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Behold, more work on relocations. Things are looking pretty good now.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30240 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nate Begeman 2006-09-10 23:03:44 +00:00
parent f369dd26fb
commit 019f851ab2
5 changed files with 213 additions and 90 deletions
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47
include/llvm/CodeGen/MachOWriter.h
View File

@ -344,6 +344,10 @@ namespace llvm {
/// SectionData - The actual data for this section which we are building
/// up for emission to the file.
DataBuffer SectionData;
/// RelocBuffer - A buffer to hold the mach-o relocations before we write
/// them out at the appropriate location in the file.
DataBuffer RelocBuffer;
/// Relocations - The relocations that we have encountered so far in this
/// section that we will need to convert to MachORelocation entries when
@ -421,7 +425,7 @@ namespace llvm {
}
MachOSection(const std::string &seg, const std::string &sect)
: sectname(sect), segname(seg), addr(0), size(0), offset(0), align(0),
: sectname(sect), segname(seg), addr(0), size(0), offset(0), align(2),
reloff(0), nreloc(0), flags(0), reserved1(0), reserved2(0),
reserved3(0) { }
};
@ -449,10 +453,13 @@ namespace llvm {
SN->flags = MachOSection::S_REGULAR | Flags;
return *SN;
}
MachOSection &getTextSection() {
return getSection("__TEXT", "__text",
MachOSection::S_ATTR_PURE_INSTRUCTIONS |
MachOSection::S_ATTR_SOME_INSTRUCTIONS);
MachOSection &getTextSection(bool isCode = true) {
if (isCode)
return getSection("__TEXT", "__text",
MachOSection::S_ATTR_PURE_INSTRUCTIONS |
MachOSection::S_ATTR_SOME_INSTRUCTIONS);
else
return getSection("__TEXT", "__text");
}
MachOSection &getBSSSection() {
return getSection("__DATA", "__bss", MachOSection::S_ZEROFILL);
@ -479,6 +486,12 @@ namespace llvm {
}
return getSection("__TEXT", "__const");
}
MachOSection &getJumpTableSection() {
if (TM.getRelocationModel() == Reloc::PIC_)
return getTextSection(false);
else
return getSection("__TEXT", "__const");
}
/// MachOSymTab - This struct contains information about the offsets and
/// size of symbol table information.
@ -563,10 +576,6 @@ namespace llvm {
/// local symbols first in the list).
std::vector<MachOSym> SymbolTable;
/// RelocBuffer - A buffer to hold the mach-o relocations before we write
/// them out at the appropriate location in the file.
DataBuffer RelocBuffer;
/// SymT - A buffer to hold the symbol table before we write it out at the
/// appropriate location in the file.
DataBuffer SymT;
@ -666,15 +675,31 @@ namespace llvm {
outbyte(Output, 0);
}
void fixhalf(DataBuffer &Output, unsigned short X, unsigned Offset) {
unsigned char *P = &Output[Offset];
P[0] = (X >> (isLittleEndian ? 0 : 8)) & 255;
P[1] = (X >> (isLittleEndian ? 8 : 0)) & 255;
}
void fixword(DataBuffer &Output, unsigned X, unsigned Offset) {
unsigned char *P = &Output[Offset];
P[0] = (X >> (isLittleEndian ? 0 : 24)) & 255;
P[1] = (X >> (isLittleEndian ? 8 : 16)) & 255;
P[2] = (X >> (isLittleEndian ? 16 : 8)) & 255;
P[3] = (X >> (isLittleEndian ? 24 : 0)) & 255;
}
private:
void AddSymbolToSection(MachOSection &MOS, GlobalVariable *GV);
void EmitGlobal(GlobalVariable *GV);
void EmitHeaderAndLoadCommands();
void EmitSections();
void BufferSymbolAndStringTable();
void CalculateRelocations(MachOSection &MOS, unsigned RelOffset);
virtual void GetTargetRelocation(MachOSection &MOS, MachineRelocation &MR,
uint64_t Addr) = 0;
virtual MachineRelocation GetJTRelocation(unsigned Offset,
MachineBasicBlock *MBB) = 0;
virtual void GetTargetRelocation(MachineRelocation &MR, MachOSection &MOS,
unsigned ToIndex) = 0;
};
}

