add clcache to Windows build

This sets up clcache for the AWS Codebuild Windows builds.
clcache is a clone of ccache for Visual Studio CL.

Author: Daniel Kroening

buildspec-windows.yml

@@ -5,6 +5,7 @@ phases:
     commands:
       - choco install cyg-get -y --no-progress
       - cyg-get bash patch bison flex make wget perl
+      - nuget install clcache -OutputDirectory "c:\tools" -ExcludeVersion -Version 4.1.0
 
   build:
     commands:
@@ -13,14 +14,22 @@ phases:
         C:\tools\cygwin\bin\bash -c "make -C src minisat2-download DOWNLOADER=wget"
 
       - |
-        $env:Path = "C:\tools\cygwin\bin;$env:Path"
-        cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make -j4 -C src BUILD_ENV=MSVC" '
-        cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make -j4 -C unit all BUILD_ENV=MSVC" '
+        $env:Path = "C:\tools\cygwin\bin;c:\tools\clcache\clcache-4.1.0;$env:Path"
+        $env:CLCACHE_DIR = "C:\clcache"
+        cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make CXX=clcache.exe -j4 -C src BUILD_ENV=MSVC" '
+        cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make CXX=clcache.exe -j4 -C unit all BUILD_ENV=MSVC" '
 
       - |
-        $env:Path = "C:\tools\cygwin\bin;$env:Path"
-        cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make -j4 -C jbmc/src setup-submodules" && bash -c "make -j4 -C jbmc/src BUILD_ENV=MSVC" '
-        cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make -j4 -C jbmc/unit all BUILD_ENV=MSVC" '
+        $env:Path = "C:\tools\cygwin\bin;c:\tools\clcache\clcache-4.1.0;$env:Path"
+        $env:CLCACHE_DIR = "C:\clcache"
+        cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make -j4 -C jbmc/src setup-submodules" && bash -c "make CXX=clcache.exe -j4 -C jbmc/src BUILD_ENV=MSVC" '
+        cmd /c 'call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 && bash -c "make CXX=clcache.exe -j4 -C jbmc/unit all BUILD_ENV=MSVC" '
+
+      - |
+        # display cache stats
+        $env:Path = "C:\tools\cygwin\bin;c:\tools\clcache\clcache-4.1.0;$env:Path"
+        $env:CLCACHE_DIR = "C:\clcache"
+        cmd /c 'clcache -s'
 
   post_build:
     commands:
@@ -72,3 +81,4 @@ artifacts:
 
 cache:
   paths:
+    - 'c:\clcache'