3 // Copyright (c) 2010, Google Inc.
4 // All rights reserved.
6 // Redistribution and use in source and binary forms, with or without
7 // modification, are permitted provided that the following conditions are
10 // * Redistributions of source code must retain the above copyright
11 // notice, this list of conditions and the following disclaimer.
12 // * Redistributions in binary form must reproduce the above
13 // copyright notice, this list of conditions and the following disclaimer
14 // in the documentation and/or other materials provided with the
16 // * Neither the name of Google Inc. nor the names of its
17 // contributors may be used to endorse or promote products derived from
18 // this software without specific prior written permission.
20 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
35 // cfi_assembler.h: Define CFISection, a class for creating properly
36 // (and improperly) formatted DWARF CFI data for unit tests.
39 // test-assembler.h: interface to class for building complex binary streams.
41 // To test the Breakpad symbol dumper and processor thoroughly, for
42 // all combinations of host system and minidump processor
43 // architecture, we need to be able to easily generate complex test
44 // data like debugging information and minidump files.
46 // For example, if we want our unit tests to provide full code
47 // coverage for stack walking, it may be difficult to persuade the
48 // compiler to generate every possible sort of stack walking
49 // information that we want to support; there are probably DWARF CFI
50 // opcodes that GCC never emits. Similarly, if we want to test our
51 // error handling, we will need to generate damaged minidumps or
52 // debugging information that (we hope) the client or compiler will
53 // never produce on its own.
55 // google_breakpad::TestAssembler provides a predictable and
56 // (relatively) simple way to generate complex formatted data streams
57 // like minidumps and CFI. Furthermore, because TestAssembler is
58 // portable, developers without access to (say) Visual Studio or a
59 // SPARC assembler can still work on test data for those targets.
61 #ifndef LUL_TEST_INFRASTRUCTURE_H
62 #define LUL_TEST_INFRASTRUCTURE_H
64 #include "LulDwarfExt.h"
73 namespace test_assembler
{
75 // A Label represents a value not yet known that we need to store in a
76 // section. As long as all the labels a section refers to are defined
77 // by the time we retrieve its contents as bytes, we can use undefined
78 // labels freely in that section's construction.
80 // A label can be in one of three states:
82 // - defined as the sum of some other label and a constant, or
85 // A label's value never changes, but it can accumulate constraints.
86 // Adding labels and integers is permitted, and yields a label.
87 // Subtracting a constant from a label is permitted, and also yields a
88 // label. Subtracting two labels that have some relationship to each
89 // other is permitted, and yields a constant.
93 // Label a; // a's value is undefined
94 // Label b; // b's value is undefined
96 // Label c = a + 4; // okay, even though a's value is unknown
97 // b = c + 4; // also okay; b is now a+8
99 // Label d = b - 2; // okay; d == a+6, even though c is gone
100 // d.Value(); // error: d's value is not yet known
101 // d - a; // is 6, even though their values are not known
102 // a = 12; // now b == 20, and d == 18
103 // d.Value(); // 18: no longer an error
105 // d = 10; // error: d is already defined.
107 // Label objects' lifetimes are unconstrained: notice that, in the
108 // above example, even though a and b are only related through c, and
109 // c goes out of scope, the assignment to a sets b's value as well. In
110 // particular, it's not necessary to ensure that a Label lives beyond
111 // Sections that refer to it.
114 Label(); // An undefined label.
115 explicit Label(uint64_t value
); // A label with a fixed value
116 Label(const Label
& value
); // A label equal to another.
119 Label
& operator=(uint64_t value
);
120 Label
& operator=(const Label
& value
);
121 Label
operator+(uint64_t addend
) const;
122 Label
operator-(uint64_t subtrahend
) const;
123 uint64_t operator-(const Label
& subtrahend
) const;
125 // We could also provide == and != that work on undefined, but
128 // Return true if this label's value is known. If VALUE_P is given,
129 // set *VALUE_P to the known value if returning true.
130 bool IsKnownConstant(uint64_t* value_p
= NULL
) const;
132 // Return true if the offset from LABEL to this label is known. If
133 // OFFSET_P is given, set *OFFSET_P to the offset when returning true.
