[llvm] r205084 - MachO: Add linker-optimisation hint framework to MC.
Tim Northover
tnorthover at apple.com
Sat Mar 29 00:35:00 PDT 2014
Author: tnorthover
Date: Sat Mar 29 02:34:53 2014
New Revision: 205084
URL: http://llvm.org/viewvc/llvm-project?rev=205084&view=rev
Log:
MachO: Add linker-optimisation hint framework to MC.
Another part of the ARM64 backend (so tests will be following soon).
This is currently used by the linker to relax adrp/ldr pairs into nops
where possible, though could well be more broadly applicable.
Added:
llvm/trunk/include/llvm/MC/MCLinkerOptimizationHint.h
llvm/trunk/lib/MC/MCLinkerOptimizationHint.cpp
Modified:
llvm/trunk/include/llvm/MC/MCAssembler.h
llvm/trunk/include/llvm/MC/MCStreamer.h
llvm/trunk/include/llvm/Support/MachO.h
llvm/trunk/lib/MC/CMakeLists.txt
llvm/trunk/lib/MC/MCAsmStreamer.cpp
llvm/trunk/lib/MC/MCAssembler.cpp
llvm/trunk/lib/MC/MCMachOStreamer.cpp
llvm/trunk/lib/MC/MachObjectWriter.cpp
Modified: llvm/trunk/include/llvm/MC/MCAssembler.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCAssembler.h?rev=205084&r1=205083&r2=205084&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCAssembler.h (original)
+++ llvm/trunk/include/llvm/MC/MCAssembler.h Sat Mar 29 02:34:53 2014
@@ -18,6 +18,7 @@
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCFixup.h"
#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCLinkerOptimizationHint.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/DataTypes.h"
@@ -932,6 +933,10 @@ private:
// which flags to be set.
unsigned ELFHeaderEFlags;
+ /// Used to communicate Linker Optimization Hint information between
+ /// the Streamer and the .o writer
+ MCLOHContainer LOHContainer;
+
VersionMinInfoType VersionMinInfo;
private:
/// Evaluate a fixup to a relocatable expression and the value which should be
@@ -1175,6 +1180,19 @@ public:
size_t data_region_size() const { return DataRegions.size(); }
/// @}
+ /// @name Data Region List Access
+ /// @{
+
+ // FIXME: This is a total hack, this should not be here. Once things are
+ // factored so that the streamer has direct access to the .o writer, it can
+ // disappear.
+ MCLOHContainer & getLOHContainer() {
+ return LOHContainer;
+ }
+ const MCLOHContainer & getLOHContainer() const {
+ return const_cast<MCAssembler *>(this)->getLOHContainer();
+ }
+ /// @}
/// @name Backend Data Access
/// @{
Added: llvm/trunk/include/llvm/MC/MCLinkerOptimizationHint.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCLinkerOptimizationHint.h?rev=205084&view=auto
==============================================================================
--- llvm/trunk/include/llvm/MC/MCLinkerOptimizationHint.h (added)
+++ llvm/trunk/include/llvm/MC/MCLinkerOptimizationHint.h Sat Mar 29 02:34:53 2014
@@ -0,0 +1,214 @@
+//===- MCLinkerOptimizationHint.h - LOH interface ---------------*- C++ -*-===//
+//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares some helpers classes to handle Linker Optimization Hint
+// (LOH).
+//
+// FIXME: LOH interface supports only MachO format at the moment.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MC_MCLINKEROPTIMIZATIONHINT_H
+#define LLVM_MC_MCLINKEROPTIMIZATIONHINT_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/MC/MCMachObjectWriter.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+
+// Forward declarations.
+class MCAsmLayout;
+class MCSymbol;
+
+/// Linker Optimization Hint Type.
+enum MCLOHType {
+ MCLOH_AdrpAdrp = 0x1u, ///< Adrp xY, _v1 at PAGE -> Adrp xY, _v2 at PAGE.
+ MCLOH_AdrpLdr = 0x2u, ///< Adrp _v at PAGE -> Ldr _v at PAGEOFF.
+ MCLOH_AdrpAddLdr = 0x3u, ///< Adrp _v at PAGE -> Add _v at PAGEOFF -> Ldr.
