From 0b57cec536236d46e3dba9bd041533462f33dbb7 Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Fri, 20 Dec 2019 19:53:05 +0000 Subject: Move all sources from the llvm project into contrib/llvm-project. This uses the new layout of the upstream repository, which was recently migrated to GitHub, and converted into a "monorepo". That is, most of the earlier separate sub-projects with their own branches and tags were consolidated into one top-level directory, and are now branched and tagged together. Updating the vendor area to match this layout is next. --- .../lib/Target/RISCV/RISCVTargetObjectFile.cpp | 114 +++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 contrib/llvm-project/llvm/lib/Target/RISCV/RISCVTargetObjectFile.cpp (limited to 'contrib/llvm-project/llvm/lib/Target/RISCV/RISCVTargetObjectFile.cpp') diff --git a/contrib/llvm-project/llvm/lib/Target/RISCV/RISCVTargetObjectFile.cpp b/contrib/llvm-project/llvm/lib/Target/RISCV/RISCVTargetObjectFile.cpp new file mode 100644 index 000000000000..bbd45c970d3d --- /dev/null +++ b/contrib/llvm-project/llvm/lib/Target/RISCV/RISCVTargetObjectFile.cpp @@ -0,0 +1,114 @@ +//===-- RISCVTargetObjectFile.cpp - RISCV Object Info -----------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "RISCVTargetObjectFile.h" +#include "RISCVTargetMachine.h" +#include "llvm/BinaryFormat/ELF.h" +#include "llvm/MC/MCContext.h" +#include "llvm/MC/MCSectionELF.h" + +using namespace llvm; + +void RISCVELFTargetObjectFile::Initialize(MCContext &Ctx, + const TargetMachine &TM) { + TargetLoweringObjectFileELF::Initialize(Ctx, TM); + InitializeELF(TM.Options.UseInitArray); + + SmallDataSection = getContext().getELFSection( + ".sdata", ELF::SHT_PROGBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC); + SmallBSSSection = getContext().getELFSection(".sbss", ELF::SHT_NOBITS, + ELF::SHF_WRITE | ELF::SHF_ALLOC); +} + +// A address must be loaded from a small section if its size is less than the +// small section size threshold. Data in this section could be addressed by +// using gp_rel operator. +bool RISCVELFTargetObjectFile::isInSmallSection(uint64_t Size) const { + // gcc has traditionally not treated zero-sized objects as small data, so this + // is effectively part of the ABI. + return Size > 0 && Size <= SSThreshold; +} + +// Return true if this global address should be placed into small data/bss +// section. +bool RISCVELFTargetObjectFile::isGlobalInSmallSection( + const GlobalObject *GO, const TargetMachine &TM) const { + // Only global variables, not functions. + const GlobalVariable *GVA = dyn_cast(GO); + if (!GVA) + return false; + + // If the variable has an explicit section, it is placed in that section. + if (GVA->hasSection()) { + StringRef Section = GVA->getSection(); + + // Explicitly placing any variable in the small data section overrides + // the global -G value. + if (Section == ".sdata" || Section == ".sbss") + return true; + + // Otherwise reject putting the variable to small section if it has an + // explicit section name. + return false; + } + + if (((GVA->hasExternalLinkage() && GVA->isDeclaration()) || + GVA->hasCommonLinkage())) + return false; + + Type *Ty = GVA->getValueType(); + // It is possible that the type of the global is unsized, i.e. a declaration + // of a extern struct. In this case don't presume it is in the small data + // section. This happens e.g. when building the FreeBSD kernel. + if (!Ty->isSized()) + return false; + + return isInSmallSection( + GVA->getParent()->getDataLayout().getTypeAllocSize(Ty)); +} + +MCSection *RISCVELFTargetObjectFile::SelectSectionForGlobal( + const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const { + // Handle Small Section classification here. + if (Kind.isBSS() && isGlobalInSmallSection(GO, TM)) + return SmallBSSSection; + if (Kind.isData() && isGlobalInSmallSection(GO, TM)) + return SmallDataSection; + + // Otherwise, we work the same as ELF. + return TargetLoweringObjectFileELF::SelectSectionForGlobal(GO, Kind, TM); +} + +void RISCVELFTargetObjectFile::getModuleMetadata(Module &M) { + SmallVector ModuleFlags; + M.getModuleFlagsMetadata(ModuleFlags); + + for (const auto &MFE : ModuleFlags) { + StringRef Key = MFE.Key->getString(); + if (Key == "SmallDataLimit") { + SSThreshold = mdconst::extract(MFE.Val)->getZExtValue(); + break; + } + } +} + +/// Return true if this constant should be placed into small data section. +bool RISCVELFTargetObjectFile::isConstantInSmallSection( + const DataLayout &DL, const Constant *CN) const { + return isInSmallSection(DL.getTypeAllocSize(CN->getType())); +} + +MCSection *RISCVELFTargetObjectFile::getSectionForConstant( + const DataLayout &DL, SectionKind Kind, const Constant *C, + unsigned &Align) const { + if (isConstantInSmallSection(DL, C)) + return SmallDataSection; + + // Otherwise, we work the same as ELF. + return TargetLoweringObjectFileELF::getSectionForConstant(DL, Kind, C, Align); +} -- cgit v1.2.3