135 // You can think of l.KnownOffsetFrom(m, &d) as being like 'd = l-m',
136 // except that it also returns a value indicating whether the
137 // subtraction is possible given what we currently know of l and m.
138 // It can be possible even if we don't know l and m's values. For
143 // l.IsKnownConstant(); // false
144 // m.IsKnownConstant(); // false
146 // l.IsKnownOffsetFrom(m, &d); // true, and sets d to -10.
149 // m.Value() // error: m's value is not known
150 bool IsKnownOffsetFrom(const Label
& label
, uint64_t* offset_p
= NULL
) const;
153 // A label's value, or if that is not yet known, how the value is
154 // related to other labels' values. A binding may be:
155 // - a known constant,
156 // - constrained to be equal to some other binding plus a constant, or
157 // - unconstrained, and free to take on any value.
159 // Many labels may point to a single binding, and each binding may
160 // refer to another, so bindings and labels form trees whose leaves
161 // are labels, whose interior nodes (and roots) are bindings, and
162 // where links point from children to parents. Bindings are
163 // reference counted, allowing labels to be lightweight, copyable,
164 // assignable, placed in containers, and so on.
168 explicit Binding(uint64_t addend
);
171 // Increment our reference count.
172 void Acquire() { reference_count_
++; };
173 // Decrement our reference count, and return true if it is zero.
174 bool Release() { return --reference_count_
== 0; }
176 // Set this binding to be equal to BINDING + ADDEND. If BINDING is
177 // NULL, then set this binding to the known constant ADDEND.
178 // Update every binding on this binding's chain to point directly
179 // to BINDING, or to be a constant, with addends adjusted
181 void Set(Binding
* binding
, uint64_t value
);
183 // Return what we know about the value of this binding.
184 // - If this binding's value is a known constant, set BASE to
185 // NULL, and set ADDEND to its value.
186 // - If this binding is not a known constant but related to other
187 // bindings, set BASE to the binding at the end of the relation
188 // chain (which will always be unconstrained), and set ADDEND to the
189 // value to add to that binding's value to get this binding's
191 // - If this binding is unconstrained, set BASE to this, and leave
193 void Get(Binding
** base
, uint64_t* addend
);
196 // There are three cases:
198 // - A binding representing a known constant value has base_ NULL,
199 // and addend_ equal to the value.
201 // - A binding representing a completely unconstrained value has
202 // base_ pointing to this; addend_ is unused.
204 // - A binding whose value is related to some other binding's
205 // value has base_ pointing to that other binding, and addend_
206 // set to the amount to add to that binding's value to get this
207 // binding's value. We only represent relationships of the form
210 // Thus, the bind_ links form a chain terminating in either a
211 // known constant value or a completely unconstrained value. Most
212 // operations on bindings do path compression: they change every
213 // binding on the chain to point directly to the final value,
214 // adjusting addends as appropriate.
218 // The number of Labels and Bindings pointing to this binding.
219 // (When a binding points to itself, indicating a completely
220 // unconstrained binding, that doesn't count as a reference.)
221 int reference_count_
;
224 // This label's value.
228 // Conventions for representing larger numbers as sequences of bytes.
230 kBigEndian
, // Big-endian: the most significant byte comes first.
231 kLittleEndian
, // Little-endian: the least significant byte comes first.
232 kUnsetEndian
, // used internally
235 // A section is a sequence of bytes, constructed by appending bytes
236 // to the end. Sections have a convenient and flexible set of member
237 // functions for appending data in various formats: big-endian and
238 // little-endian signed and unsigned values of different sizes;
239 // LEB128 and ULEB128 values (see below), and raw blocks of bytes.
241 // If you need to append a value to a section that is not convenient
242 // to compute immediately, you can create a label, append the
243 // label's value to the section, and then set the label's value
244 // later, when it's convenient to do so. Once a label's value is
245 // known, the section class takes care of updating all previously
246 // appended references to it.
