Cleanup and refinement of our "clang-tidy" pipeline. (AcademySoftwareFoundation#2093)

Clang-tidy is part of clang tooling that's a static analyzer of
everything from "unsafe" code that violates security guidelines, to
stylistic fixes.  There are many hundreds of tests. Initially we are
just enabling some basic security and correctness tests. Will add more
later.

All you need to do to run it is

    make CLANG_TIDY=1

Or if running cmake directly, use -DCLANG_TIDY=1

Warning: it is a long compile.

Set up a Travis test to run clang-tidy for static analysis. But after
much trial and error, I just couldn't get it to run in the 50 minutes
that Travis allows. So for now it's disabled. But if we ever have a CI
solution that executes faster or has longer time limits, I would love to
do a full static analysis on every PR. For now, I will have to be
content running it by hand on my own machine from time to time (and for
every tagged release).

Author: lgritz

.clang-tidy

@@ -0,0 +1,11 @@
+Checks:          '-*,clang-analyzer-security*'
+WarningsAsErrors: ''
+HeaderFilterRegex: '(OpenImageIO/[a-zA-Z0-9_]+\.h)|(imageio)|(oiio)|(iv/)|(_pvt\.h)'
+AnalyzeTemporaryDtors: false
+User:            lg
+CheckOptions:
+  - key:            modernize-use-nullptr.NullMacros
+    value:          'NULL'
+  - key:            modernize-use-emplace.SmartPointers
+    value:          'OIIO::intrusive_ptr'
+...

.travis.yml

@@ -71,13 +71,27 @@ install:
           export PATH=/usr/local/opt/qt5/bin:$PATH ;
           export PATH=/usr/local/opt/python/libexec/bin:$PATH ;
           export PYTHONPATH=/usr/local/lib/python${PYTHON_VERSION}/site-packages:$PYTHONPATH ;
+          if [ "${CLANG_TIDY}" != "" ] ; then
+              export PATH=/usr/local/Cellar/llvm/7.0.0_1/bin:$PATH ;
+              echo $PATH ;
+          fi ;
       elif [ $TRAVIS_OS_NAME == linux ] ; then
           CXX="ccache $CXX" CCACHE_CPP2=1 src/build-scripts/build_openexr.bash ;
           export ILMBASE_ROOT_DIR=$PWD/ext/openexr-install ;
           export OPENEXR_ROOT_DIR=$PWD/ext/openexr-install ;
           export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$OPENEXR_ROOT_DIR/lib ;
           CXX="ccache $CXX" CCACHE_CPP2=1 src/build-scripts/build_ocio.bash ;
           export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$PWD/ext/OpenColorIO/dist/lib ;
+          if [ "${CLANG_TIDY}" != "" ] ; then
+              export LLVM_VERSION=7.0.0 ;
+              export LLVMTAR=clang+llvm-${LLVM_VERSION}-x86_64-linux-gnu-ubuntu-14.04.tar.xz ;
+              time wget http://releases.llvm.org/${LLVM_VERSION}/${LLVMTAR} ;
+              tar xf $LLVMTAR ;
+              rm -f $LLVMTAR ;
+              mv clang+llvm* llvm-install ;
+              export LLVM_DIRECTORY=$PWD/llvm-install ;
+              export PATH=$LLVM_DIRECTORY/bin:$PATH ;
+          fi
       fi
     - src/build-scripts/install_test_images.bash
 
@@ -99,7 +113,7 @@ script:
     - git diff --color ;
       THEDIFF=`git diff` ;
       if [ "$THEDIFF" != "" ] ; then
-          echo "git diff was not empty. Failing clang-format check." ;
+          echo "git diff was not empty. Failing clang-format or clang-tidy check." ;
           exit 1 ;
       fi
 
@@ -172,7 +186,7 @@ matrix:
       ##  osx_image: xcode8.3
       ##  compiler: clang
       ##  env: LINKSTATIC=1 USE_FFMPEG=0 USE_OCIO=0 USE_OPENCV=0
-    # Build with sanitizers
+    # Dynamic analysis: build with sanitizers and run most tests.
     # Because this test takes so long to run, only build for PRs, direct
     # pushes to master or RB branches, or if the branch name includes
     # "sanitize". Other ordinary work branch pushes don't need to run this
@@ -239,6 +253,14 @@ matrix:
         compiler: clang
         env: OIIOTARGET=clang-format SKIP_TESTS=1 BUILD_MISSING_DEPS=0
         #if: branch =~ /(master|RB|travis|simd)/ OR type = pull_request
+    # Static analysis: build with clang-tidy.
+    # Disabled -- this takes so long to run, it can't complete in Travis's
+    # 50 minute time limit. Left here just to show how it should work.
+      #  - name: "Static analysis / clang-tidy"
+      #    os: linux
+      #    compiler: gcc
+      #    env: CLANG_TIDY=1 CLANG_TIDY_FIX=1 SKIP_TESTS=1
+      #    if: branch =~ /(master|RB|travis|tidy)/ OR type = pull_request
     # Build with EMBEDPLUGINS=0, both platforms.
       # FIXME: doesn't work yet on Travis
       # - os: linux

