[PATCH] D89845: Add the ability to extract the unwind rows from DWARF Call Frame Information.

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a subscriber: grimar.
MaskRay added a comment.

`UnwindTable::parseRows` duplicates a fair amount of parsing which has already been implemented by `CFIProgramm::parse: is there possible to deduplicate?

Adding @grimar who touched the code last time.



================
Comment at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:29
 
+static constexpr uint32_t INVALID_REGNUM = UINT32_MAX;
+
----------------
`static` is redundant. namespace-scope const/constexpr variables automatically have internal linkage.


================
Comment at: llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp:142
+  case DWARFExpr:
+    return *Expr == *RHS.Expr;
+  case Constant:
----------------
DW_CFA_expression and DW_CFA_val_expression have different `Dereference`


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Comment at: llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp:190
+                       unsigned IndentLevel) const {
+  for (const auto &Row : Rows)
+    Row.dump(OS, MRI, IsEH, IndentLevel);
----------------
auto -> UnwindRow


================
Comment at: llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp:207
+  if (Cie == nullptr)
+    return createStringError(errc::illegal_byte_sequence,
+                             "unable to get CIE for FDE at offset 0x%" PRIx64,
----------------
The description of illegal_byte_sequence (EILSEQ) is: Invalid or incomplete multibyte or wide character. It is about an encoding problem. Probably just use errc::invalid_argument


================
Comment at: llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp:508
+      // location is preceded by a segment selector of the given length
+      auto NewAddress = Inst.getOperandAsUnsigned(CFIP, 0);
+      if (!NewAddress)
----------------
This needs to consider the pointer encoding in FDE.


Repository:
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  https://reviews.llvm.org/D89845/new/

https://reviews.llvm.org/D89845