Fix function base address lookup on Win32 and FreeBSD

* Add a (slow but cross-platform) fallback lookup method of function name and base address
  using LLVM debug info reader
* Disable windows exported symbol lookup that never worked for sysimg function
  address lookup (since they are never exported). Also move it after
  LLVM debug info reader since it is less accurate unless LLVM couldn't get any
  debug info.

Fix #17251
Fix #20798

Author: yuyichao

src/debuginfo.cpp

@@ -716,6 +716,85 @@ static inline void ignoreError(T &err)
 #endif
 }
 
+static void get_function_name_and_base(const object::ObjectFile *object, bool insysimage,
+                                       void **saddr, char **name, size_t pointer,
+                                       int64_t slide)
+{
+    if (!object)
+        return;
+    // Assume we only need base address for sysimg for now
+    if (!insysimage || !sysimg_fvars)
+        saddr = nullptr;
+    // Try platform specific methods first since they are usually faster
+    if (saddr && !*saddr) {
+#if defined(_OS_LINUX_) && !defined(JL_DISABLE_LIBUNWIND)
+        unw_proc_info_t pip;
+        if (unw_get_proc_info_by_ip(unw_local_addr_space, pointer, &pip, NULL) == 0) {
+            *saddr = (void*)pip.start_ip;
+        }
+#endif
+#if defined(_OS_WINDOWS_) && defined(_CPU_X86_64_)
+        DWORD64 ImageBase;
+        PRUNTIME_FUNCTION fn = RtlLookupFunctionEntry(pointer, &ImageBase, NULL);
+        if (fn) {
+            *saddr = (void*)(ImageBase + fn->BeginAddress);
+        }
+#endif
+    }
+    if ((saddr && !*saddr) || (name && !*name)) {
+        size_t distance = (size_t)-1;
+        SymRef sym_found;
+        for (auto sym: object->symbols()) {
+            auto addr = sym.getAddress();
+            if (!addr)
+                continue;
+            size_t symptr = addr.get();
+            if (symptr > pointer + slide)
+                continue;
+            size_t new_dist = pointer + slide - symptr;
+            if (new_dist > distance)
+                continue;
+            distance = new_dist;
+            sym_found = sym;
+        }
+        if (distance != (size_t)-1) {
+            if (saddr && !*saddr) {
+                auto addr = sym_found.getAddress();
+                assert(addr);
+                *saddr = (void*)(uintptr_t)(addr.get() - slide);
+            }
+            if (name && !*name) {
+                if (auto name_or_err = sym_found.getName()) {
+                    auto nameref = name_or_err.get();
+                    size_t len = nameref.size();
+                    *name = (char*)malloc(len + 1);
+                    (*name)[len] = 0;
+                    memcpy(*name, nameref.data(), len);
+                }
+            }
+        }
+    }
+#ifdef _OS_WINDOWS_
+    // For ntdll and msvcrt since we are currently only parsing DWARF debug info through LLVM
+    if (!insysimage && name && !*name) {
+        static char frame_info_func[
+            sizeof(SYMBOL_INFO) +
+            MAX_SYM_NAME * sizeof(TCHAR)];
+        DWORD64 dwDisplacement64 = 0;
+        DWORD64 dwAddress = pointer;
+        PSYMBOL_INFO pSymbol = (PSYMBOL_INFO)frame_info_func;
+        pSymbol->SizeOfStruct = sizeof(SYMBOL_INFO);
+        pSymbol->MaxNameLen = MAX_SYM_NAME;
+        jl_in_stackwalk = 1;
+        if (SymFromAddr(GetCurrentProcess(), dwAddress, &dwDisplacement64, pSymbol)) {
+            // errors are ignored
+            jl_copy_str(name, pSymbol->Name);
+        }
+        jl_in_stackwalk = 0;
+    }
+#endif
+}
+
 extern "C" void jl_refresh_dbg_module_list(void);
 bool jl_dylib_DI_for_fptr(size_t pointer, const llvm::object::ObjectFile **obj, llvm::DIContext **context, int64_t *slide, int64_t *section_slide,
     bool onlySysImg, bool *isSysImg, void **saddr, char **name, char **filename)
@@ -746,35 +825,12 @@ bool jl_dylib_DI_for_fptr(size_t pointer, const llvm::object::ObjectFile **obj,
     if (onlySysImg && !insysimage) {
         return false;
     }
-    static char frame_info_func[
-        sizeof(SYMBOL_INFO) +
-        MAX_SYM_NAME * sizeof(TCHAR)];
-    DWORD64 dwDisplacement64 = 0;
-    DWORD64 dwAddress = pointer;
-    PSYMBOL_INFO pSymbol = (PSYMBOL_INFO)frame_info_func;
-    pSymbol->SizeOfStruct = sizeof(SYMBOL_INFO);
-    pSymbol->MaxNameLen = MAX_SYM_NAME;
-    jl_in_stackwalk = 1;
-    if (SymFromAddr(GetCurrentProcess(), dwAddress, &dwDisplacement64,
-                    pSymbol)) {
-        // SymFromAddr returned success
-        // errors are ignored, but are hopefully patched up by
-        // using llvm to read the object (below)
-        if (name)
-            jl_copy_str(name, pSymbol->Name);
-        if (saddr)
-            *saddr = (void*)(uintptr_t)pSymbol->Address;
-    }
-    else if (saddr) {
-        *saddr = NULL;
-    }
-
     // If we didn't find the filename before in the debug
     // info, use the dll name
     if (filename && !*filename)
         jl_copy_str(filename, fname.data());
-
-    jl_in_stackwalk = 0;
+    if (saddr)
+        *saddr = NULL;
 
