[DebugInfo] LowerDbgDeclare: Add derefs when handling CallInst users
LowerDbgDeclare inserts a dbg.value before each use of an address
described by a dbg.declare. When inserting a dbg.value before a CallInst
use, however, it fails to append DW_OP_deref to the DIExpression.
The DW_OP_deref is needed to reflect the fact that a dbg.value describes
a source variable directly (as opposed to a dbg.declare, which relies on
pointer indirection).
This patch adds in the DW_OP_deref where needed. This results in the
correct values being shown during a debug session for a program compiled
with ASan and optimizations (see https://reviews.llvm.org/D49520). Note
that ConvertDebugDeclareToDebugValue is already correct -- no changes
there were needed.
One complication is that SelectionDAG is unable to distinguish between
direct and indirect frame-index (FRAMEIX) SDDbgValues. This patch also
fixes this long-standing issue in order to not regress integration tests
relying on the incorrect assumption that all frame-index SDDbgValues are
indirect. This is a necessary fix: the newly-added DW_OP_derefs cannot
be lowered properly otherwise. Basically the fix prevents a direct
SDDbgValue with DIExpression(DW_OP_deref) from being dereferenced twice
by a debugger. There were a handful of tests relying on this incorrect
"FRAMEIX => indirect" assumption which actually had incorrect
DW_AT_locations: these are all fixed up in this patch.
Testing:
- check-llvm, and an end-to-end test using lldb to debug an optimized
program.
- Existing unit tests for DIExpression::appendToStack fully cover the
new DIExpression::append utility.
- check-debuginfo (the debug info integration tests)
Differential Revision: https://reviews.llvm.org/D49454
llvm-svn: 338069
diff --git a/llvm/lib/CodeGen/SelectionDAG/SDNodeDbgValue.h b/llvm/lib/CodeGen/SelectionDAG/SDNodeDbgValue.h
index 703eaa4..7e6b574 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SDNodeDbgValue.h
+++ b/llvm/lib/CodeGen/SelectionDAG/SDNodeDbgValue.h
@@ -71,20 +71,18 @@
u.Const = C;
}
- /// Constructor for frame indices.
- SDDbgValue(DIVariable *Var, DIExpression *Expr, unsigned FI, DebugLoc dl,
- unsigned O)
- : Var(Var), Expr(Expr), DL(std::move(dl)), Order(O), IsIndirect(false) {
- kind = FRAMEIX;
- u.FrameIx = FI;
- }
-
- /// Constructor for virtual registers.
- SDDbgValue(DIVariable *Var, DIExpression *Expr, unsigned VReg, bool indir,
- DebugLoc dl, unsigned O)
- : Var(Var), Expr(Expr), DL(std::move(dl)), Order(O), IsIndirect(indir) {
- kind = VREG;
- u.VReg = VReg;
+ /// Constructor for virtual registers and frame indices.
+ SDDbgValue(DIVariable *Var, DIExpression *Expr, unsigned VRegOrFrameIdx,
+ bool IsIndirect, DebugLoc DL, unsigned Order,
+ enum DbgValueKind Kind)
+ : Var(Var), Expr(Expr), DL(DL), Order(Order), IsIndirect(IsIndirect) {
+ assert((Kind == VREG || Kind == FRAMEIX) &&
+ "Invalid SDDbgValue constructor");
+ kind = Kind;
+ if (kind == VREG)
+ u.VReg = VRegOrFrameIdx;
+ else
+ u.FrameIx = VRegOrFrameIdx;
}
/// Returns the kind.