Fix mccas with maskray's changes #11063
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The being-removed PNaCl has a Software Fault Isolation mechanism, which requires that certain instructions and groups of instructions do not cross a bundle boundary. When `.bundle_align_mode` is in effect, each instruction is placed in its own fragment, allowing flexible NOP padding. This feature has significantly complicated our refactoring of MCStreamer and MCFragment, leading to considerable effort spent untangling it (including flushPendingLabels (7500646), MCAssembler iteration improvement, and recent MCFragment refactoring). * Make MCObjectStreamer::emitInstToData non-virtual and delete MCELFStreamer::emitInstTodata * Delete MCELFStreamer::emitValueImpl and emitValueToAlignment Minor instructions:u decrease for both -O0 -g and -O3 builds https://llvm-compile-time-tracker.com/compare.php?from=c06d3a7b728293cbc53ff91239d6cd87c0982ffb&to=9b078c7f228bc5b6cdbfe839f751c9407f8aec3e&stat=instructions:u Pull Request: llvm#148781
Delete usage of `writeFragmentPadding` that is removed from upstream. rdar://156089370
Refactor the fragment representation of `push rax; jmp foo; nop; jmp foo`, previously encoded as `MCDataFragment(nop); MCRelaxableFragment(jmp foo); MCDataFragment(nop); MCRelaxableFragment(jmp foo)`, to ``` MCFragment(fixed: push rax, variable: jmp foo) MCFragment(fixed: nop, variable: jmp foo) ``` Changes: * Eliminate MCEncodedFragment, moving content and fixup storage to MCFragment. * The new MCFragment contains a fixed-size content (similar to previous MCDataFragment) and an optional variable-size tail. * The variable-size tail supports FT_Relaxable, FT_LEB, FT_Dwarf, and FT_DwarfFrame, with plans to extend to other fragment types. dyn_cast/isa should be avoided for the converted fragment subclasses. * In `setVarFixups`, source fixup offsets are relative to the variable part's start. Stored fixup (in `FixupStorage`) offsets are relative to the fixed part's start. A lot of code does `getFragmentOffset(Frag) + Fixup.getOffset()`, expecting the fixup offset to be relative to the fixed part's start. * HexagonAsmBackend::fixupNeedsRelaxationAdvanced needs to know the associated instruction for a fixup. We have to add a `const MCFragment &` parameter. * In MCObjectStreamer, extend `absoluteSymbolDiff` to apply to FT_Relaxable as otherwise there would be many more FT_DwarfFrame fragments in -g compilations. https://llvm-compile-time-tracker.com/compare.php?from=28e1473e8e523150914e8c7ea50b44fb0d2a8d65&to=778d68ad1d48e7f111ea853dd249912c601bee89&stat=instructions:u ``` stage2-O0-g instructins:u geomeon (-0.07%) stage1-ReleaseLTO-g (link only) max-rss geomean (-0.39%) ``` ``` % /t/clang-old -g -c sqlite3.i -w -mllvm -debug-only=mc-dump &| awk '/^[0-9]+/{s[$2]++;tot++} END{print "Total",tot; n=asorti(s, si); for(i=1;i<=n;i++) print si[i],s[si[i]]}' Total 59675 Align 2215 Data 29700 Dwarf 12044 DwarfCallFrame 4216 Fill 92 LEB 12 Relaxable 11396 % /t/clang-new -g -c sqlite3.i -w -mllvm -debug-only=mc-dump &| awk '/^[0-9]+/{s[$2]++;tot++} END{print "Total",tot; n=asorti(s, si); for(i=1;i<=n;i++) print si[i],s[si[i]]}' Total 32287 Align 2215 Data 2312 Dwarf 12044 DwarfCallFrame 4216 Fill 92 LEB 12 Relaxable 11396 ``` Pull Request: llvm#148544
… constant * Fix `.reloc constant` to mean section_symbol+constant instead of .+constant . The initial .reloc support from MIPS incorrectly interpreted the offset. * Delay the evaluation of the offset expression after MCAssembler::layout, deleting a lot of code working with MCFragment. * Delete many FIXME from https://reviews.llvm.org/D79625 * Some lld/ELF/Arch/LoongArch.cpp relaxation tests rely on .reloc ., R_LARCH_ALIGN generating ALIGN relocations at specific location. Sort the relocations.
