Always use non-symbolizing disassembler for instruction encoding
validation as symbols will be treated as undefined/zeros be the encoder
and causing byte sequence mismatches.
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D136118
Simplify the logic of handling sections in BOLT. This change brings more
direct and predictable mapping of BinarySection instances to sections in
the input and output files.
* Only sections from the input binary will have a non-null SectionRef.
When a new section is created as a copy of the input section,
its SectionRef is reset to null.
* RewriteInstance::getOutputSectionName() is removed as the section name
in the output file is now defined by BinarySection::getOutputName().
* Querying BinaryContext for sections by name uses their original name.
E.g., getUniqueSectionByName(".rodata") will return the original
section even if the new .rodata section was created.
* Input file sections (with relocations applied) are emitted via MC with
".bolt.org" prefix. However, their name in the output binary is
unchanged unless a new section with the same name is created.
* New sections are emitted internally with ".bolt.new" prefix if there's
a name conflict with an input file section. Their original name is
preserved in the output file.
* Section header string table is properly populated with section names
that are actually used. Previously we used to include discarded
section names as well.
* Fix the problem when dynamic relocations were propagated to a new
section with a name that matched a section in the input binary.
E.g., the new .rodata with jump tables had dynamic relocations from
the original .rodata.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D135494
This adds a round of checks to memory references, looking for
incorrect references to jump table objects. Fix them by replacing the
jump table reference with another object reference + offset.
This solves bugs related to regular data references in code
accidentally being bound to a jump table, and this reference being
updated to a new (incorrect) location because we moved this jump
table.
Fixes#55004
Reviewed By: #bolt, maksfb
Differential Revision: https://reviews.llvm.org/D134098
Put code that creates references to symbol+addend behind MCPlusBuilder.
Will use this later in validate memory references pass.
Reviewed By: #bolt, maksfb, yota9
Differential Revision: https://reviews.llvm.org/D134097
While the order of new sections in the output binary was deterministic
in the past (i.e. there was no run-to-run variation), it wasn't always
rational as we used size to define the precedence of allocatable
sections within "code" or "data" groups (probably unintentionally).
Fix that by defining stricter section-ordering rules.
Other than the order of sections, this should be NFC.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D135235
To properly set the "_end" symbol, we need to track the last allocatable
address. Simply emitting "_end" at the end of some section is not
sufficient since the order of section allocation is unknown during the
emission step.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D135121
This does *not* link with libLLVM, but with static archives instead. Not
super-great, but at least the build works, which is probably better than
failing.
Related to #57551
Differential Revision: https://reviews.llvm.org/D134434
I'm planning to deprecate and eventually remove llvm::empty.
Note that no use of llvm::empty requires the ability of llvm::empty to
determine the emptiness from begin/end only.
When we derive EFMM from SectionMemoryManager, it brings into EFMM extra
functionality, such as the registry of exception handling sections,
page permission management, etc. Such functionality is of no use to
llvm-bolt and can even be detrimental (see
https://github.com/llvm/llvm-project/issues/56726).
Change the base class of ExecutableFileMemoryManager to MemoryManager,
avoid registering EH sections, and skip memory finalization.
Fixes#56726
Reviewed By: yota9
Differential Revision: https://reviews.llvm.org/D133994
In non-relocation mode, every function is emitted in its own section. If
a function is empty, RuntimeDyld will still allocate 1-byte section
for the function and initialize it with zero. As a result, we will
overwrite the first byte of the original function contents with zero.
Such scenario can happen when the input function had only NOP
instructions which BOLT removes by default. Even though such functions
likely cause undefined behavior, it's better to preserve their contents.
Reviewed By: yota9
Differential Revision: https://reviews.llvm.org/D133978
For functions with references to internal offsets from data, verify externally
referenced blocks against the set of jump table targets. Mark the function
as non-simple if there are any unclaimed data to code references.
Reviewed By: #bolt, maksfb
Differential Revision: https://reviews.llvm.org/D132495
In non-pie binaries BOLT unconditionally converted type encoding
from indirect to absptr, which broke std exceptions since pointers
to their typeinfo were only assigned at runtime in .data section.
In this patch we preserve original encoding so that indirect
remains indirect and can be resolved at runtime, and absolute remains absolute.
Reviewed By: rafauler, maksfb
Differential Revision: https://reviews.llvm.org/D132484
For exception handling, LSDA call sites have to be emitted for each
fragment individually. With this patch, call sites and respective LSDA
symbols are generated and associated with each fragment of their
function, such that they can be used by the emitter.
Reviewed By: maksfb
Differential Revision: https://reviews.llvm.org/D132052
To generate all symbols correctly, it is necessary to record the address
of each fragment. This patch moves the address info for the main and
cold fragments from BinaryFunction to FunctionFragment, where this data
is recorded for all fragments.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D132051
This changes `FunctionFragment` from being used as a temporary proxy
object to access basic block ranges to a heap-allocated object that can
store fragment-specific information.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D132050
A const-qualified reference to function layout allows accessing
non-const qualified basic blocks on a const-qualified function. This
patch adds or removes const-qualifiers where necessary to indicate where
basic blocks are used in a non-const manner.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D132049
To generate all symbols correctly, it is necessary to record the address
of each fragment. This patch moves the address info for the main and
cold fragments from BinaryFunction to FunctionFragment, where this data
is recorded for all fragments.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D132051
This changes `FunctionFragment` from being used as a temporary proxy
object to access basic block ranges to a heap-allocated object that can
store fragment-specific information.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D132050
A const-qualified reference to function layout allows accessing
non-const qualified basic blocks on a const-qualified function. This
patch adds or removes const-qualifiers where necessary to indicate where
basic blocks are used in a non-const manner.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D132049
Move the large lambda out of BinaryFunction::disassemble, reducing its size from
255 to 233 LoC.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D132104
Move the large lambda out of BinaryFunction::disassemble, reducing its size from
295 to 255 LoC.
