Bug Summary

File:lib/MC/WinCOFFStreamer.cpp
Location:line 259, column 1
Description:Potential leak of memory pointed to by 'Fragment'

Annotated Source Code

1//===-- llvm/MC/WinCOFFStreamer.cpp -----------------------------*- C++ -*-===//
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 file contains an implementation of a Windows COFF object file streamer.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/MC/MCAsmBackend.h"
15#include "llvm/MC/MCAsmLayout.h"
16#include "llvm/MC/MCAssembler.h"
17#include "llvm/MC/MCCodeEmitter.h"
18#include "llvm/MC/MCContext.h"
19#include "llvm/MC/MCExpr.h"
20#include "llvm/MC/MCObjectFileInfo.h"
21#include "llvm/MC/MCObjectStreamer.h"
22#include "llvm/MC/MCSection.h"
23#include "llvm/MC/MCSectionCOFF.h"
24#include "llvm/MC/MCStreamer.h"
25#include "llvm/MC/MCSymbolCOFF.h"
26#include "llvm/MC/MCValue.h"
27#include "llvm/MC/MCWinCOFFStreamer.h"
28#include "llvm/Support/COFF.h"
29#include "llvm/Support/Debug.h"
30#include "llvm/Support/ErrorHandling.h"
31#include "llvm/Support/MathExtras.h"
32#include "llvm/Support/TargetRegistry.h"
33#include "llvm/Support/raw_ostream.h"
34
35using namespace llvm;
36
37#define DEBUG_TYPE"WinCOFFStreamer" "WinCOFFStreamer"
38
39namespace llvm {
40MCWinCOFFStreamer::MCWinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
41 MCCodeEmitter &CE, raw_pwrite_stream &OS)
42 : MCObjectStreamer(Context, MAB, OS, &CE), CurSymbol(nullptr) {}
43
44void MCWinCOFFStreamer::EmitInstToData(const MCInst &Inst,
45 const MCSubtargetInfo &STI) {
46 MCDataFragment *DF = getOrCreateDataFragment();
47
48 SmallVector<MCFixup, 4> Fixups;
49 SmallString<256> Code;
50 raw_svector_ostream VecOS(Code);
51 getAssembler().getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
52
53 // Add the fixups and data.
54 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
55 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
56 DF->getFixups().push_back(Fixups[i]);
57 }
58
59 DF->getContents().append(Code.begin(), Code.end());
60}
61
62void MCWinCOFFStreamer::InitSections(bool NoExecStack) {
63 // FIXME: this is identical to the ELF one.
64 // This emulates the same behavior of GNU as. This makes it easier
65 // to compare the output as the major sections are in the same order.
66 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
67 EmitCodeAlignment(4);
68
69 SwitchSection(getContext().getObjectFileInfo()->getDataSection());
70 EmitCodeAlignment(4);
71
72 SwitchSection(getContext().getObjectFileInfo()->getBSSSection());
73 EmitCodeAlignment(4);
74
75 SwitchSection(getContext().getObjectFileInfo()->getTextSection());
76}
77
78void MCWinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
79 assert(Symbol->isUndefined() && "Cannot define a symbol twice!")((Symbol->isUndefined() && "Cannot define a symbol twice!"
) ? static_cast<void> (0) : __assert_fail ("Symbol->isUndefined() && \"Cannot define a symbol twice!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 79, __PRETTY_FUNCTION__));
80 MCObjectStreamer::EmitLabel(Symbol);
81}
82
83void MCWinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
84 llvm_unreachable("not implemented")::llvm::llvm_unreachable_internal("not implemented", "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 84);
85}
86
87void MCWinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
88 llvm_unreachable("not implemented")::llvm::llvm_unreachable_internal("not implemented", "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 88);
89}
90
91bool MCWinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
92 MCSymbolAttr Attribute) {
93 assert(Symbol && "Symbol must be non-null!")((Symbol && "Symbol must be non-null!") ? static_cast
<void> (0) : __assert_fail ("Symbol && \"Symbol must be non-null!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 93, __PRETTY_FUNCTION__));
94 assert((!Symbol->isInSection() ||(((!Symbol->isInSection() || Symbol->getSection().getVariant
() == MCSection::SV_COFF) && "Got non-COFF section in the COFF backend!"
