[llvm-branch-commits] [libcxxabi] 866d480 - [libc++abi] Add an option to avoid demangling in terminate.

[Dan Albert via llvm-branch-commits]

Author: Dan Albert
Date: 2021-01-21T13:32:29-08:00
New Revision: 866d480fe0549d616bfdd69986dd07a7b2dc5b52

URL: https://github.com/llvm/llvm-project/commit/866d480fe0549d616bfdd69986dd07a7b2dc5b52
DIFF: https://github.com/llvm/llvm-project/commit/866d480fe0549d616bfdd69986dd07a7b2dc5b52.diff

LOG: [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

Added: 
    

Modified: 
    libcxxabi/CMakeLists.txt
    libcxxabi/src/cxa_default_handlers.cpp

Removed: 
    


################################################################################
diff  --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
index c8ab9d7acb1d..ede8bd71da4c 100644
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -146,6 +146,8 @@ option(LIBCXXABI_BAREMETAL "Build libc++abi for baremetal targets." OFF)
 # 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 @@ if (LIBCXXABI_SILENT_TERMINATE)
   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()

diff  --git a/libcxxabi/src/cxa_default_handlers.cpp b/libcxxabi/src/cxa_default_handlers.cpp
index d2f823d2b778..a24ee0145343 100644
--- a/libcxxabi/src/cxa_default_handlers.cpp
+++ b/libcxxabi/src/cxa_default_handlers.cpp
@@ -45,6 +45,7 @@ static void demangling_terminate_handler()
                         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 @@ static void demangling_terminate_handler()
                 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));