Improve symbol lookup for backtraces when debug info not present

We had all the info we were just not using it. Also adjusts the OS X
sigdie_handler to the same thing as the linux one (i.e. look at the
state of the thread before the signal handler rather than including
the signal handler in the backtrace. Fixes JuliaLang#7821

Make.inc

@@ -250,7 +250,7 @@ JCFLAGS = -std=gnu99 -pipe $(fPIC) -fno-strict-aliasing -D_FILE_OFFSET_BITS=64
 JCPPFLAGS =
 JCXXFLAGS = -pipe $(fPIC) -fno-rtti
 DEBUGFLAGS = -O0 -ggdb3 -DJL_DEBUG_BUILD -fstack-protector-all
-SHIPFLAGS = -O3 -falign-functions
+SHIPFLAGS = -O3 -ggdb3 -falign-functions
 endif
 
 ifeq ($(USECLANG),1)
@@ -260,7 +260,7 @@ JCFLAGS = -pipe $(fPIC) -fno-strict-aliasing -D_FILE_OFFSET_BITS=64
 JCPPFLAGS =
 JCXXFLAGS = -pipe $(fPIC) -fno-rtti
 DEBUGFLAGS = -O0 -g -DJL_DEBUG_BUILD -fstack-protector-all
-SHIPFLAGS = -O3
+SHIPFLAGS = -O3 -g
 ifeq ($(OS), Darwin)
 ifeq ($(USE_LIBCPP), 1)
 CC += -stdlib=libc++ -mmacosx-version-min=10.7
@@ -287,7 +287,7 @@ JCFLAGS = -std=gnu99 -pipe $(fPIC) -fno-strict-aliasing -D_FILE_OFFSET_BITS=64 -
 JCPPFLAGS =
 JCXXFLAGS = -pipe $(fPIC) -fno-rtti
 DEBUGFLAGS = -O0 -ggdb3 -DJL_DEBUG_BUILD -fstack-protector-all
-SHIPFLAGS = -O3 -falign-functions
+SHIPFLAGS = -O3 -g -falign-functions
 endif
 
 ifeq ($(LLVM_VER),svn)
@@ -545,10 +545,16 @@ ifeq ($(OS), Darwin)
   INSTALL_NAME_ID_DIR = @rpath/
   INSTALL_NAME_CMD = install_name_tool -id $(INSTALL_NAME_ID_DIR)
   INSTALL_NAME_CHANGE_CMD = install_name_tool -change
+ifeq ($(shell test `dsymutil -v | cut -d\- -f2 | cut -d. -f1` -gt 102 && echo yes), yes)
+  DSYMUTIL = dsymutil
+else
+  true -ignore
+endif
 else
   INSTALL_NAME_ID_DIR =
   INSTALL_NAME_CMD = true -ignore
   INSTALL_NAME_CHANGE_CMD = true -ignore
+  DSYMUTIL = true -ignore
 endif
 
 # shared library runtime paths

Makefile

@@ -78,11 +78,7 @@ $(build_private_libdir)/sys%$(SHLIB_EXT): $(build_private_libdir)/sys%o
 	$(CXX) -shared -fPIC -L$(build_private_libdir) -L$(build_libdir) -L$(build_shlibdir) -o $@ $< \
 		$$([ $(OS) = Darwin ] && echo -Wl,-undefined,dynamic_lookup || echo -Wl,--unresolved-symbols,ignore-all ) \
 		$$([ $(OS) = WINNT ] && echo -ljulia -lssp)
-ifeq ($(OS), Darwin)
-ifeq ($(shell test `dsymutil -v | cut -d\- -f2 | cut -d. -f1` -gt 102 && echo yes), yes)
-	dsymutil $@
-endif
-endif
+	$(DSYMUTIL) $@
 
