reintroduce support for Mips "small" section handling. This is
implemented somewhat differently than before, but it should have
the same functionality and the previous testcase passes again.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78900 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsTargetObjectFile.cpp b/lib/Target/Mips/MipsTargetObjectFile.cpp
new file mode 100644
index 0000000..85e9d65
--- /dev/null
+++ b/lib/Target/Mips/MipsTargetObjectFile.cpp
@@ -0,0 +1,93 @@
+//===-- MipsTargetObjectFile.cpp - Mips object files ----------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MipsTargetObjectFile.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/GlobalVariable.h"
+#include "llvm/MC/MCSectionELF.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Support/CommandLine.h"
+using namespace llvm;
+
+static cl::opt<unsigned>
+SSThreshold("mips-ssection-threshold", cl::Hidden,
+ cl::desc("Small data and bss section threshold size (default=8)"),
+ cl::init(8));
+
+void MipsTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){
+ TargetLoweringObjectFileELF::Initialize(Ctx, TM);
+
+ SmallDataSection =
+ getELFSection(".sdata", MCSectionELF::SHT_PROGBITS,
+ MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC,
+ SectionKind::getDataRel());
+
+ SmallBSSSection =
+ getELFSection(".sbss", MCSectionELF::SHT_NOBITS,
+ MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC,
+ SectionKind::getBSS());
+
+}
+
+// A address must be loaded from a small section if its size is less than the
+// small section size threshold. Data in this section must be addressed using
+// gp_rel operator.
+static bool IsInSmallSection(uint64_t Size) {
+ return Size > 0 && Size <= SSThreshold;
+}
+
+bool MipsTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV,
+ const TargetMachine &TM) const {
+ if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
+ return false;
+
+ return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM));
+}
+
+/// IsGlobalInSmallSection - Return true if this global address should be
+/// placed into small data/bss section.
+bool MipsTargetObjectFile::
+IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM,
+ SectionKind Kind) const {
+ // Only global variables, not functions.
+ const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV);
+ if (!GVA)
+ return false;
+
+ // We can only do this for datarel or BSS objects for now.
+ if (!Kind.isBSS() && !Kind.isDataRel())
+ return false;
+
+ // If this is a internal constant string, there is a special
+ // section for it, but not in small data/bss.
+ if (Kind.isMergeable1ByteCString())
+ return false;
+
+ const Type *Ty = GV->getType()->getElementType();
+ return IsInSmallSection(TM.getTargetData()->getTypeAllocSize(Ty));
+}
+
+
+
+const MCSection *MipsTargetObjectFile::
+SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
+ Mangler *Mang, const TargetMachine &TM) const {
+ // TODO: Could also support "weak" symbols as well with ".gnu.linkonce.s.*"
+ // sections?
+
+ // Handle Small Section classification here.
+ if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind))
+ return SmallBSSSection;
+ if (Kind.isDataNoRel() && IsGlobalInSmallSection(GV, TM, Kind))
+ return SmallDataSection;
+
+ // Otherwise, we work the same as ELF.
+ return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM);
+}