Merge pull request #3502 from myungjoo/fix/3462_arm_linux_stack

ARM-Linux Fixes (Issue #3462)

4 files changed, 64 insertions, 15 deletions

diff --git a/src/coreclr/hosts/unixcoreruncommon/coreruncommon.cpp b/src/coreclr/hosts/unixcoreruncommon/coreruncommon.cpp
index 1125dfb819..8d32a7d390 100644
--- a/src/coreclr/hosts/unixcoreruncommon/coreruncommon.cpp
+++ b/src/coreclr/hosts/unixcoreruncommon/coreruncommon.cpp
@@ -268,6 +268,20 @@ int ExecuteManagedAssembly(
     // Indicates failure
     int exitCode = -1;
 
+#ifdef _ARM_
+    // LIBUNWIND-ARM has a bug of side effect with DWARF mode
+    // Ref: https://github.com/dotnet/coreclr/issues/3462
+    // This is why Fedora is disabling it by default as well.
+    // Assuming that we cannot enforce the user to set
+    // environmental variables for third party packages,
+    // we set the environmental variable of libunwind locally here.
+
+    // Without this, any exception handling will fail, so let's do this
+    // as early as possible.
+    // 0x1: DWARF / 0x2: FRAME / 0x4: EXIDX
+    putenv("UNW_ARM_UNWIND_METHOD=6");
+#endif // _ARM_
+
     std::string coreClrDllPath(clrFilesAbsolutePath);
     coreClrDllPath.append("/");
     coreClrDllPath.append(coreClrDll);
diff --git a/src/pal/src/config.h.in b/src/pal/src/config.h.in
index 68cb81ba67..784383f8dd 100644
--- a/src/pal/src/config.h.in
+++ b/src/pal/src/config.h.in
@@ -53,6 +53,8 @@
 #cmakedefine01 HAS_SYSV_SEMAPHORES
 #cmakedefine01 HAS_PTHREAD_MUTEXES
 #cmakedefine01 HAVE_TTRACE
+#cmakedefine HAVE_UNW_GET_SAVE_LOC
+#cmakedefine HAVE_UNW_GET_ACCESSORS
 
 #cmakedefine01 HAVE_STAT_TIMESPEC
 #cmakedefine01 HAVE_STAT_NSEC
diff --git a/src/pal/src/configure.cmake b/src/pal/src/configure.cmake
index be6114d48c..daa99622fe 100644
--- a/src/pal/src/configure.cmake
+++ b/src/pal/src/configure.cmake
@@ -73,8 +73,28 @@ check_function_exists(directio HAVE_DIRECTIO)
 check_function_exists(semget HAS_SYSV_SEMAPHORES)
 check_function_exists(pthread_mutex_init HAS_PTHREAD_MUTEXES)
 check_function_exists(ttrace HAVE_TTRACE)
-check_function_exists(unw_get_save_loc HAVE_UNW_GET_SAVE_LOC)
-check_function_exists(unw_get_accessors HAVE_UNW_GET_ACCESSORS)
+set(CMAKE_REQUIRED_LIBRARIES unwind unwind-generic)
+check_cxx_source_compiles("
+#include <libunwind.h>
+
+int main(int argc, char **argv) {
+  unw_cursor_t cursor;
+  unw_save_loc_t saveLoc;
+  int reg = UNW_REG_IP;
+  unw_get_save_loc(&cursor, reg, &saveLoc);
+
+  return 0;
+}" HAVE_UNW_GET_SAVE_LOC)
+check_cxx_source_compiles("
+#include <libunwind.h>
+
+int main(int argc, char **argv) {
+  unw_addr_space_t as;
+  unw_get_accessors(as);
+
+  return 0;
+}" HAVE_UNW_GET_ACCESSORS)
+set(CMAKE_REQUIRED_LIBRARIES)
 