Differential Revision: https://reviews.llvm.org/D132101
Move the large lambda out of BinaryFunction::disassemble, reducing its size from
338 to 295 LoC.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D132100
Move the large lambda out of BinaryFunction::disassemble, reducing its size from
377 to 338 LoC.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D132099
This patch adds support to generate any number of sections that are
assigned to fragments of functions that are split more than two-way.
With this, a function's *nth* split fragment goes into section
`.text.cold.n`.
This also changes `FunctionLayout::erase` to make sure, that there are
no empty fragments at the end of the function. This sometimes happens
when blocks are erased from the function. To avoid creating symbols
pointing to these fragments, they need to be removed.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D130521
This adds basic fragment awareness in the exception handling passes and
generates the necessary symbols for fragments.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D130520
This changes code emission such that it can emit specific function
fragments instead of scanning all basic blocks of a function and just
emitting those that are hot or cold.
To implement this, `FunctionLayout` explicitly distinguishes the "main"
fragment (i.e. the one that contains the entry block and is associated
with the original symbol) from "split" fragments. Additionally,
`BinaryFunction` receives support for multiple cold symbols - one for
each split fragment.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D130052
Move logging into LLVM_DEBUG scope.
Remove redundant printing of jump table parents:
Old logging:
```
failed to analyze jump table in function _ZN12_GLOBAL__N_116InitHeaderSearch23Ad
dDefaultCIncludePathsERKN4llvm6TripleERKN5clang19HeaderSearchOptionsE/1(*2)
PIC Jump table JUMP_TABLE/_ZN12_GLOBAL__N_116InitHeaderSearch23AddDefaultCInclud
ePathsERKN4llvm6TripleERKN5clang19HeaderSearchOptionsE/1.1 for function _ZN12_GL
OBAL__N_116InitHeaderSearch23AddDefaultCIncludePathsERKN4llvm6TripleERKN5clang19
HeaderSearchOptionsE/1(*2) at 0x65996e0 with a total count of 0:
0x9dc
next jump table at 0x659a810 belongs to function _ZN5clang5Lexer40LexDependencyD
irectiveTokenWhileSkippingERNS_5TokenE
PIC Jump table JUMP_TABLE/_ZN5clang5Lexer40LexDependencyDirectiveTokenWhileSkipp
ingERNS_5TokenE.0 for function _ZN5clang5Lexer40LexDependencyDirectiveTokenWhile
SkippingERNS_5TokenE at 0x659a810 with a total count of 0:
jump table heuristic failure
```
New logging:
```
failed to analyze PIC Jump table JUMP_TABLE/_ZN12_GLOBAL__N_116InitHeaderSearch2
3AddDefaultCIncludePathsERKN4llvm6TripleERKN5clang19HeaderSearchOptionsE/1.1 for
function _ZN12_GLOBAL__N_116InitHeaderSearch23AddDefaultCIncludePathsERKN4llvm6T
ripleERKN5clang19HeaderSearchOptionsE/1(*2) at 0x65996e0 with a total count of 0:
absolute offset: 0x52ac58c
next PIC Jump table JUMP_TABLE/_ZN5clang5Lexer40LexDependencyDirectiveTokenWhile
SkippingERNS_5TokenE.0 for function _ZN5clang5Lexer40LexDependencyDirectiveToken
WhileSkippingERNS_5TokenE at 0x659a810 with a total count of 0:
jump table heuristic failure
```
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D131243
If the first block of a fragment is also a landing pad, the landing pad
is not used if an exception is thrown. This is because the landing pad
is at the same start address that the corresponding LSDA describes. In
that case, the offset in the call site records to refer to that landing
pad is zero, and a zero offset is interpreted by the personality
function as "no handler" and ignored.
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D132053
Move the implementation out of the header file.
Simplify the method.
Add debug logging.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D131811
To track whether a function's new layout is different from its old
layout when updating it, the old layout would be kept around in memory
indefinitely (if the new layout is different). This was used only for
debugging/logging purposes. This patch forces the caller of function
layout's update method to copy the old layout into a temporary if they
need it by removing the old layout fields.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D131413
Functions that do not contain any code still have to be emitted. This
occurs on AArch64 where functions can consist only of a constant island.
To support fragment semantics in code emission, this commits adds a
guaranteed main fragment to function layout. This fragment might be
empty, but allows us omit checks whether the function is empty in most
places.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D130051
This diff uncovers an ASAN leak in getOrCreateJumpTable:
```
Indirect leak of 264 byte(s) in 1 object(s) allocated from:
#1 0x4f6e48c in llvm::bolt::BinaryContext::getOrCreateJumpTable ...
```
The removal of an assertion needs to be accompanied by proper deallocation of
a `JumpTable` object for which `analyzeJumpTable` was unsuccessful.
This reverts commit 52cd00cabf.
Disassembly and branch target analysis are not decoupled, so any
analysis that depends on disassembly may not operate properly.
In specific, analyzeJumpTable uses instruction bounds check property.
A jump table was analyzed twice: (a) during disassembly, and (b) after
disassembly, so there are potentially some mismatched results.
In this update, functions that access JTs which fail the second check
will be marked as ignored.
Test Plan:
```
ninja check-bolt
```
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D130431
Maksim Panchenko