Debug info for variables whose type is shrinked to bool

This patch provides such debug information for integer
variables whose type is shrinked to bool by providing
dwarf expression which returns either constant initial
value or other value.

Patch by Nikola Prica.

Differential Revision: https://reviews.llvm.org/D35994

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312318 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
index 4538bb3ff02e3a8e496bf291c03e4eb20c61d7b8..429269d36d886bcee717fae4d017823851b38e98 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
@@ -338,6 +338,7 @@ void DwarfExpression::addExpression(DIExpressionCursor &&ExprCursor,
       break;
     case dwarf::DW_OP_plus:
     case dwarf::DW_OP_minus:
+    case dwarf::DW_OP_mul:
       emitOp(Op->getOp());
       break;
     case dwarf::DW_OP_deref:

diff --git a/lib/IR/DebugInfoMetadata.cpp b/lib/IR/DebugInfoMetadata.cpp
index 005aac821f9f27ae39b174b988fa6fc72f87bec0..8f6822e3c9744d3bfd24a0e1b90f2628b4bca5d4 100644 (file)
--- a/lib/IR/DebugInfoMetadata.cpp
+++ b/lib/IR/DebugInfoMetadata.cpp
@@ -643,6 +643,7 @@ bool DIExpression::isValid() const {
     case dwarf::DW_OP_plus_uconst:
     case dwarf::DW_OP_plus:
     case dwarf::DW_OP_minus:
+    case dwarf::DW_OP_mul:
     case dwarf::DW_OP_deref:
     case dwarf::DW_OP_xderef:
       break;

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index ee8fdaebbdae8ac969bd1229dab7d93cd725db5a..8d4bde40968172311a2d5be4b15537210e2c366c 100644 (file)
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -36,6 +36,7 @@
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/ValueHandle.h"
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -1603,12 +1604,47 @@ static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) {
   assert(InitVal->getType() != Type::getInt1Ty(GV->getContext()) &&
          "No reason to shrink to bool!");
 
+  SmallVector<DIGlobalVariableExpression *, 1> GVs;
+  GV->getDebugInfo(GVs);
+
   // If initialized to zero and storing one into the global, we can use a cast
   // instead of a select to synthesize the desired value.
   bool IsOneZero = false;
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal))
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(OtherVal)){
     IsOneZero = InitVal->isNullValue() && CI->isOne();
 
+    ConstantInt *CIInit = dyn_cast<ConstantInt>(GV->getInitializer());
+    uint64_t ValInit = CIInit->getZExtValue();
+    uint64_t ValOther = CI->getZExtValue();
+    uint64_t ValMinus = ValOther - ValInit;
+
+    for(auto *GVe : GVs){
+      DIGlobalVariable *DGV = GVe->getVariable();
+      DIExpression *E = GVe->getExpression();
+
+      // val * (ValOther - ValInit) + ValInit:
+      // DW_OP_deref DW_OP_constu <ValMinus>
+      // DW_OP_mul DW_OP_constu <ValInit> DW_OP_plus DW_OP_stack_value
+      E = DIExpression::get(NewGV->getContext(),
+                           {dwarf::DW_OP_deref,
+                            dwarf::DW_OP_constu,
+                            ValMinus,
+                            dwarf::DW_OP_mul,
+                            dwarf::DW_OP_constu,
+                            ValInit,
+                            dwarf::DW_OP_plus,
+                            dwarf::DW_OP_stack_value});
+      DIGlobalVariableExpression *DGVE =
+        DIGlobalVariableExpression::get(NewGV->getContext(), DGV, E);
+      NewGV->addDebugInfo(DGVE);
+    }
+  } else {
+    // FIXME: This will only emit address for debugger on which will
+    // be written only 0 or 1.
+    for(auto *GV : GVs)
+      NewGV->addDebugInfo(GV);
+  }
+
   while (!GV->use_empty()) {
     Instruction *UI = cast<Instruction>(GV->user_back());
     if (StoreInst *SI = dyn_cast<StoreInst>(UI)) {