[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.



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.

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