summaryrefslogtreecommitdiffstats
path: root/lib/MC/MachObjectWriter.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/MC/MachObjectWriter.cpp')
-rw-r--r--lib/MC/MachObjectWriter.cpp158
1 files changed, 86 insertions, 72 deletions
diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
index 4b08c22..e073eb5 100644
--- a/lib/MC/MachObjectWriter.cpp
+++ b/lib/MC/MachObjectWriter.cpp
@@ -11,6 +11,7 @@
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/Twine.h"
#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSectionMachO.h"
@@ -271,12 +272,14 @@ public:
assert(OS.tell() - Start == SegmentLoadCommandSize);
}
- void WriteSection(const MCAssembler &Asm, const MCSectionData &SD,
- uint64_t FileOffset, uint64_t RelocationsStart,
- unsigned NumRelocations) {
+ void WriteSection(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ const MCSectionData &SD, uint64_t FileOffset,
+ uint64_t RelocationsStart, unsigned NumRelocations) {
+ uint64_t SectionSize = Layout.getSectionSize(&SD);
+
// The offset is unused for virtual sections.
if (Asm.getBackend().isVirtualSection(SD.getSection())) {
- assert(SD.getFileSize() == 0 && "Invalid file size!");
+ assert(Layout.getSectionFileSize(&SD) == 0 && "Invalid file size!");
FileOffset = 0;
}
@@ -292,11 +295,11 @@ public:
WriteBytes(Section.getSectionName(), 16);
WriteBytes(Section.getSegmentName(), 16);
if (Is64Bit) {
- Write64(SD.getAddress()); // address
- Write64(SD.getSize()); // size
+ Write64(Layout.getSectionAddress(&SD)); // address
+ Write64(SectionSize); // size
} else {
- Write32(SD.getAddress()); // address
- Write32(SD.getSize()); // size
+ Write32(Layout.getSectionAddress(&SD)); // address
+ Write32(SectionSize); // size
}
Write32(FileOffset);
@@ -372,7 +375,7 @@ public:
assert(OS.tell() - Start == DysymtabLoadCommandSize);
}
- void WriteNlist(MachSymbolData &MSD) {
+ void WriteNlist(MachSymbolData &MSD, const MCAsmLayout &Layout) {
MCSymbolData &Data = *MSD.SymbolData;
const MCSymbol &Symbol = Data.getSymbol();
uint8_t Type = 0;
@@ -403,7 +406,7 @@ public:
if (Symbol.isAbsolute()) {
llvm_unreachable("FIXME: Not yet implemented!");
} else {
- Address = Data.getAddress();
+ Address = Layout.getSymbolAddress(&Data);
}
} else if (Data.isCommon()) {
// Common symbols are encoded with the size in the address
@@ -437,8 +440,22 @@ public:
Write32(Address);
}
- void RecordX86_64Relocation(const MCAssembler &Asm,
- const MCDataFragment &Fragment,
+ // FIXME: We really need to improve the relocation validation. Basically, we
+ // want to implement a separate computation which evaluates the relocation
+ // entry as the linker would, and verifies that the resultant fixup value is
+ // exactly what the encoder wanted. This will catch several classes of
+ // problems:
+ //
+ // - Relocation entry bugs, the two algorithms are unlikely to have the same
+ // exact bug.
+ //
+ // - Relaxation issues, where we forget to relax something.
+ //
+ // - Input errors, where something cannot be correctly encoded. 'as' allows
+ // these through in many cases.
+
+ void RecordX86_64Relocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ const MCFragment *Fragment,
const MCAsmFixup &Fixup, MCValue Target,
uint64_t &FixedValue) {
unsigned IsPCRel = isFixupKindPCRel(Fixup.Kind);
@@ -446,7 +463,7 @@ public:
unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
// See <reloc.h>.
