[llvm-commits] CVS: llvm/lib/CodeGen/MachOWriter.cpp MachOWriter.h
Nate Begeman
natebegeman at mac.com
Tue Feb 27 23:41:10 PST 2007
Changes in directory llvm/lib/CodeGen:
MachOWriter.cpp updated: 1.28 -> 1.29
MachOWriter.h updated: 1.1 -> 1.2
---
Log message:
More Mach-O writer improvements.
---
Diffs of the changes: (+61 -32)
MachOWriter.cpp | 85 ++++++++++++++++++++++++++++++++++++--------------------
MachOWriter.h | 8 +++--
2 files changed, 61 insertions(+), 32 deletions(-)
Index: llvm/lib/CodeGen/MachOWriter.cpp
diff -u llvm/lib/CodeGen/MachOWriter.cpp:1.28 llvm/lib/CodeGen/MachOWriter.cpp:1.29
--- llvm/lib/CodeGen/MachOWriter.cpp:1.28 Wed Feb 14 20:26:09 2007
+++ llvm/lib/CodeGen/MachOWriter.cpp Wed Feb 28 01:40:50 2007
@@ -107,7 +107,7 @@
virtual intptr_t getConstantPoolEntryAddress(unsigned Index) const {
assert(CPLocations.size() > Index && "CP not emitted!");
- return CPLocations[Index];
+ return CPLocations[Index];\
}
virtual intptr_t getJumpTableEntryAddress(unsigned Index) const {
assert(JTLocations.size() > Index && "JT not emitted!");
@@ -225,7 +225,10 @@
Addr = getConstantPoolEntryAddress(MR.getConstantPoolIndex());
MR.setConstantVal(CPSections[MR.getConstantPoolIndex()]);
MR.setResultPointer((void*)Addr);
- } else if (!MR.isGlobalValue()) {
+ } else if (MR.isGlobalValue()) {
+ // FIXME: This should be a set or something that uniques
+ MOW.PendingGlobals.push_back(MR.getGlobalValue());
+ } else {
assert(0 && "Unhandled relocation type");
}
MOS->Relocations.push_back(MR);
@@ -334,8 +337,6 @@
if (Align == 0)
Align = TM.getTargetData()->getPrefTypeAlignment(Ty);
- MachOSym Sym(GV, Mang->getValueName(GV), Sec->Index, TM);
-
// Reserve space in the .bss section for this symbol while maintaining the
// desired section alignment, which must be at least as much as required by
// this symbol.
@@ -353,12 +354,17 @@
for (unsigned i = 0; i < AlignedSize; ++i)
SecDataOut.outbyte(0);
}
+ // Globals without external linkage apparently do not go in the symbol table.
+ if (GV->getLinkage() != GlobalValue::InternalLinkage) {
+ MachOSym Sym(GV, Mang->getValueName(GV), Sec->Index, TM);
+ Sym.n_value = Sec->size;
+ SymbolTable.push_back(Sym);
+ }
+
// Record the offset of the symbol, and then allocate space for it.
// FIXME: remove when we have unified size + output buffer
- Sym.n_value = Sec->size;
Sec->size += Size;
- SymbolTable.push_back(Sym);
-
+
// Now that we know what section the GlovalVariable is going to be emitted
// into, update our mappings.
// FIXME: We may also need to update this when outputting non-GlobalVariable
@@ -387,12 +393,9 @@
// For undefined (N_UNDF) external (N_EXT) types, n_value is the size in
// bytes of the symbol.
ExtOrCommonSym.n_value = Size;
- // If the symbol is external, we'll put it on a list of symbols whose
- // addition to the symbol table is being pended until we find a reference
- if (NoInit)
- PendingSyms.push_back(ExtOrCommonSym);
- else
- SymbolTable.push_back(ExtOrCommonSym);
+ SymbolTable.push_back(ExtOrCommonSym);
+ // Remember that we've seen this symbol
+ GVOffset[GV] = Size;
return;
}
// Otherwise, this symbol is part of the .bss section.
@@ -526,7 +529,13 @@
currentAddr += MOS->size;
}
- // Step #6: Calculate the number of relocations for each section and write out
+ // Step #6: Emit the symbol table to temporary buffers, so that we know the
+ // size of the string table when we write the next load command. This also
+ // sorts and assigns indices to each of the symbols, which is necessary for
+ // emitting relocations to externally-defined objects.
+ BufferSymbolAndStringTable();
+
+ // Step #7: Calculate the number of relocations for each section and write out
// the section commands for each section
currentAddr += SEG.fileoff;
for (std::vector<MachOSection*>::iterator I = SectionList.begin(),
@@ -554,10 +563,6 @@
FHOut.outword(MOS->reserved3);
}
- // Step #7: Emit the symbol table to temporary buffers, so that we know the
- // size of the string table when we write the next load command.
- BufferSymbolAndStringTable();
-
// Step #8: Emit LC_SYMTAB/LC_DYSYMTAB load commands
SymTab.symoff = currentAddr;
SymTab.nsyms = SymbolTable.size();
@@ -632,6 +637,17 @@
// 2. defined external symbols (sorted by name)
// 3. undefined external symbols (sorted by name)
+ // Before sorting the symbols, check the PendingGlobals for any undefined
+ // globals that need to be put in the symbol table.
