150 lines
3.8 KiB
C++
150 lines
3.8 KiB
C++
//=== - unittest/Support/OptimizedStructLayoutTest.cpp - Layout tests -----===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/OptimizedStructLayout.h"
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#include "gtest/gtest.h"
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using namespace llvm;
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namespace {
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class LayoutTest {
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struct Field {
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uint64_t Size;
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Align Alignment;
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uint64_t ForcedOffset;
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uint64_t ExpectedOffset;
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};
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SmallVector<Field, 16> Fields;
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bool Verified = false;
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public:
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LayoutTest() {}
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LayoutTest(const LayoutTest &) = delete;
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LayoutTest &operator=(const LayoutTest &) = delete;
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~LayoutTest() { assert(Verified); }
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LayoutTest &flexible(uint64_t Size, uint64_t Alignment,
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uint64_t ExpectedOffset) {
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Fields.push_back({Size, Align(Alignment),
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OptimizedStructLayoutField::FlexibleOffset, ExpectedOffset});
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return *this;
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}
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LayoutTest &fixed(uint64_t Size, uint64_t Alignment, uint64_t Offset) {
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Fields.push_back({Size, Align(Alignment), Offset, Offset});
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return *this;
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}
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void verify(uint64_t ExpectedSize, uint64_t ExpectedAlignment) {
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SmallVector<OptimizedStructLayoutField, 8> LayoutFields;
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LayoutFields.reserve(Fields.size());
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for (auto &F : Fields)
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LayoutFields.emplace_back(&F, F.Size, F.Alignment, F.ForcedOffset);
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auto SizeAndAlign = performOptimizedStructLayout(LayoutFields);
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EXPECT_EQ(SizeAndAlign.first, ExpectedSize);
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EXPECT_EQ(SizeAndAlign.second, Align(ExpectedAlignment));
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for (auto &LF : LayoutFields) {
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auto &F = *static_cast<const Field *>(LF.Id);
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EXPECT_EQ(LF.Offset, F.ExpectedOffset);
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}
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Verified = true;
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}
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};
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}
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TEST(OptimizedStructLayoutTest, Basic) {
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LayoutTest()
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.flexible(12, 4, 8)
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.flexible(8, 8, 0)
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.flexible(4, 4, 20)
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.verify(24, 8);
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}
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TEST(OptimizedStructLayoutTest, OddSize) {
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LayoutTest()
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.flexible(8, 8, 16)
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.flexible(4, 4, 12)
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.flexible(1, 1, 10)
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.flexible(10, 8, 0)
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.verify(24, 8);
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}
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TEST(OptimizedStructLayoutTest, Gaps) {
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LayoutTest()
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.fixed(4, 4, 8)
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.fixed(4, 4, 16)
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.flexible(4, 4, 0)
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.flexible(4, 4, 4)
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.flexible(4, 4, 12)
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.flexible(4, 4, 20)
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.verify(24, 4);
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}
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TEST(OptimizedStructLayoutTest, Greed) {
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// The greedy algorithm doesn't find the optimal layout here, which
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// would be to put the 5-byte field at the end.
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LayoutTest()
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.fixed(4, 4, 8)
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.flexible(5, 4, 0)
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.flexible(4, 4, 12)
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.flexible(4, 4, 16)
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.flexible(4, 4, 20)
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.verify(24, 4);
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}
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TEST(OptimizedStructLayoutTest, Jagged) {
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LayoutTest()
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.flexible(1, 2, 18)
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.flexible(13, 8, 0)
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.flexible(3, 2, 14)
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.verify(19, 8);
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}
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TEST(OptimizedStructLayoutTest, GardenPath) {
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// The 4-byte-aligned field is our highest priority, but the less-aligned
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// fields keep leaving the end offset mis-aligned.
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LayoutTest()
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.fixed(7, 4, 0)
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.flexible(4, 4, 44)
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.flexible(6, 1, 7)
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.flexible(5, 1, 13)
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.flexible(7, 2, 18)
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.flexible(4, 1, 25)
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.flexible(4, 1, 29)
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.flexible(1, 1, 33)
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.flexible(4, 2, 34)
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.flexible(4, 2, 38)
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.flexible(2, 2, 42)
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.flexible(2, 2, 48)
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.verify(50, 4);
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}
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// PR 51131
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TEST(OptimizedStructLayoutTest, HighAlignment) {
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// Handle the case where a flexible field has such a high alignment
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// requirement that aligning LastEnd to it gives an offset past the
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// end of the gap before the next fixed-alignment field.
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LayoutTest()
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.fixed(8, 8, 0)
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.fixed(8, 8, 8)
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.fixed(64, 64, 64)
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.flexible(1, 1, 16)
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.flexible(1, 1, 17)
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.flexible(4, 128, 128)
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.flexible(1, 1, 18)
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.flexible(1, 1, 19)
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.verify(132, 128);
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}
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