site/spi/Makefile-bits-arnold

@@ -199,8 +199,10 @@ else ifeq (${platform}, macosx)
         MY_CMAKE_FLAGS += \
            -DCMAKE_C_COMPILER=gcc-8 -DCMAKE_CXX_COMPILER=g++-8
         USE_LIBCPLUSPLUS := 0
+    else ifeq (${COMPILER},clang6)
+        MY_CMAKE_FLAGS += -DCMAKE_C_COMPILER=/usr/local/Cellar/llvm@6/6.0.1_1/bin/clang -DCMAKE_CXX_COMPILER=/usr/local/Cellar/llvm@6/6.0.1_1/bin/clang++
     else ifeq (${COMPILER},clang7)
-        MY_CMAKE_FLAGS += -DCMAKE_C_COMPILER=/usr/local/Cellar/llvm/7.0.0/bin/clang -DCMAKE_CXX_COMPILER=/usr/local/Cellar/llvm/7.0.0/bin/clang++
+        MY_CMAKE_FLAGS += -DCMAKE_C_COMPILER=/usr/local/Cellar/llvm/7.0.0_1/bin/clang -DCMAKE_CXX_COMPILER=/usr/local/Cellar/llvm/7.0.0_1/bin/clang++
     else ifeq (${COMPILER},clang)
         MY_CMAKE_FLAGS += -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
     else ifeq (${COMPILER},gcc)

src/build-scripts/install_homebrew_deps.bash

@@ -51,6 +51,12 @@ if [ "$LINKSTATIC" == "1" ] ; then
     brew install homebrew/dupes/bzip2
     brew install yaml-cpp --with-static-lib
 fi
+if [ "$CLANG_TIDY" != "" ] ; then
+    # If we are running for the sake of clang-tidy only, we will need
+    # a modern clang version not just the xcode one.
+    brew install llvm
+fi
+
 echo ""
 echo "After brew installs:"
 brew list --versions

src/cmake/compiler.cmake

@@ -18,7 +18,7 @@ option (LINKSTATIC  "Link with static external libraries when possible" OFF)
 option (CODECOV "Build code coverage tests" OFF)
 set (SANITIZE "" CACHE STRING "Build code using sanitizer (address, thread)")
 option (CLANG_TIDY "Enable clang-tidy" OFF)
-set (CLANG_TIDY_CHECKS "-*" CACHE STRING "clang-tidy checks to perform")
+set (CLANG_TIDY_CHECKS "" CACHE STRING "clang-tidy checks to perform (none='-*')")
 set (CLANG_TIDY_ARGS "" CACHE STRING "clang-tidy args")
 option (CLANG_TIDY_FIX "Have clang-tidy fix source" OFF)
 set (CLANG_FORMAT_INCLUDES "src/*.h" "src/*.cpp"
@@ -317,15 +317,31 @@ endif ()
 
 # clang-tidy options
 if (CLANG_TIDY)
-    set (CMAKE_CXX_CLANG_TIDY "clang-tidy;-header-filter=(${PROJECT_NAME})|(${PROJ_NAME})|(${PROJ_NAME_LOWER})|(_pvt.h)")
-    if (CLANG_TIDY_ARGS)
-        set (CMAKE_CXX_CLANG_TIDY "${CMAKE_CXX_CLANG_TIDY};${CLANG_TIDY_ARGS}")
-    endif ()
-    if (CLANG_TIDY_FIX)
-        set (CMAKE_CXX_CLANG_TIDY "${CMAKE_CXX_CLANG_TIDY};-fix")
+    find_program(CLANG_TIDY_EXE NAMES "clang-tidy"
+                 DOC "Path to clang-tidy executable")
+    message (STATUS "CLANG_TIDY_EXE ${CLANG_TIDY_EXE}")
+    if (CLANG_TIDY_EXE AND NOT ${CMAKE_VERSION} VERSION_LESS 3.6)
+        set (CMAKE_CXX_CLANG_TIDY
+             "${CLANG_TIDY_EXE}"
+             )
+        if (CLANG_TIDY_ARGS)
+            list (APPEND CMAKE_CXX_CLANG_TIDY ${CLANG_TIDY_ARGS})
+        endif ()
+        if (CLANG_TIDY_CHECKS)
+            list (APPEND CMAKE_CXX_CLANG_TIDY -checks="${CLANG_TIDY_CHECKS}")
+        endif ()
+        execute_process (COMMAND ${CMAKE_CXX_CLANG_TIDY} -list-checks
+                         OUTPUT_VARIABLE tidy_checks
+                         OUTPUT_STRIP_TRAILING_WHITESPACE)
+        if (CLANG_TIDY_FIX)
+            list (APPEND CMAKE_CXX_CLANG_TIDY "-fix")
+        endif ()
+        message (STATUS "clang-tidy command line is: ${CMAKE_CXX_CLANG_TIDY}")
+        message (STATUS "${tidy_checks}")
+    else ()
+        message (STATUS "Cannot run clang-tidy as requested")
     endif ()
-    set (CMAKE_CXX_CLANG_TIDY "${CMAKE_CXX_CLANG_TIDY};-checks=${CLANG_TIDY_CHECKS}")
-    message (STATUS "clang-tidy command line is: ${CMAKE_CXX_CLANG_TIDY}")
+    # Hint: run with CLANG_TIDY_ARGS=-list-checks to list all the checks
 endif ()
 
 # clang-format