) ? static_cast<void> (0) : __assert_fail ("(!Symbol->isInSection() || Symbol->getSection().getVariant() == MCSection::SV_COFF) && \"Got non-COFF section in the COFF backend!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 96, __PRETTY_FUNCTION__))
95 Symbol->getSection().getVariant() == MCSection::SV_COFF) &&(((!Symbol->isInSection() || Symbol->getSection().getVariant
() == MCSection::SV_COFF) && "Got non-COFF section in the COFF backend!"
) ? static_cast<void> (0) : __assert_fail ("(!Symbol->isInSection() || Symbol->getSection().getVariant() == MCSection::SV_COFF) && \"Got non-COFF section in the COFF backend!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 96, __PRETTY_FUNCTION__))
96 "Got non-COFF section in the COFF backend!")(((!Symbol->isInSection() || Symbol->getSection().getVariant
() == MCSection::SV_COFF) && "Got non-COFF section in the COFF backend!"
) ? static_cast<void> (0) : __assert_fail ("(!Symbol->isInSection() || Symbol->getSection().getVariant() == MCSection::SV_COFF) && \"Got non-COFF section in the COFF backend!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 96, __PRETTY_FUNCTION__));
97
98 getAssembler().registerSymbol(*Symbol);
99
100 switch (Attribute) {
101 default: return false;
102 case MCSA_WeakReference:
103 case MCSA_Weak:
104 cast<MCSymbolCOFF>(Symbol)->setIsWeakExternal();
105 Symbol->setExternal(true);
106 break;
107 case MCSA_Global:
108 Symbol->setExternal(true);
109 break;
110 }
111
112 return true;
113}
114
115void MCWinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
116 llvm_unreachable("not implemented")::llvm::llvm_unreachable_internal("not implemented", "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 116);
117}
118
119void MCWinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
120 assert((!Symbol->isInSection() ||(((!Symbol->isInSection() || Symbol->getSection().getVariant
() == MCSection::SV_COFF) && "Got non-COFF section in the COFF backend!"
) ? static_cast<void> (0) : __assert_fail ("(!Symbol->isInSection() || Symbol->getSection().getVariant() == MCSection::SV_COFF) && \"Got non-COFF section in the COFF backend!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 122, __PRETTY_FUNCTION__))
121 Symbol->getSection().getVariant() == MCSection::SV_COFF) &&(((!Symbol->isInSection() || Symbol->getSection().getVariant
() == MCSection::SV_COFF) && "Got non-COFF section in the COFF backend!"
) ? static_cast<void> (0) : __assert_fail ("(!Symbol->isInSection() || Symbol->getSection().getVariant() == MCSection::SV_COFF) && \"Got non-COFF section in the COFF backend!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 122, __PRETTY_FUNCTION__))
122 "Got non-COFF section in the COFF backend!")(((!Symbol->isInSection() || Symbol->getSection().getVariant
() == MCSection::SV_COFF) && "Got non-COFF section in the COFF backend!"
