# Copyright 2014 the V8 project authors. All rights reserved. # Use of this source code is governed by a BSD-style license that can be # found in the LICENSE file. # Print HeapObjects. define job call _v8_internal_Print_Object((void*)($arg0)) end document job Print a v8 JavaScript object Usage: job tagged_ptr end # Print v8::Local handle value. define jlh call _v8_internal_Print_Object(*((v8::internal::Object**)($arg0).val_)) end document jlh Print content of a v8::Local handle Usage: jlh local_handle end # Print Code objects containing given PC. define jco call _v8_internal_Print_Code((void*)($arg0)) end document jco Print a v8 Code object from an internal code address Usage: jco pc end # Print LayoutDescriptor. define jld call _v8_internal_Print_LayoutDescriptor((void*)($arg0)) end document jld Print a v8 LayoutDescriptor object Usage: jld tagged_ptr end # Print TransitionTree. define jtt call _v8_internal_Print_TransitionTree((void*)($arg0)) end document jtt Print the complete transition tree of the given v8 Map. Usage: jtt tagged_ptr end # Print JavaScript stack trace. define jst call _v8_internal_Print_StackTrace() end document jst Print the current JavaScript stack trace Usage: jst end # Skip the JavaScript stack. define jss set $js_entry_sp=v8::internal::Isolate::Current()->thread_local_top()->js_entry_sp_ set $rbp=*(void**)$js_entry_sp set $rsp=$js_entry_sp + 2*sizeof(void*) set $pc=*(void**)($js_entry_sp+sizeof(void*)) end document jss Skip the jitted stack on x64 to where we entered JS last. Usage: jss end # Print stack trace with assertion scopes. define bta python import re frame_re = re.compile("^#(\d+)\s*(?:0x[a-f\d]+ in )?(.+) \(.+ at (.+)") assert_re = re.compile("^\s*(\S+) = .+") btl = gdb.execute("backtrace full", to_string = True).splitlines() for l in btl: match = frame_re.match(l) if match: print("[%-2s] %-60s %-40s" % (match.group(1), match.group(2), match.group(3))) match = assert_re.match(l) if match: if match.group(3) == "false": prefix = "Disallow" color = "\033[91m" else: prefix = "Allow" color = "\033[92m" print("%s -> %s %s (%s)\033[0m" % (color, prefix, match.group(2), match.group(1))) end end document bta Print stack trace with assertion scopes Usage: bta end # Search for a pointer inside all valid pages. define space_find set $space = $arg0 set $current_page = $space->anchor()->next_page() while ($current_page != $space->anchor()) printf "# Searching in %p - %p\n", $current_page->area_start(), $current_page->area_end()-1 find $current_page->area_start(), $current_page->area_end()-1, $arg1 set $current_page = $current_page->next_page() end end define heap_find set $heap = v8::internal::Isolate::Current()->heap() printf "# Searching for %p in old_space ===============================\n", $arg0 space_find $heap->old_space() ($arg0) printf "# Searching for %p in map_space ===============================\n", $arg0 space_find $heap->map_space() $arg0 printf "# Searching for %p in code_space ===============================\n", $arg0 space_find $heap->code_space() $arg0 end document heap_find Find the location of a given address in V8 pages. Usage: heap_find address end set disassembly-flavor intel set disable-randomization off # Install a handler whenever the debugger stops due to a signal. It walks up the # stack looking for V8_Dcheck and moves the frame to the one above it so it's # immediately at the line of code that triggered the DCHECK. python def dcheck_stop_handler(event): orig_frame = gdb.selected_frame() frame = orig_frame select_frame = None while frame is not None: if frame.name() in ('V8_Dcheck', 'V8_Fatal'): select_frame = frame.older() frame = frame.older() if select_frame is not None: select_frame.select() gdb.execute('frame') gdb.events.stop.connect(dcheck_stop_handler) end