diff lib/Target/Hexagon/HexagonTargetObjectFile.cpp @ 0:95c75e76d11b LLVM3.4

LLVM 3.4
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Thu, 12 Dec 2013 13:56:28 +0900
parents
children 54457678186b
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Target/Hexagon/HexagonTargetObjectFile.cpp	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,100 @@
+//===-- HexagonTargetObjectFile.cpp - Hexagon asm properties --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the declarations of the HexagonTargetAsmInfo properties.
+//
+//===----------------------------------------------------------------------===//
+
+#include "HexagonTargetObjectFile.h"
+#include "HexagonSubtarget.h"
+#include "HexagonTargetMachine.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ELF.h"
+
+using namespace llvm;
+
+static cl::opt<int> SmallDataThreshold("hexagon-small-data-threshold",
+                                cl::init(8), cl::Hidden,
+                cl::desc("The maximum size of an object in the sdata section"));
+
+void HexagonTargetObjectFile::Initialize(MCContext &Ctx,
+                                         const TargetMachine &TM) {
+  TargetLoweringObjectFileELF::Initialize(Ctx, TM);
+
+
+  SmallDataSection =
+    getContext().getELFSection(".sdata", ELF::SHT_PROGBITS,
+                               ELF::SHF_WRITE | ELF::SHF_ALLOC,
+                               SectionKind::getDataRel());
+  SmallBSSSection =
+    getContext().getELFSection(".sbss", ELF::SHT_NOBITS,
+                               ELF::SHF_WRITE | ELF::SHF_ALLOC,
+                               SectionKind::getBSS());
+}
+
+// sdata/sbss support taken largely from the MIPS Backend.
+static bool IsInSmallSection(uint64_t Size) {
+  return Size > 0 && Size <= (uint64_t)SmallDataThreshold;
+}
+
+bool HexagonTargetObjectFile::IsSmallDataEnabled () const {
+  return SmallDataThreshold > 0;
+}
+
+/// IsGlobalInSmallSection - Return true if this global value should be
+/// placed into small data/bss section.
+bool HexagonTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV,
+                                                const TargetMachine &TM) const {
+  // If the primary definition of this global value is outside the current
+  // translation unit or the global value is available for inspection but not
+  // emission, then do nothing.
+  if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
+    return false;
+
+  // Otherwise, Check if GV should be in sdata/sbss, when normally it would end
+  // up in getKindForGlobal(GV, TM).
+  return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM));
+}
+
+/// IsGlobalInSmallSection - Return true if this global value should be
+/// placed into small data/bss section.
+bool HexagonTargetObjectFile::
+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;
+
+  if (Kind.isBSS() || Kind.isDataNoRel() || Kind.isCommon()) {
+    Type *Ty = GV->getType()->getElementType();
+    return IsInSmallSection(TM.getDataLayout()->getTypeAllocSize(Ty));
+  }
+
+  return false;
+}
+
+const MCSection *HexagonTargetObjectFile::
+SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
+                       Mangler *Mang, const TargetMachine &TM) const {
+
+  // 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);
+}