Build curve-specific files from json

The X25519 curves are now generated from `.json` files.  This code
only works in >= 8.7, because it makes use of the
recently-merged-from-fiat `transparent_abstract` tactic to allow
defining things in tactics without massive slowdown.  The structure is
as follows:

0. The module types and tactic definitions that set up the
infrastructure live in `src/Specific/Framework/`

1. There are `.json` files in `src/Specific/CurveParameters/` that
specify curve characteristics.   A simple example is `x2555_130.json`,
which is:
```json
{
    "modulus"          : "2^255-5",
    "base"             : "130",
    "a24"              : "121665 (* XXX TODO(andreser) FIXME?  Is this right for this curve? *)",
    "sz"               : "3",
    "bitwidth"         : "128",
    "carry_chain1"     : "default",
    "carry_chain2"     : ["0", "1"],
    "coef_div_modulus" : "2",
    "operations"       : ["ladderstep"]
}
```
A more complicated example is `x25519_c64.json`:
```json
{
    "modulus"          : "2^255-19",
    "base"             : "51",
    "a24"              : "121665",
    "sz"               : "5",
    "bitwidth"         : "64",
    "carry_chain1"     : "default",
    "carry_chain2"     : ["0", "1"],
    "coef_div_modulus" : "2",
    "operations"       : ["femul", "fesquare", "freeze", "ladderstep"],
    "extra_files"      : ["X25519_C64/scalarmult.c"],
    "compiler"         : "gcc -march=native -mtune=native -std=gnu11 -O3 -flto -fomit-frame-pointer -fwrapv -Wno-attributes",
    "mul_header"       : "(* Micro-optimized form from curve25519-donna-c64 by Adam Langley (Google) and Daniel Bernstein. See <https://github.com/agl/curve25519-donna/blob/master/LICENSE.md>;. *)",
    "mul_code"
    :
    "
  uint128_t t[5];
  limb r0,r1,r2,r3,r4,s0,s1,s2,s3,s4,c;

  r0 = in[0];
  r1 = in[1];
  r2 = in[2];
  r3 = in[3];
  r4 = in[4];

  s0 = in2[0];
  s1 = in2[1];
  s2 = in2[2];
  s3 = in2[3];
  s4 = in2[4];

  t[0]  =  ((uint128_t) r0) * s0;
  t[1]  =  ((uint128_t) r0) * s1 + ((uint128_t) r1) * s0;
  t[2]  =  ((uint128_t) r0) * s2 + ((uint128_t) r2) * s0 + ((uint128_t) r1) * s1;
  t[3]  =  ((uint128_t) r0) * s3 + ((uint128_t) r3) * s0 + ((uint128_t) r1) * s2 + ((uint128_t) r2) * s1;
  t[4]  =  ((uint128_t) r0) * s4 + ((uint128_t) r4) * s0 + ((uint128_t) r3) * s1 + ((uint128_t) r1) * s3 + ((uint128_t) r2) * s2;

  r4 *= 19;
  r1 *= 19;
  r2 *= 19;
  r3 *= 19;

  t[0] += ((uint128_t) r4) * s1 + ((uint128_t) r1) * s4 + ((uint128_t) r2) * s3 + ((uint128_t) r3) * s2;
  t[1] += ((uint128_t) r4) * s2 + ((uint128_t) r2) * s4 + ((uint128_t) r3) * s3;
  t[2] += ((uint128_t) r4) * s3 + ((uint128_t) r3) * s4;
  t[3] += ((uint128_t) r4) * s4;
",
    "square_header"    : "(* Micro-optimized form from curve25519-donna-c64 by Adam Langley (Google) and Daniel Bernstein. See <https://github.com/agl/curve25519-donna/blob/master/LICENSE.md>;. *)",
    "square_code"
    :
    "
  uint128_t t[5];
  limb r0,r1,r2,r3,r4,c;
  limb d0,d1,d2,d4,d419;

  r0 = in[0];
  r1 = in[1];
  r2 = in[2];
  r3 = in[3];
  r4 = in[4];

  do {
    d0 = r0 * 2;
    d1 = r1 * 2;
    d2 = r2 * 2 * 19;
    d419 = r4 * 19;
    d4 = d419 * 2;

    t[0] = ((uint128_t) r0) * r0 + ((uint128_t) d4) * r1 + (((uint128_t) d2) * (r3     ));
    t[1] = ((uint128_t) d0) * r1 + ((uint128_t) d4) * r2 + (((uint128_t) r3) * (r3 * 19));
    t[2] = ((uint128_t) d0) * r2 + ((uint128_t) r1) * r1 + (((uint128_t) d4) * (r3     ));
    t[3] = ((uint128_t) d0) * r3 + ((uint128_t) d1) * r2 + (((uint128_t) r4) * (d419   ));
    t[4] = ((uint128_t) d0) * r4 + ((uint128_t) d1) * r3 + (((uint128_t) r2) * (r2     ));
"
}
```
3. The `src/Specific/CurveParameters/remake_curves.sh` script holds a
list of curves to be made, what directories they should end up living
in, and it invokes `src/Specific/Framework/make_curve.py` to transform
these files into outputs.  The Python script fills in a few defaults
(such as computing `s` and `c` from the modulus, if you don't pass
them explicitly), and does a lot of processing on the C code that is
pasted verbatim from donna to get it to be in the right format for
Coq.

This Python script creates the files:
- `CurveParameters.v` (the Coq-ified version of the json file, which
  instantiates an appropriate module type);
- `Synthesis.v`, which instantiates a `MakeSynthesisTactics` with the
  curve parameter modules, invokes a tactic from the applied module
functor to synthesize all of the relevant non-reflective bits
(basically, what used to live in @jadephilipoom 's
`ArithmeticSynthesisTest.v`), and then instantiates another module
functor `PackageSynthesis` which defines notations via tactics in
terms to access the names of the various fields defined by the
synthesis tactic;
- any other files you ask it for, such as `compiler.sh`, `femul.v`,
 `femulDisplay.v`.  All of the `*Display.v` files are simple, and all
the the operation synthesis files have a single `Definition` (with the
appropriate type), and solve the definition by invoking a single
tactic defined in `PackageSynthesis`, e.g., `synthesize_mul` or
`synthesize_ladderstep`.

1 files changed, 6 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index e4788b21f..191e360a7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -45,6 +45,8 @@ src/Specific/X25519/C64/fesquare.c
 src/Specific/X25519/C64/fesquare.h
 src/Specific/X25519/C64/ladderstep.c
 src/Specific/X25519/C64/ladderstep.h
+src/Specific/X25519/C64/freeze.c
+src/Specific/X25519/C64/freeze.h
 src/Specific/X25519/C64/measure
 src/Specific/X25519/C64/test
 src/Specific/X25519/C32/femul.c
@@ -53,8 +55,12 @@ src/Specific/X25519/C32/fesquare.c
 src/Specific/X25519/C32/fesquare.h
 src/Specific/X25519/C32/ladderstep.c
 src/Specific/X25519/C32/ladderstep.h
+src/Specific/X25519/C32/freeze.c
+src/Specific/X25519/C32/freeze.h
 src/Specific/X25519/C32/measure
 src/Specific/X25519/C32/test
+src/Specific/X2555/C128/ladderstep.c
+src/Specific/X2555/C128/ladderstep.h
 third_party/openssl-curve25519/measure
 third_party/openssl-nistp256c64/measure
 third_party/openssl-nistz256-adx/measure