From a89a93bdd990f70bfd1dcc40c6fbe0615d099ebe Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Fri, 17 Apr 2026 15:38:33 +0200
Subject: [PATCH 1/8] Update the cc crate for rustc_llvm

Latest stacker needs a newer cc than 1.2.16 as older versions don't have
windows arm64ec support.
---
 Cargo.lock                     | 5 +++--
 compiler/rustc_llvm/Cargo.toml | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 6c9ac52d1c40c..6a60e5daa29f2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -544,10 +544,11 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.2.16"
+version = "1.2.50"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "be714c154be609ec7f5dad223a33bf1482fff90472de28f7362806e6d4832b8c"
+checksum = "9f50d563227a1c37cc0a263f64eca3334388c01c5e4c4861a9def205c614383c"
 dependencies = [
+ "find-msvc-tools",
  "jobserver",
  "libc",
  "shlex",
diff --git a/compiler/rustc_llvm/Cargo.toml b/compiler/rustc_llvm/Cargo.toml
index c9f8cd9495834..3bffd75ef2896 100644
--- a/compiler/rustc_llvm/Cargo.toml
+++ b/compiler/rustc_llvm/Cargo.toml
@@ -11,7 +11,7 @@ libc = "0.2.73"
 [build-dependencies]
 # tidy-alphabetical-start
 # `cc` updates often break things, so we pin it here.
-cc = "=1.2.16"
+cc = "=1.2.50"
 shlex = "1.3.0"
 # tidy-alphabetical-end
 

From c9f6738abdf6dbb8673ac80cd4135bd7bf37f950 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Thu, 23 Apr 2026 11:36:19 +0200
Subject: [PATCH 2/8] [PERF] Downgrade to 1.2.21

---
 Cargo.lock                     | 5 ++---
 compiler/rustc_llvm/Cargo.toml | 2 +-
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 6a60e5daa29f2..bfa3cf6ed75ec 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -544,11 +544,10 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.2.50"
+version = "1.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9f50d563227a1c37cc0a263f64eca3334388c01c5e4c4861a9def205c614383c"
+checksum = "8691782945451c1c383942c4874dbe63814f61cb57ef773cda2972682b7bb3c0"
 dependencies = [
- "find-msvc-tools",
  "jobserver",
  "libc",
  "shlex",
diff --git a/compiler/rustc_llvm/Cargo.toml b/compiler/rustc_llvm/Cargo.toml
index 3bffd75ef2896..0d74d736cbc37 100644
--- a/compiler/rustc_llvm/Cargo.toml
+++ b/compiler/rustc_llvm/Cargo.toml
@@ -11,7 +11,7 @@ libc = "0.2.73"
 [build-dependencies]
 # tidy-alphabetical-start
 # `cc` updates often break things, so we pin it here.
-cc = "=1.2.50"
+cc = "=1.2.21"
 shlex = "1.3.0"
 # tidy-alphabetical-end
 

From e3b31f2cc7cf0a1e6efea44ee358d07af3b90686 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Thu, 23 Apr 2026 14:28:57 +0200
Subject: [PATCH 3/8] [PERF] Update to cc 1.2.30

---
 Cargo.lock                     | 4 ++--
 compiler/rustc_llvm/Cargo.toml | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index bfa3cf6ed75ec..c7ac76fddccc0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -544,9 +544,9 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.2.21"
+version = "1.2.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8691782945451c1c383942c4874dbe63814f61cb57ef773cda2972682b7bb3c0"
+checksum = "deec109607ca693028562ed836a5f1c4b8bd77755c4e132fc5ce11b0b6211ae7"
 dependencies = [
  "jobserver",
  "libc",
diff --git a/compiler/rustc_llvm/Cargo.toml b/compiler/rustc_llvm/Cargo.toml
index 0d74d736cbc37..98832627400e8 100644
--- a/compiler/rustc_llvm/Cargo.toml
+++ b/compiler/rustc_llvm/Cargo.toml
@@ -11,7 +11,7 @@ libc = "0.2.73"
 [build-dependencies]
 # tidy-alphabetical-start
 # `cc` updates often break things, so we pin it here.
-cc = "=1.2.21"
+cc = "=1.2.30"
 shlex = "1.3.0"
 # tidy-alphabetical-end
 