144
lib/CodeGen/MachOWriter.cpp
View File

@ -25,6 +25,7 @@
#include "llvm/Module.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachOWriter.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/Target/TargetJITInfo.h"
@ -50,6 +51,14 @@ namespace llvm {
/// Relocations - These are the relocations that the function needs, as
/// emitted.
std::vector<MachineRelocation> Relocations;
/// CPLocations - This is a map of constant pool indices to offsets from the
/// start of the section for that constant pool index.
std::vector<intptr_t> CPLocations;
/// JTLocations - This is a map of jump table indices to offsets from the
/// start of the section for that jump table index.
std::vector<intptr_t> JTLocations;
/// MBBLocations - This vector is a mapping from MBB ID's to their address.
/// It is filled in by the StartMachineBasicBlock callback and queried by
@ -66,19 +75,22 @@ namespace llvm {
Relocations.push_back(MR);
}
virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
if (MBBLocations.size() <= (unsigned)MBB->getNumber())
MBBLocations.resize((MBB->getNumber()+1)*2);
MBBLocations[MBB->getNumber()] = getCurrentPCValue();
}
void emitConstantPool(MachineConstantPool *MCP);
void emitJumpTables(MachineJumpTableInfo *MJTI);
virtual intptr_t getConstantPoolEntryAddress(unsigned Index) const {
assert(0 && "CP not implementated yet!");
return 0;
}
virtual intptr_t getJumpTableEntryAddress(unsigned Index) const {
assert(0 && "JT not implementated yet!");
return 0;
assert(JTLocations.size() > Index && "JT not emitted!");
return JTLocations[Index];
}
virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
if (MBBLocations.size() <= (unsigned)MBB->getNumber())
MBBLocations.resize((MBB->getNumber()+1)*2);
MBBLocations[MBB->getNumber()] = getCurrentPCOffset();
}
virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
@ -119,7 +131,9 @@ void MachOCodeEmitter::startFunction(MachineFunction &F) {
// Upgrade the section alignment if required.
if (MOS->align < Align) MOS->align = Align;
// Make sure we only relocate to this function's MBBs.
// Clear per-function data structures.
CPLocations.clear();
JTLocations.clear();
MBBLocations.clear();
}
@ -132,26 +146,31 @@ bool MachOCodeEmitter::finishFunction(MachineFunction &F) {
const GlobalValue *FuncV = F.getFunction();
MachOSym FnSym(FuncV, MOW.Mang->getValueName(FuncV), MOS->Index);
// FIXME: emit constant pool to appropriate section(s)
// FIXME: emit jump table to appropriate section
// Emit constant pool to appropriate section(s)
emitConstantPool(F.getConstantPool());
// Emit jump tables to appropriate section
emitJumpTables(F.getJumpTableInfo());
// Resolve the function's relocations either to concrete pointers in the case
// of branches from one block to another, or to target relocation entries.
// If we have emitted any relocations to function-specific objects such as
// basic blocks, constant pools entries, or jump tables, record their
// addresses now so that we can rewrite them with the correct addresses
// later.
for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
MachineRelocation &MR = Relocations[i];
intptr_t Addr;
if (MR.isBasicBlock()) {
void *MBBAddr = (void *)getMachineBasicBlockAddress(MR.getBasicBlock());
MR.setResultPointer(MBBAddr);
MOW.TM.getJITInfo()->relocate(BufferBegin, &MR, 1, 0);
} else if (MR.isConstantPoolIndex() || MR.isJumpTableIndex()) {
// Get the address of the index.
uint64_t Addr = 0;
// Generate the relocation(s) for the index.
MOW.GetTargetRelocation(*MOS, MR, Addr);
} else {
// Handle other types later once we've finalized the sections in the file.
MOS->Relocations.push_back(MR);
Addr = getMachineBasicBlockAddress(MR.getBasicBlock());
MR.setResultPointer((void *)Addr);
} else if (MR.isConstantPoolIndex()) {
Addr = getConstantPoolEntryAddress(MR.getConstantPoolIndex());
MR.setResultPointer((void *)Addr);
} else if (MR.isJumpTableIndex()) {
// FIXME: handle PIC codegen
Addr = getJumpTableEntryAddress(MR.getJumpTableIndex());
MR.setResultPointer((void *)Addr);
}
MOS->Relocations.push_back(MR);
}
Relocations.clear();
@ -160,6 +179,42 @@ bool MachOCodeEmitter::finishFunction(MachineFunction &F) {
return false;
}
/// emitConstantPool - For each constant pool entry, figure out which section
/// the constant should live in, allocate space for it, and emit it to the
/// Section data buffer.
void MachOCodeEmitter::emitConstantPool(MachineConstantPool *MCP) {
}
/// emitJumpTables - Emit all the jump tables for a given jump table info
