[Lldb-commits] [PATCH] D153644: [lldb] Print unprintable characters as unsigned

[Jonas Devlieghere via Phabricator via lldb-commits]

JDevlieghere created this revision.
JDevlieghere added reviewers: jasonmolenda, DavidSpickett, bulbazord.
Herald added a project: All.
JDevlieghere requested review of this revision.

When specifying the C-string format for dumping memory, we treat unprintable characters as signed. Whether a character is signed or not is implementation defined, but all printable characters are signed. Therefore it's fair to assume that unprintable characters are unsigned.

Before this patch, the newly added unit test would print:

  "\xffffffcf\xfffffffa\xffffffed\xfffffffe\f”

With this patch, it prints what you would expect:

  “\xcf\xfa\xed\xfe\f”

rdar://111126134


https://reviews.llvm.org/D153644

Files:
  lldb/source/Core/DumpDataExtractor.cpp
  lldb/unittests/Core/DumpDataExtractorTest.cpp


Index: lldb/unittests/Core/DumpDataExtractorTest.cpp
===================================================================
--- lldb/unittests/Core/DumpDataExtractorTest.cpp
+++ lldb/unittests/Core/DumpDataExtractorTest.cpp
@@ -133,6 +133,8 @@
 
   TestDump(llvm::StringRef("aardvark"), lldb::Format::eFormatCString,
            "\"aardvark\"");
+  TestDump(llvm::StringRef("\xcf\xfa\xed\xfe\f"), lldb::Format::eFormatCString,
+           "\"\\xcf\\xfa\\xed\\xfe\\f\"");
   TestDump<uint16_t>(99, lldb::Format::eFormatDecimal, "99");
   // Just prints as a signed integer.
   TestDump(-1, lldb::Format::eFormatEnum, "-1");
Index: lldb/source/Core/DumpDataExtractor.cpp
===================================================================
--- lldb/source/Core/DumpDataExtractor.cpp
+++ lldb/source/Core/DumpDataExtractor.cpp
@@ -212,7 +212,8 @@
     s.PutChar(c);
     return;
   }
-  s.Printf("\\x%2.2x", c);
+  // Non-print characters can be assumed to be unsigned.
+  s.Printf("\\x%2.2x", static_cast<unsigned char>(c));
 }
 
 /// Dump a floating point type.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D153644.533985.patch
Type: text/x-patch
Size: 1057 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/lldb-commits/attachments/20230623/28b87e87/attachment-0001.bin>