From 5d0b9fbc603675259d60f4d8060aecaeb134ae60 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Thu, 23 Apr 2026 17:21:15 +0200
Subject: [PATCH 4/8] [PERF] Update to 1.2.35

---
 Cargo.lock                     | 5 +++--
 compiler/rustc_llvm/Cargo.toml | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index c7ac76fddccc0..7918288b9becb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -544,10 +544,11 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.2.30"
+version = "1.2.35"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "deec109607ca693028562ed836a5f1c4b8bd77755c4e132fc5ce11b0b6211ae7"
+checksum = "590f9024a68a8c40351881787f1934dc11afd69090f5edb6831464694d836ea3"
 dependencies = [
+ "find-msvc-tools",
  "jobserver",
  "libc",
  "shlex",
diff --git a/compiler/rustc_llvm/Cargo.toml b/compiler/rustc_llvm/Cargo.toml
index 98832627400e8..0c494e42f5380 100644
--- a/compiler/rustc_llvm/Cargo.toml
+++ b/compiler/rustc_llvm/Cargo.toml
@@ -11,7 +11,7 @@ libc = "0.2.73"
 [build-dependencies]
 # tidy-alphabetical-start
 # `cc` updates often break things, so we pin it here.
-cc = "=1.2.30"
+cc = "=1.2.35"
 shlex = "1.3.0"
 # tidy-alphabetical-end
 

From 301629af8fe2c24d3404f00164f2213c8be14245 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Sat, 25 Apr 2026 17:45:03 +0200
Subject: [PATCH 5/8] [PERF] Update to 1.2.37

---
 Cargo.lock                     | 4 ++--
 compiler/rustc_llvm/Cargo.toml | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 7918288b9becb..ace95850347d6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -544,9 +544,9 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.2.35"
+version = "1.2.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "590f9024a68a8c40351881787f1934dc11afd69090f5edb6831464694d836ea3"
+checksum = "65193589c6404eb80b450d618eaf9a2cafaaafd57ecce47370519ef674a7bd44"
 dependencies = [
  "find-msvc-tools",
  "jobserver",
diff --git a/compiler/rustc_llvm/Cargo.toml b/compiler/rustc_llvm/Cargo.toml
index 0c494e42f5380..9e808887873a9 100644
--- a/compiler/rustc_llvm/Cargo.toml
+++ b/compiler/rustc_llvm/Cargo.toml
@@ -11,7 +11,7 @@ libc = "0.2.73"
 [build-dependencies]
 # tidy-alphabetical-start
 # `cc` updates often break things, so we pin it here.
-cc = "=1.2.35"
+cc = "=1.2.37"
 shlex = "1.3.0"
 # tidy-alphabetical-end
 

From daa18b73c53bb7491c8c5d0753bff63141427697 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Fri, 8 May 2026 16:41:00 +0200
Subject: [PATCH 6/8] Fix typo

