) {
signed int phantomLeft =
(bits - scalingFactor) - phantomBits - p - paddingBits;
if (phantomLeft < 0) {
emitError() << "GLWE padding + message + phantom = "
<< phantomBits + p + paddingBits
<< " cannot be represented in bits - "
"scalingFactor = "
<< (bits - scalingFactor);
return ::mlir::failure();
}
}
return ::mlir::success();
}