 check_struct_has_member ("struct stat" st_atimespec "sys/types.h;sys/stat.h" HAVE_STAT_TIMESPEC)
 check_struct_has_member ("struct stat" st_atimensec "sys/types.h;sys/stat.h" HAVE_STAT_NSEC)
diff --git a/src/pal/src/exception/seh-unwind.cpp b/src/pal/src/exception/seh-unwind.cpp
index 5d3b353494..333544379a 100644
--- a/src/pal/src/exception/seh-unwind.cpp
+++ b/src/pal/src/exception/seh-unwind.cpp
@@ -97,17 +97,29 @@ static void WinContextToUnwindCursor(CONTEXT *winContext, unw_cursor_t *cursor)
     unw_set_reg(cursor, UNW_X86_64_R14, winContext->R14);
     unw_set_reg(cursor, UNW_X86_64_R15, winContext->R15);
 #elif defined(_ARM_)
-    unw_set_reg(cursor, UNW_ARM_R13, winContext->Sp);
-    unw_set_reg(cursor, UNW_ARM_R14, winContext->Lr);
-    unw_set_reg(cursor, UNW_ARM_R15, winContext->Pc);
-    unw_set_reg(cursor, UNW_ARM_R4, winContext->R4);
-    unw_set_reg(cursor, UNW_ARM_R5, winContext->R5);
-    unw_set_reg(cursor, UNW_ARM_R6, winContext->R6);
-    unw_set_reg(cursor, UNW_ARM_R7, winContext->R7);
-    unw_set_reg(cursor, UNW_ARM_R8, winContext->R8);
-    unw_set_reg(cursor, UNW_ARM_R9, winContext->R9);
-    unw_set_reg(cursor, UNW_ARM_R10, winContext->R10);
-    unw_set_reg(cursor, UNW_ARM_R11, winContext->R11);
+    // Assuming that unw_set_reg() on cursor will point the cursor to the
+    // supposed stack frame is dangerous for libunwind-arm in Linux.
+    // It is because libunwind's unw_cursor_t has other data structure
+    // initialized by unw_init_local(), which are not updated by
+    // unw_set_reg().
+    unw_context_t context;
+    context.regs[0] = 0;
+    context.regs[1] = 0;
+    context.regs[2] = 0;
+    context.regs[3] = 0;
+    context.regs[4] = winContext->R4;
+    context.regs[5] = winContext->R5;
+    context.regs[6] = winContext->R6;
+    context.regs[7] = winContext->R7;
+    context.regs[8] = winContext->R8;
+    context.regs[9] = winContext->R9;
+    context.regs[10] = winContext->R10;
+    context.regs[11] = winContext->R11;
+    context.regs[12] = 0;
+    context.regs[13] = winContext->Sp;
+    context.regs[14] = winContext->Lr;
+    context.regs[15] = winContext->Pc;
+    unw_init_local(cursor, &context);
 #endif
 }
 #endif
@@ -124,9 +136,10 @@ static void UnwindContextToWinContext(unw_cursor_t *cursor, CONTEXT *winContext)
     unw_get_reg(cursor, UNW_X86_64_R14, (unw_word_t *) &winContext->R14);
     unw_get_reg(cursor, UNW_X86_64_R15, (unw_word_t *) &winContext->R15);
 #elif defined(_ARM_)
-    unw_get_reg(cursor, UNW_ARM_R13, (unw_word_t *) &winContext->Sp);
+    unw_get_reg(cursor, UNW_REG_SP, (unw_word_t *) &winContext->Sp);
+    unw_get_reg(cursor, UNW_REG_IP, (unw_word_t *) &winContext->Pc);
+    winContext->Pc &= ~0x1;
     unw_get_reg(cursor, UNW_ARM_R14, (unw_word_t *) &winContext->Lr);
-    unw_get_reg(cursor, UNW_ARM_R15, (unw_word_t *) &winContext->Pc);
     unw_get_reg(cursor, UNW_ARM_R4, (unw_word_t *) &winContext->R4);
     unw_get_reg(cursor, UNW_ARM_R5, (unw_word_t *) &winContext->R5);
     unw_get_reg(cursor, UNW_ARM_R6, (unw_word_t *) &winContext->R6);