UnwindTable::parseRows() may return successfully if the CFIProgram has either
no CFI instructions or only DW_CFA_nop instructions and the UnwindRow return
argument will be empty. But currently, the callers are not checking for this case
which is leading to incorrect dumps in the unwind tables in such cases i.e.
CFA=unspecified
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D101892
D81469 introduced a check to error on CIE version different
than 1 for eh_frame, but older compilers mistakenly create binaries
with this version set to 3 for DWARF4 or 4 to DWARF5. Move the check
to dump time instead of eh_frame parse time, so we can be tolerant
with older binaries.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D97830
GCC warning:
```
/llvm-project/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp: In member function ‘llvm::Expected<long unsigned int> llvm::dwarf::CFIProgram::Instruction::getOperandAsUnsigned(const llvm::dwarf::CFIProgram&, uint32_t) const’:
/llvm-project/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp:425:1: warning: control reaches end of non-void function [-Wreturn-type]
425 | }
| ^
/llvm-project/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp: In member function ‘llvm::Expected<long int> llvm::dwarf::CFIProgram::Instruction::getOperandAsSigned(const llvm::dwarf::CFIProgram&, uint32_t) const’:
/llvm-project/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp:477:1: warning: control reaches end of non-void function [-Wreturn-type]
477 | }
| ^
```
This patch adds the ability to evaluate the state machine for CIE and FDE unwind objects and produce a UnwindTable with all UnwindRow objects needed to unwind registers. It will also dump the UnwindTable for each CIE and FDE when dumping DWARF .debug_frame or .eh_frame sections in llvm-dwarfdump or llvm-objdump. This allows users to see what the unwind rows actually look like for a given CIE or FDE instead of just seeing a list of opcodes.
This patch adds new classes: UnwindLocation, RegisterLocations, UnwindRow, and UnwindTable.
UnwindLocation is a class that describes how to unwind a register or Call Frame Address (CFA).
RegisterLocations is a class that tracks registers and their UnwindLocations. It gets populated when parsing the DWARF call frame instruction opcodes for a unwind row. The registers are mapped from their register numbers to the UnwindLocation in a map.
UnwindRow contains the result of evaluating a row of DWARF call frame instructions for the CIE, or a row from a FDE. The CIE can produce a set of initial instructions that each FDE that points to that CIE will use as the seed for the state machine when parsing FDE opcodes. A UnwindRow for a CIE will not have a valid address, whille a UnwindRow for a FDE will have a valid address.
The UnwindTable is a class that contains a sorted (by address) vector of UnwindRow objects and is the result of parsing all opcodes in a CIE, or FDE. Parsing a CIE should produce a UnwindTable with a single row. Parsing a FDE will produce a UnwindTable with one or more UnwindRow objects where all UnwindRow objects have valid addresses. The rows in the UnwindTable will be sorted from lowest Address to highest after parsing the state machine, or an error will be returned if the table isn't sorted. To parse a UnwindTable clients can use the following methods:
static Expected<UnwindTable> UnwindTable::create(const CIE *Cie);
static Expected<UnwindTable> UnwindTable::create(const FDE *Fde);
A valid table will be returned if the DWARF call frame instruction opcodes have no encoding errors. There are a few things that can go wrong during the evaluation of the state machine and these create functions will catch and return them.
Differential Revision: https://reviews.llvm.org/D89845
Register context information was already being passed into the DWARFDebugFrame code that dumps unwind information but it wasn't being used. This change adds the ability to dump registers names of a valid MC register context was passed in and if it knows about the register. Updated the tests to use the newly returned register names.
Differential Revision: https://reviews.llvm.org/D88767
There are following issues with `CFIProgram::parse` code:
1) Invalid CFI opcodes were never tested. And currently a test would fail
when the `LLVM_ENABLE_ABI_BREAKING_CHECKS` is enabled. It happens because
the `DataExtractor::Cursor C` remains unchecked when the
"Invalid extended CFI opcode" error is reported:
```
.eh_frame section at offset 0x1128 address 0x0:
Program aborted due to an unhandled Error:
Error value was Success. (Note: Success values must still be checked prior to being destroyed).
```
2) It is impossible to reach the "Invalid primary CFI opcode" error with the current code.
There are 3 possible primary opcode values and all of them are handled. Hence this error
should be replaced with llvm_unreachable.
