Bug Summary

File:tools/clang/lib/CodeGen/CGCoroutine.cpp
Warning:line 46, column 21
Called C++ object pointer is null

Annotated Source Code

1//===----- CGCoroutine.cpp - Emit LLVM Code for C++ coroutines ------------===//
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 contains code dealing with C++ code generation of coroutines.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
15#include "clang/AST/StmtCXX.h"
16
17using namespace clang;
18using namespace CodeGen;
19
20namespace clang {
21namespace CodeGen {
22
23struct CGCoroData {
24 // Stores the llvm.coro.id emitted in the function so that we can supply it
25 // as the first argument to coro.begin, coro.alloc and coro.free intrinsics.
26 // Note: llvm.coro.id returns a token that cannot be directly expressed in a
27 // builtin.
28 llvm::CallInst *CoroId = nullptr;
29 // If coro.id came from the builtin, remember the expression to give better
30 // diagnostic. If CoroIdExpr is nullptr, the coro.id was created by
31 // EmitCoroutineBody.
32 CallExpr const *CoroIdExpr = nullptr;
33};
34}
35}
36
37clang::CodeGen::CodeGenFunction::CGCoroInfo::CGCoroInfo() {}
38CodeGenFunction::CGCoroInfo::~CGCoroInfo() {}
39
40static void createCoroData(CodeGenFunction &CGF,
41 CodeGenFunction::CGCoroInfo &CurCoro,
42 llvm::CallInst *CoroId,
43 CallExpr const *CoroIdExpr = nullptr) {
44 if (CurCoro.Data) {
3
Taking true branch
45 if (CurCoro.Data->CoroIdExpr)
4
Assuming the condition is true
5
Taking true branch
46 CGF.CGM.Error(CoroIdExpr->getLocStart(),
6
Called C++ object pointer is null
47 "only one __builtin_coro_id can be used in a function");
48 else if (CoroIdExpr)
49 CGF.CGM.Error(CoroIdExpr->getLocStart(),
50 "__builtin_coro_id shall not be used in a C++ coroutine");
51 else
52 llvm_unreachable("EmitCoroutineBodyStatement called twice?")::llvm::llvm_unreachable_internal("EmitCoroutineBodyStatement called twice?"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn292767/tools/clang/lib/CodeGen/CGCoroutine.cpp"
, 52)
;
53
54 return;
55 }
56
57 CurCoro.Data = std::unique_ptr<CGCoroData>(new CGCoroData);
58 CurCoro.Data->CoroId = CoroId;
59 CurCoro.Data->CoroIdExpr = CoroIdExpr;
60}
61
62void CodeGenFunction::EmitCoroutineBody(const CoroutineBodyStmt &S) {
63 auto *NullPtr = llvm::ConstantPointerNull::get(Builder.getInt8PtrTy());
64 auto &TI = CGM.getContext().getTargetInfo();
65 unsigned NewAlign = TI.getNewAlign() / TI.getCharWidth();
66
67 auto *CoroId = Builder.CreateCall(
68 CGM.getIntrinsic(llvm::Intrinsic::coro_id),
69 {Builder.getInt32(NewAlign), NullPtr, NullPtr, NullPtr});
70 createCoroData(*this, CurCoro, CoroId);
1
Passing null pointer value via 4th parameter 'CoroIdExpr'
2
Calling 'createCoroData'
71
72 EmitScalarExpr(S.getAllocate());
73 // FIXME: Emit the rest of the coroutine.
74 EmitStmt(S.getDeallocate());
75}
76
77// Emit coroutine intrinsic and patch up arguments of the token type.
78RValue CodeGenFunction::EmitCoroutineIntrinsic(const CallExpr *E,
79 unsigned int IID) {
80 SmallVector<llvm::Value *, 8> Args;
81 switch (IID) {
82 default:
83 break;
84 // The following three intrinsics take a token parameter referring to a token
85 // returned by earlier call to @llvm.coro.id. Since we cannot represent it in
86 // builtins, we patch it up here.
87 case llvm::Intrinsic::coro_alloc:
88 case llvm::Intrinsic::coro_begin:
89 case llvm::Intrinsic::coro_free: {
90 if (CurCoro.Data && CurCoro.Data->CoroId) {
91 Args.push_back(CurCoro.Data->CoroId);
92 break;
93 }
94 CGM.Error(E->getLocStart(), "this builtin expect that __builtin_coro_id has"
95 " been used earlier in this function");
96 // Fallthrough to the next case to add TokenNone as the first argument.
97 }
98 // @llvm.coro.suspend takes a token parameter. Add token 'none' as the first
99 // argument.
100 case llvm::Intrinsic::coro_suspend:
101 Args.push_back(llvm::ConstantTokenNone::get(getLLVMContext()));
102 break;
103 }
104 for (auto &Arg : E->arguments())
105 Args.push_back(EmitScalarExpr(Arg));
106
107 llvm::Value *F = CGM.getIntrinsic(IID);
108 llvm::CallInst *Call = Builder.CreateCall(F, Args);
109
110 // If we see @llvm.coro.id remember it in the CoroData. We will update
111 // coro.alloc, coro.begin and coro.free intrinsics to refer to it.
112 if (IID == llvm::Intrinsic::coro_id) {
113 createCoroData(*this, CurCoro, Call, E);
114 }
115 return RValue::get(Call);
116}