- uint32_t Address = Fragment.getOffset() + Fixup.Offset;
+ uint32_t Address = Layout.getFragmentOffset(Fragment) + Fixup.Offset;
int64_t Value = 0;
unsigned Index = 0;
unsigned IsExtern = 0;
@@ -480,11 +497,11 @@ public:
} else if (Target.getSymB()) { // A - B + constant
const MCSymbol *A = &Target.getSymA()->getSymbol();
MCSymbolData &A_SD = Asm.getSymbolData(*A);
- const MCSymbolData *A_Base = Asm.getAtom(&A_SD);
+ const MCSymbolData *A_Base = Asm.getAtom(Layout, &A_SD);
const MCSymbol *B = &Target.getSymB()->getSymbol();
MCSymbolData &B_SD = Asm.getSymbolData(*B);
- const MCSymbolData *B_Base = Asm.getAtom(&B_SD);
+ const MCSymbolData *B_Base = Asm.getAtom(Layout, &B_SD);
// Neither symbol can be modified.
if (Target.getSymA()->getKind() != MCSymbolRefExpr::VK_None ||
@@ -507,8 +524,8 @@ public:
if (A_Base == B_Base)
llvm_report_error("unsupported relocation with identical base");
- Value += A_SD.getAddress() - A_Base->getAddress();
- Value -= B_SD.getAddress() - B_Base->getAddress();
+ Value += Layout.getSymbolAddress(&A_SD) - Layout.getSymbolAddress(A_Base);
+ Value -= Layout.getSymbolAddress(&B_SD) - Layout.getSymbolAddress(B_Base);
Index = A_Base->getIndex();
IsExtern = 1;
@@ -521,7 +538,7 @@ public:
(Log2Size << 25) |
(IsExtern << 27) |
(Type << 28));
- Relocations[Fragment.getParent()].push_back(MRE);
+ Relocations[Fragment->getParent()].push_back(MRE);
Index = B_Base->getIndex();
IsExtern = 1;
@@ -529,7 +546,7 @@ public:
} else {
const MCSymbol *Symbol = &Target.getSymA()->getSymbol();
MCSymbolData &SD = Asm.getSymbolData(*Symbol);
- const MCSymbolData *Base = Asm.getAtom(&SD);
+ const MCSymbolData *Base = Asm.getAtom(Layout, &SD);
// x86_64 almost always uses external relocations, except when there is no
// symbol to use as a base address (a local symbol with no preceeding
@@ -540,19 +557,12 @@ public:
// Add the local offset, if needed.
if (Base != &SD)
- Value += SD.getAddress() - Base->getAddress();
+ Value += Layout.getSymbolAddress(&SD) - Layout.getSymbolAddress(Base);
} else {
- // The index is the section ordinal.
- //
- // FIXME: O(N)
- Index = 1;
- MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
- for (; it != ie; ++it, ++Index)
- if (&*it == SD.getFragment()->getParent())
- break;
- assert(it != ie && "Unable to find section index!");
+ // The index is the section ordinal (1-based).
+ Index = SD.getFragment()->getParent()->getOrdinal() + 1;
IsExtern = 0;
- Value += SD.getAddress();
+ Value += Layout.getSymbolAddress(&SD);
if (IsPCRel)
Value -= Address + (1 << Log2Size);
@@ -602,9 +612,16 @@ public:
}
}
} else {
- if (Modifier == MCSymbolRefExpr::VK_GOT)
+ if (Modifier == MCSymbolRefExpr::VK_GOT) {
Type = RIT_X86_64_GOT;
- else if (Modifier != MCSymbolRefExpr::VK_None)
+ } else if (Modifier == MCSymbolRefExpr::VK_GOTPCREL) {
+ // GOTPCREL is allowed as a modifier on non-PCrel instructions, in
+ // which case all we do is set the PCrel bit in the relocation entry;
+ // this is used with exception handling, for example. The source is
+ // required to include any necessary offset directly.
