Fixes for building mono on musl-based systems

Directory.Build.props

@@ -154,7 +154,7 @@
     <_runtimeOS Condition="'$(TargetsMobile)' == 'true'">$(TargetOS.ToLowerInvariant())</_runtimeOS>
 
     <_portableOS>linux</_portableOS>
-    <_portableOS Condition="'$(_runtimeOS)' == 'linux-musl'">linux-musl</_portableOS>
+    <_portableOS Condition="'$(_runtimeOS)' == 'linux-musl' or $(_runtimeOS.StartsWith('alpine'))">linux-musl</_portableOS>
     <_portableOS Condition="'$(_runtimeOS)' == 'linux-bionic'">linux-bionic</_portableOS>
     <_portableOS Condition="'$(_hostOS)' == 'OSX'">osx</_portableOS>
     <_portableOS Condition="'$(_runtimeOS)' == 'win' or '$(TargetOS)' == 'windows'">win</_portableOS>
@@ -207,6 +207,7 @@
     <OutputRid Condition="'$(OutputRid)' == ''">$(PackageRID)</OutputRid>
     <OutputRid Condition="'$(PortableBuild)' == 'true'">$(_portableOS)-$(TargetArchitecture)</OutputRid>
     <TargetsLinuxBionic Condition="$(OutputRid.StartsWith('linux-bionic'))">true</TargetsLinuxBionic>
+    <TargetsLinuxMusl Condition="'$(_portableOS)' == 'linux-musl'">true</TargetsLinuxMusl>
   </PropertyGroup>
 
   <PropertyGroup Label="CalculateTargetOSName" Condition="'$(SkipInferTargetOSName)' != 'true'">

eng/native/tryrun.cmake

@@ -8,7 +8,11 @@ endmacro()
 
 if(EXISTS ${CROSS_ROOTFS}/usr/lib/gcc/armv7-alpine-linux-musleabihf OR
    EXISTS ${CROSS_ROOTFS}/usr/lib/gcc/armv6-alpine-linux-musleabihf OR
-   EXISTS ${CROSS_ROOTFS}/usr/lib/gcc/aarch64-alpine-linux-musl)
+   EXISTS ${CROSS_ROOTFS}/usr/lib/gcc/aarch64-alpine-linux-musl OR
+   EXISTS ${CROSS_ROOTFS}/usr/lib/gcc/s390x-alpine-linux-musl OR
+   EXISTS ${CROSS_ROOTFS}/usr/lib/gcc/ppc64le-alpine-linux-musl OR
+   EXISTS ${CROSS_ROOTFS}/usr/lib/gcc/i586-alpine-linux-musl OR
+   EXISTS ${CROSS_ROOTFS}/usr/lib/gcc/riscv64-alpine-linux-musl)
 
   set(ALPINE_LINUX 1)
 elseif(EXISTS ${CROSS_ROOTFS}/bin/freebsd-version)

src/coreclr/pal/src/CMakeLists.txt

@@ -315,6 +315,11 @@ if(CLR_CMAKE_TARGET_LINUX)
     target_link_libraries(coreclrpal ${UNWIND_LIBS})
   endif(CLR_CMAKE_USE_SYSTEM_LIBUNWIND)
 
+  # bundled libunwind requires using libucontext on alpine and x86 and ppc64le
+  if(CLR_CMAKE_TARGET_ALPINE_LINUX AND (CLR_CMAKE_TARGET_ARCH_I386 OR CLR_CMAKE_TARGET_ARCH_POWERPC64))
+    target_link_libraries(coreclrpal ucontext)
+  endif(CLR_CMAKE_TARGET_ALPINE_LINUX AND (CLR_CMAKE_TARGET_ARCH_I386 OR CLR_CMAKE_TARGET_ARCH_POWERPC64))
+
 endif(CLR_CMAKE_TARGET_LINUX)
 
 if(CLR_CMAKE_TARGET_NETBSD)

src/coreclr/pal/src/misc/perfjitdump.cpp

@@ -25,7 +25,7 @@
 #include <sys/uio.h>
 #include <time.h>
 #include <unistd.h>
-#include <linux/limits.h>
+#include <limits.h>
 
