Use DIExpression:foldConstantMath() at the result of an appendOpsToArg()

Author: rastogishubham

llvm/lib/IR/DebugInfoMetadata.cpp

@@ -1779,17 +1779,55 @@ DIExpression *DIExpression::appendOpsToArg(const DIExpression *Expr,
                                            unsigned ArgNo, bool StackValue) {
   assert(Expr && "Can't add ops to this expression");
 
+  unsigned OpCount = 0;
+
   // Handle non-variadic intrinsics by prepending the opcodes.
   if (!any_of(Expr->expr_ops(),
               [](auto Op) { return Op.getOp() == dwarf::DW_OP_LLVM_arg; })) {
     assert(ArgNo == 0 &&
            "Location Index must be 0 for a non-variadic expression.");
+
+    for (auto It = Expr->expr_op_begin(); It != Expr->expr_op_end(); It++)
+      OpCount++;
     SmallVector<uint64_t, 8> NewOps(Ops.begin(), Ops.end());
-    return DIExpression::prependOpcodes(Expr, NewOps, StackValue);
+    auto *Result = DIExpression::prependOpcodes(Expr, NewOps, StackValue);
+
+    // Instead of applying a foldConstantMath on the entire expression, apply it
+    // only on operations that are preppended + the succeeding operations
+    // totalling to the maximum foldable pattern.
+    uint64_t NewOpCount = 0;
+    for (auto It = Result->expr_op_begin(); It != Result->expr_op_end(); It++)
+      NewOpCount++;
+
+    // This is the number of new operations that were added to the expression,
+    // i.e. the number of operations in the Ops argument.
+    unsigned NumOfAddedOps = NewOpCount - OpCount;
+    // This is the number of operations that DIExpression::foldConstantMath
+    // should be applied upon, which is the number of new operations added + the
+    // succeeding operations totalling to the longest foldable pattern.
+    unsigned NumOfOpsToBeFolded = NumOfAddedOps + DIExpression::MaxRuleOpSize;
+    unsigned Count = 0;
+    SmallVector<uint64_t> OpsToBeFolded;
+    SmallVector<uint64_t> FoldedOps;
+
+    for (auto Op : Result->expr_ops()) {
+      if (Count < NumOfOpsToBeFolded) {
+        Op.appendToVector(OpsToBeFolded);
+        Count++;
+      } else {
+        Op.appendToVector(FoldedOps);
+      }
+    }
+
+    OpsToBeFolded = Result->foldConstantMath(OpsToBeFolded);
+    OpsToBeFolded.append(FoldedOps);
+    return DIExpression::get(Result->getContext(), OpsToBeFolded);
   }
 
+  unsigned ArgPos;
   SmallVector<uint64_t, 8> NewOps;
   for (auto Op : Expr->expr_ops()) {
+    OpCount++;
     // A DW_OP_stack_value comes at the end, but before a DW_OP_LLVM_fragment.
     if (StackValue) {
       if (Op.getOp() == dwarf::DW_OP_stack_value)
@@ -1800,13 +1838,54 @@ DIExpression *DIExpression::appendOpsToArg(const DIExpression *Expr,
       }
     }
     Op.appendToVector(NewOps);
-    if (Op.getOp() == dwarf::DW_OP_LLVM_arg && Op.getArg(0) == ArgNo)
+    if (Op.getOp() == dwarf::DW_OP_LLVM_arg && Op.getArg(0) == ArgNo) {
       NewOps.insert(NewOps.end(), Ops.begin(), Ops.end());
+      ArgPos = OpCount;
+    }
   }
   if (StackValue)
     NewOps.push_back(dwarf::DW_OP_stack_value);
 
-  return DIExpression::get(Expr->getContext(), NewOps);
+  auto *Result = DIExpression::get(Expr->getContext(), NewOps);
+
+  // Instead of applying a foldConstantMath on the entire expression, apply it
+  // only on operations that are inserted to the ArgNo + the preceeding
+  // operations totalling to the maximum foldable pattern.
+  unsigned NewOpCount = 0;
+  for (auto It = Result->expr_op_begin(); It != Result->expr_op_end(); It++)
+    NewOpCount++;
+
+  unsigned Count = 0;
+  SmallVector<uint64_t> OpsToBeFolded;
+  SmallVector<uint64_t> FoldedOps;
+  SmallVector<uint64_t> RemainingOps;
+
+  // This is the number of operations we can consider already folded in the
+  // expression, which precede the ArgNo that the Ops are appended to.
+  unsigned FoldedOpCount = ArgPos > DIExpression::MaxRuleOpSize
+                               ? ArgPos - DIExpression::MaxRuleOpSize
+                               : 0;
+  // This is the number of operations that DIExpression::foldConstantMath should
+  // be applied upon, which is the number of new operations added + the
+  // preceeding operations totalling to the maximum foldable pattern.
+  unsigned OpsToBeFoldedCount =
+      NewOpCount - OpCount + DIExpression::MaxRuleOpSize;
+
+  for (auto Op : Result->expr_ops()) {
+    if (Count < FoldedOpCount) {
+      Op.appendToVector(FoldedOps);
+      Count++;
+    } else if (Count >= FoldedOpCount && Count < OpsToBeFoldedCount) {
+      Op.appendToVector(OpsToBeFolded);
+      Count++;
+    } else
+      Op.appendToVector(RemainingOps);
+  }
+
+  OpsToBeFolded = Result->foldConstantMath(OpsToBeFolded);
+  FoldedOps.append(OpsToBeFolded);
+  FoldedOps.append(RemainingOps);
+  return DIExpression::get(Result->getContext(), FoldedOps);
 }
 
