81aa89592b
Known-pointer decompression used to be distinct from any-tagged-value decompression, since the latter used to detect Smis and decompress them with sign extension. However, we got rid of this distinction when we introduced Smi-corrupting loads (allowing the top 32-bits of uncompressed Smis to be undefined), which means that the TaggedPointer and TaggedAny decompression is now identical. We can remove a bunch of duplicate code by removing this distinction. Change-Id: Id66671497d63ed885f9e537494c011317dfd4788 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4221398 Reviewed-by: Toon Verwaest <verwaest@chromium.org> Commit-Queue: Toon Verwaest <verwaest@chromium.org> Auto-Submit: Leszek Swirski <leszeks@chromium.org> Cr-Commit-Position: refs/heads/main@{#85647}
93 lines
3.5 KiB
Python
93 lines
3.5 KiB
Python
#!/usr/bin/env python3
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# Copyright 2019 the V8 project authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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"""This program writes a C++ file that can be used to look up whether a given
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address matches known object locations. The first argument is the directory
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containing the file v8heapconst.py; the second argument is the output .cc file.
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"""
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import sys
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sys.path.insert(0, sys.argv[1])
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import v8heapconst
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out = """
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#include <cstdint>
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#include <string>
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// Don't bother initializing global cage base value, compute it from any
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// on heap address instead.
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#define V8_COMPRESS_POINTERS_DONT_USE_GLOBAL_BASE
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#include "src/common/ptr-compr-inl.h"
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#include "tools/debug_helper/debug-helper-internal.h"
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namespace v8 {
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namespace internal {
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namespace debug_helper_internal {
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"""
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def iterate_objects(target_space, camel_space_name):
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global out
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result = []
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for (space, offset), (instance_type, name) in v8heapconst.KNOWN_MAPS.items():
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if space == target_space:
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result.append((offset, name))
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for (space, offset), name in v8heapconst.KNOWN_OBJECTS.items():
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if space == target_space and (space, offset) not in v8heapconst.KNOWN_MAPS:
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result.append((offset, name))
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out = out + '\nstd::string FindKnownObjectIn' + camel_space_name \
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+ '(uintptr_t offset) {\n switch (offset) {\n'
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for offset, name in result:
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out = out + ' case ' + str(offset) + ': return "' + name + '";\n'
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out = out + ' default: return "";\n }\n}\n'
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iterate_objects('map_space', 'MapSpace')
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iterate_objects('old_space', 'OldSpace')
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iterate_objects('read_only_space', 'ReadOnlySpace')
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def iterate_maps(target_space, camel_space_name):
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global out
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out = out + '\nint FindKnownMapInstanceTypeIn' + camel_space_name \
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+ '(uintptr_t offset) {\n switch (offset) {\n'
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for (space, offset), (instance_type, name) in v8heapconst.KNOWN_MAPS.items():
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if space == target_space:
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out = out + ' case ' + str(offset) + ': return ' + str(instance_type) \
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+ ';\n'
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out = out + ' default: return -1;\n }\n}\n'
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iterate_maps('map_space', 'MapSpace')
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iterate_maps('old_space', 'OldSpace')
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iterate_maps('read_only_space', 'ReadOnlySpace')
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out = out + '\nvoid FillInUnknownHeapAddresses(' + \
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'd::HeapAddresses* heap_addresses, uintptr_t any_uncompressed_ptr) {\n'
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if (hasattr(v8heapconst, 'HEAP_FIRST_PAGES')): # Only exists in ptr-compr builds.
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out = out + ' if (heap_addresses->any_heap_pointer == 0) {\n'
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out = out + ' heap_addresses->any_heap_pointer = any_uncompressed_ptr;\n'
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out = out + ' }\n'
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# If we ever try to apply this to CodeSpace we might need to use
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# ExternalCodeCompressionScheme instead of V8HeapCompressionScheme for
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# decompressing external code pointers below.
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expected_spaces = set(['map_space', 'read_only_space', 'old_space'])
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for offset, space_name in v8heapconst.HEAP_FIRST_PAGES.items():
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if (space_name in expected_spaces):
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out = out + ' if (heap_addresses->' + space_name + '_first_page == 0) {\n'
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out = out + ' heap_addresses->' + space_name + \
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'_first_page = i::V8HeapCompressionScheme::DecompressTagged(' + \
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'any_uncompressed_ptr, ' + str(offset) + ');\n'
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out = out + ' }\n'
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out = out + '}\n'
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out = out + '\n}\n}\n}\n'
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try:
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with open(sys.argv[2], "r") as out_file:
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if out == out_file.read():
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sys.exit(0) # No modification needed.
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except:
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pass # File probably doesn't exist; write it.
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with open(sys.argv[2], "w") as out_file:
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out_file.write(out)
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