File: canthrow.d

package info (click to toggle)
ldc 1:1.12.0-1
  • links: PTS, VCS
  • area: main
  • in suites: buster, sid
  • size: 80,880 kB
  • sloc: ansic: 123,899; cpp: 84,038; sh: 1,402; makefile: 1,083; asm: 919; objc: 65; exp: 30; python: 22
file content (312 lines) | stat: -rw-r--r-- 9,826 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
/**
 * Compiler implementation of the
 * $(LINK2 http://www.dlang.org, D programming language).
 *
 * Copyright:   Copyright (C) 1999-2018 by The D Language Foundation, All Rights Reserved
 * Authors:     $(LINK2 http://www.digitalmars.com, Walter Bright)
 * License:     $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
 * Source:      $(LINK2 https://github.com/dlang/dmd/blob/master/src/dmd/canthrow.d, _canthrow.d)
 * Documentation:  https://dlang.org/phobos/dmd_canthrow.html
 * Coverage:    https://codecov.io/gh/dlang/dmd/src/master/src/dmd/canthrow.d
 */

module dmd.canthrow;

import dmd.aggregate;
import dmd.apply;
import dmd.arraytypes;
import dmd.attrib;
import dmd.declaration;
import dmd.dstruct;
import dmd.dsymbol;
import dmd.dtemplate;
import dmd.expression;
import dmd.func;
import dmd.globals;
import dmd.init;
import dmd.mtype;
import dmd.root.rootobject;
import dmd.tokens;
import dmd.visitor;

/********************************************
 * Returns true if the expression may throw exceptions.
 * If 'mustNotThrow' is true, generate an error if it throws
 */
extern (C++) bool canThrow(Expression e, FuncDeclaration func, bool mustNotThrow)
{
    //printf("Expression::canThrow(%d) %s\n", mustNotThrow, toChars());
    // stop walking if we determine this expression can throw
    extern (C++) final class CanThrow : StoppableVisitor
    {
        alias visit = typeof(super).visit;
        FuncDeclaration func;
        bool mustNotThrow;

    public:
        extern (D) this(FuncDeclaration func, bool mustNotThrow)
        {
            this.func = func;
            this.mustNotThrow = mustNotThrow;
        }

        override void visit(Expression)
        {
        }

        override void visit(DeclarationExp de)
        {
            stop = Dsymbol_canThrow(de.declaration, func, mustNotThrow);
        }

        override void visit(CallExp ce)
        {
            if (global.errors && !ce.e1.type)
                return; // error recovery
            /* If calling a function or delegate that is typed as nothrow,
             * then this expression cannot throw.
             * Note that pure functions can throw.
             */
            Type t = ce.e1.type.toBasetype();
            if (ce.f && ce.f == func)
                return;
            if (t.ty == Tfunction && (cast(TypeFunction)t).isnothrow)
                return;
            if (t.ty == Tdelegate && (cast(TypeFunction)(cast(TypeDelegate)t).next).isnothrow)
                return;

            if (mustNotThrow)
            {
                if (ce.f)
                {
                    ce.error("%s `%s` is not `nothrow`",
                        ce.f.kind(), ce.f.toPrettyChars());
                }
                else
                {
                    auto e1 = ce.e1;
                    if (e1.op == TOK.star)   // print 'fp' if e1 is (*fp)
                        e1 = (cast(PtrExp)e1).e1;
                    ce.error("`%s` is not `nothrow`", e1.toChars());
                }
            }
            stop = true;
        }

        override void visit(NewExp ne)
        {
            if (ne.member)
            {
                if (ne.allocator)
                {
                    // https://issues.dlang.org/show_bug.cgi?id=14407
                    Type t = ne.allocator.type.toBasetype();
                    if (t.ty == Tfunction && !(cast(TypeFunction)t).isnothrow)
                    {
                        if (mustNotThrow)
                        {
                            ne.error("%s `%s` is not `nothrow`",
                                ne.allocator.kind(), ne.allocator.toPrettyChars());
                        }
                        stop = true;
                    }
                }
                // See if constructor call can throw
                Type t = ne.member.type.toBasetype();
                if (t.ty == Tfunction && !(cast(TypeFunction)t).isnothrow)
                {
                    if (mustNotThrow)
                    {
                        ne.error("%s `%s` is not `nothrow`",
                            ne.member.kind(), ne.member.toPrettyChars());
                    }
                    stop = true;
                }
            }
            // regard storage allocation failures as not recoverable
        }

        override void visit(DeleteExp de)
        {
            Type tb = de.e1.type.toBasetype();
            AggregateDeclaration ad = null;
            switch (tb.ty)
            {
            case Tclass:
                ad = (cast(TypeClass)tb).sym;
                break;

            case Tpointer:
                tb = (cast(TypePointer)tb).next.toBasetype();
                if (tb.ty == Tstruct)
                    ad = (cast(TypeStruct)tb).sym;
                break;

