[llvm-commits] CVS: llvm/lib/CodeGen/MachOWriter.cpp
Nate Begeman
natebegeman at mac.com
Sun Sep 10 16:04:01 PDT 2006
Changes in directory llvm/lib/CodeGen:
MachOWriter.cpp updated: 1.5 -> 1.6
---
Log message:
Behold, more work on relocations. Things are looking pretty good now.
---
Diffs of the changes: (+106 -38)
MachOWriter.cpp | 144 +++++++++++++++++++++++++++++++++++++++++---------------
1 files changed, 106 insertions(+), 38 deletions(-)
Index: llvm/lib/CodeGen/MachOWriter.cpp
diff -u llvm/lib/CodeGen/MachOWriter.cpp:1.5 llvm/lib/CodeGen/MachOWriter.cpp:1.6
--- llvm/lib/CodeGen/MachOWriter.cpp:1.5 Fri Sep 8 17:42:09 2006
+++ llvm/lib/CodeGen/MachOWriter.cpp Sun Sep 10 18:03:44 2006
@@ -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 @@
/// 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 @@
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 @@
// 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 @@
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 @@
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 @@
// 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 @@
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 @@
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 @@
/// 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 @@
}
}
+/// 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) {
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