Bug Summary

File:lib/Target/NVPTX/NVPTXLowerAlloca.cpp
Warning:line 74, column 20
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name NVPTXLowerAlloca.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -mframe-pointer=none -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-10/lib/clang/10.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-10~svn374814/build-llvm/lib/Target/NVPTX -I /build/llvm-toolchain-snapshot-10~svn374814/lib/Target/NVPTX -I /build/llvm-toolchain-snapshot-10~svn374814/build-llvm/include -I /build/llvm-toolchain-snapshot-10~svn374814/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-10/lib/clang/10.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-10~svn374814/build-llvm/lib/Target/NVPTX -fdebug-prefix-map=/build/llvm-toolchain-snapshot-10~svn374814=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2019-10-15-035155-28452-1 -x c++ /build/llvm-toolchain-snapshot-10~svn374814/lib/Target/NVPTX/NVPTXLowerAlloca.cpp
1//===-- NVPTXLowerAlloca.cpp - Make alloca to use local memory =====--===//
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// For all alloca instructions, and add a pair of cast to local address for
10// each of them. For example,
11//
12// %A = alloca i32
13// store i32 0, i32* %A ; emits st.u32
14//
15// will be transformed to
16//
17// %A = alloca i32
18// %Local = addrspacecast i32* %A to i32 addrspace(5)*
19// %Generic = addrspacecast i32 addrspace(5)* %A to i32*
20// store i32 0, i32 addrspace(5)* %Generic ; emits st.local.u32
21//
22// And we will rely on NVPTXInferAddressSpaces to combine the last two
23// instructions.
24//
25//===----------------------------------------------------------------------===//
26
27#include "NVPTX.h"
28#include "NVPTXUtilities.h"
29#include "MCTargetDesc/NVPTXBaseInfo.h"
30#include "llvm/IR/Function.h"
31#include "llvm/IR/Instructions.h"
32#include "llvm/IR/IntrinsicInst.h"
33#include "llvm/IR/Module.h"
34#include "llvm/IR/Type.h"
35#include "llvm/Pass.h"
36
37using namespace llvm;
38
39namespace llvm {
40void initializeNVPTXLowerAllocaPass(PassRegistry &);
41}
42
43namespace {
44class NVPTXLowerAlloca : public FunctionPass {
45 bool runOnFunction(Function &F) override;
46
47public:
48 static char ID; // Pass identification, replacement for typeid
49 NVPTXLowerAlloca() : FunctionPass(ID) {}
50 StringRef getPassName() const override {
51 return "convert address space of alloca'ed memory to local";
52 }
53};
54} // namespace
55
56char NVPTXLowerAlloca::ID = 1;
57
58INITIALIZE_PASS(NVPTXLowerAlloca, "nvptx-lower-alloca",static void *initializeNVPTXLowerAllocaPassOnce(PassRegistry &
Registry) { PassInfo *PI = new PassInfo( "Lower Alloca", "nvptx-lower-alloca"
, &NVPTXLowerAlloca::ID, PassInfo::NormalCtor_t(callDefaultCtor
<NVPTXLowerAlloca>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeNVPTXLowerAllocaPassFlag
; void llvm::initializeNVPTXLowerAllocaPass(PassRegistry &
Registry) { llvm::call_once(InitializeNVPTXLowerAllocaPassFlag
, initializeNVPTXLowerAllocaPassOnce, std::ref(Registry)); }
59 "Lower Alloca", false, false)static void *initializeNVPTXLowerAllocaPassOnce(PassRegistry &
Registry) { PassInfo *PI = new PassInfo( "Lower Alloca", "nvptx-lower-alloca"
, &NVPTXLowerAlloca::ID, PassInfo::NormalCtor_t(callDefaultCtor
<NVPTXLowerAlloca>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeNVPTXLowerAllocaPassFlag
; void llvm::initializeNVPTXLowerAllocaPass(PassRegistry &
Registry) { llvm::call_once(InitializeNVPTXLowerAllocaPassFlag
, initializeNVPTXLowerAllocaPassOnce, std::ref(Registry)); }
60
61// =============================================================================
62// Main function for this pass.
63// =============================================================================
64bool NVPTXLowerAlloca::runOnFunction(Function &F) {
65 if (skipFunction(F))
1
Assuming the condition is false
2
Taking false branch
66 return false;
67
68 bool Changed = false;
69 for (auto &BB : F)
70 for (auto &I : BB) {
71 if (auto allocaInst
3.1
'allocaInst' is non-null
= dyn_cast<AllocaInst>(&I)) {
3
Assuming the object is a 'AllocaInst'
4
Taking true branch
72 Changed = true;
73 auto PTy = dyn_cast<PointerType>(allocaInst->getType());
5
Assuming the object is not a 'PointerType'
6
'PTy' initialized to a null pointer value
74 auto ETy = PTy->getElementType();
7
Called C++ object pointer is null
75 auto LocalAddrTy = PointerType::get(ETy, ADDRESS_SPACE_LOCAL);
76 auto NewASCToLocal = new AddrSpaceCastInst(allocaInst, LocalAddrTy, "");
77 auto GenericAddrTy = PointerType::get(ETy, ADDRESS_SPACE_GENERIC);
78 auto NewASCToGeneric =
79 new AddrSpaceCastInst(NewASCToLocal, GenericAddrTy, "");
80 NewASCToLocal->insertAfter(allocaInst);
81 NewASCToGeneric->insertAfter(NewASCToLocal);
82 for (Value::use_iterator UI = allocaInst->use_begin(),
83 UE = allocaInst->use_end();
84 UI != UE;) {
85 // Check Load, Store, GEP, and BitCast Uses on alloca and make them
86 // use the converted generic address, in order to expose non-generic
87 // addrspacecast to NVPTXInferAddressSpaces. For other types
88 // of instructions this is unnecessary and may introduce redundant
89 // address cast.
90 const auto &AllocaUse = *UI++;
91 auto LI = dyn_cast<LoadInst>(AllocaUse.getUser());
92 if (LI && LI->getPointerOperand() == allocaInst &&
93 !LI->isVolatile()) {
94 LI->setOperand(LI->getPointerOperandIndex(), NewASCToGeneric);
95 continue;
96 }
97 auto SI = dyn_cast<StoreInst>(AllocaUse.getUser());
98 if (SI && SI->getPointerOperand() == allocaInst &&
99 !SI->isVolatile()) {
100 SI->setOperand(SI->getPointerOperandIndex(), NewASCToGeneric);
101 continue;
102 }
103 auto GI = dyn_cast<GetElementPtrInst>(AllocaUse.getUser());
104 if (GI && GI->getPointerOperand() == allocaInst) {
105 GI->setOperand(GI->getPointerOperandIndex(), NewASCToGeneric);
106 continue;
107 }
108 auto BI = dyn_cast<BitCastInst>(AllocaUse.getUser());
109 if (BI && BI->getOperand(0) == allocaInst) {
110 BI->setOperand(0, NewASCToGeneric);
111 continue;
112 }
113 }
114 }
115 }
116 return Changed;
117}
118
119FunctionPass *llvm::createNVPTXLowerAllocaPass() {
120 return new NVPTXLowerAlloca();
121}