static void WriteFileData(raw_ostream &OS, const MCSectionData &SD,
MachObjectWriter &MOW);
+static uint64_t WriteNopData(uint64_t Count, MachObjectWriter &MOW);
+
/// isVirtualSection - Check if this is a section which does not actually exist
/// in the object file.
static bool isVirtualSection(const MCSection &Section) {
std::vector<MachRelocationEntry> &Relocs) {
uint32_t Address = Fragment.getOffset() + Fixup.Offset;
unsigned IsPCRel = 0;
+ unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
unsigned Type = RIT_Vanilla;
// See <reloc.h>.
Value2 = SD->getFragment()->getAddress() + SD->getOffset();
}
- unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
-
// The value which goes in the fixup is current value of the expression.
Fixup.FixedValue = Value - Value2 + Target.getConstant();
if (isFixupKindPCRel(Fixup.Kind)) {
- Fixup.FixedValue -= Address + (1 << Log2Size);
+ Fixup.FixedValue -= Address;
IsPCRel = 1;
}
uint32_t Value = 0;
unsigned Index = 0;
unsigned IsPCRel = 0;
+ unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
unsigned IsExtern = 0;
unsigned Type = 0;
// The value which goes in the fixup is current value of the expression.
Fixup.FixedValue = Value + Target.getConstant();
- unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
-
if (isFixupKindPCRel(Fixup.Kind)) {
- Fixup.FixedValue -= Address + (1<<Log2Size);
+ Fixup.FixedValue -= Address;
IsPCRel = 1;
}
SD.setFileSize(Address - SD.getAddress());
}
+/// WriteNopData - Write optimal nops to the output file for the \arg Count
+/// bytes. This returns the number of bytes written. It may return 0 if
+/// the \arg Count is more than the maximum optimal nops.
+///
+/// FIXME this is X86 32-bit specific and should move to a better place.
+static uint64_t WriteNopData(uint64_t Count, MachObjectWriter &MOW) {
+ static const uint8_t Nops[16][16] = {
+ // nop
+ {0x90},
+ // xchg %ax,%ax
+ {0x66, 0x90},
+ // nopl (%[re]ax)
+ {0x0f, 0x1f, 0x00},
+ // nopl 0(%[re]ax)
+ {0x0f, 0x1f, 0x40, 0x00},
+ // nopl 0(%[re]ax,%[re]ax,1)
+ {0x0f, 0x1f, 0x44, 0x00, 0x00},
+ // nopw 0(%[re]ax,%[re]ax,1)
+ {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
+ // nopl 0L(%[re]ax)
+ {0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
+ // nopl 0L(%[re]ax,%[re]ax,1)
+ {0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
+ // nopw 0L(%[re]ax,%[re]ax,1)
+ {0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
+ // nopw %cs:0L(%[re]ax,%[re]ax,1)
+ {0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
+ // nopl 0(%[re]ax,%[re]ax,1)
+ // nopw 0(%[re]ax,%[re]ax,1)
+ {0x0f, 0x1f, 0x44, 0x00, 0x00,
+ 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
+ // nopw 0(%[re]ax,%[re]ax,1)
+ // nopw 0(%[re]ax,%[re]ax,1)
+ {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,
+ 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
+ // nopw 0(%[re]ax,%[re]ax,1)
+ // nopl 0L(%[re]ax) */
+ {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,
+ 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
+ // nopl 0L(%[re]ax)
+ // nopl 0L(%[re]ax)
+ {0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00,
+ 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
+ // nopl 0L(%[re]ax)
+ // nopl 0L(%[re]ax,%[re]ax,1)
+ {0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00,
+ 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00}
+ };
+
+ if (Count > 15)
+ return 0;
+
+ for (uint64_t i = 0; i < Count; i++)
+ MOW.Write8 (uint8_t(Nops[Count - 1][i]));
+
+ return Count;
+}
+
/// WriteFileData - Write the \arg F data to the output file.
static void WriteFileData(raw_ostream &OS, const MCFragment &F,
MachObjectWriter &MOW) {
"' is not a divisor of padding size '" +
Twine(AF.getFileSize()) + "'");
+ // See if we are aligning with nops, and if so do that first to try to fill
+ // the Count bytes. Then if that did not fill any bytes or there are any
+ // bytes left to fill use the the Value and ValueSize to fill the rest.
+ if (AF.getEmitNops()) {
+ uint64_t NopByteCount = WriteNopData(Count, MOW);
+ Count -= NopByteCount;
+ }
+
for (uint64_t i = 0; i != Count; ++i) {
switch (AF.getValueSize()) {
default: