From 0e413aec3c473ce79b8204ba7f3c8b8d75b1ddd5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Steven=20Dee=20=28J=C5=8Dshin=29?= <git@wholezero.org>
Date: Wed, 19 Jun 2024 18:28:10 -0700
Subject: [PATCH] Make allocators weak references

new.cc now only defines three functions, and really they could all be in
one block of assembly if someone felt like being clever about it. All of
the STL functions are defined as weak references from those functions to
their g++-mangled names. (The clang-mangled names have an extra underbar
prepended, incidentally.)
---
 ctl/new.cc | 129 +++++++++++++++++++++++------------------------------
 1 file changed, 56 insertions(+), 73 deletions(-)

diff --git a/ctl/new.cc b/ctl/new.cc
index 6aa0c7962..f45d3c7b0 100644
--- a/ctl/new.cc
+++ b/ctl/new.cc
@@ -28,91 +28,74 @@ constexpr auto a1 = align_val_t(1);
 
 } // namespace
 
-#define WEAK __attribute__((weak))
+// clang-format off
 
-WEAK void*
-operator new(size_t n, align_val_t a)
+extern "C" {
+
+void* ctl_alloc(size_t n, size_t a)
 {
     void* p;
-    if (!(p = memalign(static_cast<size_t>(a), n))) {
+    if (!(p = memalign(a, n)))
         __builtin_trap();
-    }
     return p;
 }
 
-WEAK void*
-operator new[](size_t n, align_val_t a)
+void* ctl_alloc1(size_t n)
 {
-    return operator new(n, a);
-}
-WEAK void*
-operator new(size_t n)
-{
-    return operator new(n, a1);
-}
-WEAK void*
-operator new[](size_t n)
-{
-    return operator new(n, a1);
+    return ctl_alloc(n, 1);
 }
 
-WEAK void*
-operator new(size_t, void* p)
-{
-    return p;
-}
-WEAK void*
-operator new[](size_t, void* p)
+void* ctl_ret(size_t, void* p)
 {
     return p;
 }
 
-WEAK void
-operator delete(void* p) noexcept
-{
-    free(p);
-}
-WEAK void
-operator delete[](void* p) noexcept
-{
-    free(p);
-}
-WEAK void
-operator delete(void* p, align_val_t) noexcept
-{
-    free(p);
-}
-WEAK void
-operator delete[](void* p, align_val_t) noexcept
-{
-    free(p);
-}
-WEAK void
-operator delete(void* p, size_t) noexcept
-{
-    free(p);
-}
-WEAK void
-operator delete[](void* p, size_t) noexcept
-{
-    free(p);
-}
-WEAK void
-operator delete(void* p, size_t, align_val_t) noexcept
-{
-    free(p);
-}
-WEAK void
-operator delete[](void* p, size_t, align_val_t) noexcept
-{
-    free(p);
-}
+// operator new(size_t, align_val_t)
+__weak_reference(ctl_alloc, _ZnwmN3ctl11align_val_tE);
 
-WEAK void
-operator delete(void*, void*) noexcept
-{
-}
-WEAK void
-operator delete[](void*, void*) noexcept
-{
-}
+// operator new[](size_t, align_val_t)
+__weak_reference(ctl_alloc, _ZnamN3ctl11align_val_tE);
+
+// operator new(size_t)
+__weak_reference(ctl_alloc1, _Znwm);
+
+// operator new[](size_t)
+__weak_reference(ctl_alloc1, _Znam);
+
+// operator new(size_t, void*)
+__weak_reference(ctl_ret, _ZnwmPv);
+
+// operator new[](size_t, void*)
+__weak_reference(ctl_ret, _ZnamPv);
+
+// operator delete(void*)
+__weak_reference(free, _ZdlPv);
+
+// operator delete[](void*)
+__weak_reference(free, _ZdaPv);
+
+// operator delete(void*, align_val_t)
+__weak_reference(free, _ZdlPvN3ctl11align_val_tE);
+
+// operator delete[](void*, align_val_t)
+__weak_reference(free, _ZdaPvN3ctl11align_val_tE);
+
+// operator delete(void*, size_t)
+__weak_reference(free, _ZdlPvm);
+
+// operator delete[](void*, size_t)
+__weak_reference(free, _ZdaPvm);
+
+// operator delete(void*, size_t, align_val_t)
+__weak_reference(free, _ZdlPvmN3ctl11align_val_tE);
+
+// operator delete[](void*, size_t, align_val_t)
+__weak_reference(free, _ZdaPvmN3ctl11align_val_tE);
+
+// operator delete(void*, void*) noexcept
+__weak_reference(free, _ZdlPvS_);
+
+// operator delete[](void*, void*)
+__weak_reference(free, _ZdaPvS_);
+
+} // extern "C"