 $(build_private_libdir)/sys0.o:
 	@$(QUIET_JULIA) cd base && \

base/profile.jl

@@ -274,7 +274,8 @@ function tree_format(lilist::Vector{LineInfo}, counts::Vector{Int}, level::Int,
                           "; ",
                           truncto(string(li.func), widthfunc),
                           "; ")
-            strs[i] = string(base, "line: ", li.line)
+            strs[i] = li.line == -1 ? string(base,"(unknown line)") :
+                string(base, "line: ", li.line)
         else
             strs[i] = ""
         end

src/Makefile

@@ -90,6 +90,7 @@ endif
 $(build_shlibdir)/libjulia-debug.$(SHLIB_EXT): julia.expmap $(DOBJS) flisp/libflisp-debug.a support/libsupport-debug.a $(LIBUV)
 	@$(call PRINT_LINK, $(CXXLD) $(DEBUGFLAGS) $(DOBJS) $(RPATH_ORIGIN) -o $@ $(LDFLAGS) $(DEBUG_LIBS))
 	$(INSTALL_NAME_CMD)libjulia-debug.$(SHLIB_EXT) $@
+	$(DSYMUTIL) $@
 libjulia-debug.a: julia.expmap $(DOBJS) flisp/libflisp-debug.a support/libsupport-debug.a
 	rm -f $@
 	@$(call PRINT_LINK, ar -rcs $@ $(DOBJS))
@@ -104,6 +105,7 @@ endif
 $(build_shlibdir)/libjulia.$(SHLIB_EXT): julia.expmap $(OBJS) flisp/libflisp.a support/libsupport.a $(LIBUV)
 	@$(call PRINT_LINK, $(CXXLD) $(SHIPFLAGS) $(OBJS) $(RPATH_ORIGIN) -o $@ $(LDFLAGS) $(RELEASE_LIBS) $(SONAME))
 	$(INSTALL_NAME_CMD)libjulia.$(SHLIB_EXT) $@
+	$(DSYMUTIL) $@
 libjulia.a: julia.expmap $(OBJS) flisp/libflisp.a support/libsupport.a
 	rm -f $@
 	@$(call PRINT_LINK, ar -rcs $@ $(OBJS))

src/debuginfo.cpp

@@ -268,6 +268,10 @@ void jl_getDylibFunctionInfo(const char **name, int *line, const char **filename
     Dl_info dlinfo;
     const char *fname = 0;
     if ((dladdr((void*)pointer, &dlinfo) != 0) && dlinfo.dli_fname) {
+        // In case we fail with the debug info lookup, we at least still
+        // have the function name, even if we don't have line numbers
+        *name = dlinfo.dli_sname;
+        *filename = dlinfo.dli_fname;
         if (skipC && !jl_is_sysimg(dlinfo.dli_fname))
             return;
         uint64_t fbase = (uint64_t)dlinfo.dli_fbase;

src/init.c

@@ -17,6 +17,11 @@
 #include <unistd.h>
 #endif
 
+#if defined(__APPLE__)
+#define __need_ucontext64_t
+#include <machine/_structs.h>
+#endif
+
 #include <errno.h>
 #include <signal.h>
 
@@ -144,7 +149,7 @@ static int is_addr_on_stack(void *addr)
 #define SIGINFO SIGUSR1
 #endif
 
-void sigdie_handler(int sig, siginfo_t *info, void *context)
+void sigdie_handler(int sig, siginfo_t *info, ucontext64_t *context)
 {
     if (sig != SIGINFO) {
         sigset_t sset;
@@ -155,11 +160,11 @@ void sigdie_handler(int sig, siginfo_t *info, void *context)
     }
     ios_printf(ios_stderr,"\nsignal (%d): %s\n", sig, strsignal(sig));
 #ifdef __APPLE__
-    gdbbacktrace();
+    bt_size = rec_backtrace_ctx(bt_data, MAX_BT_SIZE, (bt_context_t)&((ucontext64_t*)context)->uc_mcontext64->__ss);
 #else
     bt_size = rec_backtrace_ctx(bt_data, MAX_BT_SIZE, (ucontext_t*)context);
-    jlbacktrace();
 #endif
+    jlbacktrace();
     if (sig != SIGSEGV &&
         sig != SIGBUS &&
         sig != SIGILL &&