[IR] Remove the DIExpression field from DIGlobalVariable.
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
This reapplies r289902 with additional testcase upgrades and a change
to the Bitcode record for DIGlobalVariable, that makes upgrading the
old format unambiguous also for variables without DIExpressions.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
llvm-svn: 290153
diff --git a/llvm/lib/IR/Metadata.cpp b/llvm/lib/IR/Metadata.cpp
index adc9157..1d19304 100644
--- a/llvm/lib/IR/Metadata.cpp
+++ b/llvm/lib/IR/Metadata.cpp
@@ -1419,9 +1419,15 @@
// If an offset adjustment was specified we need to modify the DIExpression
// to prepend the adjustment:
// !DIExpression(DW_OP_plus, Offset, [original expr])
+ auto *Attachment = MD.second;
if (Offset != 0 && MD.first == LLVMContext::MD_dbg) {
- DIGlobalVariable *GV = cast<DIGlobalVariable>(MD.second);
- DIExpression *E = GV->getExpr();
+ DIGlobalVariable *GV = dyn_cast<DIGlobalVariable>(Attachment);
+ DIExpression *E = nullptr;
+ if (!GV) {
+ auto *GVE = cast<DIGlobalVariableExpression>(Attachment);
+ GV = GVE->getVariable();
+ E = GVE->getExpression();
+ }
ArrayRef<uint64_t> OrigElements;
if (E)
OrigElements = E->getElements();
@@ -1429,9 +1435,10 @@
Elements[0] = dwarf::DW_OP_plus;
Elements[1] = Offset;
std::copy(OrigElements.begin(), OrigElements.end(), Elements.begin() + 2);
- GV->replaceExpr(DIExpression::get(getContext(), Elements));
+ E = DIExpression::get(getContext(), Elements);
+ Attachment = DIGlobalVariableExpression::get(getContext(), GV, E);
}
- addMetadata(MD.first, *MD.second);
+ addMetadata(MD.first, *Attachment);
}
}
@@ -1452,14 +1459,14 @@
return cast_or_null<DISubprogram>(getMetadata(LLVMContext::MD_dbg));
}
-void GlobalVariable::addDebugInfo(DIGlobalVariable *GV) {
+void GlobalVariable::addDebugInfo(DIGlobalVariableExpression *GV) {
addMetadata(LLVMContext::MD_dbg, *GV);
}
void GlobalVariable::getDebugInfo(
- SmallVectorImpl<DIGlobalVariable *> &GVs) const {
+ SmallVectorImpl<DIGlobalVariableExpression *> &GVs) const {
SmallVector<MDNode *, 1> MDs;
getMetadata(LLVMContext::MD_dbg, MDs);
for (MDNode *MD : MDs)
- GVs.push_back(cast<DIGlobalVariable>(MD));
+ GVs.push_back(cast<DIGlobalVariableExpression>(MD));
}