---
 src/bootstrap/src/core/build_steps/compile.rs | 2 +-
 src/bootstrap/src/core/build_steps/llvm.rs    | 4 ++--
 src/bootstrap/src/core/build_steps/test.rs    | 4 ++--
 src/bootstrap/src/lib.rs                      | 2 +-
 src/bootstrap/src/utils/cc_detect.rs          | 4 ++--
 5 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs
index 46d05b9d5d2f7..36ecde3a0fc67 100644
--- a/src/bootstrap/src/core/build_steps/compile.rs
+++ b/src/bootstrap/src/core/build_steps/compile.rs
@@ -1907,7 +1907,7 @@ pub fn compiler_file(
         return PathBuf::new();
     }
     let mut cmd = command(compiler);
-    cmd.args(builder.cc_handled_clags(target, c));
+    cmd.args(builder.cc_handled_cflags(target, c));
     cmd.args(builder.cc_unhandled_cflags(target, GitRepo::Rustc, c));
     cmd.arg(format!("-print-file-name={file}"));
     let out = cmd.run_capture_stdout(builder).stdout();
diff --git a/src/bootstrap/src/core/build_steps/llvm.rs b/src/bootstrap/src/core/build_steps/llvm.rs
index 087a395a067f0..6f1b8532f031b 100644
--- a/src/bootstrap/src/core/build_steps/llvm.rs
+++ b/src/bootstrap/src/core/build_steps/llvm.rs
@@ -800,7 +800,7 @@ fn configure_cmake(
     // Needs `suppressed_compiler_flag_prefixes` to be gone, and hence
     // https://github.com/llvm/llvm-project/issues/88780 to be fixed.
     for flag in builder
-        .cc_handled_clags(target, CLang::C)
+        .cc_handled_cflags(target, CLang::C)
         .into_iter()
         .chain(builder.cc_unhandled_cflags(target, GitRepo::Llvm, CLang::C))
         .filter(|flag| !suppressed_compiler_flag_prefixes.iter().any(|p| flag.starts_with(p)))
@@ -821,7 +821,7 @@ fn configure_cmake(
     cfg.define("CMAKE_C_FLAGS", cflags);
     let mut cxxflags = ccflags.cxxflags.clone();
     for flag in builder
-        .cc_handled_clags(target, CLang::Cxx)
+        .cc_handled_cflags(target, CLang::Cxx)
         .into_iter()
         .chain(builder.cc_unhandled_cflags(target, GitRepo::Llvm, CLang::Cxx))
         .filter(|flag| {
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index 991592ec522d0..cda6698e3a5a1 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -2428,9 +2428,9 @@ Please disable assertions with `rust.debug-assertions = false`.
         // Only pass correct values for these flags for the `run-make` suite as it
         // requires that a C++ compiler was configured which isn't always the case.
         if !builder.config.dry_run() && mode == CompiletestMode::RunMake {
-            let mut cflags = builder.cc_handled_clags(target, CLang::C);
+            let mut cflags = builder.cc_handled_cflags(target, CLang::C);
             cflags.extend(builder.cc_unhandled_cflags(target, GitRepo::Rustc, CLang::C));
-            let mut cxxflags = builder.cc_handled_clags(target, CLang::Cxx);
+            let mut cxxflags = builder.cc_handled_cflags(target, CLang::Cxx);
             cxxflags.extend(builder.cc_unhandled_cflags(target, GitRepo::Rustc, CLang::Cxx));
             cmd.arg("--cc")
                 .arg(builder.cc(target))
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index 6af11d9ae0a81..476836d93a648 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -1276,7 +1276,7 @@ impl Build {
 
     /// Returns C flags that `cc-rs` thinks should be enabled for the
     /// specified target by default.
-    fn cc_handled_clags(&self, target: TargetSelection, c: CLang) -> Vec<String> {
+    fn cc_handled_cflags(&self, target: TargetSelection, c: CLang) -> Vec<String> {
         if self.config.dry_run() {
             return Vec::new();
         }
diff --git a/src/bootstrap/src/utils/cc_detect.rs b/src/bootstrap/src/utils/cc_detect.rs
index d010226f0dfdb..e9fa2aada9a8c 100644
--- a/src/bootstrap/src/utils/cc_detect.rs
+++ b/src/bootstrap/src/utils/cc_detect.rs
@@ -113,7 +113,7 @@ pub fn fill_target_compiler(build: &mut Build, target: TargetSelection) {
     };
 
     build.cc.insert(target, compiler.clone());
-    let mut cflags = build.cc_handled_clags(target, CLang::C);
+    let mut cflags = build.cc_handled_cflags(target, CLang::C);
     cflags.extend(build.cc_unhandled_cflags(target, GitRepo::Rustc, CLang::C));
 