/// record to the appropriate section.
void MachOCodeEmitter::emitJumpTables(MachineJumpTableInfo *MJTI) {
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
if (JT.empty()) return;
bool isPIC = MOW.TM.getRelocationModel() == Reloc::PIC_;
assert(!isPIC && "PIC codegen not yet handled for mach-o jump tables!");
MachOWriter::MachOSection &Sec = MOW.getJumpTableSection();
for (unsigned i = 0, e = JT.size(); i != e; ++i) {
// For each jump table, record its offset from the start of the section,
// reserve space for the relocations to the MBBs, and add the relocations.
const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
JTLocations.push_back(Sec.SectionData.size());
for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
MachineRelocation MR(MOW.GetJTRelocation(Sec.SectionData.size(),
MBBs[mi]));
MR.setResultPointer((void *)JTLocations[i]);
Sec.Relocations.push_back(MR);
MOW.outaddr(Sec.SectionData, 0);
}
}
// FIXME: it really seems like keeping these in sync is redundant, someone
// should do something about that (never access section size directly, only
// look at buffer size).
Sec.size = Sec.SectionData.size();
}
//===----------------------------------------------------------------------===//
// MachOWriter Implementation
//===----------------------------------------------------------------------===//
@ -294,12 +349,9 @@ bool MachOWriter::doFinalization(Module &M) {
// Emit the header and load commands.
EmitHeaderAndLoadCommands();
// Emit the text and data sections.
// Emit the various sections and their relocation info.
EmitSections();
// Emit the relocation entry data for each section.
O.write((char*)&RelocBuffer[0], RelocBuffer.size());
// Write the symbol table and the string table to the end of the file.
O.write((char*)&SymT[0], SymT.size());
O.write((char*)&StrT[0], StrT.size());
@ -370,6 +422,7 @@ void MachOWriter::EmitHeaderAndLoadCommands() {
E = SectionList.end(); I != E; ++I) {
I->addr = currentAddr;
I->offset = currentAddr + SEG.fileoff;
// FIXME: do we need to do something with alignment here?
currentAddr += I->size;
}
@ -380,14 +433,8 @@ void MachOWriter::EmitHeaderAndLoadCommands() {
for (std::list<MachOSection>::iterator I = SectionList.begin(),
E = SectionList.end(); I != E; ++I) {
// calculate the relocation info for this section command
// FIXME: this could get complicated calculating the address argument, we
// should probably split this out into its own function.
for (unsigned i = 0, e = I->Relocations.size(); i != e; ++i)
GetTargetRelocation(*I, I->Relocations[i], 0);
if (I->nreloc != 0) {
I->reloff = currentAddr;
currentAddr += I->nreloc * 8;
}
CalculateRelocations(*I, currentAddr);
currentAddr += I->nreloc * 8;
// write the finalized section command to the output buffer
outstring(FH, I->sectname, 16);
@ -449,9 +496,13 @@ void MachOWriter::EmitHeaderAndLoadCommands() {
/// commands, emit the data for each section to the file.
void MachOWriter::EmitSections() {
for (std::list<MachOSection>::iterator I = SectionList.begin(),
E = SectionList.end(); I != E; ++I) {
E = SectionList.end(); I != E; ++I)
// Emit the contents of each section
O.write((char*)&I->SectionData[0], I->size);
}
for (std::list<MachOSection>::iterator I = SectionList.begin(),
E = SectionList.end(); I != E; ++I)
// Emit the relocation entry data for each section.
O.write((char*)&I->RelocBuffer[0], I->RelocBuffer.size());
}
/// PartitionByLocal - Simple boolean predicate that returns true if Sym is
@ -526,6 +577,23 @@ void MachOWriter::BufferSymbolAndStringTable() {
}
}
/// CalculateRelocations - For each MachineRelocation in the current section,
/// calculate the index of the section containing the object to be relocated,
/// and the offset into that section. From this information, create the
/// appropriate target-specific MachORelocation type and add buffer it to be
/// written out after we are finished writing out sections.
void MachOWriter::CalculateRelocations(MachOSection &MOS, unsigned RelOffset) {
for (unsigned i = 0, e = MOS.Relocations.size(); i != e; ++i) {
// FIXME: calculate the correct offset and section index for relocated
// object.
// FIXME: somehow convey the fact that the relocation might be external
// to the relocating code.
GetTargetRelocation(MOS.Relocations[i], MOS, MOS.Index);
}
if (MOS.nreloc != 0)
MOS.reloff = RelOffset;
}
MachOSym::MachOSym(const GlobalValue *gv, std::string name, uint8_t sect) :
GV(gv), GVName(name), n_strx(0), n_type(sect == NO_SECT ? N_UNDF : N_SECT),
n_sect(sect), n_desc(0), n_value(0) {

