[lldb][DWARFExpression] Fix DW_OP_div to use signed division

This patch resolves an issue where a value is incorrectly displayed if it is represented by DW_OP_div. This issue is caused by lldb evaluating operands of DW_OP_div as unsigned and performed unintended unsigned division. This issue is resolved by creating two temporary signed scalar and performing signed division. (Addresses GH#61727) Differential Revision: https://reviews.llvm.org/D147370
llvm · May 2, 2023 · e15d6b5 · e15d6b5
1 parent 2cdb6b8
commit e15d6b5
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Showing 2 changed files with 474 additions and 2 deletions.
diff --git a/lldb/source/Expression/DWARFExpression.cpp b/lldb/source/Expression/DWARFExpression.cpp
@@ -1436,8 +1436,12 @@ bool DWARFExpression::Evaluate(
           return false;
         } else {
           stack.pop_back();
-          stack.back() =
-              stack.back().ResolveValue(exe_ctx) / tmp.ResolveValue(exe_ctx);
+          Scalar divisor, dividend;
+          divisor = tmp.ResolveValue(exe_ctx);
+          dividend = stack.back().ResolveValue(exe_ctx);
+          divisor.MakeSigned();
+          dividend.MakeSigned();
+          stack.back() = dividend / divisor;
           if (!stack.back().ResolveValue(exe_ctx).IsValid()) {
             if (error_ptr)
               error_ptr->SetErrorString("Divide failed.");