) ? static_cast<void> (0) : __assert_fail ("(!Symbol->isInSection() || Symbol->getSection().getVariant() == MCSection::SV_COFF) && \"Got non-COFF section in the COFF backend!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 122, __PRETTY_FUNCTION__));
123
124 if (CurSymbol)
125 FatalError("starting a new symbol definition without completing the "
126 "previous one");
127 CurSymbol = Symbol;
128}
129
130void MCWinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
131 if (!CurSymbol)
132 FatalError("storage class specified outside of symbol definition");
133
134 if (StorageClass & ~COFF::SSC_Invalid)
135 FatalError("storage class value '" + Twine(StorageClass) +
136 "' out of range");
137
138 getAssembler().registerSymbol(*CurSymbol);
139 cast<MCSymbolCOFF>(CurSymbol)->setClass((uint16_t)StorageClass);
140}
141
142void MCWinCOFFStreamer::EmitCOFFSymbolType(int Type) {
143 if (!CurSymbol)
144 FatalError("symbol type specified outside of a symbol definition");
145
146 if (Type & ~0xffff)
147 FatalError("type value '" + Twine(Type) + "' out of range");
148
149 getAssembler().registerSymbol(*CurSymbol);
150 cast<MCSymbolCOFF>(CurSymbol)->setType((uint16_t)Type);
151}
152
153void MCWinCOFFStreamer::EndCOFFSymbolDef() {
154 if (!CurSymbol)
155 FatalError("ending symbol definition without starting one");
156 CurSymbol = nullptr;
157}
158
159void MCWinCOFFStreamer::EmitCOFFSafeSEH(MCSymbol const *Symbol) {
160 // SafeSEH is a feature specific to 32-bit x86. It does not exist (and is
161 // unnecessary) on all platforms which use table-based exception dispatch.
162 if (getContext().getObjectFileInfo()->getTargetTriple().getArch() !=
163 Triple::x86)
164 return;
165
166 const MCSymbolCOFF *CSymbol = cast<MCSymbolCOFF>(Symbol);
167 if (CSymbol->isSafeSEH())
168 return;
169
170 MCSection *SXData = getContext().getObjectFileInfo()->getSXDataSection();
171 getAssembler().registerSection(*SXData);
172 if (SXData->getAlignment() < 4)
173 SXData->setAlignment(4);
174
175 new MCSafeSEHFragment(Symbol, SXData);
176
177 getAssembler().registerSymbol(*Symbol);
178 CSymbol->setIsSafeSEH();
179
180 // The Microsoft linker requires that the symbol type of a handler be
181 // function. Go ahead and oblige it here.
182 CSymbol->setType(COFF::IMAGE_SYM_DTYPE_FUNCTION
183 << COFF::SCT_COMPLEX_TYPE_SHIFT);
184}
185
186void MCWinCOFFStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
187 MCDataFragment *DF = getOrCreateDataFragment();
188 const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
189 MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, FK_SecRel_2);
190 DF->getFixups().push_back(Fixup);
191 DF->getContents().resize(DF->getContents().size() + 2, 0);
192}
193
194void MCWinCOFFStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
195 MCDataFragment *DF = getOrCreateDataFragment();
196 const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
197 MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, FK_SecRel_4);
198 DF->getFixups().push_back(Fixup);
199 DF->getContents().resize(DF->getContents().size() + 4, 0);
200}
201
202void MCWinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
203 unsigned ByteAlignment) {
204 assert((!Symbol->isInSection() ||(((!Symbol->isInSection() || Symbol->getSection().getVariant
() == MCSection::SV_COFF) && "Got non-COFF section in the COFF backend!"
) ? static_cast<void> (0) : __assert_fail ("(!Symbol->isInSection() || Symbol->getSection().getVariant() == MCSection::SV_COFF) && \"Got non-COFF section in the COFF backend!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 206, __PRETTY_FUNCTION__))
205 Symbol->getSection().getVariant() == MCSection::SV_COFF) &&(((!Symbol->isInSection() || Symbol->getSection().getVariant
() == MCSection::SV_COFF) && "Got non-COFF section in the COFF backend!"
) ? static_cast<void> (0) : __assert_fail ("(!Symbol->isInSection() || Symbol->getSection().getVariant() == MCSection::SV_COFF) && \"Got non-COFF section in the COFF backend!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 206, __PRETTY_FUNCTION__))
206 "Got non-COFF section in the COFF backend!")(((!Symbol->isInSection() || Symbol->getSection().getVariant
() == MCSection::SV_COFF) && "Got non-COFF section in the COFF backend!"
