7d073b03c7
the .eh_frame format as part of the jitdump generated when FLAG_perf_prof is enabled. The final goal is allowing precise unwinding of callchains that include JITted code when profiling V8 using perf. Unwinding information is stored in the body of code objects after the code itself, prefixed with its length and aligned to a 8-byte boundary. A boolean flag in the header signals its presence, resulting in zero memory overhead when the generation of unwinding info is disabled or no such information was attached to the code object. A new jitdump record type (with id 4) is introduced for specifying optional unwinding information for code load records. The EhFrameHdr struct is also introduced, together with a constructor to initialise it from the associated code object. At this stage no unwinding information is written to the jitdump, but the infrastructure for doing so is ready in place. BUG=v8:4899 LOG=N Review-Url: https://codereview.chromium.org/1993653003 Cr-Commit-Position: refs/heads/master@{#37296}
85 lines
3.0 KiB
C++
85 lines
3.0 KiB
C++
// Copyright 2016 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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#include "src/objects.h"
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#include "test/cctest/cctest.h"
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using namespace v8::internal;
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TEST(CodeLayoutWithoutUnwindingInfo) {
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CcTest::InitializeVM();
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HandleScope handle_scope(CcTest::i_isolate());
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// "Hello, World!" in ASCII.
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byte buffer_array[13] = {0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x2c, 0x20,
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0x57, 0x6f, 0x72, 0x6c, 0x64, 0x21};
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byte* buffer = &buffer_array[0];
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int buffer_size = sizeof(buffer_array);
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CodeDesc code_desc;
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code_desc.buffer = buffer;
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code_desc.buffer_size = buffer_size;
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code_desc.constant_pool_size = 0;
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code_desc.instr_size = buffer_size;
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code_desc.reloc_size = 0;
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code_desc.origin = nullptr;
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code_desc.unwinding_info = nullptr;
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code_desc.unwinding_info_size = 0;
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Handle<Code> code = CcTest::i_isolate()->factory()->NewCode(
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code_desc, 0, Handle<Object>::null());
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CHECK(!code->has_unwinding_info());
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CHECK_EQ(code->instruction_size(), buffer_size);
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CHECK_EQ(memcmp(code->instruction_start(), buffer, buffer_size), 0);
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CHECK_EQ(code->instruction_end() - reinterpret_cast<byte*>(*code),
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Code::kHeaderSize + buffer_size - kHeapObjectTag);
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}
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TEST(CodeLayoutWithUnwindingInfo) {
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CcTest::InitializeVM();
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HandleScope handle_scope(CcTest::i_isolate());
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// "Hello, World!" in ASCII.
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byte buffer_array[13] = {0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x2c, 0x20,
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0x57, 0x6f, 0x72, 0x6c, 0x64, 0x21};
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// "JavaScript" in ASCII.
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byte unwinding_info_array[10] = {0x4a, 0x61, 0x76, 0x61, 0x53,
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0x63, 0x72, 0x69, 0x70, 0x74};
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byte* buffer = &buffer_array[0];
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int buffer_size = sizeof(buffer_array);
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byte* unwinding_info = &unwinding_info_array[0];
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int unwinding_info_size = sizeof(unwinding_info_array);
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CodeDesc code_desc;
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code_desc.buffer = buffer;
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code_desc.buffer_size = buffer_size;
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code_desc.constant_pool_size = 0;
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code_desc.instr_size = buffer_size;
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code_desc.reloc_size = 0;
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code_desc.origin = nullptr;
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code_desc.unwinding_info = unwinding_info;
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code_desc.unwinding_info_size = unwinding_info_size;
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Handle<Code> code = CcTest::i_isolate()->factory()->NewCode(
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code_desc, 0, Handle<Object>::null());
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CHECK(code->has_unwinding_info());
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CHECK_EQ(code->instruction_size(), buffer_size);
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CHECK_EQ(memcmp(code->instruction_start(), buffer, buffer_size), 0);
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CHECK(IsAligned(code->GetUnwindingInfoSizeOffset(), 8));
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CHECK_EQ(code->unwinding_info_size(), unwinding_info_size);
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CHECK(
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IsAligned(reinterpret_cast<uintptr_t>(code->unwinding_info_start()), 8));
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CHECK_EQ(
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memcmp(code->unwinding_info_start(), unwinding_info, unwinding_info_size),
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0);
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CHECK_EQ(code->unwinding_info_end() - reinterpret_cast<byte*>(*code),
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Code::kHeaderSize + RoundUp(buffer_size, kInt64Size) + kInt64Size +
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unwinding_info_size - kHeapObjectTag);
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}
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