+ MCLOH_AdrpLdrGotLdr = 0x4u, ///< Adrp _v at GOTPAGE -> Ldr _v at GOTPAGEOFF -> Ldr.
+ MCLOH_AdrpAddStr = 0x5u, ///< Adrp _v at PAGE -> Add _v at PAGEOFF -> Str.
+ MCLOH_AdrpLdrGotStr = 0x6u, ///< Adrp _v at GOTPAGE -> Ldr _v at GOTPAGEOFF -> Str.
+ MCLOH_AdrpAdd = 0x7u, ///< Adrp _v at PAGE -> Add _v at PAGEOFF.
+ MCLOH_AdrpLdrGot = 0x8u ///< Adrp _v at GOTPAGE -> Ldr _v at GOTPAGEOFF.
+};
+
+static inline StringRef MCLOHDirectiveName() {
+ return StringRef(".loh");
+}
+
+static inline bool isValidMCLOHType(MCLOHType Kind) {
+ return Kind >= MCLOH_AdrpAdrp && Kind <= MCLOH_AdrpLdrGot;
+}
+
+static inline int MCLOHNameToId(StringRef Name) {
+#define MCLOHCaseNameToId(Name) .Case(#Name, MCLOH_ ## Name)
+ return StringSwitch<int>(Name)
+ MCLOHCaseNameToId(AdrpAdrp)
+ MCLOHCaseNameToId(AdrpLdr)
+ MCLOHCaseNameToId(AdrpAddLdr)
+ MCLOHCaseNameToId(AdrpLdrGotLdr)
+ MCLOHCaseNameToId(AdrpAddStr)
+ MCLOHCaseNameToId(AdrpLdrGotStr)
+ MCLOHCaseNameToId(AdrpAdd)
+ MCLOHCaseNameToId(AdrpLdrGot)
+ .Default(-1);
+}
+
+static inline StringRef MCLOHIdToName(MCLOHType Kind) {
+#define MCLOHCaseIdToName(Name) case MCLOH_ ## Name: return StringRef(#Name);
+ switch (Kind) {
+ MCLOHCaseIdToName(AdrpAdrp);
+ MCLOHCaseIdToName(AdrpLdr);
+ MCLOHCaseIdToName(AdrpAddLdr);
+ MCLOHCaseIdToName(AdrpLdrGotLdr);
+ MCLOHCaseIdToName(AdrpAddStr);
+ MCLOHCaseIdToName(AdrpLdrGotStr);
+ MCLOHCaseIdToName(AdrpAdd);
+ MCLOHCaseIdToName(AdrpLdrGot);
+ }
+ return StringRef();
+}
+
+static inline int MCLOHIdToNbArgs(MCLOHType Kind) {
+ switch (Kind) {
+ // LOH with two arguments
+ case MCLOH_AdrpAdrp:
+ case MCLOH_AdrpLdr:
+ case MCLOH_AdrpAdd:
+ case MCLOH_AdrpLdrGot:
+ return 2;
+ // LOH with three arguments
+ case MCLOH_AdrpAddLdr:
+ case MCLOH_AdrpLdrGotLdr:
+ case MCLOH_AdrpAddStr:
+ case MCLOH_AdrpLdrGotStr:
+ return 3;
+ }
+ return -1;
+}
+
+/// Store Linker Optimization Hint information (LOH).
+template<typename T>
+class LOHDirective {
+private:
+ MCLOHType Kind;
+
+ /// Arguments of this directive. Order matters.
+ SmallVector<T *, 3> Args;
+
+ /// Emit this directive in @p OutStream using the information available
+ /// in the given @p ObjWriter and @p Layout to get the address of the
+ /// arguments within the object file.
+ /// This function is currently specialized for T = MCSymbol.
+ void Emit_impl(raw_ostream &OutStream, const MachObjectWriter &ObjWriter,
+ const MCAsmLayout &Layout) const { }
+
+public:
+ typedef SmallVectorImpl<T *> LOHArgs;
+
+ LOHDirective(MCLOHType Kind, const LOHArgs &Args)
+ : Kind(Kind), Args(Args.begin(), Args.end()) {};
+
+ MCLOHType getKind() const { return Kind; }
+
+ const LOHArgs & getArgs() const { return Args; }
+
+ /// Emit this directive as:
+ /// <kind, numArgs, addr1, ..., addrN>
+ void Emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const {
+ raw_ostream &OutStream = ObjWriter.getStream();
+ Emit_impl(OutStream, ObjWriter, Layout);
+ }
+
+ /// Get the size in bytes of this directive if emitted in @p ObjWriter with
+ /// the given @p Layout.
