Add TargetAsmInfo for all ELF-based targets

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53786 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/ELFTargetAsmInfo.h

@@ -0,0 +1,38 @@
+//===---- ELFTargetAsmInfo.h - ELF asm properties ---------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines target asm properties related what form asm statements
+// should take in general on ELF-based targets
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ELF_TARGET_ASM_INFO_H
+#define LLVM_ELF_TARGET_ASM_INFO_H
+
+#include "llvm/Target/TargetAsmInfo.h"
+#include "llvm/Target/TargetMachine.h"
+
+namespace llvm {
+  class GlobalValue;
+  class GlobalVariable;
+
+  class ELFTargetAsmInfo: public TargetAsmInfo {
+    explicit ELFTargetAsmInfo(const TargetMachine &TM);
+
+    virtual const Section* SelectSectionForGlobal(const GlobalValue *GV) const;
+    virtual std::string PrintSectionFlags(unsigned flags) const;
+    const Section* MergeableConstSection(const GlobalVariable *GV) const;
+    const Section* MergeableStringSection(const GlobalVariable *GV) const;
+  protected:
+    const TargetMachine* ETM;
+  };
+}
+
+
+#endif // LLVM_ELF_TARGET_ASM_INFO_H

lib/Target/ELFTargetAsmInfo.cpp

@@ -0,0 +1,164 @@
+//===-- ELFTargetAsmInfo.cpp - ELF asm properties ---------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines target asm properties related what form asm statements
+// should take in general on ELF-based targets
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
+#include "llvm/GlobalVariable.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Target/ELFTargetAsmInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetData.h"
+
+using namespace llvm;
+
+ELFTargetAsmInfo::ELFTargetAsmInfo(const TargetMachine &TM) {
+  ETM = &TM;
+
+  TextSection_ = getUnnamedSection("\t.text", SectionFlags::Code);
+  DataSection_ = getUnnamedSection("\t.data", SectionFlags::Writeable);
+  BSSSection_  = getUnnamedSection("\t.bss",
+                                   SectionFlags::Writeable | SectionFlags::BSS);
+  ReadOnlySection_ = getNamedSection("\t.rodata", SectionFlags::None);
+  TLSDataSection_ = getNamedSection("\t.tdata",
+                                    SectionFlags::Writeable | SectionFlags::TLS);
+  TLSBSSSection_ = getNamedSection("\t.tbss",
+                SectionFlags::Writeable | SectionFlags::TLS | SectionFlags::BSS);
+
+}
+
+const Section*
+ELFTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
+  SectionKind::Kind Kind = SectionKindForGlobal(GV);
+
+  if (const Function *F = dyn_cast<Function>(GV)) {
+    switch (F->getLinkage()) {
+     default: assert(0 && "Unknown linkage type!");
+     case Function::InternalLinkage:
+     case Function::DLLExportLinkage:
+     case Function::ExternalLinkage:
+      return getTextSection_();
+     case Function::WeakLinkage:
+     case Function::LinkOnceLinkage:
+      std::string Name = UniqueSectionForGlobal(GV, Kind);
+      unsigned Flags = SectionFlagsForGlobal(GV, Name.c_str());
+      return getNamedSection(Name.c_str(), Flags);
+    }
+  } else if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
+    if (GVar->isWeakForLinker()) {
+      std::string Name = UniqueSectionForGlobal(GVar, Kind);
+      unsigned Flags = SectionFlagsForGlobal(GVar, Name.c_str());
+      return getNamedSection(Name.c_str(), Flags);
+    } else {
+      switch (Kind) {
+       case SectionKind::Data:
+        return getDataSection_();
+       case SectionKind::BSS:
+        // ELF targets usually have BSS sections
+        return getBSSSection_();
+       case SectionKind::ROData:
+        return getReadOnlySection_();
+       case SectionKind::RODataMergeStr:
+        return MergeableStringSection(GVar);
+       case SectionKind::RODataMergeConst:
+        return MergeableConstSection(GVar);
+       case SectionKind::ThreadData:
+        // ELF targets usually support TLS stuff
+        return getTLSDataSection_();
+       case SectionKind::ThreadBSS:
+        return getTLSBSSSection_();
+       default:
+        assert(0 && "Unsuported section kind for global");
+      }
+    }
+  } else
+    assert(0 && "Unsupported global");
+}
+
+const Section*
+ELFTargetAsmInfo::MergeableConstSection(const GlobalVariable *GV) const {
+  const TargetData *TD = ETM->getTargetData();
+  Constant *C = cast<GlobalVariable>(GV)->getInitializer();
+  const Type *Type = C->getType();
+
+  // FIXME: string here is temporary, until stuff will fully land in.
+  // We cannot use {Four,Eight,Sixteen}ByteConstantSection here, since it's
+  // currently directly used by asmprinter.
+  unsigned Size = TD->getABITypeSize(Type);
+  if (Size == 4 || Size == 8 || Size == 16) {
+    std::string Name =  ".rodata.cst" + utostr(Size);
+
+    return getNamedSection(Name.c_str(),
+                           SectionFlags::setEntitySize(SectionFlags::Mergeable,
+                                                       Size));
+  }
+
+  return getReadOnlySection_();
+}
+
+const Section*
+ELFTargetAsmInfo::MergeableStringSection(const GlobalVariable *GV) const {
+  const TargetData *TD = ETM->getTargetData();
+  Constant *C = cast<GlobalVariable>(GV)->getInitializer();
+  const ConstantArray *CVA = cast<ConstantArray>(C);
+  const Type *Type = CVA->getType()->getElementType();
+
+  unsigned Size = TD->getABITypeSize(Type);
+  if (Size <= 16) {
+    // We also need alignment here
+    const TargetData *TD = ETM->getTargetData();
+    unsigned Align = TD->getPreferredAlignment(GV);
+    if (Align < Size)
+      Align = Size;
+
+    std::string Name = getCStringSection() + utostr(Size) + '.' + utostr(Align);
+    unsigned Flags = SectionFlags::setEntitySize(SectionFlags::Mergeable |
+                                                 SectionFlags::Strings,
+                                                 Size);
+    return getNamedSection(Name.c_str(), Flags);
+  }
+
+  return getReadOnlySection_();
+}
+
+std::string ELFTargetAsmInfo::PrintSectionFlags(unsigned flags) const {
+  std::string Flags = ",\"";
+
+  if (!(flags & SectionFlags::Debug))
+    Flags += 'a';
+  if (flags & SectionFlags::Code)
+    Flags += 'x';
+  if (flags & SectionFlags::Writeable)
+    Flags += 'w';
+  if (flags & SectionFlags::Mergeable)
+    Flags += 'M';
+  if (flags & SectionFlags::Strings)
+    Flags += 'S';
+  if (flags & SectionFlags::TLS)
+    Flags += 'T';
+
+  Flags += "\"";
+
+  // FIXME: There can be exceptions here
+  if (flags & SectionFlags::BSS)
+    Flags += ",@nobits";
+  else
+    Flags += ",@progbits";
+
+  if (unsigned entitySize = SectionFlags::getEntitySize(flags))
+    Flags += "," + utostr(entitySize);
+
+  return Flags;
+}
+