[release/6.0] Mono musl support (backport #76500)

Directory.Build.props

@@ -180,6 +180,8 @@
 
     <OutputRid Condition="'$(OutputRid)' == ''">$(PackageRID)</OutputRid>
     <OutputRid Condition="'$(PortableBuild)' == 'true'">$(_portableOS)-$(TargetArchitecture)</OutputRid>
+
+    <TargetsLinuxMusl Condition="$(OutputRid.StartsWith('linux-musl')) or $(OutputRid.StartsWith('alpine'))">true</TargetsLinuxMusl>
   </PropertyGroup>
 
   <PropertyGroup Label="CalculateTargetOSName" Condition="'$(SkipInferTargetOSName)' != 'true'">

eng/native/tryrun.cmake

@@ -8,7 +8,9 @@ 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/i586-alpine-linux-musl)
 
   set(ALPINE_LINUX 1)
 elseif(EXISTS ${CROSS_ROOTFS}/bin/freebsd-version)

src/coreclr/pal/src/CMakeLists.txt

@@ -319,6 +319,11 @@ 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
+  if(CLR_CMAKE_TARGET_ALPINE_LINUX AND CLR_CMAKE_TARGET_ARCH_I386)
+    target_link_libraries(coreclrpal ucontext)
+  endif(CLR_CMAKE_TARGET_ALPINE_LINUX AND CLR_CMAKE_TARGET_ARCH_I386)
+
 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

@@ -1163,6 +1163,7 @@ extern "C" DWORD __stdcall xmmYmmStateSupport()
 
 #else // !TARGET_UNIX
 
+#if !__has_builtin(__cpuid)
 void __cpuid(int cpuInfo[4], int function_id)
 {
     // Based on the Clang implementation provided in cpuid.h:
@@ -1173,7 +1174,9 @@ 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:
@@ -1184,6 +1187,7 @@ 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

@@ -208,6 +208,33 @@ 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
+  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 ${LINUX_ID_FILE} && echo \$ID"
+          OUTPUT_VARIABLE LINUX_ID
+          OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+      execute_process(
+          COMMAND bash -c "if strings \"${CMAKE_SYSROOT}/usr/bin/ldd\" 2>&1 | grep -q musl; then echo musl; fi"
+          OUTPUT_VARIABLE LINUX_MUSL
+          OUTPUT_STRIP_TRAILING_WHITESPACE)
+  endif()
+
+  if(DEFINED LINUX_ID)
+	  if(LINUX_ID STREQUAL alpine)
+          set(HOST_ALPINE_LINUX 1)
+      endif()
+
+      if(LINUX_MUSL STREQUAL musl)
+          set(HOST_LINUX_MUSL 1)
+      endif()
+  endif(DEFINED LINUX_ID)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "Android")
   set(HOST_LINUX 1)
   add_definitions(-D_GNU_SOURCE -D_REENTRANT)
@@ -784,6 +811,12 @@ if (TARGET_BROWSER)
   # sys/errno.h exists, but just emits a warning and includes errno.h
   unset(HAVE_SYS_ERRNO_H)
 endif()
+
+if(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
 
 add_subdirectory(mono)

src/mono/mono.proj

@@ -417,12 +417,18 @@
     <!-- Linux options -->
     <ItemGroup Condition="'$(TargetsLinux)' == true">
       <_MonoCFLAGS Include="-Wl,--build-id=sha1" />
+      <_MonoCFLAGS Include="-Wno-int-conversion" />
       <_MonoCXXFLAGS Include="-Wl,--build-id=sha1" />
     </ItemGroup>
     <ItemGroup Condition="'$(RealTargetOS)' == 'Linux'">
       <_MonoAOTCFLAGS Include="-Wl,--build-id=sha1" />
+      <_MonoAOTCFLAGS Include="-Wno-int-conversion" />
       <_MonoAOTCXXFLAGS Include="-Wl,--build-id=sha1" />
     </ItemGroup>
+    <ItemGroup Condition="'$(TargetsLinuxMusl)' == 'true' and '$(TargetArchitecture)' == 's390x'">
+      <_MonoAOTCFLAGS Include="-lucontext" />
+      <_MonoCFLAGS Include="-lucontext" />
+    </ItemGroup>
 
     <!-- Devloop features -->
     <ItemGroup Condition="'$(MonoMsCorDbi)' == 'true'">
@@ -500,16 +506,18 @@
       <MonoToolchainPrebuiltOS Condition="$([MSBuild]::IsOSPlatform('OSX'))">darwin-x86_64</MonoToolchainPrebuiltOS>
       <MonoToolchainPrebuiltOS Condition="'$(OS)' == 'Windows_NT'">windows-x86_64</MonoToolchainPrebuiltOS>
       <_MonoRuntimeFilePath>$(MonoObjDir)out\lib\$(MonoFileName)</_MonoRuntimeFilePath>
-      <_LinuxAbi Condition="'$(TargetsAndroid)' != 'true'">gnu</_LinuxAbi>
-      <_LinuxAbi Condition="'$(TargetsAndroid)' == 'true'">android</_LinuxAbi>
+      <_LinuxAbi Condition="'$(TargetsAndroid)' != 'true' and '$(TargetsLinuxMusl)' != 'true'">linux-gnu</_LinuxAbi>
+      <_LinuxAbi Condition="'$(TargetsAndroid)' != 'true' and '$(TargetsLinuxMusl)' == 'true'">alpine-linux-musl</_LinuxAbi>
+      <_LinuxAbi Condition="'$(TargetsAndroid)' == 'true'">linux-android</_LinuxAbi>
       <_LinuxFloatAbi Condition="'$(TargetsAndroid)' != 'true'">hf</_LinuxFloatAbi>
       <_Objcopy>objcopy</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 'arm'">arm-linux-$(_LinuxAbi)eabi$(_LinuxFloatAbi)-$(_Objcopy)</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 'arm64'">aarch64-linux-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
-      <_Objcopy Condition="'$(Platform)' == 's390x'">s390x-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="'$(Platform)' == 'arm64'">aarch64-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 's390x'">s390x-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 'x64'">x86_64-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(Platform)' == 'x86'">i686-$(_LinuxAbi)-$(_Objcopy)</_Objcopy>
       <_Objcopy Condition="'$(TargetsAndroid)' == 'true'">$(ANDROID_NDK_ROOT)/toolchains/llvm/prebuilt/$(MonoToolchainPrebuiltOS)/bin/$(_Objcopy)</_Objcopy>
+      <_Objcopy Condition="'$(TargetsLinuxMusl)' == 'true' and '$(CrossBuild)' != 'true'">objcopy</_Objcopy>
     </PropertyGroup>
     <!-- test viability of objcopy command -->
     <Exec Condition="'$(BuildMonoAOTCrossCompilerOnly)' != 'true' and ('$(TargetsLinux)' == 'true' or '$(TargetsAndroid)' == 'true')" Command="$(_Objcopy) -V" IgnoreStandardErrorWarningFormat="true" ContinueOnError="WarnAndContinue" IgnoreExitCode="true" EchoOff="true" ConsoleToMsBuild="true">

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

@@ -4313,6 +4313,30 @@ 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)
 {
@@ -4468,6 +4492,11 @@ mini_init (const char *filename, const char *runtime_version)
 	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"