From c23a457e72abe608715ac76f076f47dc42af07a5 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Thu, 30 May 2024 20:31:44 +0200
Subject: Merging upstream version 1.74.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 compiler/rustc_codegen_llvm/src/lib.rs | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

(limited to 'compiler/rustc_codegen_llvm/src/lib.rs')

diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs
index d283299ac..9c5edd6bd 100644
--- a/compiler/rustc_codegen_llvm/src/lib.rs
+++ b/compiler/rustc_codegen_llvm/src/lib.rs
@@ -10,6 +10,7 @@
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
 #![feature(never_type)]
+#![feature(slice_group_by)]
 #![feature(impl_trait_in_assoc_type)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
@@ -21,6 +22,7 @@ extern crate rustc_macros;
 #[macro_use]
 extern crate tracing;
 
+use back::owned_target_machine::OwnedTargetMachine;
 use back::write::{create_informational_target_machine, create_target_machine};
 
 use errors::ParseTargetMachineConfig;
@@ -38,8 +40,8 @@ use rustc_errors::{DiagnosticMessage, ErrorGuaranteed, FatalError, Handler, Subd
 use rustc_fluent_macro::fluent_messages;
 use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
-use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
+use rustc_middle::util::Providers;
 use rustc_session::config::{OptLevel, OutputFilenames, PrintKind, PrintRequest};
 use rustc_session::Session;
 use rustc_span::symbol::Symbol;
@@ -47,10 +49,12 @@ use rustc_span::symbol::Symbol;
 use std::any::Any;
 use std::ffi::CStr;
 use std::io::Write;
+use std::mem::ManuallyDrop;
 
 mod back {
     pub mod archive;
     pub mod lto;
+    pub mod owned_target_machine;
     mod profiling;
     pub mod write;
 }
@@ -161,7 +165,7 @@ impl ExtraBackendMethods for LlvmCodegenBackend {
 impl WriteBackendMethods for LlvmCodegenBackend {
     type Module = ModuleLlvm;
     type ModuleBuffer = back::lto::ModuleBuffer;
-    type TargetMachine = &'static mut llvm::TargetMachine;
+    type TargetMachine = OwnedTargetMachine;
     type TargetMachineError = crate::errors::LlvmError<'static>;
     type ThinData = back::lto::ThinData;
     type ThinBuffer = back::lto::ThinBuffer;
@@ -400,7 +404,10 @@ impl CodegenBackend for LlvmCodegenBackend {
 pub struct ModuleLlvm {
     llcx: &'static mut llvm::Context,
     llmod_raw: *const llvm::Module,
-    tm: &'static mut llvm::TargetMachine,
+
+    // This field is `ManuallyDrop` because it is important that the `TargetMachine`
+    // is disposed prior to the `Context` being disposed otherwise UAFs can occur.
+    tm: ManuallyDrop<OwnedTargetMachine>,
 }
 
 unsafe impl Send for ModuleLlvm {}
@@ -411,7 +418,11 @@ impl ModuleLlvm {
         unsafe {
             let llcx = llvm::LLVMRustContextCreate(tcx.sess.fewer_names());
             let llmod_raw = context::create_module(tcx, llcx, mod_name) as *const _;
-            ModuleLlvm { llmod_raw, llcx, tm: create_target_machine(tcx, mod_name) }
+            ModuleLlvm {
+                llmod_raw,
+                llcx,
+                tm: ManuallyDrop::new(create_target_machine(tcx, mod_name)),
+            }
         }
     }
 
@@ -419,7 +430,11 @@ impl ModuleLlvm {
         unsafe {
             let llcx = llvm::LLVMRustContextCreate(tcx.sess.fewer_names());
             let llmod_raw = context::create_module(tcx, llcx, mod_name) as *const _;
-            ModuleLlvm { llmod_raw, llcx, tm: create_informational_target_machine(tcx.sess) }
+            ModuleLlvm {
+                llmod_raw,
+                llcx,
+                tm: ManuallyDrop::new(create_informational_target_machine(tcx.sess)),
+            }
         }
     }
 
@@ -440,7 +455,7 @@ impl ModuleLlvm {
                 }
             };
 
-            Ok(ModuleLlvm { llmod_raw, llcx, tm })
+            Ok(ModuleLlvm { llmod_raw, llcx, tm: ManuallyDrop::new(tm) })
         }
     }
 
@@ -452,7 +467,7 @@ impl ModuleLlvm {
 impl Drop for ModuleLlvm {
     fn drop(&mut self) {
         unsafe {
-            llvm::LLVMRustDisposeTargetMachine(&mut *(self.tm as *mut _));
+            ManuallyDrop::drop(&mut self.tm);
             llvm::LLVMContextDispose(&mut *(self.llcx as *mut _));
         }
     }
-- 
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