When there is no VarFixup, VarContentStart is zero. `slice(F.VarContentStart - Contents.size(), F.getSize())` might lead to "runtime error: addition of unsigned offset to" in ubsan builds after llvm#148544
First, avoid checking MCSubtargetInfo by reducing unnecessary overhead introduced in https://reviews.llvm.org/D44928 . That change passed STI to both FT_Data and FT_Relaxable fragments, but STI is only necessary for FT_Relaxable. The use of STI in FT_Data was added for: * Bundle alignment mode, which has been removed (llvm#148781). * ARM, which inappropriately uses STI in `ARMAsmBackend::applyFixup` due to tech debt, unlike other targets. All tests passed even without the `copySTI` change. To ensure safety, `copySTI` now starts a new fragment to prevent mixed STI values. Second, avoid checking LinkerRelaxable by eagerly starting a new fragment when a FT_Data/FT_Align fragment is marked linker-relaxable. There is currently an extra empty FT_Data if an alignment immediately follows a linker-relaxable fragment, which will be improved in the future when FT_Align information is moved to the variable-tail. Pull Request: llvm#149471
* Deduplicate creation of SLEB128/ULEB128 with makeLEB. * Call newFragment to prepare for removing getOrCreateDataFragment.
The fragment type introduced by https://reviews.llvm.org/D91878 is unnecessary and can be replaced with FT_LEB.
and reduce the reliance on the FT_Align/FT_Data layout, which will be changed by llvm#149030
... by eagerly allocating an empty fragment when adding a fragment
with a variable-size tail.
X86AsmBackend, The JCC erratum mitigation and x86-pad-for-align set a
flag for FT_Relaxable, which needs to be moved to emitInstructionBegin.
```
if (CF->getKind() == MCFragment::FT_Relaxable)
CF->setAllowAutoPadding(canPadInst(Inst, OS));
```
Follow-up to llvm#148544
MCObjectStreamer::emitInstructionImpl is hot. Devirtualize allowEnhancedRelaxation introduced by https://reviews.llvm.org/D76286
Move the FT_Relaxable-in-BSS check from frequently-called MCObjectStreamer::emitInstruction to MCAssembler::writeSectionData, along with existing checks for other fragment types. For the uncommon diagnostics, losing the location information is acceptable.
Follow-up to llvm#148544 Pull Request: llvm#149030
Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentEnd (content is ignored). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm#149465
The term BSS (Block Started by Symbol) is a standard, widely recognized term, available in the a.out object file format and adopted by formats like COFF, XCOFF, Mach-O (called S_ZEROFILL while `__bss` is also used), and ELF. To avoid introducing unfamiliar terms, we should use isBSSSection instead of isVirtualSection.
Add an assert to ensure `CurFrag` is either null or an `FT_Data` fragment. Follow-up to 39c8cfb. Extracted from llvm#149721
* Handle non-zero fill values for `.fill` and `.org` directives. * Restore the fragment type check (5ee34ff removed a reachable `llvm_unreachable`) to detect unintended API usage. Remove virtual functions `getVirtualSectionKind` (added in https://reviews.llvm.org/D78138) as they are unnecessary in diagnostics. The a.out object file format has the BSS concept, which has been inherited by COFF, XCOFF, Mach-O, and ELF object file formats. Pull Request: llvm#149721
… from MCCASObjectV1.def
…MCFragment::FT_Align
…pe not staying the same after materialization, does it not get saved?
…o FragType not staying the same after materialization, does it not get saved?" This reverts commit 36becd8.
|
@swift-ci please test llvm |
…e in MCAssembler.cpp writeFragment, FT_Align fragments have data in them now?
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