It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/CodeEmitterGen.cpp b/utils/TableGen/CodeEmitterGen.cpp
new file mode 100644
index 0000000..300a100
--- /dev/null
+++ b/utils/TableGen/CodeEmitterGen.cpp
@@ -0,0 +1,228 @@
+//===- CodeEmitterGen.cpp - Code Emitter Generator ------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// CodeEmitterGen uses the descriptions of instructions and their fields to
+// construct an automated code emitter: a function that, given a MachineInstr,
+// returns the (currently, 32-bit unsigned) value of the instruction.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeEmitterGen.h"
+#include "CodeGenTarget.h"
+#include "Record.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Debug.h"
+using namespace llvm;
+
+void CodeEmitterGen::reverseBits(std::vector<Record*> &Insts) {
+ for (std::vector<Record*>::iterator I = Insts.begin(), E = Insts.end();
+ I != E; ++I) {
+ Record *R = *I;
+ if (R->getName() == "PHI" ||
+ R->getName() == "INLINEASM" ||
+ R->getName() == "LABEL") continue;
+
+ BitsInit *BI = R->getValueAsBitsInit("Inst");
+
+ unsigned numBits = BI->getNumBits();
+ BitsInit *NewBI = new BitsInit(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);
+ NewBI->setBit(bit, BitSwap);
+ NewBI->setBit(bitSwapIdx, OrigBit);
+ }
+ if (numBits % 2) {
+ unsigned middle = (numBits + 1) / 2;
+ NewBI->setBit(middle, BI->getBit(middle));
+ }
+
+ // Update the bits in reversed order so that emitInstrOpBits will get the
+ // correct endianness.
+ R->getValue("Inst")->setValue(NewBI);
+ }
+}
+
+
+// If the VarBitInit at position 'bit' matches the specified variable then
+// return the variable bit position. Otherwise return -1.
+int CodeEmitterGen::getVariableBit(const std::string &VarName,
+ BitsInit *BI, int bit) {
+ if (VarBitInit *VBI = dynamic_cast<VarBitInit*>(BI->getBit(bit))) {
+ TypedInit *TI = VBI->getVariable();
+
+ if (VarInit *VI = dynamic_cast<VarInit*>(TI)) {
+ if (VI->getName() == VarName) return VBI->getBitNum();
+ }
+ }
+
+ return -1;
+}
+
+
+void CodeEmitterGen::run(std::ostream &o) {
+ CodeGenTarget Target;
+ std::vector<Record*> Insts = Records.getAllDerivedDefinitions("Instruction");
+
+ // For little-endian instruction bit encodings, reverse the bit order
+ if (Target.isLittleEndianEncoding()) reverseBits(Insts);
+
+ EmitSourceFileHeader("Machine Code Emitter", o);
+ std::string Namespace = Insts[0]->getValueAsString("Namespace") + "::";
+
+ std::vector<const CodeGenInstruction*> NumberedInstructions;
+ Target.getInstructionsByEnumValue(NumberedInstructions);
+
+ // Emit function declaration
+ o << "unsigned " << Target.getName() << "CodeEmitter::"
+ << "getBinaryCodeForInstr(MachineInstr &MI) {\n";
+
+ // Emit instruction base values
+ o << " static const unsigned InstBits[] = {\n";
+ for (std::vector<const CodeGenInstruction*>::iterator
+ IN = NumberedInstructions.begin(),
+ EN = NumberedInstructions.end();
+ IN != EN; ++IN) {
+ const CodeGenInstruction *CGI = *IN;
+ Record *R = CGI->TheDef;
+
+ if (IN != NumberedInstructions.begin()) o << ",\n";
+
+ if (R->getName() == "PHI" ||
+ R->getName() == "INLINEASM" ||
+ R->getName() == "LABEL") {
+ o << " 0U";
+ continue;
+ }
+
+ BitsInit *BI = R->getValueAsBitsInit("Inst");
+
+ // Start by filling in fixed values...
+ unsigned Value = 0;
+ for (unsigned i = 0, e = BI->getNumBits(); i != e; ++i) {
+ if (BitInit *B = dynamic_cast<BitInit*>(BI->getBit(e-i-1))) {
+ Value |= B->getValue() << (e-i-1);
+ }
+ }
+ o << " " << Value << "U";
+ }
+ o << "\n };\n";
+
+ // Map to accumulate all the cases.