2
lib/ExecutionEngine/JIT/JITEmitter.cpp
View File

@ -673,7 +673,7 @@ namespace {
///
void *ConstantPoolBase;
/// ConstantPool - The constant pool for the current function.
/// JumpTable - The jump tables for the current function.
///
MachineJumpTableInfo *JumpTable;

106
lib/Target/PowerPC/PPCMachOWriter.cpp
View File

@ -31,9 +31,15 @@ namespace {
Header.cpusubtype = MachOHeader::CPU_SUBTYPE_POWERPC_ALL;
}
virtual void GetTargetRelocation(MachOSection &MOS, MachineRelocation &MR,
uint64_t Addr);
virtual void GetTargetRelocation(MachineRelocation &MR, MachOSection &MOS,
unsigned ToIndex);
virtual MachineRelocation GetJTRelocation(unsigned Offset,
MachineBasicBlock *MBB);
virtual const char *getPassName() const {
return "PowerPC Mach-O Writer";
}
// Constants for the relocation r_type field.
// see <mach-o/ppc/reloc.h>
enum { PPC_RELOC_VANILLA, // generic relocation
@ -53,73 +59,93 @@ namespace {
///
void llvm::addPPCMachOObjectWriterPass(FunctionPassManager &FPM,
std::ostream &O, PPCTargetMachine &TM) {
PPCMachOWriter *EW = new PPCMachOWriter(O, TM);
FPM.add(EW);
FPM.add(createPPCCodeEmitterPass(TM, EW->getMachineCodeEmitter()));
PPCMachOWriter *MOW = new PPCMachOWriter(O, TM);
FPM.add(MOW);
FPM.add(createPPCCodeEmitterPass(TM, MOW->getMachineCodeEmitter()));
}
/// GetTargetRelocation - For the MachineRelocation MR, convert it to one or
/// more PowerPC MachORelocation(s), add the new relocations to the
/// MachOSection, and rewrite the instruction at the section offset if required
/// by that relocation type.
void PPCMachOWriter::GetTargetRelocation(MachOSection &MOS,
MachineRelocation &MR,
uint64_t Addr) {
void PPCMachOWriter::GetTargetRelocation(MachineRelocation &MR,
MachOSection &MOS,
unsigned ToIndex) {
uint64_t Addr = 0;
// Keep track of whether or not this is an externally defined relocation.
uint32_t index = MOS.Index;
bool isExtern = false;
// Get the address of the instruction to rewrite
unsigned char *RelocPos = &MOS.SectionData[0] + MR.getMachineCodeOffset();
// Get the address of whatever it is we're relocating, if possible.
if (MR.isGlobalValue()) {
// determine whether or not its external and then figure out what section
// we put it in if it's a locally defined symbol.
} else if (MR.isString()) {
// lookup in global values?
} else {
assert((MR.isConstantPoolIndex() || MR.isJumpTableIndex()) &&
"Unhandled MachineRelocation type!");
}
if (!isExtern)
Addr = (uintptr_t)MR.getResultPointer();
switch ((PPC::RelocationType)MR.getRelocationType()) {
default: assert(0 && "Unknown PPC relocation type!");
case PPC::reloc_pcrel_bx:
case PPC::reloc_pcrel_bcx:
case PPC::reloc_absolute_low_ix:
assert(0 && "Unhandled PPC relocation type!");
break;
case PPC::reloc_vanilla:
{
// FIXME: need to handle 64 bit vanilla relocs
MachORelocation VANILLA(MR.getMachineCodeOffset(), ToIndex, false, 2,
isExtern, PPC_RELOC_VANILLA);