248 // Once all the labels to which a section refers have had their
249 // values determined, you can get a copy of the section's contents
252 // Note that there is no specified "start of section" label. This is
253 // because there are typically several different meanings for "the
254 // start of a section": the offset of the section within an object
255 // file, the address in memory at which the section's content appear,
256 // and so on. It's up to the code that uses the Section class to
257 // keep track of these explicitly, as they depend on the application.
260 explicit Section(Endianness endianness
= kUnsetEndian
)
261 : endianness_(endianness
) {};
263 // A base class destructor should be either public and virtual,
264 // or protected and nonvirtual.
265 virtual ~Section() = default;
267 // Return the default endianness of this section.
268 Endianness
endianness() const { return endianness_
; }
270 // Append the SIZE bytes at DATA to the end of this section. Return
271 // a reference to this section.
272 Section
& Append(const string
& data
) {
273 contents_
.append(data
);
277 // Append data from SLICE to the end of this section. Return
278 // a reference to this section.
279 Section
& Append(const lul::ImageSlice
& slice
) {
280 for (size_t i
= 0; i
< slice
.length_
; i
++) {
281 contents_
.append(1, slice
.start_
[i
]);
286 // Append data from CSTRING to the end of this section. The terminating
287 // zero is not included. Return a reference to this section.
288 Section
& Append(const char* cstring
) {
289 for (size_t i
= 0; cstring
[i
] != '\0'; i
++) {
290 contents_
.append(1, cstring
[i
]);
295 // Append SIZE copies of BYTE to the end of this section. Return a
296 // reference to this section.
297 Section
& Append(size_t size
, uint8_t byte
) {
298 contents_
.append(size
, (char)byte
);
302 // Append NUMBER to this section. ENDIANNESS is the endianness to
303 // use to write the number. SIZE is the length of the number in
304 // bytes. Return a reference to this section.
305 Section
& Append(Endianness endianness
, size_t size
, uint64_t number
);
306 Section
& Append(Endianness endianness
, size_t size
, const Label
& label
);
308 // Append SECTION to the end of this section. The labels SECTION
309 // refers to need not be defined yet.
311 // Note that this has no effect on any Labels' values, or on
312 // SECTION. If placing SECTION within 'this' provides new
313 // constraints on existing labels' values, then it's up to the
314 // caller to fiddle with those labels as needed.
315 Section
& Append(const Section
& section
);
317 // Append the contents of DATA as a series of bytes terminated by
319 Section
& AppendCString(const string
& data
) {
325 // Append VALUE or LABEL to this section, with the given bit width and
326 // endianness. Return a reference to this section.
328 // The names of these functions have the form <ENDIANNESS><BITWIDTH>:
329 // <ENDIANNESS> is either 'L' (little-endian, least significant byte first),
330 // 'B' (big-endian, most significant byte first), or
331 // 'D' (default, the section's default endianness)
332 // <BITWIDTH> is 8, 16, 32, or 64.
334 // Since endianness doesn't matter for a single byte, all the
335 // <BITWIDTH>=8 functions are equivalent.
337 // These can be used to write both signed and unsigned values, as
338 // the compiler will properly sign-extend a signed value before
339 // passing it to the function, at which point the function's
340 // behavior is the same either way.
341 Section
& L8(uint8_t value
) {
345 Section
& B8(uint8_t value
) {
349 Section
& D8(uint8_t value
) {
353 Section
&L16(uint16_t), &L32(uint32_t), &L64(uint64_t), &B16(uint16_t),
354 &B32(uint32_t), &B64(uint64_t), &D16(uint16_t), &D32(uint32_t),
356 Section
&L8(const Label
& label
), &L16(const Label
& label
),
357 &L32(const Label
& label
), &L64(const Label
& label
),
358 &B8(const Label
& label
), &B16(const Label
& label
),
359 &B32(const Label
& label
), &B64(const Label
& label
),
360 &D8(const Label
& label
), &D16(const Label
& label
),
361 &D32(const Label
& label
), &D64(const Label
& label
);
363 // Append VALUE in a signed LEB128 (Little-Endian Base 128) form.
365 // The signed LEB128 representation of an integer N is a variable
368 // - If N is between -0x40 and 0x3f, then its signed LEB128
369 // representation is a single byte whose value is N.
