150 lines · cpp
1//=== - unittest/Support/OptimizedStructLayoutTest.cpp - Layout tests -----===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "llvm/Support/OptimizedStructLayout.h"10#include "gtest/gtest.h"11 12using namespace llvm;13 14namespace {15 16class LayoutTest {17 struct Field {18 uint64_t Size;19 Align Alignment;20 uint64_t ForcedOffset;21 uint64_t ExpectedOffset;22 };23 24 SmallVector<Field, 16> Fields;25 bool Verified = false;26 27public:28 LayoutTest() = default;29 LayoutTest(const LayoutTest &) = delete;30 LayoutTest &operator=(const LayoutTest &) = delete;31 ~LayoutTest() { assert(Verified); }32 33 LayoutTest &flexible(uint64_t Size, uint64_t Alignment,34 uint64_t ExpectedOffset) {35 Fields.push_back({Size, Align(Alignment),36 OptimizedStructLayoutField::FlexibleOffset, ExpectedOffset});37 return *this;38 }39 40 LayoutTest &fixed(uint64_t Size, uint64_t Alignment, uint64_t Offset) {41 Fields.push_back({Size, Align(Alignment), Offset, Offset});42 return *this;43 }44 45 void verify(uint64_t ExpectedSize, uint64_t ExpectedAlignment) {46 SmallVector<OptimizedStructLayoutField, 8> LayoutFields;47 LayoutFields.reserve(Fields.size());48 for (auto &F : Fields)49 LayoutFields.emplace_back(&F, F.Size, F.Alignment, F.ForcedOffset);50 51 auto SizeAndAlign = performOptimizedStructLayout(LayoutFields);52 53 EXPECT_EQ(SizeAndAlign.first, ExpectedSize);54 EXPECT_EQ(SizeAndAlign.second, Align(ExpectedAlignment));55 56 for (auto &LF : LayoutFields) {57 auto &F = *static_cast<const Field *>(LF.Id);58 EXPECT_EQ(LF.Offset, F.ExpectedOffset);59 }60 61 Verified = true;62 }63};64 65}66 67TEST(OptimizedStructLayoutTest, Basic) {68 LayoutTest()69 .flexible(12, 4, 8)70 .flexible(8, 8, 0)71 .flexible(4, 4, 20)72 .verify(24, 8);73}74 75TEST(OptimizedStructLayoutTest, OddSize) {76 LayoutTest()77 .flexible(8, 8, 16)78 .flexible(4, 4, 12)79 .flexible(1, 1, 10)80 .flexible(10, 8, 0)81 .verify(24, 8);82}83 84TEST(OptimizedStructLayoutTest, Gaps) {85 LayoutTest()86 .fixed(4, 4, 8)87 .fixed(4, 4, 16)88 .flexible(4, 4, 0)89 .flexible(4, 4, 4)90 .flexible(4, 4, 12)91 .flexible(4, 4, 20)92 .verify(24, 4);93}94 95TEST(OptimizedStructLayoutTest, Greed) {96 // The greedy algorithm doesn't find the optimal layout here, which97 // would be to put the 5-byte field at the end.98 LayoutTest()99 .fixed(4, 4, 8)100 .flexible(5, 4, 0)101 .flexible(4, 4, 12)102 .flexible(4, 4, 16)103 .flexible(4, 4, 20)104 .verify(24, 4);105}106 107TEST(OptimizedStructLayoutTest, Jagged) {108 LayoutTest()109 .flexible(1, 2, 18)110 .flexible(13, 8, 0)111 .flexible(3, 2, 14)112 .verify(19, 8);113}114 115TEST(OptimizedStructLayoutTest, GardenPath) {116 // The 4-byte-aligned field is our highest priority, but the less-aligned117 // fields keep leaving the end offset mis-aligned.118 LayoutTest()119 .fixed(7, 4, 0)120 .flexible(4, 4, 44)121 .flexible(6, 1, 7)122 .flexible(5, 1, 13)123 .flexible(7, 2, 18)124 .flexible(4, 1, 25)125 .flexible(4, 1, 29)126 .flexible(1, 1, 33)127 .flexible(4, 2, 34)128 .flexible(4, 2, 38)129 .flexible(2, 2, 42)130 .flexible(2, 2, 48)131 .verify(50, 4);132}133 134// PR 51131135TEST(OptimizedStructLayoutTest, HighAlignment) {136 // Handle the case where a flexible field has such a high alignment137 // requirement that aligning LastEnd to it gives an offset past the138 // end of the gap before the next fixed-alignment field.139 LayoutTest()140 .fixed(8, 8, 0)141 .fixed(8, 8, 8)142 .fixed(64, 64, 64)143 .flexible(1, 1, 16)144 .flexible(1, 1, 17)145 .flexible(4, 128, 128)146 .flexible(1, 1, 18)147 .flexible(1, 1, 19)148 .verify(132, 128);149}150