m_debuginfo: Suppress warning about not handling entry_value ops

The warning: evaluate_Dwarf3_Expr: unhandled DW_OP_ 0xf3 isn't
very helpful. This means we didn't handle DW_OP_GNU_entry_value.

DW_OP_GNU_entry_value (or DWARF5 DW_OP_entry_value) means interpreting
the given DWARF expression using register values as they were upon
entering the function. Which is non-trivial to implement.

We can fail the evaluation of the DWARF expression without warning
about it by default, since it isn't really needed for any current
valgrind functionality (and it is only done with --read-var-info=yes.

diff --git a/coregrind/m_debuginfo/d3basics.c b/coregrind/m_debuginfo/d3basics.c
index d48589a30ca2555761ad221fe400b44297d1ca00..e9e8944af8d62f8a553c758ab91f77187f1f3f78 100644 (file)
--- a/coregrind/m_debuginfo/d3basics.c
+++ b/coregrind/m_debuginfo/d3basics.c
@@ -1048,6 +1048,14 @@ GXResult ML_(evaluate_Dwarf3_Expr) ( const UChar* expr, UWord exprszB,
                FAIL("evaluate_Dwarf3_Expr: DW_OP_stack_value "
                     "does not terminate expression");
             break;
+        case DW_OP_entry_value:
+        case DW_OP_GNU_entry_value:
+            /* This provides a DWARF expression where any register op
+               needs tobe evaluated as if the value that register had
+               upon entering the function.  Which is non-trivial to
+               implement.  */
+            FAIL("evaluate_Dwarf3_Expr: Unhandled DW_OP entry_value");
+            return res;
          default:
             if (!VG_(clo_xml))
                VG_(message)(Vg_DebugMsg,