) ? static_cast<void> (0) : __assert_fail ("(!Symbol->isInSection() || Symbol->getSection().getVariant() == MCSection::SV_COFF) && \"Got non-COFF section in the COFF backend!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 206, __PRETTY_FUNCTION__));
207
208 const Triple &T = getContext().getObjectFileInfo()->getTargetTriple();
209 if (T.isKnownWindowsMSVCEnvironment()) {
210 if (ByteAlignment > 32)
211 report_fatal_error("alignment is limited to 32-bytes");
212
213 // Round size up to alignment so that we will honor the alignment request.
214 Size = std::max(Size, static_cast<uint64_t>(ByteAlignment));
215 }
216
217 AssignSection(Symbol, nullptr);
218
219 getAssembler().registerSymbol(*Symbol);
220 Symbol->setExternal(true);
221 Symbol->setCommon(Size, ByteAlignment);
222
223 if (!T.isKnownWindowsMSVCEnvironment() && ByteAlignment > 1) {
224 SmallString<128> Directive;
225 raw_svector_ostream OS(Directive);
226 const MCObjectFileInfo *MFI = getContext().getObjectFileInfo();
227
228 OS << " -aligncomm:\"" << Symbol->getName() << "\","
229 << Log2_32_Ceil(ByteAlignment);
230
231 PushSection();
232 SwitchSection(MFI->getDrectveSection());
233 EmitBytes(Directive);
234 PopSection();
235 }
236}
237
238void MCWinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
239 unsigned ByteAlignment) {
240 assert(!Symbol->isInSection() && "Symbol must not already have a section!")((!Symbol->isInSection() && "Symbol must not already have a section!"
) ? static_cast<void> (0) : __assert_fail ("!Symbol->isInSection() && \"Symbol must not already have a section!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 240, __PRETTY_FUNCTION__));
241
242 MCSection *Section = getContext().getObjectFileInfo()->getBSSSection();
243 getAssembler().registerSection(*Section);
244 if (Section->getAlignment() < ByteAlignment)
1
Taking false branch
→
245 Section->setAlignment(ByteAlignment);
246
247 getAssembler().registerSymbol(*Symbol);
248 Symbol->setExternal(false);
249
250 AssignSection(Symbol, Section);
251
252 if (ByteAlignment != 1)
2
←
Assuming 'ByteAlignment' is equal to 1
→
3
←
Taking false branch
→
253 new MCAlignFragment(ByteAlignment, /*Value=*/0, /*ValueSize=*/0,
254 ByteAlignment, Section);
255
256 MCFillFragment *Fragment = new MCFillFragment(
4
←
Memory is allocated
→
257 /*Value=*/0, /*ValueSize=*/0, Size, Section);
258 Symbol->setFragment(Fragment);
259}
5
←
Potential leak of memory pointed to by 'Fragment'
260
261void MCWinCOFFStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
262 uint64_t Size, unsigned ByteAlignment) {
263 llvm_unreachable("not implemented")::llvm::llvm_unreachable_internal("not implemented", "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 263);
264}
265
266void MCWinCOFFStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
267 uint64_t Size, unsigned ByteAlignment) {
268 llvm_unreachable("not implemented")::llvm::llvm_unreachable_internal("not implemented", "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 268);
269}
270
271void MCWinCOFFStreamer::EmitFileDirective(StringRef Filename) {
272 getAssembler().addFileName(Filename);
273}
274
275// TODO: Implement this if you want to emit .comment section in COFF obj files.
276void MCWinCOFFStreamer::EmitIdent(StringRef IdentString) {
277 llvm_unreachable("not implemented")::llvm::llvm_unreachable_internal("not implemented", "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 277);
278}
279
280void MCWinCOFFStreamer::EmitWinEHHandlerData() {
281 llvm_unreachable("not implemented")::llvm::llvm_unreachable_internal("not implemented", "/tmp/buildd/llvm-toolchain-snapshot-3.8~svn246424/lib/MC/WinCOFFStreamer.cpp"
, 281);
282}
283
284void MCWinCOFFStreamer::FinishImpl() {
285 MCObjectStreamer::FinishImpl();
286}
287
288LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
289void MCWinCOFFStreamer::FatalError(const Twine &Msg) const {
290 getContext().reportFatalError(SMLoc(), Msg);
291}
292}
293