clarify: stub emission depends on the version of the linker you use, it has nothing

[oota-llvm.git] / lib / Target / TargetRegisterInfo.cpp

diff --git a/lib/Target/TargetRegisterInfo.cpp b/lib/Target/TargetRegisterInfo.cpp
index e69496f4b287ba372c2f4871a9c1d999d07027c6..a84fdaa4a8029f8a2b09c71c0eab0220939b49f9 100644 (file)
--- a/lib/Target/TargetRegisterInfo.cpp
+++ b/lib/Target/TargetRegisterInfo.cpp
@@ -22,38 +22,23 @@ using namespace llvm;
 
 TargetRegisterInfo::TargetRegisterInfo(const TargetRegisterDesc *D, unsigned NR,
                              regclass_iterator RCB, regclass_iterator RCE,
-                             int CFSO, int CFDO)
-  : Desc(D), NumRegs(NR), RegClassBegin(RCB), RegClassEnd(RCE) {
+                             int CFSO, int CFDO,
+                             const unsigned* subregs, const unsigned subregsize,
+                         const unsigned* superregs, const unsigned superregsize,
+                         const unsigned* aliases, const unsigned aliasessize)
+  : SubregHash(subregs), SubregHashSize(subregsize),
+    SuperregHash(superregs), SuperregHashSize(superregsize),
+    AliasesHash(aliases), AliasesHashSize(aliasessize),
+    Desc(D), NumRegs(NR), RegClassBegin(RCB), RegClassEnd(RCE) {
   assert(NumRegs < FirstVirtualRegister &&
          "Target has too many physical registers!");
 
   CallFrameSetupOpcode   = CFSO;
   CallFrameDestroyOpcode = CFDO;
-  
-  for (unsigned i = 0; i < NumRegs; ++i) {
-    const TargetRegisterDesc* CurrReg = Desc + i;
-    
-    // Initialize the Subregs set, which stores pairs (a, b) where
-    // b is a subreg of a.
-    if (CurrReg->SubRegs)
-      for (const unsigned* CurrSR = CurrReg->SubRegs; *CurrSR; ++CurrSR)
-        Subregs.insert(std::make_pair(i, *CurrSR));
-  }
 }
 
 TargetRegisterInfo::~TargetRegisterInfo() {}
 
-namespace {
-  // Sort according to super- / sub- class relations.
-  // i.e. super- register class < sub- register class.
-  struct RCCompare {
-    bool operator()(const TargetRegisterClass* const &LHS,
-                    const TargetRegisterClass* const &RHS) {
-      return RHS->hasSuperClass(LHS);
-    }
-  };
-}
-
 /// getPhysicalRegisterRegClass - Returns the Register Class of a physical
 /// register of the given type. If type is MVT::Other, then just return any
 /// register class the register belongs to.
@@ -61,24 +46,18 @@ const TargetRegisterClass *
 TargetRegisterInfo::getPhysicalRegisterRegClass(unsigned reg, MVT VT) const {
   assert(isPhysicalRegister(reg) && "reg must be a physical register");
 
-  // Pick the register class of the right type that contains this physreg.
-  SmallVector<const TargetRegisterClass*, 4> RCs;
+  // Pick the most super register class of the right type that contains
+  // this physreg.
+  const TargetRegisterClass* BestRC = 0;
   for (regclass_iterator I = regclass_begin(), E = regclass_end(); I != E; ++I){
-    if ((VT == MVT::Other || (*I)->hasType(VT)) && (*I)->contains(reg))
-      RCs.push_back(*I);
-  }
-
-  if (RCs.size() == 1)
-    return RCs[0];
-
-  if (RCs.size()) {
-    // Multiple compatible register classes. Get the super- class.
-    std::stable_sort(RCs.begin(), RCs.end(), RCCompare());
-    return RCs[0];
+    const TargetRegisterClass* RC = *I;
+    if ((VT == MVT::Other || RC->hasType(VT)) && RC->contains(reg) &&
+        (!BestRC || BestRC->hasSuperClass(RC)))
+      BestRC = RC;
   }
 
-  assert(false && "Couldn't find the register class");
-  return 0;
+  assert(BestRC && "Couldn't find the register class");
+  return BestRC;
 }
 
 /// getAllocatableSetForRC - Toggle the bits that represent allocatable
@@ -121,3 +100,45 @@ TargetRegisterInfo::getInitialFrameState(std::vector<MachineMove> &Moves) const
   // Default is to do nothing.
 }
 
+const TargetRegisterClass *
+llvm::getCommonSubClass(const TargetRegisterClass *A,
+                        const TargetRegisterClass *B) {
+  // First take care of the trivial cases
+  if (A == B)
+    return A;
+  if (!A || !B)
+    return 0;
+
+  // If B is a subclass of A, it will be handled in the loop below
+  if (B->hasSubClass(A))
+    return A;
+
+  const TargetRegisterClass *Best = 0;
+  for (TargetRegisterClass::sc_iterator I = A->subclasses_begin();
+       const TargetRegisterClass *X = *I; ++I) {
+    if (X == B)
+      return B;                 // B is a subclass of A
+
+    // X must be a common subclass of A and B
+    if (!B->hasSubClass(X))
+      continue;
+
+    // A superclass is definitely better.
+    if (!Best || Best->hasSuperClass(X)) {
+      Best = X;
+      continue;
+    }
+
+    // A subclass is definitely worse
+    if (Best->hasSubClass(X))
+      continue;
+
+    // Best and *I have no super/sub class relation - pick the larger class, or
+    // the smaller spill size.
+    int nb = std::distance(Best->begin(), Best->end());
+    int ni = std::distance(X->begin(), X->end());
+    if (ni>nb || (ni==nb && X->getSize() < Best->getSize()))
+      Best = X;
+  }
+  return Best;
+}