Global variables don't have a corresponding llvm.dbg.declare, yet it is possible

to obtain debug info about them.
Introduce helpers to access debug info for global variables. Also introduce a
helper that works for both local and global variables.

llvm-svn: 66541

2 files changed, 75 insertions, 6 deletions

diff --git a/llvm/lib/Analysis/DbgInfoPrinter.cpp b/llvm/lib/Analysis/DbgInfoPrinter.cpp
index 127f931b6ed..e43bc81ffac 100644
--- a/llvm/lib/Analysis/DbgInfoPrinter.cpp
+++ b/llvm/lib/Analysis/DbgInfoPrinter.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Module.h"
 #include "llvm/Value.h"
 #include "llvm/IntrinsicInst.h"
+#include "llvm/Assembly/Writer.h"
 #include "llvm/Analysis/DebugInfo.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Analysis/ValueTracking.h"
@@ -57,12 +58,17 @@ FunctionPass *llvm::createDbgInfoPrinterPass() { return new PrintDbgInfo(); }
 
 void PrintDbgInfo::printVariableDeclaration(const Value *V)
 {
-  if(const DbgDeclareInst* DDI = findDbgDeclare(V)) {
-    DIVariable Var(cast<GlobalVariable>(DDI->getVariable()));
-    std::string Res1, Res2;
-    Out << "; variable " << Var.getName(Res1)
-      << " of type " << Var.getType().getName(Res2)
-      << " at line " << Var.getLineNumber() << "\n";
+  std::string DisplayName, File, Directory, Type;
+  unsigned LineNo;
+  if (getLocationInfo(V, DisplayName, Type, LineNo, File, Directory)) {
+    Out << "; ";
+    WriteAsOperand(Out, V, false, 0);
+    Out << " is variable " << DisplayName
+      << " of type " << Type << " declared at ";
+    if (PrintDirectory) {
+      Out << Directory << "/";
+    }
+    Out << File << ":" << LineNo << "\n";
   }
 }
 
@@ -140,6 +146,11 @@ bool PrintDbgInfo::runOnFunction(Function &F)
         }
         Out << *i;
         printVariableDeclaration(i);
+        if (const User *U = dyn_cast<User>(i)) {
+          for(unsigned i=0;i<U->getNumOperands();i++) {
+            printVariableDeclaration(U->getOperand(i));
+          }
+        }
       }
     }
   }
diff --git a/llvm/lib/Analysis/DebugInfo.cpp b/llvm/lib/Analysis/DebugInfo.cpp
index 4e229e96690..d9f0aa53e9d 100644
--- a/llvm/lib/Analysis/DebugInfo.cpp
+++ b/llvm/lib/Analysis/DebugInfo.cpp
@@ -841,6 +841,34 @@ namespace llvm {
     return 0;
   }
 
+  Value *findDbgGlobalDeclare(GlobalVariable *V)
+  {
+    const Module *M = V->getParent();
+    const Type *Ty = M->getTypeByName("llvm.dbg.global_variable.type");
+    if (!Ty)
+      return 0;
+    Ty = PointerType::get(Ty, 0);
+
+    Value *Val = V->stripPointerCasts();
+    for (Value::use_iterator I = Val->use_begin(), E =Val->use_end();
+         I != E; ++I) {
+      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(I)) {
+        if (CE->getOpcode() == Instruction::BitCast) {
+          Value *VV = CE;
+          while (VV->hasOneUse()) {
+            VV = *VV->use_begin();
+          }
+          if (VV->getType() == Ty)
+            return VV;
+        }
+      }
+    }
+    
+    if (Val->getType() == Ty)
+      return Val;
+    return 0;
+  }
+
   /// Finds the dbg.declare intrinsic corresponding to this value if any.
   /// It looks through pointer casts too.
   const DbgDeclareInst *findDbgDeclare(const Value *V, bool stripCasts)
@@ -864,6 +892,36 @@ namespace llvm {
     }
     return 0;
   }
+
+  bool getLocationInfo(const Value *V, std::string &DisplayName, std::string &Type,
+                       unsigned &LineNo, std::string &File, std::string &Dir)
+  {
+    DICompileUnit Unit;
+    DIType TypeD;
+    if (GlobalVariable *GV = dyn_cast<GlobalVariable>(const_cast<Value*>(V))) {
+      Value *DIGV = findDbgGlobalDeclare(GV);
+      if (!DIGV)
+        return false;
+      DIGlobalVariable Var(cast<GlobalVariable>(DIGV));
+      Var.getDisplayName(DisplayName);
+      LineNo = Var.getLineNumber();
+      Unit = Var.getCompileUnit();
+      TypeD = Var.getType();
+    } else {
+      const DbgDeclareInst *DDI = findDbgDeclare(V);
+      if (!DDI)
+        return false;
+      DIVariable Var(cast<GlobalVariable>(DDI->getVariable()));
+      Var.getName(DisplayName);
+      LineNo = Var.getLineNumber();
+      Unit = Var.getCompileUnit();
+      TypeD = Var.getType();
+    }
+    TypeD.getName(Type);
+    Unit.getFilename(File);
+    Unit.getDirectory(Dir);
+    return true;
+  }
 }
 
 /// dump - print compile unit.