+ for (std::vector<GlobalValue*>::iterator I = PendingGlobals.begin(),
+ E = PendingGlobals.end(); I != E; ++I) {
+ if (GVOffset[*I] == 0 && GVSection[*I] == 0) {
+ MachOSym UndfSym(*I, Mang->getValueName(*I), MachOSym::NO_SECT, TM);
+ SymbolTable.push_back(UndfSym);
+ GVOffset[*I] = -1;
+ }
+ }
+
// Sort the symbols by name, so that when we partition the symbols by scope
// of definition, we won't have to sort by name within each partition.
std::sort(SymbolTable.begin(), SymbolTable.end(), MachOSymCmp());
@@ -690,14 +706,17 @@
OutputBuffer SymTOut(SymT, is64Bit, isLittleEndian);
+ unsigned index = 0;
for (std::vector<MachOSym>::iterator I = SymbolTable.begin(),
- E = SymbolTable.end(); I != E; ++I) {
+ E = SymbolTable.end(); I != E; ++I, ++index) {
// Add the section base address to the section offset in the n_value field
// to calculate the full address.
// FIXME: handle symbols where the n_value field is not the address
GlobalValue *GV = const_cast<GlobalValue*>(I->GV);
if (GV && GVSection[GV])
I->n_value += GVSection[GV]->addr;
+ if (GV && (GVOffset[GV] == -1))
+ GVOffset[GV] = index;
// Emit nlist to buffer
SymTOut.outword(I->n_strx);
@@ -717,10 +736,13 @@
for (unsigned i = 0, e = MOS.Relocations.size(); i != e; ++i) {
MachineRelocation &MR = MOS.Relocations[i];
unsigned TargetSection = MR.getConstantVal();
+ unsigned TargetAddr;
+ unsigned TargetIndex;
// This is a scattered relocation entry if it points to a global value with
// a non-zero offset.
bool Scattered = false;
+ bool Extern = false;
// Since we may not have seen the GlobalValue we were interested in yet at
// the time we emitted the relocation for it, fix it up now so that it
@@ -729,24 +751,29 @@
GlobalValue *GV = MR.getGlobalValue();
MachOSection *MOSPtr = GVSection[GV];
intptr_t Offset = GVOffset[GV];
- Scattered = TargetSection != 0;
+ // If we have never seen the global before, it must be to a symbol
+ // defined in another module (N_UNDF).
if (!MOSPtr) {
- cerr << "Trying to relocate unknown global " << *GV << '\n';
- continue;
- //abort();
+ // FIXME: need to append stub suffix
+ Extern = true;
+ TargetAddr = 0;
+ TargetIndex = GVOffset[GV];
+ } else {
+ Scattered = TargetSection != 0;
+ TargetSection = MOSPtr->Index;
+ MachOSection &To = *SectionList[TargetSection - 1];
+ TargetAddr = To.addr;
+ TargetIndex = To.Index;
}
-
- TargetSection = MOSPtr->Index;
MR.setResultPointer((void*)Offset);
}
OutputBuffer RelocOut(MOS.RelocBuffer, is64Bit, isLittleEndian);
OutputBuffer SecOut(MOS.SectionData, is64Bit, isLittleEndian);
- MachOSection &To = *SectionList[TargetSection - 1];
-
- MOS.nreloc += GetTargetRelocation(MR, MOS.Index, To.addr, To.Index,
- RelocOut, SecOut, Scattered);
+
+ MOS.nreloc += GetTargetRelocation(MR, MOS.Index, TargetAddr, TargetIndex,
+ RelocOut, SecOut, Scattered, Extern);
}
}
Index: llvm/lib/CodeGen/MachOWriter.h
diff -u llvm/lib/CodeGen/MachOWriter.h:1.1 llvm/lib/CodeGen/MachOWriter.h:1.2
--- llvm/lib/CodeGen/MachOWriter.h:1.1 Wed Feb 7 19:30:50 2007
+++ llvm/lib/CodeGen/MachOWriter.h Wed Feb 28 01:40:50 2007
@@ -583,7 +583,7 @@
/// PendingSyms - This is a list of externally defined symbols that we have
/// been asked to emit, but have not seen a reference to. When a reference
/// is seen, the symbol will move from this list to the SymbolTable.
- std::vector<MachOSym> PendingSyms;
+ std::vector<GlobalValue*> PendingGlobals;
/// DynamicSymbolTable - This is just a vector of indices into
/// SymbolTable to aid in emitting the DYSYMTAB load command.
@@ -613,10 +613,12 @@
unsigned ToIndex,
OutputBuffer &RelocOut,
OutputBuffer &SecOut,
- bool Scattered) {
+ bool Scattered,
+ bool Extern) {
return TM.getMachOWriterInfo()->GetTargetRelocation(MR, FromIdx, ToAddr,
ToIndex, RelocOut,
- SecOut, Scattered);
+ SecOut, Scattered,
+ Extern);
}
};
}
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