Do not drop constant values when a variable's content is described using .debug_loc...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132427 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 3c42f2de44a7a650fd46bbec246a12218651757c..0dc5b74fa378abbbb9ab851a5d3bd62c6ad53299 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1410,16 +1410,6 @@ DwarfDebug::collectVariableInfo(const MachineFunction *MF,
            HI = History.begin(), HE = History.end(); HI != HE; ++HI) {
       const MachineInstr *Begin = *HI;
       assert(Begin->isDebugValue() && "Invalid History entry");
-      MachineLocation MLoc;
-      if (Begin->getNumOperands() == 3) {
-        if (Begin->getOperand(0).isReg() && Begin->getOperand(1).isImm())
-          MLoc.set(Begin->getOperand(0).getReg(), Begin->getOperand(1).getImm());
-      } else
-        MLoc = Asm->getDebugValueLocation(Begin);
-
-      // FIXME: emitDebugLoc only understands registers.
-      if (!MLoc.getReg())
-        continue;
 
       // Compute the range for a register location.
       const MCSymbol *FLabel = getLabelBeforeInsn(Begin);
@@ -1442,7 +1432,25 @@ DwarfDebug::collectVariableInfo(const MachineFunction *MF,
       }
 
       // The value is valid until the next DBG_VALUE or clobber.
-      DotDebugLocEntries.push_back(DotDebugLocEntry(FLabel, SLabel, MLoc, Var));
+      MachineLocation MLoc;
+      if (Begin->getNumOperands() == 3) {
+        if (Begin->getOperand(0).isReg() && Begin->getOperand(1).isImm()) {
+          MLoc.set(Begin->getOperand(0).getReg(), 
+                   Begin->getOperand(1).getImm());
+          DotDebugLocEntries.
+            push_back(DotDebugLocEntry(FLabel, SLabel, MLoc, Var));
+        }
+        // FIXME: Handle isFPImm also.
+        else if (Begin->getOperand(0).isImm()) {
+          DotDebugLocEntries.
+            push_back(DotDebugLocEntry(FLabel, SLabel, 
+                                       Begin->getOperand(0).getImm()));
+        }
+      } else {
+        MLoc = Asm->getDebugValueLocation(Begin);
+        DotDebugLocEntries.
+          push_back(DotDebugLocEntry(FLabel, SLabel, MLoc, Var));
+      }
     }
     DotDebugLocEntries.push_back(DotDebugLocEntry());
   }
@@ -2586,7 +2594,20 @@ void DwarfDebug::emitDebugLoc() {
       MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
       Asm->EmitLabelDifference(end, begin, 2);
       Asm->OutStreamer.EmitLabel(begin);
-      if (DV.hasComplexAddress()) {
+      if (Entry.isConstant()) {
+        DIBasicType BTy(DV.getType());
+        if (BTy.Verify() &&
+            (BTy.getEncoding()  == dwarf::DW_ATE_signed 
+             || BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
+          Asm->OutStreamer.AddComment("DW_OP_consts");
+          Asm->EmitInt8(dwarf::DW_OP_consts);
+          Asm->EmitSLEB128(Entry.getConstant());
+        } else {
+          Asm->OutStreamer.AddComment("DW_OP_constu");
+          Asm->EmitInt8(dwarf::DW_OP_constu);
+          Asm->EmitULEB128(Entry.getConstant());
+        }
+      } else if (DV.hasComplexAddress()) {
         unsigned N = DV.getNumAddrElements();
         unsigned i = 0;
         if (N >= 2 && DV.getAddrElement(0) == DIBuilder::OpPlus) {
@@ -2620,6 +2641,7 @@ void DwarfDebug::emitDebugLoc() {
           else llvm_unreachable("unknown Opcode found in complex address");
         }
       } else {
+        // Regular entry.
         Asm->EmitDwarfRegOp(Entry.Loc);
       }
       Asm->OutStreamer.EmitLabel(end);

