LLVM 19.0.0git
i386.cpp
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1//===---- i386.cpp - Generic JITLink i386 edge kinds, utilities -----===//
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// Generic utilities for graphs representing i386 objects.
10//
11//===----------------------------------------------------------------------===//
12
14
15#define DEBUG_TYPE "jitlink"
16
17namespace llvm::jitlink::i386 {
18
20 switch (K) {
21 case None:
22 return "None";
23 case Pointer32:
24 return "Pointer32";
25 case PCRel32:
26 return "PCRel32";
27 case Pointer16:
28 return "Pointer16";
29 case PCRel16:
30 return "PCRel16";
31 case Delta32:
32 return "Delta32";
33 case Delta32FromGOT:
34 return "Delta32FromGOT";
36 return "RequestGOTAndTransformToDelta32FromGOT";
37 case BranchPCRel32:
38 return "BranchPCRel32";
40 return "BranchPCRel32ToPtrJumpStub";
42 return "BranchPCRel32ToPtrJumpStubBypassable";
43 }
44
45 return getGenericEdgeKindName(K);
46}
47
48const char NullPointerContent[PointerSize] = {0x00, 0x00, 0x00, 0x00};
49
50const char PointerJumpStubContent[6] = {
51 static_cast<char>(0xFFu), 0x25, 0x00, 0x00, 0x00, 0x00};
52
54 LLVM_DEBUG(dbgs() << "Optimizing GOT entries and stubs:\n");
55
56 for (auto *B : G.blocks())
57 for (auto &E : B->edges()) {
59 auto &StubBlock = E.getTarget().getBlock();
60 assert(StubBlock.getSize() == sizeof(PointerJumpStubContent) &&
61 "Stub block should be stub sized");
62 assert(StubBlock.edges_size() == 1 &&
63 "Stub block should only have one outgoing edge");
64
65 auto &GOTBlock = StubBlock.edges().begin()->getTarget().getBlock();
66 assert(GOTBlock.getSize() == G.getPointerSize() &&
67 "GOT block should be pointer sized");
68 assert(GOTBlock.edges_size() == 1 &&
69 "GOT block should only have one outgoing edge");
70
71 auto &GOTTarget = GOTBlock.edges().begin()->getTarget();
72 orc::ExecutorAddr EdgeAddr = B->getAddress() + E.getOffset();
73 orc::ExecutorAddr TargetAddr = GOTTarget.getAddress();
74
75 int64_t Displacement = TargetAddr - EdgeAddr + 4;
76 if (isInt<32>(Displacement)) {
77 E.setKind(i386::BranchPCRel32);
78 E.setTarget(GOTTarget);
80 dbgs() << " Replaced stub branch with direct branch:\n ";
81 printEdge(dbgs(), *B, E, getEdgeKindName(E.getKind()));
82 dbgs() << "\n";
83 });
84 }
85 }
86 }
87
88 return Error::success();
89}
90
91} // namespace llvm::jitlink::i386
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
#define LLVM_DEBUG(X)
Definition: Debug.h:101
#define G(x, y, z)
Definition: MD5.cpp:56
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
Lightweight error class with error context and mandatory checking.
Definition: Error.h:160
static ErrorSuccess success()
Create a success value.
Definition: Error.h:334
Represents an address in the executor process.
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:163