371 // - Otherwise, its signed LEB128 representation is (N & 0x7f) |
372 // 0x80, followed by the signed LEB128 representation of N / 128,
373 // rounded towards negative infinity.
375 // In other words, we break VALUE into groups of seven bits, put
376 // them in little-endian order, and then write them as eight-bit
377 // bytes with the high bit on all but the last.
379 // Note that VALUE cannot be a Label (we would have to implement
381 Section
& LEB128(long long value
);
383 // Append VALUE in unsigned LEB128 (Little-Endian Base 128) form.
385 // The unsigned LEB128 representation of an integer N is a variable
388 // - If N is between 0 and 0x7f, then its unsigned LEB128
389 // representation is a single byte whose value is N.
391 // - Otherwise, its unsigned LEB128 representation is (N & 0x7f) |
392 // 0x80, followed by the unsigned LEB128 representation of N /
393 // 128, rounded towards negative infinity.
395 // Note that VALUE cannot be a Label (we would have to implement
397 Section
& ULEB128(uint64_t value
);
399 // Jump to the next location aligned on an ALIGNMENT-byte boundary,
400 // relative to the start of the section. Fill the gap with PAD_BYTE.
401 // ALIGNMENT must be a power of two. Return a reference to this
403 Section
& Align(size_t alignment
, uint8_t pad_byte
= 0);
405 // Return the current size of the section.
406 size_t Size() const { return contents_
.size(); }
408 // Return a label representing the start of the section.
410 // It is up to the user whether this label represents the section's
411 // position in an object file, the section's address in memory, or
412 // what have you; some applications may need both, in which case
413 // this simple-minded interface won't be enough. This class only
414 // provides a single start label, for use with the Here and Mark
417 // Ideally, we'd provide this in a subclass that actually knows more
418 // about the application at hand and can provide an appropriate
419 // collection of start labels. But then the appending member
420 // functions like Append and D32 would return a reference to the
421 // base class, not the derived class, and the chaining won't work.
422 // Since the only value here is in pretty notation, that's a fatal
424 Label
start() const { return start_
; }
426 // Return a label representing the point at which the next Appended
427 // item will appear in the section, relative to start().
428 Label
Here() const { return start_
+ Size(); }
430 // Set *LABEL to Here, and return a reference to this section.
431 Section
& Mark(Label
* label
) {
436 // If there are no undefined label references left in this
437 // section, set CONTENTS to the contents of this section, as a
438 // string, and clear this section. Return true on success, or false
439 // if there were still undefined labels.
440 bool GetContents(string
* contents
);
443 // Used internally. A reference to a label's value.
445 Reference(size_t set_offset
, Endianness set_endianness
, size_t set_size
,
446 const Label
& set_label
)
447 : offset(set_offset
),
448 endianness(set_endianness
),
452 // The offset of the reference within the section.
455 // The endianness of the reference.
456 Endianness endianness
;
458 // The size of the reference.
461 // The label to which this is a reference.
465 // The default endianness of this section.
466 Endianness endianness_
;
468 // The contents of the section.
471 // References to labels within those contents.
472 vector
<Reference
> references_
;
474 // A label referring to the beginning of the section.
478 } // namespace test_assembler
479 } // namespace lul_test
483 using lul::DwarfPointerEncoding
;
484 using lul_test::test_assembler::Endianness
;
485 using lul_test::test_assembler::Label
;
486 using lul_test::test_assembler::Section
;
488 class CFISection
: public Section
{
490 // CFI augmentation strings beginning with 'z', defined by the
491 // Linux/IA-64 C++ ABI, can specify interesting encodings for
492 // addresses appearing in FDE headers and call frame instructions (and
493 // for additional fields whose presence the augmentation string
494 // specifies). In particular, pointers can be specified to be relative
495 // to various base address: the start of the .text section, the
496 // location holding the address itself, and so on. These allow the
497 // frame data to be position-independent even when they live in
498 // write-protected pages. These variants are specified at the
499 // following two URLs:
501 // http://refspecs.linux-foundation.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/dwarfext.html
502 // http://refspecs.linux-foundation.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html
504 // CFISection leaves the production of well-formed 'z'-augmented CIEs and
505 // FDEs to the user, but does provide EncodedPointer, to emit
506 // properly-encoded addresses for a given pointer encoding.