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 5b29f787df645d6bc65360b9188e06052fdd4f85..abda2e61d31e5668ead0bf5e668569308ee7144b 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -68,10 +68,19 @@ typedef struct DotDebugLocEntry {
   MachineLocation Loc;
   const MDNode *Variable;
   bool Merged;
-  DotDebugLocEntry() : Begin(0), End(0), Variable(0), Merged(false) {}
+  bool Constant;
+  int64_t iConstant;
+  DotDebugLocEntry() 
+    : Begin(0), End(0), Variable(0), Merged(false), 
+      Constant(false), iConstant(0) {}
   DotDebugLocEntry(const MCSymbol *B, const MCSymbol *E, MachineLocation &L,
                    const MDNode *V) 
-    : Begin(B), End(E), Loc(L), Variable(V), Merged(false) {}
+    : Begin(B), End(E), Loc(L), Variable(V), Merged(false), 
+      Constant(false), iConstant(0) {}
+  DotDebugLocEntry(const MCSymbol *B, const MCSymbol *E, int64_t i)
+    : Begin(B), End(E), Variable(0), Merged(false), 
+      Constant(true), iConstant(i) {}
+
   /// Empty entries are also used as a trigger to emit temp label. Such
   /// labels are referenced is used to find debug_loc offset for a given DIE.
   bool isEmpty() { return Begin == 0 && End == 0; }
@@ -82,6 +91,8 @@ typedef struct DotDebugLocEntry {
     Next->Begin = Begin;
     Merged = true;
   }
+  bool isConstant() { return Constant; }
+  int64_t getConstant() { return iConstant; }
 } DotDebugLocEntry;
 
 //===----------------------------------------------------------------------===//

diff --git a/test/CodeGen/X86/dbg-const.ll b/test/CodeGen/X86/dbg-const.ll
new file mode 100644 (file)
index 0000000..5a51eb8
--- /dev/null
+++ b/test/CodeGen/X86/dbg-const.ll
@@ -0,0 +1,34 @@
+; RUN: llc < %s - | FileCheck %s
+target triple = "x86_64-apple-darwin10.0.0"
+
+;CHECK:        ## DW_OP_constu
+;CHECK-NEXT:  .byte    42
+define i32 @foobar() nounwind readonly noinline ssp {
+entry:
+  %call = tail call i32 @bar(), !dbg !11
+  tail call void @llvm.dbg.value(metadata !8, i64 0, metadata !6), !dbg !9
+  %call2 = tail call i32 @bar(), !dbg !11
+  tail call void @llvm.dbg.value(metadata !{i32 %call}, i64 0, metadata !6), !dbg !11
+  %add = add nsw i32 %call2, %call, !dbg !12
+  ret i32 %add, !dbg !10
+}
+
+declare void @llvm.dbg.value(metadata, i64, metadata) nounwind readnone
+declare i32 @bar() nounwind readnone
+
+!llvm.dbg.sp = !{!0}
+!llvm.dbg.lv.foobar = !{!6}
+
+!0 = metadata !{i32 524334, i32 0, metadata !1, metadata !"foobar", metadata !"foobar", metadata !"foobar", metadata !1, i32 12, metadata !3, i1 false, i1 true, i32 0, i32 0, null, i1 false, i1 true, i32 ()* @foobar}
+!1 = metadata !{i32 524329, metadata !"mu.c", metadata !"/private/tmp", metadata !2}
+!2 = metadata !{i32 524305, i32 0, i32 12, metadata !"mu.c", metadata !"/private/tmp", metadata !"clang version 2.9 (trunk 114183)", i1 true, i1 true, metadata !"", i32 0}
+!3 = metadata !{i32 524309, metadata !1, metadata !"", metadata !1, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !4, i32 0, null}
+!4 = metadata !{metadata !5}
+!5 = metadata !{i32 524324, metadata !1, metadata !"int", metadata !1, i32 0, i64 32, i64 32, i64 0, i32 0, i32 5}
+!6 = metadata !{i32 524544, metadata !7, metadata !"j", metadata !1, i32 15, metadata !5}
+!7 = metadata !{i32 524299, metadata !0, i32 12, i32 52, metadata !1, i32 0}
+!8 = metadata !{i32 42}
+!9 = metadata !{i32 15, i32 12, metadata !7, null}
+!10 = metadata !{i32 23, i32 3, metadata !7, null}
+!11 = metadata !{i32 17, i32 3, metadata !7, null}
+!12 = metadata !{i32 18, i32 3, metadata !7, null}