+ uint64_t getEmitSize(const MachObjectWriter &ObjWriter,
+ const MCAsmLayout &Layout) const {
+ std::string Buffer;
+ raw_string_ostream OutStream(Buffer);
+ Emit_impl(OutStream, ObjWriter, Layout);
+ return OutStream.tell();
+ }
+};
+
+template<typename T>
+class LOHContainer {
+public:
+ typedef SmallVectorImpl<LOHDirective<T> > LOHDirectives;
+
+private:
+ /// Keep track of the emit size of all the LOHs.
+ mutable uint64_t EmitSize;
+
+ /// Keep track of all LOH directives.
+ SmallVector<LOHDirective<T>, 32> Directives;
+
+ /// Accessor to the directives.
+ LOHDirectives &getDirectives() { return Directives; }
+
+public:
+ LOHContainer() : EmitSize(0) {};
+
+ /// Const accessor to the directives.
+ const LOHDirectives &getDirectives() const {
+ return const_cast<LOHContainer *>(this)->getDirectives();
+ }
+
+ /// Add the directive of the given kind @p Kind with the given arguments
+ /// @p Args to the container.
+ void addDirective(MCLOHType Kind,
+ const typename LOHDirective<T>::LOHArgs &Args) {
+ assert(isValidMCLOHType(Kind) && "Invalid LOH directive type!");
+ getDirectives().push_back(LOHDirective<T>(Kind, Args));
+ }
+
+ /// Get the size of the directives if emitted.
+ uint64_t getEmitSize(const MachObjectWriter &ObjWriter,
+ const MCAsmLayout &Layout) const {
+ if (!EmitSize) {
+ for (typename LOHDirectives::const_iterator It = getDirectives().begin(),
+ EndIt = getDirectives().end(); It != EndIt; ++It)
+ EmitSize += It->getEmitSize(ObjWriter, Layout);
+ }
+ return EmitSize;
+ }
+
+ /// Emit all Linker Optimization Hint in one big table.
+ /// Each line of the table is emitted by LOHDirective::Emit.
+ void Emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const {
+ for (typename LOHDirectives::const_iterator It = getDirectives().begin(),
+ EndIt = getDirectives().end(); It != EndIt; ++It)
+ It->Emit(ObjWriter, Layout);
+ }
+
+ void reset() {
+ getDirectives().clear();
+ EmitSize = 0;
+ }
+};
+
+// Add types for specialized template using MCSymbol.
+typedef LOHDirective<MCSymbol> MCLOHDirective;
+typedef LOHDirective<MCSymbol>::LOHArgs MCLOHArgs;
+
+typedef LOHContainer<MCLOHDirective>::LOHDirectives MCLOHDirectives;
+
+typedef LOHContainer<MCSymbol> MCLOHContainer;
+
+// Declare the specialization for MCSymbol.
+template<>
+void MCLOHDirective::Emit_impl(raw_ostream &OutStream,
+ const MachObjectWriter &ObjWriter,
+ const MCAsmLayout &Layout) const;
+} // end namespace llvm
+
+#endif
Modified: llvm/trunk/include/llvm/MC/MCStreamer.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCStreamer.h?rev=205084&r1=205083&r2=205084&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCStreamer.h (original)
+++ llvm/trunk/include/llvm/MC/MCStreamer.h Sat Mar 29 02:34:53 2014
@@ -19,6 +19,7 @@
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCDwarf.h"
+#include "llvm/MC/MCLinkerOptimizationHint.h"
#include "llvm/MC/MCWin64EH.h"
#include "llvm/Support/DataTypes.h"
#include <string>
@@ -466,6 +467,10 @@ public:
///
virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) = 0;
+ /// \brief Emit a Linker Optimization Hint (LOH) directive.
+ /// \param Args - Arguments of the LOH.
+ virtual void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {}
+
/// EmitCommonSymbol - Emit a common symbol.
///
/// @param Symbol - The common symbol to emit.
