Add initial macOS support for stacktraces

So far a binary file name and a local address works.

CMakeLists.txt

@@ -144,6 +144,8 @@ set(WITH_BFD no
     CACHE BOOL "Build with BFD support")
 set(WITH_LINKH no
     CACHE BOOL "Build with link.h support")
+set(WITH_MACHO no
+    CACHE BOOL "Build with mach-o support")
 set(WITH_STACKTRACE no
     CACHE BOOL "Build with stacktrace support (requires binutils-dev)")
 if (WITH_STACKTRACE)
@@ -160,6 +162,10 @@ if (WITH_LINKH)
     find_package(LINKH REQUIRED)
     set(HAVE_LFORTRAN_LINK yes)
 endif()
+if (WITH_MACHO)
+    find_package(MACHO REQUIRED)
+    set(HAVE_LFORTRAN_MACHO yes)
+endif()
 if (WITH_UNWIND)
     set(HAVE_LFORTRAN_UNWIND yes)
 endif()
@@ -188,6 +194,7 @@ message("WITH_STACKTRACE: ${WITH_STACKTRACE}")
 message("WITH_UNWIND: ${WITH_UNWIND}")
 message("WITH_BFD: ${WITH_BFD}")
 message("WITH_LINKH: ${WITH_LINKH}")
+message("WITH_MACHO: ${WITH_MACHO}")
 message("HAVE_LFORTRAN_DEMANGLE: ${HAVE_LFORTRAN_DEMANGLE}")
 message("WITH_LLVM: ${WITH_LLVM}")
 message("WITH_XEUS: ${WITH_XEUS}")

cmake/FindMACHO.cmake

@@ -0,0 +1,8 @@
+find_path(MACHO_INCLUDE_DIR mach-o/dyld.h)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(MACHO DEFAULT_MSG MACHO_INCLUDE_DIR)
+
+add_library(p::macho INTERFACE IMPORTED)
+set_property(TARGET p::macho PROPERTY INTERFACE_INCLUDE_DIRECTORIES
+    ${MACHO_INCLUDE_DIR})

src/lfortran/config.h.in

@@ -14,6 +14,7 @@
 #cmakedefine HAVE_LFORTRAN_STACKTRACE
 #cmakedefine HAVE_LFORTRAN_BFD
 #cmakedefine HAVE_LFORTRAN_LINK
+#cmakedefine HAVE_LFORTRAN_MACHO
 #cmakedefine HAVE_LFORTRAN_UNWIND
 
 /* Define if cxxabi.h is present */

src/lfortran/stacktrace.cpp

@@ -33,6 +33,10 @@
 #  include <link.h>
 #endif
 
+#ifdef HAVE_LFORTRAN_MACHO
+#  include <mach-o/dyld.h>
+#endif
+
 #ifdef HAVE_LFORTRAN_BFD
 // For bfd_* family of functions for loading debugging symbols from the binary
 // This is the only nonstandard header file and the binary needs to be linked
@@ -94,12 +98,24 @@ int shared_lib_callback(struct dl_phdr_info *info,
   return 0;
 }
 
+#endif // HAVE_LFORTRAN_LINK
+
+
 // Fills in `local_pc` and `binary_filename` of `item`
 void get_local_address(StacktraceItem &item)
 {
+#ifdef HAVE_LFORTRAN_LINK
     // Iterate over all loaded shared libraries (see dl_iterate_phdr(3) -
     // Linux man page for more documentation)
     if (dl_iterate_phdr(shared_lib_callback, &item) == 0) {
+      // `dl_iterate_phdr` returns the last value returned by our
+      // `shared_lib_callback`. It will only be 0 if no shared library
+      // (including the main program) contains the address `match.addr`. Given
+      // that the addresses are collected from a stacktrace, this should only
+      // happen if the stacktrace is somehow corrupted. In that case, we simply
+      // abort here.
+      // `dl_iterate_phdr` returns the last value returned by our
+      // `shared_lib_callback`. It will only be 0 if no shared library
       // `dl_iterate_phdr` returns the last value returned by our
       // `shared_lib_callback`. It will only be 0 if no shared library
       // (including the main program) contains the address `match.addr`. Given
@@ -109,10 +125,44 @@ void get_local_address(StacktraceItem &item)
       std::cout << "The stack address was not found in any shared library or the main program, the stack is probably corrupted. Aborting." << std::endl;
       abort();
     }
+#else
+#ifdef HAVE_LFORTRAN_MACHO
+    for (uint32_t i = 0; i < _dyld_image_count(); i++) {
+        const struct mach_header *header = _dyld_get_image_header(i);
+        intptr_t offset = _dyld_get_image_vmaddr_slide(i);
+        struct load_command* cmd = (struct load_command*)((char *)header + sizeof(struct mach_header));
+        if(header->magic == MH_MAGIC_64) {
+            cmd = (struct load_command*)((char *)header + sizeof(struct mach_header_64));
+        }
+        for (uint32_t j = 0; j < header->ncmds; j++) {
+            if (cmd->cmd == LC_SEGMENT) {
+                struct segment_command* seg = (struct segment_command*)cmd;
+                if (((intptr_t)item.pc >= (seg->vmaddr+offset)) &&
+                    ((intptr_t)item.pc < (seg->vmaddr+offset + seg->vmsize))) {
+                    item.local_pc = item.pc - offset;
+                    item.binary_filename = _dyld_get_image_name(i);
+                    return;
+                }
+            }
+            if (cmd->cmd == LC_SEGMENT_64) {
+                struct segment_command_64* seg = (struct segment_command_64*)cmd;
+                if ((item.pc >= (seg->vmaddr + offset)) &&
+                    (item.pc < (seg->vmaddr + offset + seg->vmsize))) {
+                    item.local_pc = item.pc - offset;
+                    item.binary_filename = _dyld_get_image_name(i);
+                    return;
+                }
+            }
+            cmd = (struct load_command*)((char*)cmd + cmd->cmdsize);
+        }
+    }
+    std::cout << "The stack address was not found in any shared library or the main program, the stack is probably corrupted. Aborting." << std::endl;
+    abort();
+#endif // HAVE_LFORTRAN_MACHO
+#endif // HAVE_LFORTRAN_LINK
 }
 
 
-#endif // HAVE_LFORTRAN_LINK
 
 
 /* Demangles the function name if needed (if the 'name' is coming from C, it
@@ -457,9 +507,7 @@ std::vector<StacktraceItem> get_stacktrace_addresses()
 void get_local_addresses(std::vector<StacktraceItem> &d)
 {
   for (size_t i=0; i < d.size(); i++) {
-#ifdef HAVE_LFORTRAN_LINK
     get_local_address(d[i]);
-#endif
   }
 }