[lldb] Make char[N] formatters respect the end of the array (PR44649)

[labath]

Summary

I believe this is a more natural behavior, and it also matches what gdb
does.

[labath]

lldb/test/API/functionalities/data-formatter/stringprinter/main.cpp

42–43

This would be consistent with gdb as well, and it was the preferred result of last years irc straw poll, but it will require a different fix.

[teemperor]

LGTM, but maybe give the test comment a FIXME.

lldb/test/API/functionalities/data-formatter/stringprinter/main.cpp

39

If you align the start of these comments when merging this, then I'll address you from now on as "Pavel the Great".

[labath]

lldb/test/API/functionalities/data-formatter/stringprinter/main.cpp

39

uh-oh

lldb/source/DataFormatters/FormatManager.cpp

string_array_flags.SetCascades(true)
       .SetDontShowValue(true)
       .SetShowMembersOneLiner(false)
       .SetHideItemNames(false);
 
   lldb::TypeSummaryImplSP string_format(
       new StringSummaryFormat(string_flags, "${var%s}"));
 
   lldb::TypeSummaryImplSP string_array_format(
-      new StringSummaryFormat(string_array_flags, "${var%s}"));
+      new StringSummaryFormat(string_array_flags, "${var%char[]}"));
 
   RegularExpression any_size_char_arr(llvm::StringRef("char \\[[0-9]+\\]"));
 
   TypeCategoryImpl::SharedPointer sys_category_sp =
       GetCategory(m_system_category_name);
 
   sys_category_sp->GetTypeSummariesContainer()->Add(ConstString("char *"),
                                                     string_format);

lldb/test/API/functionalities/data-formatter/stringprinter/main.cpp

 #include <string>
+#include <cstring>
+
+struct A {
+  char data[4];
+  char overflow[4];
+};
 
 int main (int argc, char const *argv[])
 {
+    A a, b;
+    // Deliberately write past the end of data to test that the formatter stops
+    // at the end of array.
+    memcpy(a.data, "FOOBAR", 7);
+    memcpy(b.data, "FO\0BAR", 7);
     std::string stdstring("Hello\t\tWorld\nI am here\t\tto say hello\n"); //%self.addTearDownHook(lambda x: x.runCmd("setting set escape-non-printables true"))
     const char* constcharstar = stdstring.c_str();
     std::string longstring(
 "I am a very long string; in fact I am longer than any reasonable length that a string should be; quite long indeed; oh my, so many words; so many letters; this is kind of like writing a poem; except in real life all that is happening"
 " is just me producing a very very long set of words; there is text here, text there, text everywhere; it fills me with glee to see so much text; all around me it's just letters, and symbols, and other pleasant drawings that cause me"
 " a large amount of joy upon visually seeing them with my eyes; well, this is now a lot of letters, but it is still not enough for the purpose of the test I want to test, so maybe I should copy and paste this a few times, you know.."
 " for science, or something"
       "I am a very long string; in fact I am longer than any reasonable length that a string should be; quite long indeed; oh my, so many words; so many letters; this is kind of like writing a poem; except in real life all that is happening"
       " is just me producing a very very long set of words; there is text here, text there, text everywhere; it fills me with glee to see so much text; all around me it's just letters, and symbols, and other pleasant drawings that cause me"
       " a large amount of joy upon visually seeing them with my eyes; well, this is now a lot of letters, but it is still not enough for the purpose of the test I want to test, so maybe I should copy and paste this a few times, you know.."
       " for science, or something"
             "I am a very long string; in fact I am longer than any reasonable length that a string should be; quite long indeed; oh my, so many words; so many letters; this is kind of like writing a poem; except in real life all that is happening"
             " is just me producing a very very long set of words; there is text here, text there, text everywhere; it fills me with glee to see so much text; all around me it's just letters, and symbols, and other pleasant drawings that cause me"
             " a large amount of joy upon visually seeing them with my eyes; well, this is now a lot of letters, but it is still not enough for the purpose of the test I want to test, so maybe I should copy and paste this a few times, you know.."
             " for science, or something"
       );
     const char* longconstcharstar = longstring.c_str();
     return 0;     //% if self.TraceOn(): self.runCmd('frame variable')
-      //% self.assertTrue(self.frame().FindVariable('stdstring').GetSummary() == '"Hello\\t\\tWorld\\nI am here\\t\\tto say hello\\n"')
-     //% self.assertTrue(self.frame().FindVariable('constcharstar').GetSummary() == '"Hello\\t\\tWorld\\nI am here\\t\\tto say hello\\n"')
-     //% self.runCmd("setting set escape-non-printables false")
-     //% self.assertTrue(self.frame().FindVariable('stdstring').GetSummary() == '"Hello\t\tWorld\nI am here\t\tto say hello\n"')
-     //% self.assertTrue(self.frame().FindVariable('constcharstar').GetSummary() == '"Hello\t\tWorld\nI am here\t\tto say hello\n"')
+    //% self.expect_var_path('stdstring', summary='"Hello\\t\\tWorld\\nI am here\\t\\tto say hello\\n"')
+    //% self.expect_var_path('constcharstar', summary='"Hello\\t\\tWorld\\nI am here\\t\\tto say hello\\n"')
+    //% self.expect_var_path('stdstring', summary='"Hello\t\tWorld\nI am here\t\tto say hello\n"')
+    //% self.expect_var_path('constcharstar', summary='"Hello\t\tWorld\nI am here\t\tto say hello\n"')
     //% self.assertTrue(self.frame().FindVariable('longstring').GetSummary().endswith('"...'))
     //% self.assertTrue(self.frame().FindVariable('longconstcharstar').GetSummary().endswith('"...'))
+    //% self.expect_var_path("a.data", summary='"FOOB"')
+    // FIXME: Should this be "FO\0B" instead?
+    //% self.expect_var_path("b.data", summary='"FO"')
 }