[WinEH] Mark calls inside cleanups as noinline
This works around PR25162. The MSVC tables make it very difficult to
correctly inline a C++ destructor that contains try / catch. We've
attempted to address PR25162 in LLVM's backend, but it feels pretty
infeasible. MSVC and ICC both appear to avoid inlining such complex
destructors.
Long term, we want to fix this by making the inliner smart enough to
know when it is inlining into a cleanup, so it can inline simple
destructors (~unique_ptr and ~vector) while avoiding destructors
containing try / catch.
llvm-svn: 251576
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 8a2006f..05fbfa0 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -3440,8 +3440,14 @@
Attrs.addAttribute(getLLVMContext(), llvm::AttributeSet::FunctionIndex,
llvm::Attribute::AlwaysInline);
- // Disable inlining inside SEH __try blocks.
- if (isSEHTryScope())
+ // Disable inlining inside SEH __try blocks and cleanup funclets. None of the
+ // funclet EH personalities that clang supports have tables that are
+ // expressive enough to describe catching an exception inside a cleanup.
+ // __CxxFrameHandler3, for example, will terminate the program without
+ // catching it.
+ // FIXME: Move this decision to the LLVM inliner. Before we can do that, the
+ // inliner needs to know if a given call site is part of a cleanuppad.
+ if (isSEHTryScope() || isCleanupPadScope())
Attrs =
Attrs.addAttribute(getLLVMContext(), llvm::AttributeSet::FunctionIndex,
llvm::Attribute::NoInline);