[Demangle] Add another test for ItaniumPartialDemangler

[sgraenitz]

Summary

Show the behavior of print operations in the ItaniumPartialDemangler. It's a summary of what the current integration in LLDB assumes. For new users this may be a useful example.

[erik.pilkington]

LGTM, thanks for doing this!

unittests/Demangle/PartialDemangleTest.cpp

188

Does LLDB actually pass in a N that is less than the length of Buf? Its not wrong to do that per se, realloc will sort it out, but it seems kinda strange.

[sgraenitz]

unittests/Demangle/PartialDemangleTest.cpp

188

My first version used only one variable for N, so the pretended buffer size was decreasing continuously while the actual buffer remained unchanged.. That caused unnecessary allocations. I fixed that a few days ago. Basically it's these three cases to consider:
https://github.com/llvm-mirror/lldb/blob/a063373af4d295e48017ca218d1030aac13b0af5/source/Core/RichManglingContext.cpp#L91

[clayborg]

BTW: warning I saw during recent build:

[98/790] Building CXX object tools/lldb/source/Core/CMakeFiles/lldbCore.dir/RichManglingContext.cpp.o
/home/gclayton/local/src/llvm/svn/llvm/tools/lldb/source/Core/RichManglingContext.cpp: In member function ‘bool lldb_private::RichManglingContext::IsCtorOrDtor() const’:
/home/gclayton/local/src/llvm/svn/llvm/tools/lldb/source/Core/RichManglingContext.cpp:77:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/home/gclayton/local/src/llvm/svn/llvm/tools/lldb/source/Core/RichManglingContext.cpp: In member function ‘bool lldb_private::RichManglingContext::IsFunction() const’:
/home/gclayton/local/src/llvm/svn/llvm/tools/lldb/source/Core/RichManglingContext.cpp:89:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

unittests/Demangle/PartialDemangleTest.cpp

TEST(PartialDemanglerTest, TestMisc) {
 
   EXPECT_FALSE(D1.partialDemangle("_Z1fv"));
   EXPECT_FALSE(D2.partialDemangle("_Z1g"));
   std::swap(D1, D2);
   EXPECT_FALSE(D1.isFunction());
   EXPECT_TRUE(D2.isFunction());
 
   EXPECT_TRUE(D1.partialDemangle("Not a mangled name!"));
+}
+
+TEST(PartialDemanglerTest, TestPrintCases) {
+  llvm::ItaniumPartialDemangler D;
 
+  const size_t OriginalSize = 4;
+  char *Buf = static_cast<char *>(std::malloc(OriginalSize));
+  const char *OriginalBuf = Buf;
+
+  // Default success case: Result fits into the given buffer.
+  // Res points to Buf. N returns string size including null termination.
+  {
+    EXPECT_FALSE(D.partialDemangle("_ZN1a1bEv"));
+
+    size_t N = OriginalSize;
+    char *Res = D.getFunctionDeclContextName(Buf, &N);
+    EXPECT_STREQ("a", Res);
+    EXPECT_EQ(OriginalBuf, Res);
+    EXPECT_EQ(strlen(Res) + 1, N);
+  }
+
+  // Realloc success case: Result does not fit into the given buffer.
+  // Res points to the new or extended buffer. N returns string size
+  // including null termination. Buf was extended or freed.
+  {
+    EXPECT_FALSE(D.partialDemangle("_ZN1a1b1cIiiiEEvm"));
+
+    size_t N = OriginalSize;
+    char *Res = D.finishDemangle(Buf, &N);
+    EXPECT_STREQ("void a::b::c<int, int, int>(unsigned long)", Res);
+    EXPECT_EQ(strlen(Res) + 1, N);
+    Buf = Res;
+  }
+
+  // Failure case: a::c is not a function.
+  // Res is nullptr. N remains unchanged.
+  {
+    EXPECT_FALSE(D.partialDemangle("_ZN1a1cE"));
+
+    size_t N = OriginalSize;
+    char *Res = D.getFunctionName(Buf, &N);
+    EXPECT_EQ(nullptr, Res);
+    EXPECT_EQ(OriginalSize, N);
+  }
+
+  std::free(Buf);
 }