[libc] enable stack protectors and frame pointers on default

Author: SchrodingerZhu

libc/CMakeLists.txt

@@ -47,6 +47,10 @@ set(LIBC_NAMESPACE ${default_namespace}
   CACHE STRING "The namespace to use to enclose internal implementations. Must start with '__llvm_libc'."
 )
 
+# Codegen options.
+option(LLVM_LIBC_KEEP_FRAME_POINTER "Keep frame pointers in LLVM libc" ON)
+option(LLVM_LIBC_ENABLE_STACK_PROTECTOR "Enable stack protector for LLVM libc" ON)
+
 if(LLVM_LIBC_FULL_BUILD OR LLVM_LIBC_GPU_BUILD)
   if(NOT LIBC_HDRGEN_EXE)
     # We need to set up hdrgen first since other targets depend on it.

libc/cmake/modules/LLVMLibCCompileOptionRules.cmake

@@ -60,6 +60,15 @@ function(_get_common_compile_options output_var flags)
     if (LIBC_CC_SUPPORTS_PATTERN_INIT)
       list(APPEND compile_options "-ftrivial-auto-var-init=pattern")
     endif()
+    if (LLVM_LIBC_KEEP_FRAME_POINTER)
+      list(APPEND compile_options "-fno-omit-frame-pointer")
+      if (LIBC_TARGET_ARCHITECTURE_IS_X86)
+        list(APPEND compile_options "-mno-omit-leaf-frame-pointer")
+      endif()
+    endif()
+    if (LLVM_LIBC_ENABLE_STACK_PROTECTOR)
+      list(APPEND compile_options "-fstack-protector-strong")
+    endif()
     list(APPEND compile_options "-Wall")
     list(APPEND compile_options "-Wextra")
     # -DLIBC_WNO_ERROR=ON if you can't build cleanly with -Werror.

utils/bazel/llvm-project-overlay/libc/libc_build_rules.bzl

@@ -78,15 +78,20 @@ def libc_function(
                      its deps.
       **kwargs: Other attributes relevant for a cc_library. For example, deps.
     """
-
+    # x86 targets have -mno-omit-leaf-frame-pointer.
+    copts = selects.with_or({
+        PLATFORM_CPU_X86_64: ["-mno-omit-leaf-frame-pointer"],
+        "//conditions:default": []
+    })
     # We use the explicit equals pattern here because append and += mutate the
     # original list, where this creates a new list and stores it in deps.
-    copts = copts or []
     copts = copts + [
         "-O3",
         "-fno-builtin",
         "-fno-lax-vector-conversions",
         "-ftrivial-auto-var-init=pattern",
+        "-fno-omit-frame-pointer",
+        "-fstack-protector-strong",
     ]
 
     # We compile the code twice, the first target is suffixed with ".__internal__" and contains the