outword(MOS.RelocBuffer, VANILLA.r_address);
outword(MOS.RelocBuffer, VANILLA.getPackedFields());
}
MOS.nreloc += 1;
fixword(MOS.SectionData, Addr, MR.getMachineCodeOffset());
break;
case PPC::reloc_pcrel_bx:
Addr -= MR.getMachineCodeOffset();
Addr >>= 2;
Addr & 0xFFFFFF;
Addr <<= 2;
Addr |= (MOS.SectionData[MR.getMachineCodeOffset()] << 24);
fixword(MOS.SectionData, Addr, MR.getMachineCodeOffset());
break;
case PPC::reloc_pcrel_bcx:
Addr -= MR.getMachineCodeOffset();
Addr &= 0xFFFC;
fixhalf(MOS.SectionData, Addr, MR.getMachineCodeOffset() + 2);
break;
case PPC::reloc_absolute_high:
{
MachORelocation HA16(MR.getMachineCodeOffset(), index, false, 2, isExtern,
PPC_RELOC_HA16);
MachORelocation HA16(MR.getMachineCodeOffset(), ToIndex, false, 2,
isExtern, PPC_RELOC_HA16);
MachORelocation PAIR(Addr & 0xFFFF, 0xFFFFFF, false, 2, isExtern,
PPC_RELOC_PAIR);
outword(RelocBuffer, HA16.r_address);
outword(RelocBuffer, HA16.getPackedFields());
outword(RelocBuffer, PAIR.r_address);
outword(RelocBuffer, PAIR.getPackedFields());
outword(MOS.RelocBuffer, HA16.r_address);
outword(MOS.RelocBuffer, HA16.getPackedFields());
outword(MOS.RelocBuffer, PAIR.r_address);
outword(MOS.RelocBuffer, PAIR.getPackedFields());
}
printf("ha16: %x\n", (unsigned)Addr);
MOS.nreloc += 2;
Addr += 0x8000;
*(unsigned *)RelocPos &= 0xFFFF0000;
*(unsigned *)RelocPos |= ((Addr >> 16) & 0xFFFF);
fixhalf(MOS.SectionData, Addr >> 16, MR.getMachineCodeOffset() + 2);
break;
case PPC::reloc_absolute_low:
{
MachORelocation LO16(MR.getMachineCodeOffset(), index, false, 2, isExtern,
PPC_RELOC_LO16);
MachORelocation LO16(MR.getMachineCodeOffset(), ToIndex, false, 2,
isExtern, PPC_RELOC_LO16);
MachORelocation PAIR(Addr >> 16, 0xFFFFFF, false, 2, isExtern,
PPC_RELOC_PAIR);
outword(RelocBuffer, LO16.r_address);
outword(RelocBuffer, LO16.getPackedFields());
outword(RelocBuffer, PAIR.r_address);
outword(RelocBuffer, PAIR.getPackedFields());
outword(MOS.RelocBuffer, LO16.r_address);
outword(MOS.RelocBuffer, LO16.getPackedFields());
outword(MOS.RelocBuffer, PAIR.r_address);
outword(MOS.RelocBuffer, PAIR.getPackedFields());
}
printf("lo16: %x\n", (unsigned)Addr);
MOS.nreloc += 2;
*(unsigned *)RelocPos &= 0xFFFF0000;
*(unsigned *)RelocPos |= (Addr & 0xFFFF);
fixhalf(MOS.SectionData, Addr, MR.getMachineCodeOffset() + 2);
break;
}
}
MachineRelocation PPCMachOWriter::GetJTRelocation(unsigned Offset,
MachineBasicBlock *MBB) {
// FIXME: do something about PIC
return MachineRelocation::getBB(Offset, PPC::reloc_vanilla, MBB);
}

4
lib/Target/PowerPC/PPCRelocations.h
View File

@ -25,6 +25,10 @@
namespace llvm {
namespace PPC {
enum RelocationType {
// reloc_vanilla - A standard relocation, where the address of the
// relocated object completely overwrites the address of the relocation.
reloc_vanilla,
// reloc_pcrel_bx - PC relative relocation, for the b or bl instructions.
reloc_pcrel_bx,