Add support for a pattern matching instruction selector. This is still in
the early implementation phases, so it is disabled by default
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7719 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/InstSelectPattern.cpp b/lib/Target/X86/InstSelectPattern.cpp
new file mode 100644
index 0000000..4b9e381
--- /dev/null
+++ b/lib/Target/X86/InstSelectPattern.cpp
@@ -0,0 +1,117 @@
+//===-- InstSelectPattern.cpp - A pattern matching inst selector for X86 --===//
+//
+// This file defines a pattern matching instruction selector for X86.
+//
+// FIXME: we could allocate one big array of unsigneds to use as the backing
+// store for all of the nodes costs arrays.
+//
+//===----------------------------------------------------------------------===//
+
+#include "X86.h"
+#include "llvm/Pass.h"
+#include "llvm/Function.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/SSARegMap.h"
+
+#include "X86RegisterInfo.h"
+
+// Include the generated instruction selector...
+#include "X86GenInstrSelector.inc"
+
+
+//===----------------------------------------------------------------------===//
+// User code
+//
+
+
+namespace {
+ struct ISel : public FunctionPass, SelectionDAGTargetBuilder {
+ TargetMachine &TM;
+ ISel(TargetMachine &tm) : TM(tm) {}
+ int VarArgsFrameIndex; // FrameIndex for start of varargs area
+
+ bool runOnFunction(Function &Fn) {
+ MachineFunction &MF = MachineFunction::construct(&Fn, TM);
+ SelectionDAG DAG(MF, TM, *this);
+
+ std::cerr << "\n\n\n=== "
+ << DAG.getMachineFunction().getFunction()->getName() << "\n";
+
+ DAG.dump();
+ X86ISel(DAG).generateCode();
+ std::cerr << "\n\n\n";
+ return true;
+ }
+
+ public: // Implementation of the SelectionDAGTargetBuilder class...
+ /// expandArguments - Add nodes to the DAG to indicate how to load arguments
+ /// off of the X86 stack.
+ void expandArguments(SelectionDAG &SD, MachineFunction &MF);
+ };
+}
+
+
+void ISel::expandArguments(SelectionDAG &SD, MachineFunction &F) {
+ // Add DAG nodes to load the arguments... On entry to a function on the X86,
+ // the stack frame looks like this:
+ //
+ // [ESP] -- return address
+ // [ESP + 4] -- first argument (leftmost lexically)
+ // [ESP + 8] -- second argument, if first argument is four bytes in size
+ // ...
+ //
+ unsigned ArgOffset = 0; // Frame mechanisms handle retaddr slot
+ MachineFrameInfo *MFI = F.getFrameInfo();
+ const Function &Fn = *F.getFunction();
+
+ for (Function::const_aiterator I = Fn.abegin(), E = Fn.aend(); I != E; ++I) {
+ MVT::ValueType ObjectVT = SD.getValueType(I->getType());
+ unsigned ArgIncrement = 4;
+ unsigned ObjSize;
+ switch (ObjectVT) {
+ default: assert(0 && "Unhandled argument type!");
+ case MVT::i8: ObjSize = 1; break;
+ case MVT::i16: ObjSize = 2; break;
+ case MVT::i32: ObjSize = 4; break;
+ case MVT::i64: ObjSize = ArgIncrement = 8; break;
+ case MVT::f32: ObjSize = 4; break;
+ case MVT::f64: ObjSize = ArgIncrement = 8; break;
+ }
+ // Create the frame index object for this incoming parameter...
+ int FI = MFI->CreateFixedObject(ObjSize, ArgOffset);
+
+ // Create the SelectionDAG nodes corresponding to a load from this parameter
+ // FIXME:
+ SelectionDAGNode *FIN = new SelectionDAGNode(ISD::FrameIndex, MVT::i32);
+ FIN->addValue(new ReducedValue_FrameIndex_i32(FI));
+
+ SelectionDAGNode *Arg
+ = new SelectionDAGNode(ISD::Load, ObjectVT, F.begin(), FIN);
+
+ // Add the SelectionDAGNodes to the SelectionDAG... note that there is no
+ // reason to add chain nodes here. We know that no loads ore stores will
+ // ever alias these loads, so we are free to perform the load at any time in
+ // the function
+ SD.addNode(FIN);
+ SD.addNodeForValue(Arg, I);
+
+ ArgOffset += ArgIncrement; // Move on to the next argument...
+ }
+
+ // If the function takes variable number of arguments, make a frame index for
+ // the start of the first vararg value... for expansion of llvm.va_start.
+ if (Fn.getFunctionType()->isVarArg())
+ VarArgsFrameIndex = MFI->CreateFixedObject(1, ArgOffset);
+}
+
+
+/// createX86PatternInstructionSelector - This pass converts an LLVM function
+/// into a machine code representation using pattern matching and a machine
+/// description file.
+///
+Pass *createX86PatternInstructionSelector(TargetMachine &TM) {
+ return new ISel(TM);
+}