+ std::map<std::string, std::vector<std::string> > CaseMap;
+
+ // Construct all cases statement for each opcode
+ for (std::vector<Record*>::iterator IC = Insts.begin(), EC = Insts.end();
+ IC != EC; ++IC) {
+ Record *R = *IC;
+ const std::string &InstName = R->getName();
+ std::string Case("");
+
+ if (InstName == "PHI" ||
+ InstName == "INLINEASM" ||
+ InstName == "LABEL") continue;
+
+ BitsInit *BI = R->getValueAsBitsInit("Inst");
+ const std::vector<RecordVal> &Vals = R->getValues();
+ CodeGenInstruction &CGI = Target.getInstruction(InstName);
+
+ // Loop over all of the fields in the instruction, determining which are the
+ // operands to the instruction.
+ unsigned op = 0;
+ for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
+ if (!Vals[i].getPrefix() && !Vals[i].getValue()->isComplete()) {
+ // Is the operand continuous? If so, we can just mask and OR it in
+ // instead of doing it bit-by-bit, saving a lot in runtime cost.
+ const std::string &VarName = Vals[i].getName();
+ bool gotOp = false;
+
+ for (int bit = BI->getNumBits()-1; bit >= 0; ) {
+ int varBit = getVariableBit(VarName, BI, bit);
+
+ if (varBit == -1) {
+ --bit;
+ } else {
+ int beginInstBit = bit;
+ int beginVarBit = varBit;
+ int N = 1;
+
+ for (--bit; bit >= 0;) {
+ varBit = getVariableBit(VarName, BI, bit);
+ if (varBit == -1 || varBit != (beginVarBit - N)) break;
+ ++N;
+ --bit;
+ }
+
+ if (!gotOp) {
+ /// If this operand is not supposed to be emitted by the generated
+ /// emitter, skip it.
+ while (CGI.isFlatOperandNotEmitted(op))
+ ++op;
+
+ Case += " // op: " + VarName + "\n"
+ + " op = getMachineOpValue(MI, MI.getOperand("
+ + utostr(op++) + "));\n";
+ gotOp = true;
+ }
+
+ unsigned opMask = (1 << N) - 1;
+ int opShift = beginVarBit - N + 1;
+ opMask <<= opShift;
+ opShift = beginInstBit - beginVarBit;
+
+ if (opShift > 0) {
+ Case += " Value |= (op & " + utostr(opMask) + "U) << "
+ + itostr(opShift) + ";\n";
+ } else if (opShift < 0) {
+ Case += " Value |= (op & " + utostr(opMask) + "U) >> "
+ + itostr(-opShift) + ";\n";
+ } else {
+ Case += " Value |= op & " + utostr(opMask) + "U;\n";
+ }
+ }
+ }
+ }
+ }
+
+ std::vector<std::string> &InstList = CaseMap[Case];
+ InstList.push_back(InstName);
+ }
+
+
+ // Emit initial function code
+ o << " const unsigned opcode = MI.getOpcode();\n"
+ << " unsigned Value = InstBits[opcode];\n"
+ << " unsigned op;\n"
+ << " switch (opcode) {\n";
+
+ // Emit each case statement
+ std::map<std::string, std::vector<std::string> >::iterator IE, EE;
+ for (IE = CaseMap.begin(), EE = CaseMap.end(); IE != EE; ++IE) {
+ const std::string &Case = IE->first;
+ std::vector<std::string> &InstList = IE->second;
+
+ for (int i = 0, N = InstList.size(); i < N; i++) {
+ if (i) o << "\n";
+ o << " case " << Namespace << InstList[i] << ":";
+ }
+ o << " {\n";
+ o << Case;
+ o << " break;\n"
+ << " }\n";
+ }
+
+ // Default case: unhandled opcode
+ o << " default:\n"
+ << " cerr << \"Not supported instr: \" << MI << \"\\n\";\n"
+ << " abort();\n"
+ << " }\n"
+ << " return Value;\n"
+ << "}\n\n";
+}