The debug information for an LLVM Instruction applies to that Instruction

and that Instruction only. Implement this by setting the "current debug position"
back to Unknown after processing each instruction.

llvm-svn: 90632

llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

@@ -362,6 +362,39 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
   return true;
 }
 
+/// SetDebugLoc - Update MF's and SDB's DebugLocs if debug information is
+/// attached with this instruction.
+static void SetDebugLoc(unsigned MDDbgKind,
+                        MetadataContext &TheMetadata,
+                        Instruction *I,
+                        SelectionDAGBuilder *SDB,
+                        FastISel *FastIS,
+                        MachineFunction *MF) {
+  if (!isa<DbgInfoIntrinsic>(I)) 
+    if (MDNode *Dbg = TheMetadata.getMD(MDDbgKind, I)) {
+      DILocation DILoc(Dbg);
+      DebugLoc Loc = ExtractDebugLocation(DILoc, MF->getDebugLocInfo());
+
+      SDB->setCurDebugLoc(Loc);
+
+      if (FastIS)
+        FastIS->setCurDebugLoc(Loc);
+
+      // If the function doesn't have a default debug location yet, set
+      // it. This is kind of a hack.
+      if (MF->getDefaultDebugLoc().isUnknown())
+        MF->setDefaultDebugLoc(Loc);
+    }
+}
+
+/// ResetDebugLoc - Set MF's and SDB's DebugLocs to Unknown.
+static void ResetDebugLoc(SelectionDAGBuilder *SDB,
+                          FastISel *FastIS) {
+  SDB->setCurDebugLoc(DebugLoc::getUnknownLoc());
+  if (FastIS)
+    SDB->setCurDebugLoc(DebugLoc::getUnknownLoc());
+}
+
 void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB,
                                         BasicBlock::iterator Begin,
                                         BasicBlock::iterator End,
@@ -373,20 +406,16 @@ void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB,
   // Lower all of the non-terminator instructions. If a call is emitted
   // as a tail call, cease emitting nodes for this block.
   for (BasicBlock::iterator I = Begin; I != End && !SDB->HasTailCall; ++I) {
-    if (MDDbgKind) {
+    if (MDDbgKind)
-      // Update DebugLoc if debug information is attached with this
+      SetDebugLoc(MDDbgKind, TheMetadata, I, SDB, 0, MF);
-      // instruction.
+
-      if (!isa<DbgInfoIntrinsic>(I)) 
+    if (!isa<TerminatorInst>(I)) {
-        if (MDNode *Dbg = TheMetadata.getMD(MDDbgKind, I)) {
-          DILocation DILoc(Dbg);
-          DebugLoc Loc = ExtractDebugLocation(DILoc, MF->getDebugLocInfo());
-          SDB->setCurDebugLoc(Loc);
-          if (MF->getDefaultDebugLoc().isUnknown())
-            MF->setDefaultDebugLoc(Loc);
-        }
-    }
-    if (!isa<TerminatorInst>(I))
       SDB->visit(*I);
+
+      // Set the current debug location back to "unknown" so that it doesn't
+      // spuriously apply to subsequent instructions.
+      ResetDebugLoc(SDB, 0);
+    }
   }
 
   if (!SDB->HasTailCall) {
@@ -401,7 +430,9 @@ void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB,
       HandlePHINodesInSuccessorBlocks(LLVMBB);
 
       // Lower the terminator after the copies are emitted.
+      SetDebugLoc(MDDbgKind, TheMetadata, LLVMBB->getTerminator(), SDB, 0, MF);
       SDB->visit(*LLVMBB->getTerminator());
+      ResetDebugLoc(SDB, 0);
     }
   }
 
@@ -738,24 +769,14 @@ void SelectionDAGISel::SelectAllBasicBlocks(Function &Fn,
       FastIS->startNewBlock(BB);
       // Do FastISel on as many instructions as possible.
       for (; BI != End; ++BI) {
-        if (MDDbgKind) {
+        if (MDDbgKind)
-          // Update DebugLoc if debug information is attached with this
+          SetDebugLoc(MDDbgKind, TheMetadata, BI, SDB, FastIS, &MF);
-          // instruction.
-          if (!isa<DbgInfoIntrinsic>(BI)) 
-            if (MDNode *Dbg = TheMetadata.getMD(MDDbgKind, BI)) {
-              DILocation DILoc(Dbg);
-              DebugLoc Loc = ExtractDebugLocation(DILoc,
-                                                  MF.getDebugLocInfo());
-              FastIS->setCurDebugLoc(Loc);
-              if (MF.getDefaultDebugLoc().isUnknown())
-                MF.setDefaultDebugLoc(Loc);
-            }
-        }
 
         // Just before the terminator instruction, insert instructions to
         // feed PHI nodes in successor blocks.
         if (isa<TerminatorInst>(BI))
           if (!HandlePHINodesInSuccessorBlocksFast(LLVMBB, FastIS)) {
+            ResetDebugLoc(SDB, FastIS);
             if (EnableFastISelVerbose || EnableFastISelAbort) {
               errs() << "FastISel miss: ";
               BI->dump();
@@ -766,12 +787,20 @@ void SelectionDAGISel::SelectAllBasicBlocks(Function &Fn,
           }
 
         // First try normal tablegen-generated "fast" selection.
-        if (FastIS->SelectInstruction(BI))
+        if (FastIS->SelectInstruction(BI)) {
+          ResetDebugLoc(SDB, FastIS);
           continue;
+        }
 
         // Next, try calling the target to attempt to handle the instruction.
-        if (FastIS->TargetSelectInstruction(BI))
+        if (FastIS->TargetSelectInstruction(BI)) {
+          ResetDebugLoc(SDB, FastIS);
           continue;
+        }
+
+        // Clear out the debug location so that it doesn't carry over to
+        // unrelated instructions.
+        ResetDebugLoc(SDB, FastIS);
 
         // Then handle certain instructions as single-LLVM-Instruction blocks.
         if (isa<CallInst>(BI)) {
@@ -786,8 +815,6 @@ void SelectionDAGISel::SelectAllBasicBlocks(Function &Fn,
               R = FuncInfo->CreateRegForValue(BI);
           }
 
-          SDB->setCurDebugLoc(FastIS->getCurDebugLoc());
-
           bool HadTailCall = false;
           SelectBasicBlock(LLVMBB, BI, llvm::next(BI), HadTailCall);
 
@@ -823,9 +850,6 @@ void SelectionDAGISel::SelectAllBasicBlocks(Function &Fn,
     // not handled by FastISel. If FastISel is not run, this is the entire
     // block.
     if (BI != End) {
-      // If FastISel is run and it has known DebugLoc then use it.
-      if (FastIS && !FastIS->getCurDebugLoc().isUnknown())
-        SDB->setCurDebugLoc(FastIS->getCurDebugLoc());
       bool HadTailCall;
       SelectBasicBlock(LLVMBB, BI, End, HadTailCall);
     }