Use configure_file in CMake to force rebuild if git commit changes

* We also only use GIT_COMMIT_HASH where necessary to avoid rebuilding many
  files for no reason, including splitting version.cpp out into a separate
  project as we do with VS since otherwise changing its preprocessor defines
  rebuilds the whole renderdoc project.
* At the same time, move the git hash to be internal only so we don't have to
  try to link version.cpp into other projects like renderdoccmd or qrenderdoc.

CMakeLists.txt

@@ -65,7 +65,7 @@ endif()
 
 # version setting variables. See renderdoc/api/replay/version.h
 
-set(BUILD_VERSION_HASH "" CACHE STRING "The current git commit hash. See GIT_COMMIT_HASH in renderdoc/api/replay/version.cpp")
+set(BUILD_VERSION_HASH "" CACHE STRING "The current git commit hash. See renderdoc/replay/version.cpp")
 option(BUILD_VERSION_STABLE "If this is a stable build. See RENDERDOC_STABLE_BUILD in renderdoc/api/replay/version.h" OFF)
 set(BUILD_VERSION_DIST_NAME "" CACHE STRING "The name of the distribution. See DISTRIBUTION_NAME in renderdoc/api/replay/version.h")
 set(BUILD_VERSION_DIST_VER "" CACHE STRING "The distribution-specific version number. See DISTRIBUTION_VERSION in renderdoc/api/replay/version.h")
@@ -134,7 +134,26 @@ endfunction(get_git_hash)
 # get git commit hash
 get_git_hash(GIT_COMMIT_HASH)
 string(STRIP ${GIT_COMMIT_HASH} GIT_COMMIT_HASH)
-add_definitions(-DGIT_COMMIT_HASH="${GIT_COMMIT_HASH}")
+
+if(EXISTS "${CMAKE_SOURCE_DIR}/.git/HEAD")
+    # Use configure_file to force a re-configure if the HEAD file changes. That means changing branch.
+    # The re-configure will pick up a new git commit hash above, if it exists and is valid.
+    # This will be slightly redundant if BUILD_VERSION_HASH is specified but that is not a case we expect to care about.
+    configure_file("${CMAKE_SOURCE_DIR}/.git/HEAD" "${CMAKE_BINARY_DIR}/git_HEAD" COPYONLY)
+
+    # in addition, if HEAD is a ref, do the same on the file it's pointing to (since HEAD won't change for commits to the current branch)
+    # if we change branch then this will correspondingly 
+    file(READ ${CMAKE_SOURCE_DIR}/.git/HEAD HEAD_CONTENTS)
+    string(STRIP "${HEAD_CONTENTS}" HEAD_CONTENTS)
+
+    if("${HEAD_CONTENTS}" MATCHES "ref: ")
+        string(REPLACE "ref: " "" REF_LOCATION "${HEAD_CONTENTS}")
+
+        if(EXISTS "${CMAKE_SOURCE_DIR}/.git/${REF_LOCATION}")
+            configure_file("${CMAKE_SOURCE_DIR}/.git/${REF_LOCATION}" "${CMAKE_BINARY_DIR}/git_ref" COPYONLY)
+        endif()
+    endif()
+endif()
 
 project(RenderDoc CXX C)
 

qrenderdoc/CMakeLists.txt

@@ -153,10 +153,6 @@ if(CMAKE_COMPILER_IS_GNUCXX)
 endif()
 
 # propagate build version info. Lots of escaping needed here to pass ""s into the define value
-file(APPEND
-    ${CMAKE_BINARY_DIR}/qrenderdoc/qrenderdoc_cmake.pri
-    "DEFINES+=GIT_COMMIT_HASH='\\\\\"${GIT_COMMIT_HASH}\\\\\"'\n")
-
 if(BUILD_VERSION_STABLE)
     file(APPEND
          ${CMAKE_BINARY_DIR}/qrenderdoc/qrenderdoc_cmake.pri

qrenderdoc/Code/qrenderdoc.cpp

@@ -183,7 +183,7 @@ int main(int argc, char *argv[])
 
   if(parser.isSet(versionOption))
   {
-    printf("QRenderDoc v%s (%s)\n", MAJOR_MINOR_VERSION_STRING, GitVersionHash);
+    printf("QRenderDoc v%s (%s)\n", MAJOR_MINOR_VERSION_STRING, RENDERDOC_GetCommitHash());
 #if defined(DISTRIBUTION_VERSION)
     printf("Packaged for %s - %s\n", DISTRIBUTION_NAME, DISTRIBUTION_CONTACT);
 #endif

qrenderdoc/Windows/Dialogs/AboutDialog.cpp

@@ -34,7 +34,7 @@ AboutDialog::AboutDialog(QWidget *parent) : QDialog(parent), ui(new Ui::AboutDia
 {
   ui->setupUi(this);
 
