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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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144
lib/CodeGen/MachOWriter.cpp
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@@ -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) {