 #include "../inc/llvm/ELF.h"
 

src/coreclr/vm/i386/cgenx86.cpp

@@ -1133,6 +1133,7 @@ extern "C" DWORD __stdcall avx512StateSupport()
 
 #else // !TARGET_UNIX
 
+#if !__has_builtin(__cpuid)
 void __cpuid(int cpuInfo[4], int function_id)
 {
     // Based on the Clang implementation provided in cpuid.h:
@@ -1143,7 +1144,9 @@ void __cpuid(int cpuInfo[4], int function_id)
         : "0"(function_id)
     );
 }
+#endif
 
+#if !__has_builtin(__cpuidex)
 void __cpuidex(int cpuInfo[4], int function_id, int subFunction_id)
 {
     // Based on the Clang implementation provided in cpuid.h:
@@ -1154,6 +1157,7 @@ void __cpuidex(int cpuInfo[4], int function_id, int subFunction_id)
         : "0"(function_id), "2"(subFunction_id)
     );
 }
+#endif
 
 extern "C" DWORD __stdcall xmmYmmStateSupport()
 {

src/mono/CMakeLists.txt

@@ -216,6 +216,35 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
   # Enable the "full RELRO" options (RELRO & BIND_NOW) at link time
   add_link_options(-Wl,-z,relro)
   add_link_options(-Wl,-z,now)
+  # Detect Linux ID
+  # TODO: Eventually merge with eng/native/configureplatform.cmake
+  set(LINUX_ID_FILE "/etc/os-release")
+  if(CMAKE_CROSSCOMPILING)
+      set(LINUX_ID_FILE "${CMAKE_SYSROOT}${LINUX_ID_FILE}")
+  endif()
+
+  if(EXISTS ${LINUX_ID_FILE})
+      execute_process(
+          COMMAND bash -c "source ${LINUX_ID_FILE} && echo \$ID"
+          OUTPUT_VARIABLE CLR_CMAKE_LINUX_ID
+          OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+      execute_process(
+          COMMAND bash -c "if strings \"${CMAKE_SYSROOT}/usr/bin/ldd\" 2>&1 | grep -q musl; then echo musl; fi"
+          OUTPUT_VARIABLE CLR_CMAKE_LINUX_MUSL
+          OUTPUT_STRIP_TRAILING_WHITESPACE)
+  endif()
+
+  if(DEFINED CLR_CMAKE_LINUX_ID)
+      if(CLR_CMAKE_LINUX_ID STREQUAL alpine)
+          set(CLR_CMAKE_HOST_ALPINE_LINUX 1)
+          set(CLR_CMAKE_HOST_OS ${CLR_CMAKE_LINUX_ID})
+      endif()
+
+      if(CLR_CMAKE_LINUX_MUSL STREQUAL musl)
+          set(CLR_CMAKE_HOST_LINUX_MUSL 1)
+      endif()
+  endif(DEFINED CLR_CMAKE_LINUX_ID)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "Android")
   set(HOST_LINUX 1)
   add_definitions(-D_GNU_SOURCE -D_REENTRANT)
@@ -893,6 +922,12 @@ if(HOST_IOS OR HOST_ANDROID OR HOST_MACCAT)
 else()
   set(DISABLE_DLLMAP 1)
 endif()
+
+if(CLR_CMAKE_HOST_ALPINE_LINUX)
+  # On Alpine Linux, we need to ensure that the reported stack range for the primary thread is
+  # larger than the initial committed stack size.
+  add_definitions(-DENSURE_PRIMARY_STACK_SIZE)
+endif()
 ### End of OS specific checks
 
 include_directories("${CLR_SRC_NATIVE_DIR}")