Modified: llvm/trunk/include/llvm/Support/MachO.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/MachO.h?rev=205084&r1=205083&r2=205084&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/MachO.h (original)
+++ llvm/trunk/include/llvm/Support/MachO.h Sat Mar 29 02:34:53 2014
@@ -128,7 +128,8 @@ namespace llvm {
LC_SOURCE_VERSION = 0x0000002Au,
LC_DYLIB_CODE_SIGN_DRS = 0x0000002Bu,
// 0x0000002Cu,
- LC_LINKER_OPTIONS = 0x0000002Du
+ LC_LINKER_OPTIONS = 0x0000002Du,
+ LC_LINKER_OPTIMIZATION_HINT = 0x0000002Eu
};
enum : uint32_t {
Modified: llvm/trunk/lib/MC/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/CMakeLists.txt?rev=205084&r1=205083&r2=205084&view=diff
==============================================================================
--- llvm/trunk/lib/MC/CMakeLists.txt (original)
+++ llvm/trunk/lib/MC/CMakeLists.txt Sat Mar 29 02:34:53 2014
@@ -24,6 +24,7 @@ add_llvm_library(LLVMMC
MCInstPrinter.cpp
MCInstrAnalysis.cpp
MCLabel.cpp
+ MCLinkerOptimizationHint.cpp
MCMachOStreamer.cpp
MCMachObjectTargetWriter.cpp
MCModule.cpp
Modified: llvm/trunk/lib/MC/MCAsmStreamer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAsmStreamer.cpp?rev=205084&r1=205083&r2=205084&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCAsmStreamer.cpp (original)
+++ llvm/trunk/lib/MC/MCAsmStreamer.cpp Sat Mar 29 02:34:53 2014
@@ -126,6 +126,7 @@ public:
void ChangeSection(const MCSection *Section,
const MCExpr *Subsection) override;
+ void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) override;
void EmitLabel(MCSymbol *Symbol) override;
void EmitDebugLabel(MCSymbol *Symbol) override;
@@ -342,6 +343,27 @@ void MCAsmStreamer::EmitLabel(MCSymbol *
EmitEOL();
}
+void MCAsmStreamer::EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {
+ StringRef str = MCLOHIdToName(Kind);
+
+#ifndef NDEBUG
+ int NbArgs = MCLOHIdToNbArgs(Kind);
+ assert(NbArgs != -1 && ((size_t)NbArgs) == Args.size() && "Malformed LOH!");
+ assert(str != "" && "Invalid LOH name");
+#endif
+
+ OS << "\t" << MCLOHDirectiveName() << " " << str << "\t";
+ bool IsFirst = true;
+ for (MCLOHArgs::const_iterator It = Args.begin(), EndIt = Args.end();
+ It != EndIt; ++It) {
+ if (!IsFirst)
+ OS << ", ";
+ IsFirst = false;
+ OS << **It;
+ }
+ EmitEOL();
+}
+
void MCAsmStreamer::EmitDebugLabel(MCSymbol *Symbol) {
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
MCStreamer::EmitDebugLabel(Symbol);
Modified: llvm/trunk/lib/MC/MCAssembler.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAssembler.cpp?rev=205084&r1=205083&r2=205084&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCAssembler.cpp (original)
+++ llvm/trunk/lib/MC/MCAssembler.cpp Sat Mar 29 02:34:53 2014
@@ -355,6 +355,7 @@ void MCAssembler::reset() {
getBackend().reset();
getEmitter().reset();
getWriter().reset();
+ getLOHContainer().reset();
}
bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {
Added: llvm/trunk/lib/MC/MCLinkerOptimizationHint.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCLinkerOptimizationHint.cpp?rev=205084&view=auto
==============================================================================
--- llvm/trunk/lib/MC/MCLinkerOptimizationHint.cpp (added)
+++ llvm/trunk/lib/MC/MCLinkerOptimizationHint.cpp Sat Mar 29 02:34:53 2014
@@ -0,0 +1,30 @@
+//===-- llvm/MC/MCLinkerOptimizationHint.cpp ----- LOH handling -*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCLinkerOptimizationHint.h"
+#include "llvm/MC/MCAsmLayout.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/MC/MCStreamer.h"
+
+using namespace llvm;
+
+namespace llvm {
+template<>
