## Purpose This patch is one in a series of code-mods that annotate LLVM’s public interface for export. This patch annotates the `llvm/Target` library. These annotations currently have no meaningful impact on the LLVM build; however, they are a prerequisite to support an LLVM Windows DLL (shared library) build. ## Background This effort is tracked in #109483. Additional context is provided in [this discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307), and documentation for `LLVM_ABI` and related annotations is found in the LLVM repo [here](https://github.com/llvm/llvm-project/blob/main/llvm/docs/InterfaceExportAnnotations.rst). A sub-set of these changes were generated automatically using the [Interface Definition Scanner (IDS)](https://github.com/compnerd/ids) tool, followed formatting with `git clang-format`. The bulk of this change is manual additions of `LLVM_ABI` to `LLVMInitializeX` functions defined in .cpp files under llvm/lib/Target. Adding `LLVM_ABI` to the function implementation is required here because they do not `#include "llvm/Support/TargetSelect.h"`, which contains the declarations for this functions and was already updated with `LLVM_ABI` in a previous patch. I considered patching these files with `#include "llvm/Support/TargetSelect.h"` instead, but since TargetSelect.h is a large file with a bunch of preprocessor x-macro stuff in it I was concerned it would unnecessarily impact compile times. In addition, a number of unit tests under llvm/unittests/Target required additional dependencies to make them build correctly against the LLVM DLL on Windows using MSVC. ## Validation Local builds and tests to validate cross-platform compatibility. This included llvm, clang, and lldb on the following configurations: - Windows with MSVC - Windows with Clang - Linux with GCC - Linux with Clang - Darwin with Clang
Register assembly printer passes in the pass registry. This makes it possible to use `llc -start-before=<target>-asm-printer ...` in tests. Adds a `char &ID` parameter to the AssemblyPrinter constructor to allow targets to use the `INITIALIZE_PASS` macros and register the pass in the pass registry. This currently has a default parameter so it won't break any targets that have not been updated.
This restores the functionality of AsmPrinterHandlers to what it was prior to https://github.com/llvm/llvm-project/pull/96785. The attempted hack there of adding a duplicate DebugHandlerBase handling added a lot of hidden state and assumptions, which just segfaulted when we tried to continuing using this API. Instead, this just goes back to the old design, but adds a separate array for the basic EH handles. The duplicate array is identical to the other array of handler, but which doesn't get their begin/endInstruction callbacks called. This still saves the negligible but measurable amount of virtual function calls as was the goal of #96785, while restoring the API to the pre-LLVM-19 status quo.
Identified with misc-include-cleaner.
Timers are an out-of-line function call and a global variable access, here twice per emitted instruction. At this granularity, not only the time results become skewed, but the timers also add a performance overhead when profiling is disabled. Also outside of the innermost loop, timers add a measurable overhead. As this is quite expensive for a mostly unused profiling facility, remove the timers. Fixes #39650.
Currently, an AsmPrinterHandler has several methods that allow to
dynamically hook in unwind or debug info emission, e.g. at begin/end of
every function or instruction. The class hierarchy and the actually
overridden functions are as follows:
(SymSz=setSymbolSize, mFE=markFunctionEnd, BBS=BasicBlockSection,
FL=Funclet; b=beginX, e=endX)
SymSz Mod Fn mFE BBS FL Inst
AsmPrinterHandler - - - - - - -
` PseudoProbeHandler - - - - - - -
` WinCFGuard - e e - - - -
` EHStreamer - - - - - - -
` DwarfCFIException - e be - be - -
` ARMException - - be e - - -
` AIXException - - e - - - -
` WinException - e be e - be -
` WasmException - e be - - - -
` DebugHandlerBase - b be - be - be
` BTFDebug - e - - - - b
` CodeViewDebug - be - - - - b
` DWARFDebug yes be - - - - b
Doing virtual function calls per instruction is costly and useless when
the called function does nothing.
