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