3) Errors currently reported are upper-case.
This patch refines the code in the `CFIProgram::parse` method to fix all issues mentioned
and adds unit tests for all possible invalid extended CFI opcodes.
Differential revision: https://reviews.llvm.org/D82868
Currently when the .eh_frame section is truncated so that
CFI instructions can't be read, it is possible to enter
an infinite loop.
It happens because `CFIProgram::parse` does not handle errors properly.
This patch fixes the issue.
Differential revision: https://reviews.llvm.org/D82017
A CIE with the Length == 0 is a terminator:
https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html
And GNU objdump recognizes them and prints the following for such entries:
"00000000 ZERO terminator"
This patch teaches llvm-objdump to do the same. I had to update tests to use
"CHECK-NEXT" too.
(Note: it looks perhaps not right that printing is done inside the DebugInfo library,
I'd expect to see the change in the llvm-objdump's code somewhere instead,
but that is how it done atm).
Differential revision: https://reviews.llvm.org/D80476
I've noticed an issue with "Data.getRelocatedValue(...)" call.
it might silently ignore an error when a content is truncated.
That leads to an infinite loop in the code (e.g. llvm-readobj hangs).
After fixing the issue I've found that actually we always tried
to read past the end of a section, even when a content was valid.
It happened because the terminator CIE (a CIE with the length == 0)
was never handled. At first I've tried just to stop adding the terminator
entry (and return), but it does not seem to be correct, because tools like
llvm-objdump might want to print something for such entries
(see comments in the code and test cases).
This patch fixes issues mentioned, provides new test cases for
both llvm-readobj and lib/DebugInfo and adds FIXMEs to existent
test cases related.
Differential revision: https://reviews.llvm.org/D80299
Imagine we have a broken .eh_frame.
Below is a possible sample output of llvm-readelf:
```
...
entry 2 {
initial_location: 0x10f5
address: 0x2080
}
}
}
.eh_frame section at offset 0x2028 address 0x2028:
LLVM ERROR: Parsing entry instructions at 0 failed
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
Stack dump:
0. Program arguments: /home/umb/LLVM/LLVM/llvm-project/build/bin/llvm-readelf -a 1
#0 0x000055f4a2ff5a1a llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/home/umb/LLVM/LLVM/llvm-project/build/bin/llvm-readelf+0x2b9a1a)
...
#15 0x00007fdae5dc209b __libc_start_main /build/glibc-B9XfQf/glibc-2.28/csu/../csu/libc-start.c:342:3
#16 0x000055f4a2db746a _start (/home/umb/LLVM/LLVM/llvm-project/build/bin/llvm-readelf+0x7b46a)
Aborted
```
I.e. it calls abort(), suggests to submit a bug report and exits with the code 134.
This patch changes the logic to propagate errors to callers.
This fixes the behavior for llvm-dwarfdump, llvm-readobj and other possible tools.
Differential revision: https://reviews.llvm.org/D79165
With a fix to uninitialized EndOffset.
DW_OP_call_ref is the only operation that has an operand which depends
on the DWARF format. The patch fixes handling that operation in DWARF64
units.
Differential Revision: https://reviews.llvm.org/D79501
DW_OP_call_ref is the only operation that has an operand which depends
on the DWARF format. The patch fixes handling that operation in DWARF64
units.
Differential Revision: https://reviews.llvm.org/D79501
This fixes printing long values that might reside in CIE and FDE,
including offsets, lengths, and addresses.
Differential Revision: https://reviews.llvm.org/D73887
The condition was not accurate enough and could interpret some FDEs in
.eh_frame or 64-bit DWARF .debug_frame sections as CIEs. Even though
such FDEs are unlikely in a normal situation, the wrong interpretation
could hide an issue in a buggy generator.
Differential Revision: https://reviews.llvm.org/D73886
While the value of the CIE pointer field in a DWARF FDE record is
an offset to the corresponding CIE record from the beginning of
the section, for EH FDE records it is relative to the current offset.
Previously, we did not make that distinction when dumped both kinds
of FDE records and just printed the same value for the CIE pointer
field and the CIE offset; that was acceptable for DWARF FDEs but was
wrong for EH FDEs.
This patch fixes the issue by explicitly printing the offset of the
linked CIE object.
