From c71848f961059d7aa5fc67220017227fa3ec8dc3 Mon Sep 17 00:00:00 2001
From: liushuyu <liushuyu011@gmail.com>
Date: Thu, 23 Jan 2025 13:23:24 -0700
Subject: [PATCH] gen: fix control-flow protection attribute marking (#4828)

* gen/modules.cpp: use setModuleFlag API to replace ...

... the module attribute to avoid LLVM assertions if specified module
attribute already exists

* changelog for gen/module.cpp cf-protection fix
---
 CHANGELOG.md    | 1 +
 gen/modules.cpp | 7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 87a6313c54..04e691309c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 #### Platform support
 
 #### Bug fixes
+- Building multi-file D applications with control-flow protection will no longer cause LDC to throw an internal compiler error. (#4828)
 
 # LDC 1.40.0 (2024-12-15)
 
diff --git a/gen/modules.cpp b/gen/modules.cpp
index 67191e1d9b..dce1b59f6f 100644
--- a/gen/modules.cpp
+++ b/gen/modules.cpp
@@ -391,15 +391,18 @@ void registerModuleInfo(Module *m) {
 
 void addModuleFlags(llvm::Module &m) {
   const auto ModuleMinFlag = llvm::Module::Min;
+  const auto ConstantOne =
+      llvm::ConstantInt::get(LLType::getInt32Ty(m.getContext()), 1);
+  const auto ConstantOneMetadata = llvm::ConstantAsMetadata::get(ConstantOne);
 
   if (opts::fCFProtection == opts::CFProtectionType::Return ||
       opts::fCFProtection == opts::CFProtectionType::Full) {
-    m.addModuleFlag(ModuleMinFlag, "cf-protection-return", 1);
+    m.setModuleFlag(ModuleMinFlag, "cf-protection-return", ConstantOneMetadata);
   }
 
   if (opts::fCFProtection == opts::CFProtectionType::Branch ||
       opts::fCFProtection == opts::CFProtectionType::Full) {
-    m.addModuleFlag(ModuleMinFlag, "cf-protection-branch", 1);
+    m.setModuleFlag(ModuleMinFlag, "cf-protection-branch", ConstantOneMetadata);
   }
 }