1 //===------ LinkGraphTests.cpp - Unit tests for core JITLink classes ------===//
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-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/ADT/STLExtras.h"
10 #include "llvm/ExecutionEngine/JITLink/JITLink.h"
11 #include "llvm/Support/Endian.h"
12 #include "llvm/Support/Memory.h"
13 #include "gtest/gtest.h"
14 
15 using namespace llvm;
16 using namespace llvm::jitlink;
17 
18 static auto RWFlags =
19     sys::Memory::ProtectionFlags(sys::Memory::MF_READ | sys::Memory::MF_WRITE);
20 
21 static const char BlockContentBytes[] = {0x10, 0x11, 0x12, 0x13, 0x14, 0x15,
22                                          0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B,
23                                          0x1C, 0x1D, 0x1E, 0x1F, 0x00};
24 static StringRef BlockContent(BlockContentBytes);
25 
26 TEST(LinkGraphTest, Construction) {
27   // Check that LinkGraph construction works as expected.
28   LinkGraph G("foo", Triple("x86_64-apple-darwin"), 8, support::little,
29               getGenericEdgeKindName);
30   EXPECT_EQ(G.getName(), "foo");
31   EXPECT_EQ(G.getTargetTriple().str(), "x86_64-apple-darwin");
32   EXPECT_EQ(G.getPointerSize(), 8U);
33   EXPECT_EQ(G.getEndianness(), support::little);
34   EXPECT_TRUE(llvm::empty(G.external_symbols()));
35   EXPECT_TRUE(llvm::empty(G.absolute_symbols()));
36   EXPECT_TRUE(llvm::empty(G.defined_symbols()));
37   EXPECT_TRUE(llvm::empty(G.blocks()));
38 }
39 
40 TEST(LinkGraphTest, AddressAccess) {
41   // Check that we can get addresses for blocks, symbols, and edges.
42   LinkGraph G("foo", Triple("x86_64-apple-darwin"), 8, support::little,
43               getGenericEdgeKindName);
44 
45   auto Sec1 = G.createSection("__data.1", RWFlags);
46   auto &B1 = G.createContentBlock(Sec1, BlockContent, 0x1000, 8, 0);
47   auto &S1 = G.addDefinedSymbol(B1, 4, "S1", 4, Linkage::Strong, Scope::Default,
48                                 false, false);
49   B1.addEdge(Edge::FirstRelocation, 8, S1, 0);
50   auto &E1 = *B1.edges().begin();
51 
52   EXPECT_EQ(B1.getAddress(), 0x1000U) << "Incorrect block address";
53   EXPECT_EQ(S1.getAddress(), 0x1004U) << "Incorrect symbol address";
54   EXPECT_EQ(B1.getFixupAddress(E1), 0x1008U) << "Incorrect fixup address";
55 }
56 
57 TEST(LinkGraphTest, BlockAndSymbolIteration) {
58   // Check that we can iterate over blocks within Sections and across sections.
59   LinkGraph G("foo", Triple("x86_64-apple-darwin"), 8, support::little,
60               getGenericEdgeKindName);
61   auto &Sec1 = G.createSection("__data.1", RWFlags);
62   auto &B1 = G.createContentBlock(Sec1, BlockContent, 0x1000, 8, 0);
63   auto &B2 = G.createContentBlock(Sec1, BlockContent, 0x2000, 8, 0);
64   auto &S1 = G.addDefinedSymbol(B1, 0, "S1", 4, Linkage::Strong, Scope::Default,
65                                 false, false);
66   auto &S2 = G.addDefinedSymbol(B2, 4, "S2", 4, Linkage::Strong, Scope::Default,
67                                 false, false);
68 
69   auto &Sec2 = G.createSection("__data.2", RWFlags);
70   auto &B3 = G.createContentBlock(Sec2, BlockContent, 0x3000, 8, 0);
71   auto &B4 = G.createContentBlock(Sec2, BlockContent, 0x4000, 8, 0);
72   auto &S3 = G.addDefinedSymbol(B3, 0, "S3", 4, Linkage::Strong, Scope::Default,
73                                 false, false);
74   auto &S4 = G.addDefinedSymbol(B4, 4, "S4", 4, Linkage::Strong, Scope::Default,
75                                 false, false);
76 
77   // Check that iteration of blocks within a section behaves as expected.
78   EXPECT_EQ(std::distance(Sec1.blocks().begin(), Sec1.blocks().end()), 2);
79   EXPECT_TRUE(llvm::count(Sec1.blocks(), &B1));
80   EXPECT_TRUE(llvm::count(Sec1.blocks(), &B2));
81 
82   // Check that iteration of symbols within a section behaves as expected.
83   EXPECT_EQ(std::distance(Sec1.symbols().begin(), Sec1.symbols().end()), 2);
84   EXPECT_TRUE(llvm::count(Sec1.symbols(), &S1));
85   EXPECT_TRUE(llvm::count(Sec1.symbols(), &S2));
86 
87   // Check that iteration of blocks across sections behaves as expected.
88   EXPECT_EQ(std::distance(G.blocks().begin(), G.blocks().end()), 4);
89   EXPECT_TRUE(llvm::count(G.blocks(), &B1));
90   EXPECT_TRUE(llvm::count(G.blocks(), &B2));
91   EXPECT_TRUE(llvm::count(G.blocks(), &B3));
92   EXPECT_TRUE(llvm::count(G.blocks(), &B4));
93 
94   // Check that iteration of defined symbols across sections behaves as
95   // expected.
