Fix remote unwind (#17351)

The change that removed dependency on the external libunwind has broken
remote unwinding. I have not realized that the unw_create_addr_space
and other remote unwinding functions are just dummies.

This change adds the remote unwind related sources to the libunwind
compilation, enables remote unwinding support in the remote-unwind.cpp
and also does some magic in the CMakeLists.txt to fix issues caused
by the fact that the local and remote unwinding code was not expected
to be compiled into the same binary. There was one general and one
arm related function whose names needed to be different for local and
remote unwind code. And there was one function that was the same for
both local and remote case and so I had to ensure that it gets compiled
in just once.

Fortunately, all of these could still be achieved without changing the
libunwind sources.

2 files changed, 15 insertions, 6 deletions

diff --git a/src/pal/src/exception/remote-unwind.cpp b/src/pal/src/exception/remote-unwind.cpp
index c30c463cfd..4934e77115 100644
--- a/src/pal/src/exception/remote-unwind.cpp
+++ b/src/pal/src/exception/remote-unwind.cpp
@@ -48,7 +48,6 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include "pal.h"
 #include <dlfcn.h>
 
-#define UNW_LOCAL_ONLY
 // Sub-headers included from the libunwind.h contain an empty struct
 // and clang issues a warning. Until the libunwind is fixed, disable
 // the warning.
diff --git a/src/pal/src/libunwind/src/CMakeLists.txt b/src/pal/src/libunwind/src/CMakeLists.txt
index 537177716d..c035f64c11 100644
--- a/src/pal/src/libunwind/src/CMakeLists.txt
+++ b/src/pal/src/libunwind/src/CMakeLists.txt
@@ -16,10 +16,14 @@ add_definitions(-DPACKAGE_STRING="")
 add_definitions(-DPACKAGE_BUGREPORT="")
 
 add_definitions(-D_GNU_SOURCE)
+# Ensure that the remote and local unwind code can reside in the same binary without name clashing
+add_definitions("-Ddwarf_search_unwind_table_int=UNW_OBJ(dwarf_search_unwind_table_int)")
 
 add_compile_options(-Wno-header-guard)
 
 if(CLR_CMAKE_PLATFORM_ARCH_ARM)
+    # Ensure that the remote and local unwind code can reside in the same binary without name clashing
+    add_definitions("-Darm_search_unwind_table=UNW_OBJ(arm_search_unwind_table)")
     # Disable warning in asm: use of SP or PC in the list is deprecated
     add_compile_options(-Wno-inline-asm)
     # Disable warning due to labs function called on unsigned argument
@@ -28,6 +32,8 @@ if(CLR_CMAKE_PLATFORM_ARCH_ARM)
     add_compile_options(-Wno-format)
     # Disable warning for a bug in the libunwind source src/arm/Gtrace.c:529, but not in code that we exercise
     add_compile_options(-Wno-implicit-function-declaration)
+    # Disable warning due to an unused function prel31_read
+    add_compile_options(-Wno-unused-function)
     # We compile code with -std=c99 and the asm keyword is not recognized as it is a gnu extension
     add_definitions(-Dasm=__asm__)
     # The arm sources include ex_tables.h from include/tdep-arm without going through a redirection
@@ -75,7 +81,9 @@ SET(libunwind_coredump_la_SOURCES
 # List of arch-independent files needed by generic library (libunwind-$ARCH):
 SET(libunwind_la_SOURCES_generic
     mi/Gdyn-extract.c mi/Gdyn-remote.c mi/Gfind_dynamic_proc_info.c
-    mi/Gget_accessors.c
+    # The Gget_accessors.c implements the same function as Lget_accessors.c, so
+    # the source is excluded here to prevent name clash
+    #mi/Gget_accessors.c
     mi/Gget_proc_info_by_ip.c mi/Gget_proc_name.c
     mi/Gput_dynamic_unwind_info.c mi/Gdestroy_addr_space.c
     mi/Gget_reg.c mi/Gset_reg.c
@@ -307,22 +315,22 @@ SET(libunwind_x86_64_la_SOURCES_x86_64
 
 if(CLR_CMAKE_PLATFORM_ARCH_ARM64)
     SET(libunwind_la_SOURCES                    ${libunwind_la_SOURCES_aarch64})
-    SET(libunwind_aarch64_la_SOURCES            ${libunwind_aarch64_la_SOURCES_aarch64})
+    SET(libunwind_remote_la_SOURCES             ${libunwind_aarch64_la_SOURCES_aarch64})
     SET(libunwind_elf_la_SOURCES                ${libunwind_elf64_la_SOURCES})
     list(APPEND libunwind_setjmp_la_SOURCES     aarch64/siglongjmp.S)
 elseif(CLR_CMAKE_PLATFORM_ARCH_ARM)
     SET(libunwind_la_SOURCES                    ${libunwind_la_SOURCES_arm})
-    SET(libunwind_arm_la_SOURCES                ${libunwind_arm_la_SOURCES_arm})
+    SET(libunwind_remote_la_SOURCES             ${libunwind_arm_la_SOURCES_arm})
     SET(libunwind_elf_la_SOURCES                ${libunwind_elf32_la_SOURCES})
     list(APPEND libunwind_setjmp_la_SOURCES     arm/siglongjmp.S)
 elseif(CLR_CMAKE_PLATFORM_ARCH_I386)
     SET(libunwind_la_SOURCES                    ${libunwind_la_SOURCES_x86} ${libunwind_x86_la_SOURCES_os})
-    SET(libunwind_x86_la_SOURCES                ${libunwind_x86_la_SOURCES_x86})
+    SET(libunwind_remote_la_SOURCES             ${libunwind_x86_la_SOURCES_x86})
     SET(libunwind_elf_la_SOURCES                ${libunwind_elf32_la_SOURCES})
     list(APPEND libunwind_setjmp_la_SOURCES     x86/longjmp.S x86/siglongjmp.S)
 elseif(CLR_CMAKE_PLATFORM_ARCH_AMD64)
     SET(libunwind_la_SOURCES                    ${libunwind_la_SOURCES_x86_64})
-    SET(libunwind_x86_64_la_SOURCES             ${libunwind_x86_64_la_SOURCES_x86_64})
+    SET(libunwind_remote_la_SOURCES             ${libunwind_x86_64_la_SOURCES_x86_64})
     SET(libunwind_elf_la_SOURCES                ${libunwind_elf64_la_SOURCES})
     list(APPEND libunwind_setjmp_la_SOURCES     x86_64/longjmp.S x86_64/siglongjmp.SA)
 endif()
@@ -330,8 +338,10 @@ endif()
 add_library(libunwind
   OBJECT
   ${libunwind_la_SOURCES}
+  ${libunwind_remote_la_SOURCES}
   ${libunwind_dwarf_local_la_SOURCES}
   ${libunwind_dwarf_common_la_SOURCES}
+  ${libunwind_dwarf_generic_la_SOURCES}
   ${libunwind_elf_la_SOURCES}
 )