Switch Win build to MPIR instead of GMP

.gitmodules

@@ -11,4 +11,4 @@
 [submodule "libff"]
 	path = libff
 	url = https://github.com/torquem-ch/libff.git
-	branch = optional_openssl
+	branch = mpir

CMakeLists.txt

@@ -61,16 +61,11 @@ set(
   "Default curve: one of ALT_BN128, BN128, EDWARDS, MNT4, MNT6"
   FORCE
 )
-option(
-  WITH_PROCPS
-  "Use procps for memory profiling"
-  OFF
-)
-option(
-  IS_LIBFF_PARENT
-  "Install submodule dependencies if caller originates from here"
-  OFF
-)
+option(WITH_PROCPS "" OFF)
+option(IS_LIBFF_PARENT "" OFF)
+if(MSVC)
+  option(MPIR_INSTEAD_OF_GMP "" ON)
+endif()
 add_subdirectory(libff)
 
 # Compiler options

README.md

@@ -16,9 +16,9 @@ as outlined in its [release commentary](https://ledgerwatch.github.io/turbo_geth
 
 ## Linux & macOS
 Building silkworm requires:
+* C++17 compiler (GCC or Clang)
 * [CMake](http://cmake.org)
 * [GMP](http://gmplib.org) (`sudo apt-get install libgmp3-dev` or `brew install gmp`)
-* C++17 compiler (Clang or GCC)
 
 Once the prerequisites are installed, bootstrap cmake build by running
 ```
@@ -40,10 +40,13 @@ or run tests
 ```
 ./tests
 ```
-## Windows (Visual Studio Community Edition 2019)
-* Download [GMP](https://github.com/ShiftMediaProject/gmp/releases) and add it to your `INCLUDE` and `PATH` environment variables.
-* Install [Visual Studio](https://www.visualstudio.com/downloads/). Community edition is fine.
+## Windows
+* Install [Visual Studio](https://www.visualstudio.com/downloads) 2019. Community edition is fine.
 * Make sure your setup includes CMake support and Windows 10 SDK.
+* Install [vcpkg](https://github.com/microsoft/vcpkg#quick-start-windows).
+* `.\vcpkg\vcpkg install mpir:x64-windows`
+* Add <VCPKG_ROOT>\installed\x64-windows\include to your `INCLUDE` environment variable.
+* Add <VCPKG_ROOT>\installed\x64-windows\bin to your `PATH` environment variable.
 * Open Visual Studio and select File -> CMake... 
 * Browse the folder where you have cloned this repository and select the file CMakeLists.txt
 * Let CMake cache generation complete (it may take several minutes)

appveyor.yml

@@ -15,16 +15,19 @@
 image: Visual Studio 2019
 platform: x64
 
+install:
+  - cd c:\Tools\vcpkg
+  - vcpkg install mpir:x64-windows
+
 cache:
+  - C:\Tools\vcpkg\installed -> .appveyor.yml
   - C:\.hunter
 
 before_build:
-  - curl -o C:\gmp.zip -L https://github.com/ShiftMediaProject/gmp/releases/download/6.2.1/libgmp_6.2.1_msvc16.zip
-  - 7z x C:\gmp.zip -oC:\GMP
   - cd "%APPVEYOR_BUILD_FOLDER%"
   - git submodule update --init --recursive
-  - SET INCLUDE=C:\GMP\include;%INCLUDE%
-  - SET PATH=C:\GMP\lib\x64;%PATH%
+  - SET INCLUDE=C:\Tools\vcpkg\installed\x64-windows\include;%INCLUDE%
+  - SET PATH=C:\Tools\vcpkg\installed\x64-windows\bin;%PATH%
   - cmake -H. -Bbuild
 
 build:

silkworm/execution/precompiled.cpp

@@ -177,19 +177,19 @@ std::optional<Bytes> expmod_run(ByteView input) noexcept {
 
   boost::multiprecision::cpp_int base{};
   if (base_len) {
-    import_bits(base, &input[0], &input[base_len]);
+    import_bits(base, input.data(), input.data() + base_len);
     input.remove_prefix(base_len);
   }
 
   boost::multiprecision::cpp_int exponent{};
   if (exponent_len) {
-    import_bits(exponent, &input[0], &input[exponent_len]);
+    import_bits(exponent, input.data(), input.data() + exponent_len);
     input.remove_prefix(exponent_len);
   }
 
   boost::multiprecision::cpp_int modulus{};
   if (modulus_len) {
-    import_bits(modulus, &input[0], &input[modulus_len]);
+    import_bits(modulus, input.data(), input.data() + modulus_len);
   }
 
   if (modulus == 0) {