+/// reverseBitsForLittleEndianEncoding - For little-endian instruction bit
+/// encodings, reverse the bit order of all instructions.
+void CodeGenTarget::reverseBitsForLittleEndianEncoding() {
+ if (!isLittleEndianEncoding())
+ return;
+
+ std::vector<Record*> Insts = Records.getAllDerivedDefinitions("Instruction");
+ for (std::vector<Record*>::iterator I = Insts.begin(), E = Insts.end();
+ I != E; ++I) {
+ Record *R = *I;
+ if (R->getValueAsString("Namespace") == "TargetOpcode" ||
+ R->getValueAsBit("isPseudo"))
+ continue;
+
+ BitsInit *BI = R->getValueAsBitsInit("Inst");
+
+ unsigned numBits = BI->getNumBits();
+
+ SmallVector<Init *, 16> NewBits(numBits);
+
+ for (unsigned bit = 0, end = numBits / 2; bit != end; ++bit) {
+ unsigned bitSwapIdx = numBits - bit - 1;
+ Init *OrigBit = BI->getBit(bit);
+ Init *BitSwap = BI->getBit(bitSwapIdx);
+ NewBits[bit] = BitSwap;
+ NewBits[bitSwapIdx] = OrigBit;
+ }
+ if (numBits % 2) {
+ unsigned middle = (numBits + 1) / 2;
+ NewBits[middle] = BI->getBit(middle);
+ }
+
+ BitsInit *NewBI = BitsInit::get(NewBits);
+
+ // Update the bits in reversed order so that emitInstrOpBits will get the
+ // correct endianness.
+ R->getValue("Inst")->setValue(NewBI);
+ }
+}
+