src/mono/mono.proj

@@ -554,19 +554,21 @@
       <MonoToolchainPrebuiltOS Condition="$([MSBuild]::IsOSPlatform('OSX'))">darwin-x86_64</MonoToolchainPrebuiltOS>
       <MonoToolchainPrebuiltOS Condition="'$(HostOS)' == 'windows'">windows-x86_64</MonoToolchainPrebuiltOS>
       <_MonoRuntimeFilePath>$(MonoObjDir)out\lib\$(MonoFileName)</_MonoRuntimeFilePath>
-      <_LinuxAbi Condition="'$(TargetsAndroid)' != 'true' and '$(TargetsLinuxBionic)' != 'true'">gnu</_LinuxAbi>
-      <_LinuxAbi Condition="'$(TargetsAndroid)' == 'true' or '$(TargetsLinuxBionic)' == 'true'">android</_LinuxAbi>
+      <_LinuxAbi Condition="'$(TargetsAndroid)' != 'true' and '$(TargetsLinuxBionic)' != 'true' and '$(TargetsLinuxMusl)' != 'true'">linux-gnu</_LinuxAbi>
+      <_LinuxAbi Condition="'$(TargetsAndroid)' != 'true' and '$(TargetsLinuxBionic)' != 'true' and '$(TargetsLinuxMusl)' == 'true'">alpine-linux-musl</_LinuxAbi>
+      <_LinuxAbi Condition="'$(TargetsAndroid)' == 'true' or '$(TargetsLinuxBionic)' == 'true'">linux-android</_LinuxAbi>
       <_LinuxFloatAbi Condition="'$(TargetsAndroid)' != 'true' and '$(TargetsLinuxBionic)' != 'true'">hf</_LinuxFloatAbi>
       <_Objcopy>objcopy</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 'arm'">arm-linux-$(_LinuxAbi)eabi$(_LinuxFloatAbi)-$(_Objcopy)</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 'armv6'">arm-linux-$(_LinuxAbi)eabi$(_LinuxFloatAbi)-$(_Objcopy)</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 'arm64'">aarch64-linux-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 'riscv64'">riscv64-linux-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 's390x'">s390x-linux-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 'ppc64le'">powerpc64le-linux-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 'x64'">x86_64-linux-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 'x86'">i686-linux-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 'arm'">arm-$(_LinuxAbi)eabi$(_LinuxFloatAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 'armv6'">arm-$(_LinuxAbi)eabi$(_LinuxFloatAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 'arm64'">aarch64-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 'riscv64'">riscv64-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 's390x'">s390x-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 'ppc64le'">powerpc64le-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 'x64'">x86_64-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 'x86'">i686-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
       <_Objcopy Condition="'$(TargetsAndroid)' == 'true' or '$(TargetsLinuxBionic)' == 'true'">$(ANDROID_NDK_ROOT)/toolchains/llvm/prebuilt/$(MonoToolchainPrebuiltOS)/bin/llvm-objcopy</_Objcopy>
+      <_Objcopy Condition="'$(TargetsLinuxMusl)' == 'true' and '$(CrossBuild)' != 'true'">objcopy</_Objcopy>
 
       <_ObjcopyPrefix Condition="'$(MonoCrossDir)' != '' and '$(Platform)' == 'riscv64'">llvm-objcopy-</_ObjcopyPrefix>
     </PropertyGroup>

src/mono/mono/mini/CMakeLists.txt

@@ -373,6 +373,10 @@ if(NOT DISABLE_SHARED_LIBS)
     target_compile_definitions(monosgen-objects PRIVATE -DMONO_DLL_EXPORT)
   endif()
   target_sources(monosgen-shared PRIVATE $<TARGET_OBJECTS:eglib_objects>)
+  # Alpine Linux implements ucontext in a different library
+  if(CLR_CMAKE_HOST_ALPINE_LINUX AND TARGET_S390X)
+    target_link_libraries(monosgen-shared PRIVATE ucontext)
+  endif(CLR_CMAKE_HOST_ALPINE_LINUX AND TARGET_S390X)
   set_target_properties(monosgen-shared PROPERTIES OUTPUT_NAME ${MONO_SHARED_LIB_NAME})
   target_link_libraries (monosgen-shared PRIVATE monoapi)
   target_include_directories (monosgen-shared PRIVATE monoapi)
@@ -534,6 +538,10 @@ if(NOT DISABLE_EXECUTABLES)
     set_target_properties(mono-sgen PROPERTIES OUTPUT_NAME mono-aot-cross)
   endif()
   target_link_libraries(mono-sgen PRIVATE monoapi monosgen-static ${OS_LIBS} ${LLVM_LIBS} ${ICU_LIBS} ${Z_LIBS})
+  # Alpine Linux implements ucontext in a different library
+  if(CLR_CMAKE_HOST_ALPINE_LINUX AND TARGET_S390X)
+    target_link_libraries(mono-sgen PRIVATE ucontext)
+  endif(CLR_CMAKE_HOST_ALPINE_LINUX AND TARGET_S390X)
   if(NOT DISABLE_COMPONENTS AND STATIC_COMPONENTS AND NOT DISABLE_LINK_STATIC_COMPONENTS)
     # if components are built statically, link them into runtime.
     target_sources(mono-sgen PRIVATE "${mono-components-objects}")

src/mono/mono/mini/mini-runtime.c

@@ -4383,6 +4383,30 @@ mini_llvm_init (void)
 #endif
 }
 
+#ifdef ENSURE_PRIMARY_STACK_SIZE
+/*++ 
+ Function: 
+   EnsureStackSize 
+  
+ Abstract: 
+   This fixes a problem on MUSL where the initial stack size reported by the 
+   pthread_attr_getstack is about 128kB, but this limit is not fixed and 
+   the stack can grow dynamically. The problem is that it makes the 
+   functions ReflectionInvocation::[Try]EnsureSufficientExecutionStack 
+   to fail for real life scenarios like e.g. compilation of corefx. 
+   Since there is no real fixed limit for the stack, the code below 
+   ensures moving the stack limit to a value that makes reasonable 
+   real life scenarios work. 
+  
+ --*/
+static MONO_NO_OPTIMIZATION MONO_NEVER_INLINE void
+ensure_stack_size (size_t size)
+{
+	volatile uint8_t *s = (uint8_t *)g_alloca(size);
+	*s = 0;
+}
+#endif // ENSURE_PRIMARY_STACK_SIZE
+
 void
 mini_add_profiler_argument (const char *desc)
 {
@@ -4544,6 +4568,11 @@ mini_init (const char *filename)
 	mono_w32handle_init ();
 #endif
 
+#ifdef ENSURE_PRIMARY_STACK_SIZE 
+	// TODO: https://github.com/dotnet/runtime/issues/72920
+	ensure_stack_size (5 * 1024 * 1024);
+#endif // ENSURE_PRIMARY_STACK_SIZE
+
 	mono_thread_info_runtime_init (&ticallbacks);
 
 	if (g_hasenv ("MONO_DEBUG")) {

src/mono/mono/utils/mono-context.h

@@ -11,6 +11,14 @@
 #ifndef __MONO_MONO_CONTEXT_H__
 #define __MONO_MONO_CONTEXT_H__
 
+/* 
+ * Handle non-gnu libc versions with nothing in features.h 
+ * We have no idea what they're compatible with, so always fail.
+ */
+#ifndef __GLIBC_PREREQ
+# define __GLIBC_PREREQ(x,y) 0
+#endif
+
 #include "mono-compiler.h"
 #include "mono-sigcontext.h"
 #include "mono-machine.h"

src/native/libs/System.Native/pal_io.c

@@ -1267,7 +1267,7 @@ int32_t SystemNative_CopyFile(intptr_t sourceFd, intptr_t destinationFd, int64_t
     // Try copying data using a copy-on-write clone. This shares storage between the files.
     if (sourceLength != 0)
     {
-        while ((ret = ioctl(outFd, FICLONE, inFd)) < 0 && errno == EINTR);
+        while ((ret = ioctl(outFd, (int)FICLONE, inFd)) < 0 && errno == EINTR);
         copied = ret == 0;
     }
 #endif