+ Type = RIT_X86_64_GOT;
+ IsPCRel = 1;
+ } else if (Modifier != MCSymbolRefExpr::VK_None)
llvm_report_error("unsupported symbol modifier in relocation");
else
Type = RIT_X86_64_Unsigned;
@@ -622,14 +639,15 @@ public:
(Log2Size << 25) |
(IsExtern << 27) |
(Type << 28));
- Relocations[Fragment.getParent()].push_back(MRE);
+ Relocations[Fragment->getParent()].push_back(MRE);
}
void RecordScatteredRelocation(const MCAssembler &Asm,
- const MCFragment &Fragment,
+ const MCAsmLayout &Layout,
+ const MCFragment *Fragment,
const MCAsmFixup &Fixup, MCValue Target,
uint64_t &FixedValue) {
- uint32_t Address = Fragment.getOffset() + Fixup.Offset;
+ uint32_t Address = Layout.getFragmentOffset(Fragment) + Fixup.Offset;
unsigned IsPCRel = isFixupKindPCRel(Fixup.Kind);
unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
unsigned Type = RIT_Vanilla;
@@ -642,7 +660,7 @@ public:
llvm_report_error("symbol '" + A->getName() +
"' can not be undefined in a subtraction expression");
- uint32_t Value = A_SD->getAddress();
+ uint32_t Value = Layout.getSymbolAddress(A_SD);
uint32_t Value2 = 0;
if (const MCSymbolRefExpr *B = Target.getSymB()) {
@@ -658,7 +676,7 @@ public:
// relocation types from the linkers point of view, this is done solely
// for pedantic compatibility with 'as'.
Type = A_SD->isExternal() ? RIT_Difference : RIT_LocalDifference;
- Value2 = B_SD->getAddress();
+ Value2 = Layout.getSymbolAddress(B_SD);
}
// Relocations are written out in reverse order, so the PAIR comes first.
@@ -670,7 +688,7 @@ public:
(IsPCRel << 30) |
RF_Scattered);
MRE.Word1 = Value2;
- Relocations[Fragment.getParent()].push_back(MRE);
+ Relocations[Fragment->getParent()].push_back(MRE);
}
MachRelocationEntry MRE;
@@ -680,14 +698,14 @@ public:
(IsPCRel << 30) |
RF_Scattered);
MRE.Word1 = Value;
- Relocations[Fragment.getParent()].push_back(MRE);
+ Relocations[Fragment->getParent()].push_back(MRE);
}
- void RecordRelocation(const MCAssembler &Asm, const MCDataFragment &Fragment,
- const MCAsmFixup &Fixup, MCValue Target,
- uint64_t &FixedValue) {
+ void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ const MCFragment *Fragment, const MCAsmFixup &Fixup,
+ MCValue Target, uint64_t &FixedValue) {
if (Is64Bit) {
- RecordX86_64Relocation(Asm, Fragment, Fixup, Target, FixedValue);
+ RecordX86_64Relocation(Asm, Layout, Fragment, Fixup, Target, FixedValue);
return;
}
@@ -702,12 +720,12 @@ public:
if (Target.getSymB() ||
(Target.getSymA() && !Target.getSymA()->getSymbol().isUndefined() &&
Offset)) {
- RecordScatteredRelocation(Asm, Fragment, Fixup, Target, FixedValue);
+ RecordScatteredRelocation(Asm, Layout, Fragment, Fixup,Target,FixedValue);
return;
}
// See <reloc.h>.
- uint32_t Address = Fragment.getOffset() + Fixup.Offset;
+ uint32_t Address = Layout.getFragmentOffset(Fragment) + Fixup.Offset;
uint32_t Value = 0;
unsigned Index = 0;
unsigned IsExtern = 0;
@@ -729,16 +747,9 @@ public:
Index = SD->getIndex();
Value = 0;
} else {
- // The index is the section ordinal.
- //
- // FIXME: O(N)
- Index = 1;
- MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
- for (; it != ie; ++it, ++Index)
- if (&*it == SD->getFragment()->getParent())
- break;
- assert(it != ie && "Unable to find section index!");
- Value = SD->getAddress();
+ // The index is the section ordinal (1-based).
