Make lttng-ust an optional dependency. (#113876)

* Make lttng-ust an optional dependency.

* Fix android build.

* Fix android build...

* Remove CLR_CMAKE_DISABLE_XPLAT_EVENTSOURCE=1.

Author: tmds

eng/DotNetBuild.props

@@ -112,13 +112,14 @@
       <InnerBuildArgs Condition="'$(GitHubRepositoryName)' != ''">$(InnerBuildArgs) /p:GitHubRepositoryName=$(GitHubRepositoryName)</InnerBuildArgs>
 
       <!-- Handle system libraries -->
-      <UseSystemLibs Condition="'$(UseSystemLibs)' != ''">+$(UseSystemLibs)+</UseSystemLibs>
-      <InnerBuildArgs Condition="$(UseSystemLibs.Contains('+brotli+'))">$(InnerBuildArgs) --cmakeargs -DCLR_CMAKE_USE_SYSTEM_BROTLI=true</InnerBuildArgs>
-      <InnerBuildArgs Condition="$(UseSystemLibs.Contains('+libunwind+'))">$(InnerBuildArgs) --cmakeargs -DCLR_CMAKE_USE_SYSTEM_LIBUNWIND=true</InnerBuildArgs>
+      <UseSystemLibs Condition="'$(UseSystemLibs)' != ''">+$(UseSystemLibs)</UseSystemLibs>
+      <InnerBuildArgs Condition="$(UseSystemLibs.Contains('+brotli'))">$(InnerBuildArgs) --cmakeargs -DCLR_CMAKE_USE_SYSTEM_BROTLI=true</InnerBuildArgs>
+      <InnerBuildArgs Condition="$(UseSystemLibs.Contains('+libunwind'))">$(InnerBuildArgs) --cmakeargs -DCLR_CMAKE_USE_SYSTEM_LIBUNWIND=true</InnerBuildArgs>
       <!-- TODO: llvm-libunwind -->
       <!-- TODO: LinuxTracepoints -->
-      <InnerBuildArgs Condition="$(UseSystemLibs.Contains('+rapidjson+'))">$(InnerBuildArgs) --cmakeargs -DCLR_CMAKE_USE_SYSTEM_RAPIDJSON=true</InnerBuildArgs>
-      <InnerBuildArgs Condition="$(UseSystemLibs.Contains('+zlib+'))">$(InnerBuildArgs) --cmakeargs -DCLR_CMAKE_USE_SYSTEM_ZLIB=true</InnerBuildArgs>
+      <InnerBuildArgs Condition="$(UseSystemLibs.Contains('+rapidjson'))">$(InnerBuildArgs) --cmakeargs -DCLR_CMAKE_USE_SYSTEM_RAPIDJSON=true</InnerBuildArgs>
+      <InnerBuildArgs Condition="$(UseSystemLibs.Contains('+zlib'))">$(InnerBuildArgs) --cmakeargs -DCLR_CMAKE_USE_SYSTEM_ZLIB=true</InnerBuildArgs>
+      <InnerBuildArgs Condition="$(UseSystemLibs.Contains('-lttng'))">$(InnerBuildArgs) /p:FeatureXplatEventSource=false</InnerBuildArgs>
 
       <!-- Needed until https://github.com/dotnet/runtime/issues/109329 is fixed. -->
       <InnerBuildArgs Condition="'$(NetCoreAppToolCurrentVersion)' != ''">$(InnerBuildArgs) /p:NetCoreAppToolCurrentVersion=$(NetCoreAppToolCurrentVersion)</InnerBuildArgs>

src/coreclr/clr.featuredefines.props

@@ -6,7 +6,7 @@
     </PropertyGroup>
 
     <PropertyGroup Condition="'$(TargetsUnix)' == 'true'">
-        <FeatureXplatEventSource Condition="'$(TargetOS)' == 'linux'">true</FeatureXplatEventSource>
+        <FeatureXplatEventSource Condition="'$(FeatureXplatEventSource)' == '' AND '$(TargetOS)' == 'linux'">true</FeatureXplatEventSource>
         <FeatureComWrappers>true</FeatureComWrappers>
     </PropertyGroup>
 

