Generate DBG_VALUE from dbg.value intrinsics. These currently

comes out as comments but will eventually generate DWARF.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96601 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index 69a9d60bda..c2e675a032 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -1161,10 +1161,41 @@ bool X86FastISel::X86VisitIntrinsicCall(IntrinsicInst &I) {
     if (!X86SelectAddress(DI->getAddress(), AM))
       return false;
     const TargetInstrDesc &II = TII.get(TargetOpcode::DBG_VALUE);
+    // FIXME may need to add RegState::Debug to any registers produced,
+    // although ESP/EBP should be the only ones at the moment.
     addFullAddress(BuildMI(MBB, DL, II), AM).addImm(0).
                                         addMetadata(DI->getVariable());
     return true;
   }
+  case Intrinsic::dbg_value: {
+    // FIXME this should eventually be moved to FastISel, when all targets
+    // are able to cope with DBG_VALUE.  There is nothing target dependent here.
+    DbgValueInst *DI = cast<DbgValueInst>(&I);
+    const TargetInstrDesc &II = TII.get(TargetOpcode::DBG_VALUE);
+    Value *V = DI->getValue();
+    if (!V) {
+      // Currently the optimizer can produce this; insert an undef to
+      // help debugging.  Probably the optimizer should not do this.
+      BuildMI(MBB, DL, II).addReg(0U).addImm(DI->getOffset()).
+                                     addMetadata(DI->getVariable());
+    } else if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+      BuildMI(MBB, DL, II).addImm(CI->getZExtValue()).addImm(DI->getOffset()).
+                                     addMetadata(DI->getVariable());
+    } else if (ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
+      BuildMI(MBB, DL, II).addFPImm(CF).addImm(DI->getOffset()).
+                                     addMetadata(DI->getVariable());
+    } else if (unsigned Reg = lookUpRegForValue(V)) {
+      BuildMI(MBB, DL, II).addReg(Reg, RegState::Debug).addImm(DI->getOffset()).
+                                     addMetadata(DI->getVariable());
+    } else {
+      // We can't yet handle anything else here because it would require
+      // generating code, thus altering codegen because of debug info.
+      // Insert an undef so we can see what we dropped.
+      BuildMI(MBB, DL, II).addReg(0U).addImm(DI->getOffset()).
+                                     addMetadata(DI->getVariable());
+    }     
+    return true;
+  }
   case Intrinsic::trap: {
     BuildMI(MBB, DL, TII.get(X86::TRAP));
     return true;