diff options
| -rw-r--r-- | compiler/semfold.nim | 2 | ||||
| -rw-r--r-- | tests/macros/t23784.nim | 157 |
2 files changed, 158 insertions, 1 deletions
diff --git a/compiler/semfold.nim b/compiler/semfold.nim index 466df2e4e..10361eb79 100644 --- a/compiler/semfold.nim +++ b/compiler/semfold.nim @@ -703,7 +703,7 @@ proc getConstExpr(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode of nkAddr: var a = getConstExpr(m, n[0], idgen, g) if a != nil: - result = n + result = nil # don't fold paths containing nkAddr n[0] = a of nkBracket, nkCurly: result = copyNode(n) diff --git a/tests/macros/t23784.nim b/tests/macros/t23784.nim new file mode 100644 index 000000000..31b4544c6 --- /dev/null +++ b/tests/macros/t23784.nim @@ -0,0 +1,157 @@ +discard """ + joinable: false +""" + + +# debug ICE: genCheckedRecordField +# apparently after https://github.com/nim-lang/Nim/pull/23477 + +# bug #23784 + +import std/bitops, std/macros + +# -------------------------------------------------------------- + +type Algebra = enum + BN254_Snarks + +type SecretWord* = distinct uint64 +const WordBitWidth* = sizeof(SecretWord) * 8 + +func wordsRequired*(bits: int): int {.inline.} = + const divShiftor = fastLog2(WordBitWidth) + result = (bits + WordBitWidth - 1) shr divShiftor + +type + BigInt*[bits: static int] = object + limbs*: array[bits.wordsRequired, SecretWord] # <--- crash points to here + +# -------------------------------------------------------------- + +const CurveBitWidth = [ + BN254_Snarks: 254 +] + +const BN254_Snarks_Modulus = BigInt[254](limbs: [SecretWord 0x1, SecretWord 0x2, SecretWord 0x3, SecretWord 0x4]) +const BN254_Snarks_Order = BigInt[254](limbs: [SecretWord 0x1, SecretWord 0x1, SecretWord 0x2, SecretWord 0x2]) + +func montyOne*(M: BigInt[254]): BigInt[254] = + ## Returns "1 (mod M)" in the Montgomery domain. + ## This is equivalent to R (mod M) in the natural domain + BigInt[254](limbs: [SecretWord 0x1, SecretWord 0x1, SecretWord 0x1, SecretWord 0x1]) + + +{.experimental: "dynamicBindSym".} + +type + DerivedConstantMode* = enum + kModulus + kOrder + +macro genDerivedConstants*(mode: static DerivedConstantMode): untyped = + ## Generate constants derived from the main constants + ## + ## For example + ## - the Montgomery magic constant "R^2 mod N" in ROM + ## For each curve under the private symbol "MyCurve_R2modP" + ## - the Montgomery magic constant -1/P mod 2^Wordbitwidth + ## For each curve under the private symbol "MyCurve_NegInvModWord + ## - ... + + # Now typedesc are NimNode and there is no way to translate + # NimNode -> typedesc easily so we can't + # "for curve in low(Curve) .. high(Curve):" + # As an ugly workaround, we count + # The item at position 0 is a pragma + result = newStmtList() + + template used(name: string): NimNode = + nnkPragmaExpr.newTree( + ident(name), + nnkPragma.newTree(ident"used") + ) + + let ff = if mode == kModulus: "_Fp" else: "_Fr" + + for curveSym in low(Algebra) .. high(Algebra): + let curve = $curveSym + let M = if mode == kModulus: bindSym(curve & "_Modulus") + else: bindSym(curve & "_Order") + + # const MyCurve_montyOne = montyOne(MyCurve_Modulus) + result.add newConstStmt( + used(curve & ff & "_MontyOne"), newCall( + bindSym"montyOne", + M + ) + ) + +# -------------------------------------------------------------- + +{.experimental: "dynamicBindSym".} + +genDerivedConstants(kModulus) +genDerivedConstants(kOrder) + +proc bindConstant(ff: NimNode, property: string): NimNode = + # Need to workaround https://github.com/nim-lang/Nim/issues/14021 + # which prevents checking if a type FF[Name] = Fp[Name] or Fr[Name] + # was instantiated with Fp or Fr. + # getTypeInst only returns FF and sameType doesn't work. + # so quote do + when checks. + let T = getTypeInst(ff) + T.expectKind(nnkBracketExpr) + doAssert T[0].eqIdent("typedesc") + + let curve = + if T[1].kind == nnkBracketExpr: # typedesc[Fp[BLS12_381]] as used internally + # doAssert T[1][0].eqIdent"Fp" or T[1][0].eqIdent"Fr", "Found ident: '" & $T[1][0] & "' instead of 'Fp' or 'Fr'" + T[1][1].expectKind(nnkIntLit) # static enum are ints in the VM + $Algebra(T[1][1].intVal) + else: # typedesc[bls12381_fp] alias as used for C exports + let T1 = getTypeInst(T[1].getImpl()[2]) + if T1.kind != nnkBracketExpr or + T1[1].kind != nnkIntLit: + echo T.repr() + echo T1.repr() + echo getTypeInst(T1).treerepr() + error "getTypeInst didn't return the full instantiation." & + " Dealing with types in macros is hard, complain at https://github.com/nim-lang/RFCs/issues/44" + $Algebra(T1[1].intVal) + + let curve_fp = bindSym(curve & "_Fp_" & property) + let curve_fr = bindSym(curve & "_Fr_" & property) + result = quote do: + when `ff` is Fp: + `curve_fp` + elif `ff` is Fr: + `curve_fr` + else: + {.error: "Unreachable, received type: " & $`ff`.} + +# -------------------------------------------------------------- + +template matchingBigInt*(Name: static Algebra): untyped = + ## BigInt type necessary to store the prime field Fp + # Workaround: https://github.com/nim-lang/Nim/issues/16774 + # as we cannot do array accesses in type section. + # Due to generic sandwiches, it must be exported. + BigInt[CurveBitWidth[Name]] + +type + Fp*[Name: static Algebra] = object + mres*: matchingBigInt(Name) + +macro getMontyOne*(ff: type Fp): untyped = + ## Get one in Montgomery representation (i.e. R mod P) + result = bindConstant(ff, "MontyOne") + +func getOne*(T: type Fp): T {.noInit, inline.} = + result = cast[ptr T](unsafeAddr getMontyOne(T))[] + +# -------------------------------------------------------------- +proc foo(T: Fp) = + discard T + +let a = Fp[BN254_Snarks].getOne() +foo(a) # oops this was a leftover that broke the bisect. |