[Lldb-commits] [lldb] ed0a141 - [LLDB] Fix type formatting empty c-strings (#68924)

[via lldb-commits]

Author: Walter Erquinigo
Date: 2023-10-13T14:14:23-04:00
New Revision: ed0a14144ba980ceb29e86c9ca615b785e667dcf

URL: https://github.com/llvm/llvm-project/commit/ed0a14144ba980ceb29e86c9ca615b785e667dcf
DIFF: https://github.com/llvm/llvm-project/commit/ed0a14144ba980ceb29e86c9ca615b785e667dcf.diff

LOG: [LLDB] Fix type formatting empty c-strings (#68924)

The type formatter code is effectively considering empty strings as read
errors, which is wrong. The fix is very simple. We should rely on the
error object and stop checking the size. I also added a test.

Added: 
    

Modified: 
    lldb/source/DataFormatters/TypeFormat.cpp
    lldb/test/API/functionalities/data-formatter/builtin-formats/TestBuiltinFormats.py
    lldb/test/API/functionalities/data-formatter/builtin-formats/main.cpp

Removed: 
    


################################################################################
diff  --git a/lldb/source/DataFormatters/TypeFormat.cpp b/lldb/source/DataFormatters/TypeFormat.cpp
index 5ee89fc0d5eb319..126240aeca65e43 100644
--- a/lldb/source/DataFormatters/TypeFormat.cpp
+++ b/lldb/source/DataFormatters/TypeFormat.cpp
@@ -81,9 +81,9 @@ bool TypeFormatImpl_Format::FormatObject(ValueObject *valobj,
               WritableDataBufferSP buffer_sp(
                   new DataBufferHeap(max_len + 1, 0));
               Address address(valobj->GetPointerValue());
-              if (target_sp->ReadCStringFromMemory(
-                      address, (char *)buffer_sp->GetBytes(), max_len, error) &&
-                  error.Success())
+              target_sp->ReadCStringFromMemory(
+                  address, (char *)buffer_sp->GetBytes(), max_len, error);
+              if (error.Success())
                 data.SetData(buffer_sp);
             }
           }

diff  --git a/lldb/test/API/functionalities/data-formatter/builtin-formats/TestBuiltinFormats.py b/lldb/test/API/functionalities/data-formatter/builtin-formats/TestBuiltinFormats.py
index aa768c158b5b5ff..4e0f14d039a743f 100644
--- a/lldb/test/API/functionalities/data-formatter/builtin-formats/TestBuiltinFormats.py
+++ b/lldb/test/API/functionalities/data-formatter/builtin-formats/TestBuiltinFormats.py
@@ -3,9 +3,9 @@
 """
 
 import lldb
+from lldbsuite.test import lldbutil
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
-from lldbsuite.test import lldbutil
 
 
 class TestCase(TestBase):
@@ -19,6 +19,20 @@ def getFormatted(self, format, expr):
         self.assertTrue(result.Succeeded(), result.GetError())
         return result.GetOutput()
 
+    @no_debug_info_test
+    @skipIfWindows
+    def testAllPlatforms(self):
+        self.build()
+        lldbutil.run_to_source_breakpoint(
+            self, "// break here", lldb.SBFileSpec("main.cpp")
+        )
+        # We can dump correctly non char* c-strings with explicit formatting.
+        self.assertIn(' = ""', self.getFormatted("c-string", "void_empty_cstring"))
+        self.assertIn(' = ""', self.getFormatted("c-string", "empty_cstring"))
+
+    # TODO: Move as many asserts as possible within this function to `testAllPlatforms`.
+    # Currently `arm` is being skipped even though many asserts would effectively
+    # pass.
     @no_debug_info_test
     @skipIfWindows
     # uint128_t not available on arm.

diff  --git a/lldb/test/API/functionalities/data-formatter/builtin-formats/main.cpp b/lldb/test/API/functionalities/data-formatter/builtin-formats/main.cpp
index 58b8116dfa1ec9b..573c111306c14de 100644
--- a/lldb/test/API/functionalities/data-formatter/builtin-formats/main.cpp
+++ b/lldb/test/API/functionalities/data-formatter/builtin-formats/main.cpp
@@ -1,8 +1,10 @@
 #include <cstdint>
 
 const char cstring[15] = " \033\a\b\f\n\r\t\vaA09\0";
+const char *empty_cstring = "";
 
 int main() {
   int use = *cstring;
+  void *void_empty_cstring = (void *)empty_cstring;
   return use; // break here
 }