507 // EncodedPointer uses an instance of this structure to find the base
508 // addresses it should use; you can establish a default for all encoded
509 // pointers appended to this section with SetEncodedPointerBases.
510 struct EncodedPointerBases
{
511 EncodedPointerBases() : cfi(), text(), data() {}
513 // The starting address of this CFI section in memory, for
514 // DW_EH_PE_pcrel. DW_EH_PE_pcrel pointers may only be used in data
515 // that has is loaded into the program's address space.
518 // The starting address of this file's .text section, for DW_EH_PE_textrel.
521 // The starting address of this file's .got or .eh_frame_hdr section,
522 // for DW_EH_PE_datarel.
526 // Create a CFISection whose endianness is ENDIANNESS, and where
527 // machine addresses are ADDRESS_SIZE bytes long. If EH_FRAME is
528 // true, use the .eh_frame format, as described by the Linux
529 // Standards Base Core Specification, instead of the DWARF CFI
531 CFISection(Endianness endianness
, size_t address_size
, bool eh_frame
= false)
532 : Section(endianness
),
533 address_size_(address_size
),
535 pointer_encoding_(lul::DW_EH_PE_absptr
),
538 // The 'start', 'Here', and 'Mark' members of a CFISection all refer
539 // to section offsets.
543 // Return this CFISection's address size.
544 size_t AddressSize() const { return address_size_
; }
546 // Return true if this CFISection uses the .eh_frame format, or
547 // false if it contains ordinary DWARF CFI data.
548 bool ContainsEHFrame() const { return eh_frame_
; }
550 // Use ENCODING for pointers in calls to FDEHeader and EncodedPointer.
551 void SetPointerEncoding(DwarfPointerEncoding encoding
) {
552 pointer_encoding_
= encoding
;
555 // Use the addresses in BASES as the base addresses for encoded
556 // pointers in subsequent calls to FDEHeader or EncodedPointer.
557 // This function makes a copy of BASES.
558 void SetEncodedPointerBases(const EncodedPointerBases
& bases
) {
559 encoded_pointer_bases_
= bases
;
562 // Append a Common Information Entry header to this section with the
563 // given values. If dwarf64 is true, use the 64-bit DWARF initial
564 // length format for the CIE's initial length. Return a reference to
565 // this section. You should call FinishEntry after writing the last
566 // instruction for the CIE.
568 // Before calling this function, you will typically want to use Mark
569 // or Here to make a label to pass to FDEHeader that refers to this
570 // CIE's position in the section.
571 CFISection
& CIEHeader(uint64_t code_alignment_factor
,
572 int data_alignment_factor
,
573 unsigned return_address_register
, uint8_t version
= 3,
574 const string
& augmentation
= "", bool dwarf64
= false);
576 // Append a Frame Description Entry header to this section with the
577 // given values. If dwarf64 is true, use the 64-bit DWARF initial
578 // length format for the CIE's initial length. Return a reference to
579 // this section. You should call FinishEntry after writing the last
580 // instruction for the CIE.
582 // This function doesn't support entries that are longer than
583 // 0xffffff00 bytes. (The "initial length" is always a 32-bit
584 // value.) Nor does it support .debug_frame sections longer than
586 CFISection
& FDEHeader(Label cie_pointer
, uint64_t initial_location
,
587 uint64_t address_range
, bool dwarf64
= false);
589 // Note the current position as the end of the last CIE or FDE we
590 // started, after padding with DW_CFA_nops for alignment. This
591 // defines the label representing the entry's length, cited in the
592 // entry's header. Return a reference to this section.
593 CFISection
& FinishEntry();
595 // Append the contents of BLOCK as a DW_FORM_block value: an
596 // unsigned LEB128 length, followed by that many bytes of data.