+ Index = SD->getFragment()->getParent()->getOrdinal() + 1;
+ Value = Layout.getSymbolAddress(SD);
}
Type = RIT_Vanilla;
@@ -752,7 +763,7 @@ public:
(Log2Size << 25) |
(IsExtern << 27) |
(Type << 28));
- Relocations[Fragment.getParent()].push_back(MRE);
+ Relocations[Fragment->getParent()].push_back(MRE);
}
void BindIndirectSymbols(MCAssembler &Asm) {
@@ -920,7 +931,7 @@ public:
UndefinedSymbolData);
}
- void WriteObject(const MCAssembler &Asm) {
+ void WriteObject(const MCAssembler &Asm, const MCAsmLayout &Layout) {
unsigned NumSections = Asm.size();
// The section data starts after the header, the segment load command (and
@@ -948,16 +959,17 @@ public:
for (MCAssembler::const_iterator it = Asm.begin(),
ie = Asm.end(); it != ie; ++it) {
const MCSectionData &SD = *it;
+ uint64_t Address = Layout.getSectionAddress(&SD);
+ uint64_t Size = Layout.getSectionSize(&SD);
+ uint64_t FileSize = Layout.getSectionFileSize(&SD);
- VMSize = std::max(VMSize, SD.getAddress() + SD.getSize());
+ VMSize = std::max(VMSize, Address + Size);
if (Asm.getBackend().isVirtualSection(SD.getSection()))
continue;
- SectionDataSize = std::max(SectionDataSize,
- SD.getAddress() + SD.getSize());
- SectionDataFileSize = std::max(SectionDataFileSize,
- SD.getAddress() + SD.getFileSize());
+ SectionDataSize = std::max(SectionDataSize, Address + Size);
+ SectionDataFileSize = std::max(SectionDataFileSize, Address + FileSize);
}
// The section data is padded to 4 bytes.
@@ -978,8 +990,8 @@ public:
ie = Asm.end(); it != ie; ++it) {
std::vector<MachRelocationEntry> &Relocs = Relocations[it];
unsigned NumRelocs = Relocs.size();
- uint64_t SectionStart = SectionDataStart + it->getAddress();
- WriteSection(Asm, *it, SectionStart, RelocTableEnd, NumRelocs);
+ uint64_t SectionStart = SectionDataStart + Layout.getSectionAddress(it);
+ WriteSection(Asm, Layout, *it, SectionStart, RelocTableEnd, NumRelocs);
RelocTableEnd += NumRelocs * RelocationInfoSize;
}
@@ -1020,7 +1032,7 @@ public:
// Write the actual section data.
for (MCAssembler::const_iterator it = Asm.begin(),
ie = Asm.end(); it != ie; ++it)
- Asm.WriteSectionData(it, Writer);
+ Asm.WriteSectionData(it, Layout, Writer);
// Write the extra padding.
WriteZeros(SectionDataPadding);
@@ -1066,11 +1078,11 @@ public:
// Write the symbol table entries.
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
- WriteNlist(LocalSymbolData[i]);
+ WriteNlist(LocalSymbolData[i], Layout);
for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
- WriteNlist(ExternalSymbolData[i]);
+ WriteNlist(ExternalSymbolData[i], Layout);
for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
- WriteNlist(UndefinedSymbolData[i]);
+ WriteNlist(UndefinedSymbolData[i], Layout);
// Write the string table.
OS << StringTable.str();
@@ -1097,13 +1109,15 @@ void MachObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm) {
}
void MachObjectWriter::RecordRelocation(const MCAssembler &Asm,
- const MCDataFragment &Fragment,
+ const MCAsmLayout &Layout,
+ const MCFragment *Fragment,
const MCAsmFixup &Fixup, MCValue Target,
uint64_t &FixedValue) {
- ((MachObjectWriterImpl*) Impl)->RecordRelocation(Asm, Fragment, Fixup,
+ ((MachObjectWriterImpl*) Impl)->RecordRelocation(Asm, Layout, Fragment, Fixup,
Target, FixedValue);
}
-void MachObjectWriter::WriteObject(const MCAssembler &Asm) {
- ((MachObjectWriterImpl*) Impl)->WriteObject(Asm);
+void MachObjectWriter::WriteObject(const MCAssembler &Asm,
+ const MCAsmLayout &Layout) {
+ ((MachObjectWriterImpl*) Impl)->WriteObject(Asm, Layout);
}
OpenPOWER on IntegriCloud