Inliner: Use replaceDbgDeclareForAlloca() instead of splicing the

instruction and generalize it to optionally dereference the variable.
Follow-up to r227544.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227604 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Transforms/Utils/Local.h

@@ -274,10 +274,11 @@ bool LowerDbgDeclare(Function &F);
 /// an alloca, if any.
 DbgDeclareInst *FindAllocaDbgDeclare(Value *V);
 
-/// replaceDbgDeclareForAlloca - Replaces llvm.dbg.declare instruction when
-/// alloca is replaced with a new value.
+/// \brief Replaces llvm.dbg.declare instruction when an alloca is replaced with
+/// a new value.  If Deref is true, tan additional DW_OP_deref is prepended to
+/// the expression.
 bool replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
-                                DIBuilder &Builder);
+                                DIBuilder &Builder, bool Deref);
 
 /// \brief Remove all blocks that can not be reached from the function's entry.
 ///

lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -1739,7 +1739,7 @@ void FunctionStackPoisoner::poisonStack() {
     Value *NewAllocaPtr = IRB.CreateIntToPtr(
         IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Desc.Offset)),
         AI->getType());
-    replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB);
+    replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB, /*Deref=*/true);
     AI->replaceAllUsesWith(NewAllocaPtr);
   }
 

lib/Transforms/Utils/InlineFunction.cpp

@@ -30,6 +30,7 @@
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instructions.h"
@@ -1112,13 +1113,10 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
                                                    AI, I);
     }
     // Move any dbg.declares describing the allocas into the entry basic block.
+    DIBuilder DIB(*Caller->getParent());
     for (auto &I : IFI.StaticAllocas)
       if (auto AI = dyn_cast<AllocaInst>(I))
-        if (auto *DDI = FindAllocaDbgDeclare(AI))
-          if (DDI->getParent() != Caller->begin())
-            Caller->getEntryBlock().getInstList()
-              .splice(AI->getNextNode(), FirstNewBlock->getInstList(),
-                      DDI, DDI->getNextNode());
+        replaceDbgDeclareForAlloca(AI, AI, DIB, /*Deref=*/false);
   }
 
   bool InlinedMustTailCalls = false;

lib/Transforms/Utils/Local.cpp

@@ -1106,10 +1106,11 @@ DbgDeclareInst *llvm::FindAllocaDbgDeclare(Value *V) {
 }
 
 bool llvm::replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
-                                      DIBuilder &Builder) {
+                                      DIBuilder &Builder, bool Deref) {
   DbgDeclareInst *DDI = FindAllocaDbgDeclare(AI);
   if (!DDI)
     return false;
+  DebugLoc Loc = DDI->getDebugLoc();
   DIVariable DIVar(DDI->getVariable());
   DIExpression DIExpr(DDI->getExpression());
   assert((!DIVar || DIVar.isVariable()) &&
@@ -1117,21 +1118,24 @@ bool llvm::replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
   if (!DIVar)
     return false;
 
-  // Create a copy of the original DIDescriptor for user variable, prepending
-  // "deref" operation to a list of address elements, as new llvm.dbg.declare
-  // will take a value storing address of the memory for variable, not
-  // alloca itself.
-  SmallVector<int64_t, 4> NewDIExpr;
-  NewDIExpr.push_back(dwarf::DW_OP_deref);
-  if (DIExpr)
-    for (unsigned i = 0, n = DIExpr.getNumElements(); i < n; ++i)
-      NewDIExpr.push_back(DIExpr.getElement(i));
+  if (Deref) {
+    // Create a copy of the original DIDescriptor for user variable, prepending
+    // "deref" operation to a list of address elements, as new llvm.dbg.declare
+    // will take a value storing address of the memory for variable, not
+    // alloca itself.
+    SmallVector<int64_t, 4> NewDIExpr;
+    NewDIExpr.push_back(dwarf::DW_OP_deref);
+    if (DIExpr)
+      for (unsigned i = 0, n = DIExpr.getNumElements(); i < n; ++i)
+        NewDIExpr.push_back(DIExpr.getElement(i));
+    DIExpr = Builder.createExpression(NewDIExpr);
+  }
 
   // Insert llvm.dbg.declare in the same basic block as the original alloca,
   // and remove old llvm.dbg.declare.
   BasicBlock *BB = AI->getParent();
-  Builder.insertDeclare(NewAllocaAddress, DIVar,
-                        Builder.createExpression(NewDIExpr), BB);
+  Builder.insertDeclare(NewAllocaAddress, DIVar, DIExpr, BB)
+    ->setDebugLoc(Loc);
   DDI->eraseFromParent();
   return true;
 }

test/Transforms/Inline/alloca-dbgdeclare.ll

@@ -40,7 +40,7 @@ entry:
 ; CHECK: define void @_Z3fn5v()
 ; CHECK-NEXT: entry:
 ; CHECK-NEXT:   %agg.tmp.sroa.3.i = alloca [20 x i8], align 4
-; CHECK-NEXT:   tail call void @llvm.dbg.declare(metadata [20 x i8]* %agg.tmp.sroa.3.i,
+; CHECK-NEXT:   call void @llvm.dbg.declare(metadata [20 x i8]* %agg.tmp.sroa.3.i,
   %agg.tmp.sroa.3 = alloca [20 x i8], align 4
   tail call void @llvm.dbg.declare(metadata [20 x i8]* %agg.tmp.sroa.3, metadata !46, metadata !48), !dbg !49
   %agg.tmp.sroa.0.0.copyload = load i32* getelementptr inbounds (%struct.A* @b, i64 0, i32 0), align 8, !dbg !50

test/Transforms/Inline/inline_dbg_declare.ll

@@ -92,6 +92,6 @@ attributes #1 = { nounwind readnone }
 !22 = !MDLocation(line: 8, column: 14, scope: !9)
 !23 = !MDLocation(line: 9, column: 1, scope: !9)
 
-; CHECK: [[m23]] = !{!"0x101\00x\0016777217\000", !4, !5, !8, [[CALL_SITE:![0-9]*]]} ; [ DW_TAG_arg_variable ] [x] [line 1]
-; CHECK: [[CALL_SITE]] = distinct !MDLocation(line: 8, column: 14, scope: !9)
+; CHECK: [[CALL_SITE:![0-9]+]] = distinct !MDLocation(line: 8, column: 14, scope: !9)
+; CHECK: [[m23]] = !{!"0x101\00x\0016777217\000", !4, !5, !8, [[CALL_SITE]]} ; [ DW_TAG_arg_variable ] [x] [line 1]
 ; CHECK: [[m24]] = !MDLocation(line: 1, column: 17, scope: !4, inlinedAt: [[CALL_SITE]])