     // If we use llvm-libunwind, we will need a C++ compiler as well for all targets
@@ -140,7 +140,7 @@ pub fn fill_target_compiler(build: &mut Build, target: TargetSelection) {
     build.do_if_verbose(|| println!("CC_{} = {:?}", target.triple, build.cc(target)));
     build.do_if_verbose(|| println!("CFLAGS_{} = {cflags:?}", target.triple));
     if let Ok(cxx) = build.cxx(target) {
-        let mut cxxflags = build.cc_handled_clags(target, CLang::Cxx);
+        let mut cxxflags = build.cc_handled_cflags(target, CLang::Cxx);
         cxxflags.extend(build.cc_unhandled_cflags(target, GitRepo::Rustc, CLang::Cxx));
         build.do_if_verbose(|| println!("CXX_{} = {cxx:?}", target.triple));
         build.do_if_verbose(|| println!("CXXFLAGS_{} = {cxxflags:?}", target.triple));

From 3db1c063101857e6a0ea4572cbd2fe7c189a72bd Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Fri, 8 May 2026 16:41:40 +0200
Subject: [PATCH 7/8] Build C code with LTO when LTO is enabled for rust code

---
 src/bootstrap/src/utils/cc_detect.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/bootstrap/src/utils/cc_detect.rs b/src/bootstrap/src/utils/cc_detect.rs
index e9fa2aada9a8c..347d2710c1420 100644
--- a/src/bootstrap/src/utils/cc_detect.rs
+++ b/src/bootstrap/src/utils/cc_detect.rs
@@ -25,7 +25,7 @@ use std::collections::HashSet;
 use std::iter;
 use std::path::{Path, PathBuf};
 
-use crate::core::config::TargetSelection;
+use crate::core::config::{RustcLto, TargetSelection};
 use crate::utils::exec::{BootstrapCommand, command};
 use crate::{Build, CLang, GitRepo};
 
@@ -53,6 +53,15 @@ fn new_cc_build(build: &Build, target: TargetSelection) -> cc::Build {
             }
         }
     }
+    match build.config.rust_lto {
+        RustcLto::Off | RustcLto::ThinLocal => {}
+        RustcLto::Thin => {
+            cfg.flag_if_supported("-flto=thin");
+        }
+        RustcLto::Fat => {
+            cfg.flag_if_supported("-flto=full");
+        }
+    }
     cfg
 }
 

From 5d562601460db766903424fe54da59cec36d6d33 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Fri, 17 Apr 2026 15:38:33 +0200
Subject: [PATCH 8/8] Update the cc crate for rustc_llvm

Latest stacker needs a newer cc than 1.2.16 as older versions don't have
windows arm64ec support.
---
 Cargo.lock                     | 4 ++--
 compiler/rustc_llvm/Cargo.toml | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index ace95850347d6..6a60e5daa29f2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -544,9 +544,9 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.2.37"
+version = "1.2.50"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "65193589c6404eb80b450d618eaf9a2cafaaafd57ecce47370519ef674a7bd44"
+checksum = "9f50d563227a1c37cc0a263f64eca3334388c01c5e4c4861a9def205c614383c"
 dependencies = [
  "find-msvc-tools",
  "jobserver",
diff --git a/compiler/rustc_llvm/Cargo.toml b/compiler/rustc_llvm/Cargo.toml
index 9e808887873a9..3bffd75ef2896 100644
--- a/compiler/rustc_llvm/Cargo.toml
+++ b/compiler/rustc_llvm/Cargo.toml
@@ -11,7 +11,7 @@ libc = "0.2.73"
 [build-dependencies]
 # tidy-alphabetical-start
 # `cc` updates often break things, so we pin it here.
-cc = "=1.2.37"
+cc = "=1.2.50"
 shlex = "1.3.0"
 # tidy-alphabetical-end