From aba78537a17917a29e3b5112e777db0b164e3812 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Sun, 3 Nov 2024 14:37:42 +0100
Subject: [PATCH] llvm: Use no-builtins attribute instead of nobuiltin.

The former prevents recognizing code patterns and turning them into libcalls,
which is what we want for compiler-rt. The latter is meant to be used on call
sites to prevent them from being turned into intrinsics.

Context: https://github.com/ziglang/zig/issues/21842
---
 src/codegen/llvm.zig | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index b70940325648..c87dda2d6d64 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -3242,13 +3242,16 @@ pub const Object = struct {
         if (owner_mod.unwind_tables) {
             try attributes.addFnAttr(.{ .uwtable = Builder.Attribute.UwTable.default }, &o.builder);
         }
-        if (comp.skip_linker_dependencies or comp.no_builtin) {
+        if (comp.skip_linker_dependencies or comp.no_builtin or target.cpu.arch.isBpf()) {
             // The intent here is for compiler-rt and libc functions to not generate
             // infinite recursion. For example, if we are compiling the memcpy function,
             // and llvm detects that the body is equivalent to memcpy, it may replace the
             // body of memcpy with a call to memcpy, which would then cause a stack
             // overflow instead of performing memcpy.
-            try attributes.addFnAttr(.nobuiltin, &o.builder);
+            try attributes.addFnAttr(.{ .string = .{
+                .kind = try o.builder.string("no-builtins"),
+                .value = .empty,
+            } }, &o.builder);
         }
         if (owner_mod.optimize_mode == .ReleaseSmall) {
             try attributes.addFnAttr(.minsize, &o.builder);
@@ -3267,12 +3270,6 @@ pub const Object = struct {
                 .value = try o.builder.string(std.mem.span(s)),
             } }, &o.builder);
         }
-        if (target.cpu.arch.isBpf()) {
-            try attributes.addFnAttr(.{ .string = .{
-                .kind = try o.builder.string("no-builtins"),
-                .value = .empty,
-            } }, &o.builder);
-        }
         if (target.floatAbi() == .soft) {
             // `use-soft-float` means "use software routines for floating point computations". In
             // other words, it configures how LLVM lowers basic float instructions like `fcmp`,