From c1608f7f691438d6d457b317c681775621aeac7c Mon Sep 17 00:00:00 2001 From: Alex Lorenz Date: Wed, 4 Jan 2017 13:40:34 +0000 Subject: Add -f[no-]strict-return flag that can be used to avoid undefined behaviour in non-void functions that fall off at the end without returning a value when compiling C++. Clang uses the new compiler flag to determine when it should treat control flow paths that fall off the end of a non-void function as unreachable. If -fno-strict-return is on, the code generator emits the ureachable and trap IR only when the function returns either a record type with a non-trivial destructor or another non-trivially copyable type. The primary goal of this flag is to avoid treating falling off the end of a non-void function as undefined behaviour. The burden of undefined behaviour is placed on the caller instead: if the caller ignores the returned value then the undefined behaviour is avoided. This kind of behaviour is useful in several cases, e.g. when compiling C code in C++ mode. rdar://13102603 Differential Revision: https://reviews.llvm.org/D27163 llvm-svn: 290960 --- clang/lib/Frontend/CompilerInvocation.cpp | 1 + 1 file changed, 1 insertion(+) (limited to 'clang/lib/Frontend/CompilerInvocation.cpp') diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index a0682e2..ca4a765 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -602,6 +602,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK, Opts.NoDwarfDirectoryAsm = Args.hasArg(OPT_fno_dwarf_directory_asm); Opts.SoftFloat = Args.hasArg(OPT_msoft_float); Opts.StrictEnums = Args.hasArg(OPT_fstrict_enums); + Opts.StrictReturn = !Args.hasArg(OPT_fno_strict_return); Opts.StrictVTablePointers = Args.hasArg(OPT_fstrict_vtable_pointers); Opts.UnsafeFPMath = Args.hasArg(OPT_menable_unsafe_fp_math) || Args.hasArg(OPT_cl_unsafe_math_optimizations) || -- cgit v1.1