Differential Revision: https://reviews.llvm.org/D74613
The CIE pointer field of an FDE record contains an offset to
a corresponding CIE record. In object files, this value comes with
relocation because the value has to be fixed when a linker combines
the final section from multiple sources. In most object files there is
only one CIE record at offset 0 of the .debug_frame section, so reading
a relocated or a raw value makes no difference. However, in partially
linked object files there are multiple CIE records and the relocations
should be applied to recover the right offset value.
Differential Revision: https://reviews.llvm.org/D74612
We do not keep the actual value of the CIE ID field, because it is
predefined, and use a constant when dumping a CIE record. The issue
was that the predefined value is different for .debug_frame and
.eh_frame sections, but we always printed the one which corresponds
to .debug_frame. The patch fixes that by choosing an appropriate
constant to print.
See the following for more information about .eh_frame sections:
https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html
Differential Revision: https://reviews.llvm.org/D73627
The Version was used only to determine the size of an operand of
DW_OP_call_ref. The size was 4 for all versions apart from 2, but
the DW_OP_call_ref operation was introduced only in DWARF3. Thus,
the code may be simplified and using of Version may be eliminated.
Differential Revision: https://reviews.llvm.org/D73264
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
This updates all libraries and tools in LLVM Core to use 64-bit offsets
which directly or indirectly come to DataExtractor.
Differential Revision: https://reviews.llvm.org/D65638
llvm-svn: 368014
It is necessary to generate fixups in .debug_frame or .eh_frame as
relaxation is enabled due to the address delta may be changed after
relaxation.
There is an opcode with 6-bits data in debug frame encoding. So, we
also need 6-bits fixup types.
Differential Revision: https://reviews.llvm.org/D58335
llvm-svn: 366524
It is necessary to generate fixups in .debug_frame or .eh_frame as
relaxation is enabled due to the address delta may be changed after
relaxation.
There is an opcode with 6-bits data in debug frame encoding. So, we
also need 6-bits fixup types.
Differential Revision: https://reviews.llvm.org/D58335
llvm-svn: 366442
Change the format type of *Personality and *LSDAAddress to PRIx64 since
they are of type uint64_t.
The problem was detected on mips builds, where it was printing junk values
and causing test failure.
Patch by Milos Stojanovic.
Differential Revision: https://reviews.llvm.org/D58451
llvm-svn: 355607
Adds llvm-dwarfdump support for pretty printing Dwarf5 expressions ops
that reference a base type (right now only DW_OP_convert is added).
Includes verification to verify that the ops operand is actually a
DW_TAG_base_type DIE.
Differential Revision: https://reviews.llvm.org/D58442
llvm-svn: 354552
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
- When signing return addresses with -msign-return-address=<scope>{+<key>},
either the A key instructions or the B key instructions can be used. To
correctly authenticate the return address, the unwinder/debugger must know
which key was used to sign the return address.
- When and exception is thrown or a break point reached, it may be necessary to
unwind the stack. To accomplish this, the unwinder/debugger must be able to
first authenticate an the return address if it has been signed.
- To enable this, the augmentation string of CIEs has been extended to allow
inclusion of a 'B' character. Functions that are signed using the B key
variant of the instructions should have and FDE whose associated CIE has a 'B'
in the augmentation string.
- One must also be able to preserve these semantics when first stepping from a
high level language into assembly and then, as a second step, into an object
file. To achieve this, I have introduced a new assembly directive
'.cfi_b_key_frame ', that tells the assembler the current frame uses return
address signing with the B key.
- This ensures that the FDE is associated with a CIE that has 'B' in the
augmentation string.
Differential Revision: https://reviews.llvm.org/D51798
llvm-svn: 349895
- Reapply changes intially introduced in r343089
- The archtecture info is no longer loaded whenever a DWARFContext is created
- The runtimes libraries (santiziers) make use of the dwarf context classes but
do not intialise the target info
- The architecture of the object can be obtained without loading the target info
- Adding a method to the dwarf context to get this information and multiplex the
string printing later on
Differential Revision: https://reviews.llvm.org/D55774
llvm-svn: 349472
- Add fix so that all code paths that create DWARFContext
with an ObjectFile initialise the target architecture in the context
- Add an assert that the Arch is known in the Dwarf CallFrameString method
llvm-svn: 343317
RamNalamothu