Summary:
Gracefully handle binaries with split functions where two fragments are folded
into one, resulting in a fragment with two parent functions.
This behavior is expected in GCC8+ with -O2 optimization level, where both
function splitting and ICF are enabled by default.
On the BOLT side, the changes are:
- BinaryFunction: allow multiple parent fragments:
- `ParentFragment` --> `ParentFragments`,
- `setParentFragment` --> `addParentFragment`.
- BinaryContext:
- `populateJumpTables`: mark fragments to be skipped later,
- `registerFragment`: add a name heuristic check, return false if it failed,
- `processInterproceduralReferences`: check if `registerFragment`
succeeded, otherwise issue a warning,
- `skipMarkedFragments`: move out fragment traversal and skipping from
`populateJumpTables` into a separate function.
This change fixes an issue where unrelated functions might be registered
as fragments:
```
BOLT-WARNING: interprocedural reference between unrelated fragments:
bad_gs/1(*2) and amd_decode_mce.cold.27/1(*2)
```
(Linux kernel binary)
(cherry picked from FBD32786688)
Summary:
Switched members of BinaryFunction to ADT where it was possible and
made sense. As a result, the size of BinaryFunction on x86-64 Linux
reduced from 1624 bytes to 1448.
(cherry picked from FBD32981555)
Summary:
The debug message for the last fall-through block was printed under the
reverse condition, i.e. when the block was not a fall-through. Remove
the debug message. If we'll need such information, we can add a pass
with more analysis, i.e. checking the last instruction, if the block is
reachable, etc.
(cherry picked from FBD32670816)
Summary:
Make BOLT build in VisualStudio compiler and run without
crashing on a simple test. Other tests are not running.
(cherry picked from FBD32378736)
Summary:
Moves source files into separate components, and make explicit
component dependency on each other, so LLVM build system knows how to
build BOLT in BUILD_SHARED_LIBS=ON.
Please use the -c merge.renamelimit=230 git option when rebasing your
work on top of this change.
To achieve this, we create a new library to hold core IR files (most
classes beginning with Binary in their names), a new library to hold
Utils, some command line options shared across both RewriteInstance
and core IR files, a new library called Rewrite to hold most classes
concerned with running top-level functions coordinating the binary
rewriting process, and a new library called Profile to hold classes
dealing with profile reading and writing.
To remove the dependency from BinaryContext into X86-specific classes,
we do some refactoring on the BinaryContext constructor to receive a
reference to the specific backend directly from RewriteInstance. Then,
the dependency on X86 or AArch64-specific classes is transfered to the
Rewrite library. We can't have the Core library depend on targets
because targets depend on Core (which would create a cycle).
Files implementing the entry point of a tool are transferred to the
tools/ folder. All header files are transferred to the include/
folder. The src/ folder was renamed to lib/.
(cherry picked from FBD32746834)