src/coreclr/clrdefinitions.cmake

@@ -115,9 +115,9 @@ endif(FEATURE_GDBJIT_LANGID_CS)
 if(FEATURE_GDBJIT_SYMTAB)
     add_definitions(-DFEATURE_GDBJIT_SYMTAB)
 endif(FEATURE_GDBJIT_SYMTAB)
-if(CLR_CMAKE_TARGET_LINUX)
+if(FEATURE_EVENTSOURCE_XPLAT)
     add_definitions(-DFEATURE_EVENTSOURCE_XPLAT)
-endif(CLR_CMAKE_TARGET_LINUX)
+endif(FEATURE_EVENTSOURCE_XPLAT)
 # NetBSD doesn't implement this feature
 if(NOT CLR_CMAKE_TARGET_NETBSD AND NOT CLR_CMAKE_TARGET_ARCH_WASM)
     add_definitions(-DFEATURE_HIJACK)

src/coreclr/clrfeatures.cmake

@@ -9,6 +9,13 @@ if(NOT DEFINED FEATURE_EVENT_TRACE)
   endif()
 endif(NOT DEFINED FEATURE_EVENT_TRACE)
 
+if(NOT DEFINED FEATURE_EVENTSOURCE_XPLAT)
+  if (CLR_CMAKE_TARGET_LINUX AND NOT CLR_CMAKE_TARGET_ANDROID)
+    # To actually disable FEATURE_EVENTSOURCE_XPLAT, also change clr.featuredefines.props
+    set(FEATURE_EVENTSOURCE_XPLAT 1)
+  endif()
+endif(NOT DEFINED FEATURE_EVENTSOURCE_XPLAT)
+
 if(NOT DEFINED FEATURE_PERFTRACING AND FEATURE_EVENT_TRACE)
   set(FEATURE_PERFTRACING 1)
 endif(NOT DEFINED FEATURE_PERFTRACING AND FEATURE_EVENT_TRACE)

src/coreclr/pal/src/configure.cmake

@@ -942,7 +942,7 @@ elseif(CLR_CMAKE_TARGET_BROWSER)
   set(HAVE_SCHED_OTHER_ASSIGNABLE 0)
 else() # Anything else is Linux
   # LTTNG is not available on Android, so don't error out
-  if(NOT HAVE_LTTNG_TRACEPOINT_H AND NOT CLR_CMAKE_TARGET_ANDROID AND FEATURE_EVENT_TRACE)
+  if(FEATURE_EVENTSOURCE_XPLAT AND NOT HAVE_LTTNG_TRACEPOINT_H)
     unset(HAVE_LTTNG_TRACEPOINT_H CACHE)
     message(FATAL_ERROR "Cannot find liblttng-ust-dev. Try installing liblttng-ust-dev  (or the appropriate packages for your platform)")
   endif()

src/coreclr/pal/src/eventprovider/CMakeLists.txt

@@ -1,6 +1,6 @@
 set(EVENT_MANIFEST ${VM_DIR}/ClrEtwAll.man)
 
-if(CLR_CMAKE_HOST_LINUX AND NOT CLR_CMAKE_HOST_ANDROID)
+if(FEATURE_EVENTSOURCE_XPLAT)
   add_subdirectory(lttngprovider)
 else()
   add_subdirectory(dummyprovider)

src/coreclr/runtime.proj

@@ -54,6 +54,7 @@
       <_CoreClrBuildArg Include="-cmakeargs &quot;-DCLR_DOTNET_HOST_PATH=$(DOTNET_HOST_PATH)&quot;" />
       <_CoreClrBuildArg Condition="'$(HasCdacBuildTool)' == 'true'" Include="-cmakeargs &quot;-DCDAC_BUILD_TOOL_BINARY_PATH=$(RuntimeBinDir)cdac-build-tool\cdac-build-tool.dll&quot;" />
       <_CoreClrBuildArg Condition="'$(_IcuDir)' != ''" Include="-cmakeargs &quot;-DCLR_CMAKE_ICU_DIR=$(_IcuDir)&quot;" />
+      <_CoreClrBuildArg Condition="'$(FeatureXplatEventSource)' == 'false'" Include="-cmakeargs &quot;-DFEATURE_EVENTSOURCE_XPLAT=0&quot;" />
     </ItemGroup>
 
     <ItemGroup Condition="'$(CxxStandardLibrary)' != ''">