[LLDB] Compile API tests with exceptions enabled on Windows

[Nerixyz]

From #148554 - compile tests with exceptions on Windows (-fno-exceptions was added 11 years ago in c782652). The variant test uses try {} catch {} to create variants that are valueless by exception. On other platforms, exceptions are enabled as well.

I have no clue why compiling with exceptions will optimize out a_long_guy in the changed test (even with -O0). Taking the address of that value will ensure it's kept.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: nerix (Nerixyz)

Changes

From #148554 - compile tests with exceptions on Windows (-fno-exceptions was added 11 years ago in c782652). The variant test uses try {} catch {} to create variants that are valueless by exception. On other platforms, exceptions are enabled as well.

I have no clue why compiling with exceptions will optimize out a_long_guy in the changed test (even with -O0). Taking the address of that value will ensure it's kept.

---

Full diff: https://github.com/llvm/llvm-project/pull/148691.diff

2 Files Affected:

• (modified) lldb/packages/Python/lldbsuite/test/make/Makefile.rules (-4)
• (modified) lldb/test/API/functionalities/data-formatter/data-formatter-advanced/main.cpp (+1)

diff --git a/lldb/packages/Python/lldbsuite/test/make/Makefile.rules b/lldb/packages/Python/lldbsuite/test/make/Makefile.rules
index 58833e1b0cc78..8521ca508a479 100644
--- a/lldb/packages/Python/lldbsuite/test/make/Makefile.rules
+++ b/lldb/packages/Python/lldbsuite/test/make/Makefile.rules
@@ -344,10 +344,6 @@ endif
 #----------------------------------------------------------------------
 ifeq "$(OS)" "Windows_NT"
 	ifeq ($(CC_TYPE), clang)
-		# Clang for Windows doesn't support C++ Exceptions
-		CXXFLAGS += -fno-exceptions
-		CXXFLAGS += -D_HAS_EXCEPTIONS=0
-
 		# MSVC 2015 or higher is required, which depends on c++14, so
 		# append these values unconditionally.
 		CXXFLAGS += -fms-compatibility-version=19.0
diff --git a/lldb/test/API/functionalities/data-formatter/data-formatter-advanced/main.cpp b/lldb/test/API/functionalities/data-formatter/data-formatter-advanced/main.cpp
index 9d12ca30f984c..32f5f2ce436fe 100644
--- a/lldb/test/API/functionalities/data-formatter/data-formatter-advanced/main.cpp
+++ b/lldb/test/API/functionalities/data-formatter/data-formatter-advanced/main.cpp
@@ -165,6 +165,7 @@ int main (int argc, const char * argv[])
     Simple a_simple_object(3,0.14,'E');
     
     VeryLong a_long_guy;
+    auto *unused = &a_long_guy; // ensure a_long_guy isn't optimized out
 
     std::string some_string = "012345678901234567890123456789"
                               "012345678901234567890123456789"

[JDevlieghere]

Ignore my previous comment, I read "unit tests" and replied before looking at the change.

[Nerixyz]

I can't merge this on my own, could you merge this for me please? @JDevlieghere