96   EXPECT_EQ(
97       std::distance(G.defined_symbols().begin(), G.defined_symbols().end()), 4);
98   EXPECT_TRUE(llvm::count(G.defined_symbols(), &S1));
99   EXPECT_TRUE(llvm::count(G.defined_symbols(), &S2));
100   EXPECT_TRUE(llvm::count(G.defined_symbols(), &S3));
101   EXPECT_TRUE(llvm::count(G.defined_symbols(), &S4));
102 }
103 
104 TEST(LinkGraphTest, SplitBlock) {
105   // Check that the LinkGraph::splitBlock test works as expected.
106 
107   const char BlockContentBytes[] = {0x10, 0x11, 0x12, 0x13, 0x14, 0x15,
108                                     0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B,
109                                     0x1C, 0x1D, 0x1E, 0x1F, 0x00};
110   StringRef BlockContent(BlockContentBytes);
111 
112   LinkGraph G("foo", Triple("x86_64-apple-darwin"), 8, support::little,
113               getGenericEdgeKindName);
114   auto &Sec = G.createSection("__data", RWFlags);
115 
116   // Create the block to split.
117   auto &B1 = G.createContentBlock(Sec, BlockContent, 0x1000, 8, 0);
118 
119   // Add some symbols to the block.
120   auto &S1 = G.addDefinedSymbol(B1, 0, "S1", 4, Linkage::Strong, Scope::Default,
121                                 false, false);
122   auto &S2 = G.addDefinedSymbol(B1, 4, "S2", 4, Linkage::Strong, Scope::Default,
123                                 false, false);
124   auto &S3 = G.addDefinedSymbol(B1, 8, "S3", 4, Linkage::Strong, Scope::Default,
125                                 false, false);
126   auto &S4 = G.addDefinedSymbol(B1, 12, "S4", 4, Linkage::Strong,
127                                 Scope::Default, false, false);
128 
129   // Add an extra block, EB, and target symbols, and use these to add edges
130   // from B1 to EB.
131   auto &EB = G.createContentBlock(Sec, BlockContent, 0x2000, 8, 0);
132   auto &ES1 = G.addDefinedSymbol(EB, 0, "TS1", 4, Linkage::Strong,
133                                  Scope::Default, false, false);
134   auto &ES2 = G.addDefinedSymbol(EB, 4, "TS2", 4, Linkage::Strong,
135                                  Scope::Default, false, false);
136   auto &ES3 = G.addDefinedSymbol(EB, 8, "TS3", 4, Linkage::Strong,
137                                  Scope::Default, false, false);
138   auto &ES4 = G.addDefinedSymbol(EB, 12, "TS4", 4, Linkage::Strong,
139                                  Scope::Default, false, false);
140 
141   // Add edges from B1 to EB.
142   B1.addEdge(Edge::FirstRelocation, 0, ES1, 0);
143   B1.addEdge(Edge::FirstRelocation, 4, ES2, 0);
144   B1.addEdge(Edge::FirstRelocation, 8, ES3, 0);
145   B1.addEdge(Edge::FirstRelocation, 12, ES4, 0);
146 
147   // Split B1.
148   auto &B2 = G.splitBlock(B1, 8);
149 
150   // Check that the block addresses and content matches what we would expect.
151   EXPECT_EQ(B1.getAddress(), 0x1008U);
152   EXPECT_EQ(B1.getContent(), BlockContent.substr(8));
153 
154   EXPECT_EQ(B2.getAddress(), 0x1000U);
155   EXPECT_EQ(B2.getContent(), BlockContent.substr(0, 8));
156 
157   // Check that symbols in B1 were transferred as expected:
158   // We expect S1 and S2 to have been transferred to B2, and S3 and S4 to have
159   // remained attached to B1. Symbols S3 and S4 should have had their offsets
160   // slid to account for the change in address of B2.
161   EXPECT_EQ(&S1.getBlock(), &B2);
162   EXPECT_EQ(S1.getOffset(), 0U);
163 
164   EXPECT_EQ(&S2.getBlock(), &B2);
165   EXPECT_EQ(S2.getOffset(), 4U);
166 
167   EXPECT_EQ(&S3.getBlock(), &B1);
168   EXPECT_EQ(S3.getOffset(), 0U);
169 
170   EXPECT_EQ(&S4.getBlock(), &B1);
171   EXPECT_EQ(S4.getOffset(), 4U);
172 
173   // Check that edges in B1 have been transferred as expected:
174   // Both blocks should now have two edges each at offsets 0 and 4.
175   EXPECT_EQ(llvm::size(B1.edges()), 2);
176   if (size(B1.edges()) == 2) {
177     auto *E1 = &*B1.edges().begin();
178     auto *E2 = &*(B1.edges().begin() + 1);
179     if (E2->getOffset() < E1->getOffset())
180       std::swap(E1, E2);
181     EXPECT_EQ(E1->getOffset(), 0U);
182     EXPECT_EQ(E2->getOffset(), 4U);
183   }
184 
185   EXPECT_EQ(llvm::size(B2.edges()), 2);
186   if (size(B2.edges()) == 2) {
187     auto *E1 = &*B2.edges().begin();
188     auto *E2 = &*(B2.edges().begin() + 1);
189     if (E2->getOffset() < E1->getOffset())
190       std::swap(E1, E2);
191     EXPECT_EQ(E1->getOffset(), 0U);
192     EXPECT_EQ(E2->getOffset(), 4U);
193   }
194 }
195