/Users/buildslave/jenkins/sharedspace/clang-stage2-coverage-R@2/llvm/lib/Transforms/Utils/StripGCRelocates.cpp
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1 | | //===- StripGCRelocates.cpp - Remove gc.relocates inserted by RewriteStatePoints===// |
2 | | // |
3 | | // The LLVM Compiler Infrastructure |
4 | | // |
5 | | // This file is distributed under the University of Illinois Open Source |
6 | | // License. See LICENSE.TXT for details. |
7 | | // |
8 | | //===----------------------------------------------------------------------===// |
9 | | // |
10 | | // This is a little utility pass that removes the gc.relocates inserted by |
11 | | // RewriteStatepointsForGC. Note that the generated IR is incorrect, |
12 | | // but this is useful as a single pass in itself, for analysis of IR, without |
13 | | // the GC.relocates. The statepoint and gc.result instrinsics would still be |
14 | | // present. |
15 | | //===----------------------------------------------------------------------===// |
16 | | |
17 | | #include "llvm/IR/Function.h" |
18 | | #include "llvm/IR/InstIterator.h" |
19 | | #include "llvm/IR/Instructions.h" |
20 | | #include "llvm/IR/Statepoint.h" |
21 | | #include "llvm/IR/Type.h" |
22 | | #include "llvm/Pass.h" |
23 | | #include "llvm/Support/raw_ostream.h" |
24 | | #include "llvm/Transforms/Scalar.h" |
25 | | |
26 | | using namespace llvm; |
27 | | |
28 | | namespace { |
29 | | struct StripGCRelocates : public FunctionPass { |
30 | | static char ID; // Pass identification, replacement for typeid |
31 | 1 | StripGCRelocates() : FunctionPass(ID) { |
32 | 1 | initializeStripGCRelocatesPass(*PassRegistry::getPassRegistry()); |
33 | 1 | } |
34 | | |
35 | 1 | void getAnalysisUsage(AnalysisUsage &Info) const override {} |
36 | | |
37 | | bool runOnFunction(Function &F) override; |
38 | | |
39 | | }; |
40 | | char StripGCRelocates::ID = 0; |
41 | | } |
42 | | |
43 | 5 | bool StripGCRelocates::runOnFunction(Function &F) { |
44 | 5 | // Nothing to do for declarations. |
45 | 5 | if (F.isDeclaration()) |
46 | 0 | return false; |
47 | 5 | SmallVector<GCRelocateInst *, 20> GCRelocates; |
48 | 5 | // TODO: We currently do not handle gc.relocates that are in landing pads, |
49 | 5 | // i.e. not bound to a single statepoint token. |
50 | 44 | for (Instruction &I : instructions(F)) { |
51 | 44 | if (auto *GCR = dyn_cast<GCRelocateInst>(&I)) |
52 | 9 | if (9 isStatepoint(GCR->getOperand(0))9 ) |
53 | 8 | GCRelocates.push_back(GCR); |
54 | 44 | } |
55 | 5 | // All gc.relocates are bound to a single statepoint token. The order of |
56 | 5 | // visiting gc.relocates for deletion does not matter. |
57 | 8 | for (GCRelocateInst *GCRel : GCRelocates) { |
58 | 8 | Value *OrigPtr = GCRel->getDerivedPtr(); |
59 | 8 | Value *ReplaceGCRel = OrigPtr; |
60 | 8 | |
61 | 8 | // All gc_relocates are i8 addrspace(1)* typed, we need a bitcast from i8 |
62 | 8 | // addrspace(1)* to the type of the OrigPtr, if the are not the same. |
63 | 8 | if (GCRel->getType() != OrigPtr->getType()) |
64 | 8 | ReplaceGCRel = new BitCastInst(OrigPtr, GCRel->getType(), "cast", GCRel); |
65 | 8 | |
66 | 8 | // Replace all uses of gc.relocate and delete the gc.relocate |
67 | 8 | // There maybe unncessary bitcasts back to the OrigPtr type, an instcombine |
68 | 8 | // pass would clear this up. |
69 | 8 | GCRel->replaceAllUsesWith(ReplaceGCRel); |
70 | 8 | GCRel->eraseFromParent(); |
71 | 8 | } |
72 | 5 | return !GCRelocates.empty(); |
73 | 5 | } |
74 | | |
75 | | INITIALIZE_PASS(StripGCRelocates, "strip-gc-relocates", |
76 | | "Strip gc.relocates inserted through RewriteStatepointsForGC", |
77 | | true, false) |
78 | 0 | FunctionPass *llvm::createStripGCRelocatesPass() { |
79 | 0 | return new StripGCRelocates(); |
80 | 0 | } |