commit 24878cf6b025a1db14feee2d9197b129a504e041
author Dan Albert <danalbert@google.com> Thu Jan 21 13:27:14 2021 -0800
committer Copybara-Service <copybara-worker@google.com> Thu Jan 21 17:25:02 2021 -0800
tree 8e72ce8964e67d68afa5952420f8d9cdcf3ec931
parent d94a1e9df2012258e2e61513c53a6960a0ffc76f

[libc++abi] Add an option to avoid demangling in terminate.

We've been using this patch in Android so we can avoid including the
demangler in libc++.so. It comes with a rather large cost in RSS and
isn't commonly needed.

Reviewed By: #libc_abi, compnerd

Differential Revision: https://reviews.llvm.org/D88189

GitOrigin-RevId: 866d480fe0549d616bfdd69986dd07a7b2dc5b52

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c8ab9d7..ede8bd7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -146,6 +146,8 @@
 # The default terminate handler attempts to demangle uncaught exceptions, which
 # causes extra I/O and demangling code to be pulled in.
 option(LIBCXXABI_SILENT_TERMINATE "Set this to make the terminate handler default to a silent alternative" OFF)
+option(LIBCXXABI_NON_DEMANGLING_TERMINATE "Set this to make the terminate handler
+avoid demangling" OFF)
 
 if (NOT LIBCXXABI_ENABLE_SHARED AND NOT LIBCXXABI_ENABLE_STATIC)
   message(FATAL_ERROR "libc++abi must be built as either a shared or static library.")
@@ -452,6 +454,10 @@
   add_definitions(-DLIBCXXABI_SILENT_TERMINATE)
 endif()
 
+if (LIBCXXABI_NON_DEMANGLING_TERMINATE)
+  add_definitions(-DLIBCXXABI_NON_DEMANGLING_TERMINATE)
+endif()
+
 if (LIBCXXABI_BAREMETAL)
     add_definitions(-DLIBCXXABI_BAREMETAL)
 endif()

src/cxa_default_handlers.cpp

diff --git a/src/cxa_default_handlers.cpp b/src/cxa_default_handlers.cpp
index d2f823d..a24ee01 100644
--- a/src/cxa_default_handlers.cpp
+++ b/src/cxa_default_handlers.cpp
@@ -45,6 +45,7 @@
                         exception_header + 1;
                 const __shim_type_info* thrown_type =
                     static_cast<const __shim_type_info*>(exception_header->exceptionType);
+#if !defined(LIBCXXABI_NON_DEMANGLING_TERMINATE)
                 // Try to get demangled name of thrown_type
                 int status;
                 char buf[1024];
@@ -52,6 +53,9 @@
                 const char* name = __cxa_demangle(thrown_type->name(), buf, &len, &status);
                 if (status != 0)
                     name = thrown_type->name();
+#else
+                const char* name = thrown_type->name();
+#endif
                 // If the uncaught exception can be caught with std::exception&
                 const __shim_type_info* catch_type =
                     static_cast<const __shim_type_info*>(&typeid(std::exception));