Move the complex address expression out of DIVariable and into an extra
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.
Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.
By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.
The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)
This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.
What this patch doesn't do:
This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.
http://reviews.llvm.org/D4919
rdar://problem/17994491
Thanks to dblaikie and dexonsmith for reviewing this patch!
Note: I accidentally committed a bogus older version of this patch previously.
llvm-svn: 218787
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index e4ce699..69c9346 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -993,6 +993,7 @@
bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
StoreInst *SI, DIBuilder &Builder) {
DIVariable DIVar(DDI->getVariable());
+ DIExpression DIExpr(DDI->getExpression());
assert((!DIVar || DIVar.isVariable()) &&
"Variable in DbgDeclareInst should be either null or a DIVariable.");
if (!DIVar)
@@ -1010,9 +1011,10 @@
if (SExtInst *SExt = dyn_cast<SExtInst>(SI->getOperand(0)))
ExtendedArg = dyn_cast<Argument>(SExt->getOperand(0));
if (ExtendedArg)
- DbgVal = Builder.insertDbgValueIntrinsic(ExtendedArg, 0, DIVar, SI);
+ DbgVal = Builder.insertDbgValueIntrinsic(ExtendedArg, 0, DIVar, DIExpr, SI);
else
- DbgVal = Builder.insertDbgValueIntrinsic(SI->getOperand(0), 0, DIVar, SI);
+ DbgVal = Builder.insertDbgValueIntrinsic(SI->getOperand(0), 0, DIVar,
+ DIExpr, SI);
DbgVal->setDebugLoc(DDI->getDebugLoc());
return true;
}
@@ -1022,6 +1024,7 @@
bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
LoadInst *LI, DIBuilder &Builder) {
DIVariable DIVar(DDI->getVariable());
+ DIExpression DIExpr(DDI->getExpression());
assert((!DIVar || DIVar.isVariable()) &&
"Variable in DbgDeclareInst should be either null or a DIVariable.");
if (!DIVar)
@@ -1031,8 +1034,7 @@
return true;
Instruction *DbgVal =
- Builder.insertDbgValueIntrinsic(LI->getOperand(0), 0,
- DIVar, LI);
+ Builder.insertDbgValueIntrinsic(LI->getOperand(0), 0, DIVar, DIExpr, LI);
DbgVal->setDebugLoc(DDI->getDebugLoc());
return true;
}
@@ -1075,11 +1077,11 @@
// This is a call by-value or some other instruction that
// takes a pointer to the variable. Insert a *value*
// intrinsic that describes the alloca.
- auto DbgVal =
- DIB.insertDbgValueIntrinsic(AI, 0,
- DIVariable(DDI->getVariable()), CI);
- DbgVal->setDebugLoc(DDI->getDebugLoc());
- }
+ auto DbgVal = DIB.insertDbgValueIntrinsic(
+ AI, 0, DIVariable(DDI->getVariable()),
+ DIExpression(DDI->getExpression()), CI);
+ DbgVal->setDebugLoc(DDI->getDebugLoc());
+ }
DDI->eraseFromParent();
}
}
@@ -1103,6 +1105,7 @@
if (!DDI)
return false;
DIVariable DIVar(DDI->getVariable());
+ DIExpression DIExpr(DDI->getExpression());
assert((!DIVar || DIVar.isVariable()) &&
"Variable in DbgDeclareInst should be either null or a DIVariable.");
if (!DIVar)
@@ -1113,23 +1116,19 @@
// will take a value storing address of the memory for variable, not
// alloca itself.
Type *Int64Ty = Type::getInt64Ty(AI->getContext());
- SmallVector<Value*, 4> NewDIVarAddress;
- if (DIVar.hasComplexAddress()) {
- for (unsigned i = 0, n = DIVar.getNumAddrElements(); i < n; ++i) {
- NewDIVarAddress.push_back(
- ConstantInt::get(Int64Ty, DIVar.getAddrElement(i)));
+ SmallVector<Value *, 4> NewDIExpr;
+ if (DIExpr) {
+ for (unsigned i = 0, n = DIExpr.getNumElements(); i < n; ++i) {
+ NewDIExpr.push_back(ConstantInt::get(Int64Ty, DIExpr.getElement(i)));
}
}
- NewDIVarAddress.push_back(ConstantInt::get(Int64Ty, DIBuilder::OpDeref));
- DIVariable NewDIVar = Builder.createComplexVariable(
- DIVar.getTag(), DIVar.getContext(), DIVar.getName(),
- DIVar.getFile(), DIVar.getLineNumber(), DIVar.getType(),
- NewDIVarAddress, DIVar.getArgNumber());
+ NewDIExpr.push_back(ConstantInt::get(Int64Ty, dwarf::DW_OP_deref));
// 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, NewDIVar, BB);
+ Builder.insertDeclare(NewAllocaAddress, DIVar,
+ Builder.createExpression(NewDIExpr), BB);
DDI->eraseFromParent();
return true;
}