This commit performs the following clean-up/improvements:
- PseudoProbeHandler is no longer an AsmPrinterHandler -- it used
nothing of its functionality to hook in at the possible points. This
avoids virtual function calls when a pseudo probe printer is present.
- DebugHandlerBase is no longer an AsmPrinterHandler, but a separate
base class. DebugHandlerBase is the only remaining "hook" for begin/end
instruction and setSymbolSize (only used by DWARFDebug). begin/end for
function and basic block sections are never overriden and therefore are
no longer virtual. (Originally I intended there to be only one debug
handler, but BPF as the only target supports two at the same time: DWARF
and BTF.)
- AsmPrinterHandler no longer has begin/end instruction and
setSymbolSize hooks -- these were only used by DebugHandlerBase. This
avoid iterating over handlers in every instruction.
AsmPrinterHandler Mod Fn mFE BBS FL
` WinCFGuard e e - - -
` EHStreamer - - - - -
` DwarfCFIException e be - be -
` ARMException - be e - -
` AIXException - e - - -
` WinException e be e - be
` WasmException e be - - -
SymSz Mod Fn BBS Inst
DebugHandlerBase - b be be be
` BTFDebug - e b
` CodeViewDebug - be b
` DWARFDebug yes be b
PseudoProbeHandler (no shared methods)
To continue allowing external users (e.g., Julia) to hook in at every
instruction, a new method addDebugHandler is exposed.
This results in a performance improvement, especially in the -O0 -g0
case with unwind information (e.g., JIT baseline).
Replace it with a forward declaration instead. Analysis.h is pulled in by all passes, but not all passes need to access the module.
D25618 added a method to verify the instruction predicates for an emitted instruction, through verifyInstructionPredicates added into <Target>MCCodeEmitter::encodeInstruction. This is a very useful idea, but the implementation inside MCCodeEmitter made it only fire for object files, not assembly which most of the llvm test suite uses. This patch moves the code into the <Target>_MC::verifyInstructionPredicates method, inside the InstrInfo. The allows it to be called from other places, such as in this patch where it is called from the <Target>AsmPrinter::emitInstruction methods which should trigger for both assembly and object files. It can also be called from other places such as verifyInstruction, but that is not done here (it tends to catch errors earlier, but in reality just shows all the mir tests that have incorrect feature predicates). The interface was also simplified slightly, moving computeAvailableFeatures into the function so that it does not need to be called externally. The ARM, AMDGPU (but not R600), AVR, Mips and X86 backends all currently show errors in the test-suite, so have been disabled with FIXME comments. Recommitted with some fixes for the leftover MCII variables in release builds. Differential Revision: https://reviews.llvm.org/D129506
This reverts commit e2fb8c0f4b940e0285ee36c112469fa75d4b60ff as it does not build for Release builds, and some buildbots are giving more warning than I saw locally. Reverting to fix those issues.
D25618 added a method to verify the instruction predicates for an emitted instruction, through verifyInstructionPredicates added into <Target>MCCodeEmitter::encodeInstruction. This is a very useful idea, but the implementation inside MCCodeEmitter made it only fire for object files, not assembly which most of the llvm test suite uses. This patch moves the code into the <Target>_MC::verifyInstructionPredicates method, inside the InstrInfo. The allows it to be called from other places, such as in this patch where it is called from the <Target>AsmPrinter::emitInstruction methods which should trigger for both assembly and object files. It can also be called from other places such as verifyInstruction, but that is not done here (it tends to catch errors earlier, but in reality just shows all the mir tests that have incorrect feature predicates). The interface was also simplified slightly, moving computeAvailableFeatures into the function so that it does not need to be called externally. The ARM, AMDGPU (but not R600), AVR, Mips and X86 backends all currently show errors in the test-suite, so have been disabled with FIXME comments. Differential Revision: https://reviews.llvm.org/D129506