-  QString hash = QString::fromLatin1(GitVersionHash);
+  QString hash = QString::fromLatin1(RENDERDOC_GetCommitHash());
 
   if(hash[0] == QLatin1Char('N') && hash[1] == QLatin1Char('O'))
   {

qrenderdoc/Windows/MainWindow.cpp

@@ -1015,7 +1015,7 @@ void MainWindow::SetTitle(const QString &filename)
   else
     text += tr("Unstable release (%1 - %2)")
                 .arg(lit(FULL_VERSION_STRING))
-                .arg(QString::fromLatin1(GitVersionHash));
+                .arg(QString::fromLatin1(RENDERDOC_GetCommitHash()));
 
   if(IsRunningAsAdmin())
     text += tr(" (Administrator)");
@@ -2631,7 +2631,7 @@ void MainWindow::on_action_Send_Error_Report_triggered()
   QVariantMap json;
 
   json[lit("version")] = lit(FULL_VERSION_STRING);
-  json[lit("gitcommit")] = QString::fromLatin1(GitVersionHash);
+  json[lit("gitcommit")] = QString::fromLatin1(RENDERDOC_GetCommitHash());
   json[lit("replaycrash")] = 1;
   json[lit("report")] = (QString)report;
 

qrenderdoc/qrenderdoc.pro

@@ -124,8 +124,6 @@ win32 {
 	SOURCES += $$CMAKE_DIR/qrenderdoc/qrenderdoc_python.cxx
 	SOURCES += $$CMAKE_DIR/qrenderdoc/qrenderdoc.py.c
 
-	SOURCES += $$_PRO_FILE_PWD_/../renderdoc/api/replay/version.cpp
-
 	CONFIG += warn_off
 	CONFIG += c++14
 	QMAKE_CFLAGS_WARN_OFF -= -w

renderdoc/CMakeLists.txt

@@ -93,7 +93,6 @@ set(sources
     api/replay/vk_pipestate.h
     api/replay/version.h
     api/replay/renderdoc_tostr.inl
-    api/replay/version.cpp
     common/common.cpp
     common/common.h
     common/custom_assert.h
@@ -473,6 +472,12 @@ list(APPEND renderdoc_objects
     $<TARGET_OBJECTS:rdoc>
     ${data_objects})
 
+add_library(rdoc_version OBJECT replay/version.cpp)
+target_compile_definitions(rdoc_version PRIVATE -DGIT_COMMIT_HASH="${GIT_COMMIT_HASH}")
+
+list(APPEND renderdoc_objects
+    $<TARGET_OBJECTS:rdoc_version>)
+
 # posix_libentry must be the last so that library_loaded is called after
 # static objects are constructed. We guarantee this happens after even
 # any other static libraries that we link by making it its own static

renderdoc/api/replay/version.h

@@ -41,12 +41,14 @@
 //
 
 // To prevent a project rebuild cascading when the git commit changes, we declare a char array
-// that's implemented in version.inl, which can be included in each module that uses the version.
+// that's implemented in version.cpp, which is linked into the core module.
 // It's 41 characters to allow 40 characters of commit hash plus trailing NULL.
-// Then the .cpp that includes version.inl is the only one that actually needs to have the hash
-// defined properly.
-// This replaces the previous GIT_COMMIT_HASH define here.
+// Then version.cpp is the only thing that needs to be rebuilt when the git commit changes
+//
+// Only available internally, external users should use RENDERDOC_GetCommitHash()
+#if defined(RENDERDOC_EXPORTS)
 extern "C" const char GitVersionHash[41];
+#endif
 
 // If this variable is set to 1, then this build is considered a stable version - based on a tagged
 // version number upstream, possibly with some patches applied as necessary.

renderdoc/renderdoc_version.vcxproj

@@ -122,6 +122,6 @@ namespace GitIntrospection {
     </ItemGroup>
   </Target>
   <ItemGroup>
-    <ClCompile Include="api\replay\version.cpp" />
+    <ClCompile Include="replay\version.cpp" />
   </ItemGroup>
 </Project>

renderdoc/renderdoc_version.vcxproj.filters

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <ClCompile Include="api\replay\version.cpp" />
+    <ClCompile Include="replay\version.cpp" />
   </ItemGroup>
 </Project>

renderdoccmd/CMakeLists.txt

@@ -1,4 +1,4 @@
-set(sources renderdoccmd.cpp ${CMAKE_SOURCE_DIR}/renderdoc/api/replay/version.cpp)
+set(sources renderdoccmd.cpp)
 set(includes PRIVATE ${CMAKE_SOURCE_DIR}/renderdoc/api)
 set(libraries PRIVATE renderdoc)
 

renderdoccmd/renderdoccmd.cpp

@@ -171,7 +171,8 @@ struct VersionCommand : public Command
   virtual int Execute(cmdline::parser &parser, const CaptureOptions &)
   {
     std::cout << "renderdoccmd " << (sizeof(uintptr_t) == sizeof(uint64_t) ? "x64" : "x86")
-              << " v" MAJOR_MINOR_VERSION_STRING << " built from " << GitVersionHash << std::endl;
+              << " v" MAJOR_MINOR_VERSION_STRING << " built from " << RENDERDOC_GetCommitHash()
+              << std::endl;
 
 #if defined(DISTRIBUTION_VERSION)
     std::cout << "Packaged for " << DISTRIBUTION_NAME << " (" << DISTRIBUTION_VERSION << ") - "