 DIExpression *DIExpression::replaceArg(const DIExpression *Expr,

llvm/test/DebugInfo/MIR/InstrRef/deref-spills-with-size.mir

@@ -83,9 +83,9 @@
 # DWARF-NEXT: DW_OP_breg7 RSP-8
 # DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value
 ## scalar / stack value with various sizes.
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value)
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_plus_uconst 0x1, DW_OP_stack_value
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_plus_uconst 0x1, DW_OP_stack_value
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_plus_uconst 0x1, DW_OP_stack_value)
 # DWARF:      DW_AT_name ("flannel")
 
 # Variable with fragments.
@@ -96,9 +96,9 @@
 # DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_piece 0x4
 # DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value, DW_OP_piece 0x4
 ## Scalar / stack value with various sizes.
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value, DW_OP_piece 0x4
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x4, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value, DW_OP_piece 0x4
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value, DW_OP_piece 0x4)
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_plus_uconst 0x1, DW_OP_stack_value, DW_OP_piece 0x4
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x4, DW_OP_plus_uconst 0x1, DW_OP_stack_value, DW_OP_piece 0x4
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_plus_uconst 0x1, DW_OP_stack_value, DW_OP_piece 0x4)
 # DWARF:      DW_AT_name ("shoes")
 
 --- |
@@ -308,7 +308,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !8, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), dbg-instr-ref(16, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_plus_uconst, 1, DW_OP_stack_value), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -319,7 +319,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !8, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), dbg-instr-ref(17, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_plus_uconst, 1, DW_OP_stack_value), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -330,7 +330,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !8, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), dbg-instr-ref(18, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_plus_uconst, 1, DW_OP_stack_value), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -341,7 +341,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !10, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), dbg-instr-ref(19, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM2]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_plus_uconst, 1, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -352,7 +352,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !10, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), dbg-instr-ref(20, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM2]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 4, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 4, DW_OP_plus_uconst, 1, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -363,7 +363,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !10, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), dbg-instr-ref(21, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM2]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_plus_uconst, 1, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg

llvm/test/DebugInfo/MIR/InstrRef/follow-spill-of-indir-value.mir

@@ -27,7 +27,7 @@
 ## 
 ## Second location, variable pointed to by the register value plus eight.
 ##
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_lit8, DW_OP_plus)
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_plus_uconst 0x8)
 ##
 ## Spilt to stack: push stack location and deref the pointer onto the dwarf
 ## expr stack. Then add eight to it, and it points to the variable.
@@ -135,7 +135,7 @@ body:             |
     ; CHECK: DBG_VALUE $rdi,
     MOV64mr $rsp, 1, $noreg, -8, $noreg, $rdi :: (store (s64) into %stack.0)
     $rdi = MOV64ri 0
-    ; CHECK: DBG_VALUE $rsp, 0, ![[VARNUM]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_constu, 8, DW_OP_plus),
+    ; CHECK: DBG_VALUE $rsp, 0, ![[VARNUM]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_plus_uconst, 8),
 
     renamable $rax = MOV64rm $rsp, 1, $noreg, -8, $noreg :: (load (s64) from %stack.0)
     renamable $eax = MOV32rm killed renamable $rax, 1, $noreg, 0, $noreg, debug-location !24 :: (load (s32) from %ir.i1, !tbaa !25)

llvm/test/DebugInfo/salvage-icmp.ll

@@ -5,7 +5,7 @@
 
 ; CHECK: call void @llvm.dbg.value(metadata i32 %a,
 ; CHECK-SAME: ![[VAR_C:[0-9]+]],
-; CHECK-SAME: !DIExpression(DW_OP_constu, 0, DW_OP_ne, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 0, DW_OP_eq, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 1, DW_OP_gt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551615, DW_OP_gt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 2, DW_OP_ge, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551614, DW_OP_ge, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 3, DW_OP_lt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551613, DW_OP_lt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 4, DW_OP_le, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551612, DW_OP_le, DW_OP_stack_value))
+; CHECK-SAME: !DIExpression(DW_OP_lit0, DW_OP_ne, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_lit0, DW_OP_eq, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 1, DW_OP_gt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551615, DW_OP_gt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 2, DW_OP_ge, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551614, DW_OP_ge, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 3, DW_OP_lt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551613, DW_OP_lt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 4, DW_OP_le, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551612, DW_OP_le, DW_OP_stack_value))
 
 ; CHECK: call void @llvm.dbg.value(metadata !DIArgList(i32 %a, i32 %a, i32 %a, i32 %b, i32 %a, i32 %b, i32 %b, i32 %a, i32 %a, i32 %b, i32 %b),
 ; CHECK-SAME: ![[VAR_C:[0-9]+]],