 #else // ifdef _OS_WINDOWS_
     Dl_info dlinfo;
@@ -832,6 +888,7 @@ bool jl_dylib_DI_for_fptr(size_t pointer, const llvm::object::ObjectFile **obj,
         *context = it->second.ctx;
         *slide = it->second.slide;
         *section_slide = it->second.section_slide;
+        get_function_name_and_base(*obj, insysimage, saddr, name, pointer, *slide);
         return true;
     }
 
@@ -961,6 +1018,7 @@ bool jl_dylib_DI_for_fptr(size_t pointer, const llvm::object::ObjectFile **obj,
     // update cache
     objfileentry_t entry = {*obj, *context, *slide, *section_slide};
     objfilemap[fbase] = entry;
+    get_function_name_and_base(*obj, insysimage, saddr, name, pointer, *slide);
     return true;
 }
 
@@ -999,32 +1057,15 @@ static int jl_getDylibFunctionInfo(jl_frame_t **frames, size_t pointer, int skip
         return 1;
     }
     frame0->fromC = !isSysImg;
-    if (isSysImg && sysimg_fvars) {
-#if defined(_OS_LINUX_) && !defined(JL_DISABLE_LIBUNWIND)
-        unw_proc_info_t pip;
-        if (!saddr && unw_get_proc_info_by_ip(unw_local_addr_space,
-                                              pointer, &pip, NULL) == 0)
-            saddr = (void*)pip.start_ip;
-#endif
-#if defined(_OS_WINDOWS_) && defined(_CPU_X86_64_)
-        if (!saddr) {
-            DWORD64 ImageBase;
-            PRUNTIME_FUNCTION fn = RtlLookupFunctionEntry(pointer, &ImageBase, NULL);
-            if (fn)
-                saddr = (void*)(ImageBase + fn->BeginAddress);
-        }
-#endif
-        if (saddr) {
-            for (size_t i = 0; i < sysimg_fvars_n; i++) {
-                if (saddr == sysimg_fvars[i]) {
-                    frame0->linfo = sysimg_fvars_linfo[i];
-                    break;
-                }
+    if (isSysImg && sysimg_fvars && saddr) {
+        for (size_t i = 0; i < sysimg_fvars_n; i++) {
+            if (saddr == sysimg_fvars[i]) {
+                frame0->linfo = sysimg_fvars_linfo[i];
+                break;
             }
         }
-        return lookup_pointer(context, frames, pointer+slide, isSysImg, noInline);
     }
-    return lookup_pointer(context, frames, pointer+slide, isSysImg, noInline);
+    return lookup_pointer(context, frames, pointer + slide, isSysImg, noInline);
 }
 
 int jl_DI_for_fptr(uint64_t fptr, uint64_t *symsize, int64_t *slide, int64_t *section_slide,

test/cmdlineargs.jl

@@ -423,13 +423,7 @@ end
 for precomp in ("yes", "no")
     bt = readstring(pipeline(ignorestatus(`$(Base.julia_cmd()) --startup-file=no --precompiled=$precomp
         -E 'include("____nonexistent_file")'`), stderr=catcmd))
-    @test contains(bt, "include_from_node1")
-    if ((is_windows() && Sys.WORD_SIZE == 32) || (is_bsd() && !is_apple())) && precomp == "yes"
-        # FIXME: Issue #17251 (Windows), #20798 (FreeBSD)
-        @test_broken contains(bt, "include_from_node1(::Module, ::String) at $(joinpath(".", "loading.jl"))")
-    else
-        @test contains(bt, "include_from_node1(::Module, ::String) at $(joinpath(".", "loading.jl"))")
-    end
+    @test contains(bt, "include_from_node1(::Module, ::String) at $(joinpath(".", "loading.jl"))")
     lno = match(r"at \.[\/\\]loading\.jl:(\d+)", bt)
     @test length(lno.captures) == 1
     @test parse(Int, lno.captures[1]) > 0