            case Tarray:
                Type tv = tb.nextOf().baseElemOf();
                if (tv.ty == Tstruct)
                    ad = (cast(TypeStruct)tv).sym;
                break;

            default:
                break;
            }
            if (!ad)
                return;

            if (ad.dtor)
            {
                Type t = ad.dtor.type.toBasetype();
                if (t.ty == Tfunction && !(cast(TypeFunction)t).isnothrow)
                {
                    if (mustNotThrow)
                    {
                        de.error("%s `%s` is not `nothrow`",
                            ad.dtor.kind(), ad.dtor.toPrettyChars());
                    }
                    stop = true;
                }
            }
            if (ad.aggDelete && tb.ty != Tarray)
            {
                Type t = ad.aggDelete.type;
                if (t.ty == Tfunction && !(cast(TypeFunction)t).isnothrow)
                {
                    if (mustNotThrow)
                    {
                        de.error("%s `%s` is not `nothrow`",
                            ad.aggDelete.kind(), ad.aggDelete.toPrettyChars());
                    }
                    stop = true;
                }
            }
        }

        override void visit(AssignExp ae)
        {
            // blit-init cannot throw
            if (ae.op == TOK.blit)
                return;
            /* Element-wise assignment could invoke postblits.
             */
            Type t;
            if (ae.type.toBasetype().ty == Tsarray)
            {
                if (!ae.e2.isLvalue())
                    return;
                t = ae.type;
            }
            else if (ae.e1.op == TOK.slice)
                t = (cast(SliceExp)ae.e1).e1.type;
            else
                return;
            Type tv = t.baseElemOf();
            if (tv.ty != Tstruct)
                return;
            StructDeclaration sd = (cast(TypeStruct)tv).sym;
            if (!sd.postblit || sd.postblit.type.ty != Tfunction)
                return;
            if ((cast(TypeFunction)sd.postblit.type).isnothrow)
            {
            }
            else
            {
                if (mustNotThrow)
                {
                    ae.error("%s `%s` is not `nothrow`",
                        sd.postblit.kind(), sd.postblit.toPrettyChars());
                }
                stop = true;
            }
        }

        override void visit(NewAnonClassExp)
        {
            assert(0); // should have been lowered by semantic()
        }
    }

    scope CanThrow ct = new CanThrow(func, mustNotThrow);
    return walkPostorder(e, ct);
}

/**************************************
 * Does symbol, when initialized, throw?
 * Mirrors logic in Dsymbol_toElem().
 */
private bool Dsymbol_canThrow(Dsymbol s, FuncDeclaration func, bool mustNotThrow)
{
    AttribDeclaration ad;
    VarDeclaration vd;
    TemplateMixin tm;
    TupleDeclaration td;
    //printf("Dsymbol_toElem() %s\n", s.toChars());
    ad = s.isAttribDeclaration();
    if (ad)
    {
        Dsymbols* decl = ad.include(null);
        if (decl && decl.dim)
        {
            for (size_t i = 0; i < decl.dim; i++)
            {
                s = (*decl)[i];
                if (Dsymbol_canThrow(s, func, mustNotThrow))
                    return true;
            }
        }
    }
    else if ((vd = s.isVarDeclaration()) !is null)
    {
        s = s.toAlias();
        if (s != vd)
            return Dsymbol_canThrow(s, func, mustNotThrow);
        if (vd.storage_class & STC.manifest)
        {
        }
        else if (vd.isStatic() || vd.storage_class & (STC.extern_ | STC.tls | STC.gshared))
        {
        }
        else
        {
            if (vd._init)
            {
                ExpInitializer ie = vd._init.isExpInitializer();
                if (ie && canThrow(ie.exp, func, mustNotThrow))
                    return true;
            }
            if (vd.needsScopeDtor())
                return canThrow(vd.edtor, func, mustNotThrow);
        }
    }
    else if ((tm = s.isTemplateMixin()) !is null)
    {
        //printf("%s\n", tm.toChars());
        if (tm.members)
        {
            for (size_t i = 0; i < tm.members.dim; i++)
            {
                Dsymbol sm = (*tm.members)[i];
                if (Dsymbol_canThrow(sm, func, mustNotThrow))
                    return true;
            }
        }
    }
    else if ((td = s.isTupleDeclaration()) !is null)
    {
        for (size_t i = 0; i < td.objects.dim; i++)
        {
            RootObject o = (*td.objects)[i];
            if (o.dyncast() == DYNCAST.expression)
            {
                Expression eo = cast(Expression)o;
                if (eo.op == TOK.dSymbol)
                {
                    DsymbolExp se = cast(DsymbolExp)eo;
                    if (Dsymbol_canThrow(se.s, func, mustNotThrow))
                        return true;
                }
            }
        }
    }
    return false;
}