+void MCLOHDirective::Emit_impl(raw_ostream &OutStream,
+ const MachObjectWriter &ObjWriter,
+ const MCAsmLayout &Layout) const {
+ const MCAssembler &Asm = Layout.getAssembler();
+ encodeULEB128(Kind, OutStream);
+ encodeULEB128(Args.size(), OutStream);
+ for (LOHArgs::const_iterator It = Args.begin(), EndIt = Args.end();
+ It != EndIt; ++It)
+ encodeULEB128(ObjWriter.getSymbolAddress(&Asm.getSymbolData(**It), Layout),
+ OutStream);
+}
+} // end namespace llvm
Modified: llvm/trunk/lib/MC/MCMachOStreamer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCMachOStreamer.cpp?rev=205084&r1=205083&r2=205084&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCMachOStreamer.cpp (original)
+++ llvm/trunk/lib/MC/MCMachOStreamer.cpp Sat Mar 29 02:34:53 2014
@@ -17,6 +17,7 @@
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCLinkerOptimizationHint.h"
#include "llvm/MC/MCMachOSymbolFlags.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCObjectStreamer.h"
@@ -104,6 +105,10 @@ public:
llvm_unreachable("macho doesn't support this directive");
}
+ void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) override {
+ getAssembler().getLOHContainer().addDirective(Kind, Args);
+ }
+
void FinishImpl() override;
};
Modified: llvm/trunk/lib/MC/MachObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MachObjectWriter.cpp?rev=205084&r1=205083&r2=205084&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MachObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/MachObjectWriter.cpp Sat Mar 29 02:34:53 2014
@@ -761,6 +761,14 @@ void MachObjectWriter::WriteObject(MCAss
LoadCommandsSize += sizeof(MachO::linkedit_data_command);
}
+ // Add the loh load command size, if used.
+ uint64_t LOHRawSize = Asm.getLOHContainer().getEmitSize(*this, Layout);
+ uint64_t LOHSize = RoundUpToAlignment(LOHRawSize, is64Bit() ? 8 : 4);
+ if (LOHSize) {
+ ++NumLoadCommands;
+ LoadCommandsSize += sizeof(MachO::linkedit_data_command);
+ }
+
// Add the symbol table load command sizes, if used.
unsigned NumSymbols = LocalSymbolData.size() + ExternalSymbolData.size() +
UndefinedSymbolData.size();
@@ -849,6 +857,12 @@ void MachObjectWriter::WriteObject(MCAss
DataRegionsSize);
}
+ // Write the loh load command, if used.
+ uint64_t LOHTableEnd = DataInCodeTableEnd + LOHSize;
+ if (LOHSize)
+ WriteLinkeditLoadCommand(MachO::LC_LINKER_OPTIMIZATION_HINT,
+ DataInCodeTableEnd, LOHSize);
+
// Write the symbol table load command, if used.
if (NumSymbols) {
unsigned FirstLocalSymbol = 0;
@@ -865,10 +879,10 @@ void MachObjectWriter::WriteObject(MCAss
// If used, the indirect symbols are written after the section data.
if (NumIndirectSymbols)
- IndirectSymbolOffset = DataInCodeTableEnd;
+ IndirectSymbolOffset = LOHTableEnd;
// The symbol table is written after the indirect symbol data.
- uint64_t SymbolTableOffset = DataInCodeTableEnd + IndirectSymbolSize;
+ uint64_t SymbolTableOffset = LOHTableEnd + IndirectSymbolSize;
// The string table is written after symbol table.
uint64_t StringTableOffset =
@@ -935,6 +949,17 @@ void MachObjectWriter::WriteObject(MCAss
Write16(Data->Kind);
}
+ // Write out the loh commands, if there is one.
+ if (LOHSize) {
+#ifndef NDEBUG
+ unsigned Start = OS.tell();
+#endif
+ Asm.getLOHContainer().Emit(*this, Layout);
+ // Pad to a multiple of the pointer size.
+ WriteBytes("", OffsetToAlignment(LOHRawSize, is64Bit() ? 8 : 4));
+ assert(OS.tell() - Start == LOHSize);
+ }
+
// Write the symbol table data, if used.
if (NumSymbols) {
// Write the indirect symbol entries.
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