[LLDB][Test] Fix the test case of listing verbose break info on Windows

[bvlgah]

I noticed a failure of running LLDB test suites on Windows AArch64. The failed test case is about
checking output of command breakpoint list -v -L c++, and an mismatch on the demangled
name of a function occurred. The test case expects ns::func(void), but on Windows it is int ns::func(void).
It results from the different mangling scheme used by MSVC, and the comparison is as follows:

Scheme	Mangled	Demangled (fully)	Note
MSVC	?func@ns@@YAHXZ	int __cdecl ns::func(void)	Godbolt (I have no available Windows device)
Itanium	_ZN2ns4funcEv	ns::func()

According to the current use of MSVC demangling,

llvm-project/lldb/source/Core/Mangled.cpp

Lines 128 to 143 in 8f68022

	static char *GetMSVCDemangledStr(llvm::StringRef M) {
	char *demangled_cstr = llvm::microsoftDemangle(
	M, nullptr, nullptr,
	llvm::MSDemangleFlags(
	llvm::MSDF_NoAccessSpecifier | llvm::MSDF_NoCallingConvention |
	llvm::MSDF_NoMemberType | llvm::MSDF_NoVariableType));
	if (Log *log = GetLog(LLDBLog::Demangle)) {
	if (demangled_cstr && demangled_cstr[0])
	LLDB_LOGF(log, "demangled msvc: %s -> \"%s\"", M.data(), demangled_cstr);
	else
	LLDB_LOGF(log, "demangled msvc: %s -> error", M.data());
	}
	return demangled_cstr;
	}

the __cdecl specifier is not part of the name. However, the function's parameter types should be present
as llvm::MSDF_NoVariableType does not affect a symbol for functions.

Therefore, it is inappropriate to assume the demangled name are the same on all platforms. Instead of tweaking the
existing code of demangling to get the same (demangled) name, I think it is more reasonable to modify the test case.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: None (bvlgah)

Changes

I noticed a failure of running LLDB test suites on Windows AArch64. The failed test case is about
checking output of command breakpoint list -v -L c++, and an mismatch on the demangled
name of a function occurred. The test case expects ns::func(void), but on Windows it is int ns::func(void).
It results from the different mangling scheme used by MSVC, and the comparison is as follows:

Scheme	Mangled	Demangled (fully)	Note
MSVC	?func@<!-- -->ns@@<!-- -->YAHXZ	int __cdecl ns::func(void)	Godbolt (I have no available Windows device)
Itanium	_ZN2ns4funcEv	ns::func()

According to the current use of MSVC demangling,

llvm-project/lldb/source/Core/Mangled.cpp

Lines 128 to 143 in 8f68022

	static char *GetMSVCDemangledStr(llvm::StringRef M) {
	char *demangled_cstr = llvm::microsoftDemangle(
	M, nullptr, nullptr,
	llvm::MSDemangleFlags(
	llvm::MSDF_NoAccessSpecifier | llvm::MSDF_NoCallingConvention |
	llvm::MSDF_NoMemberType | llvm::MSDF_NoVariableType));
	if (Log *log = GetLog(LLDBLog::Demangle)) {
	if (demangled_cstr && demangled_cstr[0])
	LLDB_LOGF(log, "demangled msvc: %s -> \"%s\"", M.data(), demangled_cstr);
	else
	LLDB_LOGF(log, "demangled msvc: %s -> error", M.data());
	}
	return demangled_cstr;
	}

the __cdecl specifier is not part of the name. However, the function's parameter types should be present
as llvm::MSDF_NoVariableType does not affect a symbol for functions.

Therefore, it is inappropriate to assume the demangled name are the same on all platforms. Instead of tweaking the
existing code of demangling to get the same (demangled) name, I think it is more reasonable to modify the test case.

---

Full diff: https://github.com/llvm/llvm-project/pull/85200.diff

1 Files Affected:

• (modified) lldb/test/API/functionalities/breakpoint/breakpoint_options/TestBreakpointOptions.py (+3-1)

diff --git a/lldb/test/API/functionalities/breakpoint/breakpoint_options/TestBreakpointOptions.py b/lldb/test/API/functionalities/breakpoint/breakpoint_options/TestBreakpointOptions.py
index 5179ffe730b9a0..d262b627195bc8 100644
--- a/lldb/test/API/functionalities/breakpoint/breakpoint_options/TestBreakpointOptions.py
+++ b/lldb/test/API/functionalities/breakpoint/breakpoint_options/TestBreakpointOptions.py
@@ -95,8 +95,10 @@ def breakpoint_options_language_test(self):
         self.expect(
             "breakpoint list -v",
             "Verbose breakpoint list contains mangled names",
+            # The demangled function name is system-dependent, e.g.
+            # 'int ns::func(void)' on Windows and 'ns::func()' on Linux.
             substrs=[
-                "function = ns::func",
+                f"function = {function.GetName()}",
                 f"mangled function = {function.GetMangledName()}",
             ],
         )

[DavidSpickett]

Thanks for the fix! We (Linaro) were about to look into this ourselves.

I'm going to merge this now so we can see if it works ASAP.