597 CFISection
& Block(const lul::ImageSlice
& block
) {
598 ULEB128(block
.length_
);
603 // Append data from CSTRING as a DW_FORM_block value: an unsigned LEB128
604 // length, followed by that many bytes of data. The terminating zero is not
606 CFISection
& Block(const char* cstring
) {
607 ULEB128(strlen(cstring
));
612 // Append ADDRESS to this section, in the appropriate size and
613 // endianness. Return a reference to this section.
614 CFISection
& Address(uint64_t address
) {
615 Section::Append(endianness(), address_size_
, address
);
619 // Append ADDRESS to this section, using ENCODING and BASES. ENCODING
620 // defaults to this section's default encoding, established by
621 // SetPointerEncoding. BASES defaults to this section's bases, set by
622 // SetEncodedPointerBases. If the DW_EH_PE_indirect bit is set in the
623 // encoding, assume that ADDRESS is where the true address is stored.
624 // Return a reference to this section.
626 // (C++ doesn't let me use default arguments here, because I want to
627 // refer to members of *this in the default argument expression.)
628 CFISection
& EncodedPointer(uint64_t address
) {
629 return EncodedPointer(address
, pointer_encoding_
, encoded_pointer_bases_
);
631 CFISection
& EncodedPointer(uint64_t address
, DwarfPointerEncoding encoding
) {
632 return EncodedPointer(address
, encoding
, encoded_pointer_bases_
);
634 CFISection
& EncodedPointer(uint64_t address
, DwarfPointerEncoding encoding
,
635 const EncodedPointerBases
& bases
);
637 // Restate some member functions, to keep chaining working nicely.
638 CFISection
& Mark(Label
* label
) {
639 Section::Mark(label
);
642 CFISection
& D8(uint8_t v
) {
646 CFISection
& D16(uint16_t v
) {
650 CFISection
& D16(Label v
) {
654 CFISection
& D32(uint32_t v
) {
658 CFISection
& D32(const Label
& v
) {
662 CFISection
& D64(uint64_t v
) {
666 CFISection
& D64(const Label
& v
) {
670 CFISection
& LEB128(long long v
) {
674 CFISection
& ULEB128(uint64_t v
) {
680 // A length value that we've appended to the section, but is not yet
681 // known. LENGTH is the appended value; START is a label referring
682 // to the start of the data whose length was cited.
683 struct PendingLength
{
688 // Constants used in CFI/.eh_frame data:
690 // If the first four bytes of an "initial length" are this constant, then
691 // the data uses the 64-bit DWARF format, and the length itself is the
692 // subsequent eight bytes.
693 static const uint32_t kDwarf64InitialLengthMarker
= 0xffffffffU
;
695 // The CIE identifier for 32- and 64-bit DWARF CFI and .eh_frame data.
696 static const uint32_t kDwarf32CIEIdentifier
= ~(uint32_t)0;
697 static const uint64_t kDwarf64CIEIdentifier
= ~(uint64_t)0;
698 static const uint32_t kEHFrame32CIEIdentifier
= 0;
699 static const uint64_t kEHFrame64CIEIdentifier
= 0;
701 // The size of a machine address for the data in this section.
702 size_t address_size_
;
704 // If true, we are generating a Linux .eh_frame section, instead of
705 // a standard DWARF .debug_frame section.
708 // The encoding to use for FDE pointers.
709 DwarfPointerEncoding pointer_encoding_
;
711 // The base addresses to use when emitting encoded pointers.
712 EncodedPointerBases encoded_pointer_bases_
;
714 // The length value for the current entry.
716 // Oddly, this must be dynamically allocated. Labels never get new
717 // values; they only acquire constraints on the value they already
718 // have, or assert if you assign them something incompatible. So
719 // each header needs truly fresh Label objects to cite in their
720 // headers and track their positions. The alternative is explicit
721 // destructor invocation and a placement new. Ick.
722 PendingLength
* entry_length_
;
724 // True if we are currently emitting an FDE --- that is, we have
725 // called FDEHeader but have not yet called FinishEntry.
728 // If in_fde_ is true, this is its starting address. We use this for
729 // emitting DW_EH_PE_funcrel pointers.
730 uint64_t fde_start_address_
;
733 } // namespace lul_test
735 #endif // LUL_TEST_INFRASTRUCTURE_H