CppTests fail to build with GCC due to duplicate compile definitions

[FIM43-Redeye]

Problem

Building mlir-aie with GCC fails on the CppTests targets (target_model, target_model_rtti, register_database) with errors like:

<command-line>: error: token '=' is not valid in preprocessor expressions

The generated compile command has garbled -D flags where multiple definitions are concatenated into a single quoted string:

-D_GLIBCXX_USE_CXX11_ABI=1
-D_GLIBCXX_USE_CXX11_ABI="1 -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS"

GCC rejects these; Clang also rejects them when they reach GCC's libstdc++ headers (which evaluate _GLIBCXX_USE_CXX11_ABI in preprocessor conditionals).

Root Cause

LLVM_DEFINITIONS is a space-separated string:

"-D_GNU_SOURCE -D_GLIBCXX_USE_CXX11_ABI=1 -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS"

When passed directly to add_definitions(${LLVM_DEFINITIONS}), CMake does not split this into individual flags -- it passes it as one token, which produces garbled quoted output in the generated build rules.

This happens in two places:

• CMakeLists.txt:165
• test/CMakeLists.txt:97

Both files also include(HandleLLVMOptions), which independently adds the same definitions via add_compile_definitions(), creating a second layer of duplication.

Verified Fix

Replace:

add_definitions(${LLVM_DEFINITIONS})

With:

separate_arguments(LLVM_DEFS_LIST NATIVE_COMMAND "${LLVM_DEFINITIONS}")
add_definitions(${LLVM_DEFS_LIST})

This converts the space-separated string into a proper CMake list before passing it. Tested in both CMakeLists.txt and test/CMakeLists.txt -- all three CppTests build and pass with both GCC 15 and Clang 20.

Environment

• GCC 15 / Clang 20 (Ubuntu 25.10)
• LLVM 23 (built from mlir-aie's pinned commit 979132a)
• CMake 3.31
• Ubuntu 25.10 (kernel 6.19)

[FIM43-Redeye]

Came back with fresh eyes, HandleLLVMOptions already adds compile definitions for all the flags itself. The add_definitions(${LLVM_DEFINITIONS}) calls appear fully redundant. Cleaner fix is probably to remove the lines entirely at all six call sites. Draft PR up at #3021.