From 53238c3db6b293546f0b3bbd835ca85517ae9d8f Mon Sep 17 00:00:00 2001
From: Flakebi <flakebi@t-online.de>
Date: Thu, 2 Jan 2025 13:15:21 +0100
Subject: [PATCH] Target option to require explicit cpu
Some targets have many different CPUs and no generic CPU that can be
used as a default. For these targets, the user needs to explicitly
specify a CPU through `-C target-cpu=`.
Add an option for targets and an error message if no CPU is set.
This affects the proposed amdgpu and avr targets.
---
compiler/rustc_codegen_ssa/messages.ftl | 2 ++
compiler/rustc_codegen_ssa/src/base.rs | 5 +++++
compiler/rustc_codegen_ssa/src/errors.rs | 4 ++++
compiler/rustc_target/src/spec/json.rs | 2 ++
compiler/rustc_target/src/spec/mod.rs | 4 ++++
.../run-make/target-specs/require-explicit-cpu.json | 11 +++++++++++
tests/run-make/target-specs/rmake.rs | 13 +++++++++++++
7 files changed, 41 insertions(+)
create mode 100644 tests/run-make/target-specs/require-explicit-cpu.json
diff --git a/compiler/rustc_codegen_ssa/messages.ftl b/compiler/rustc_codegen_ssa/messages.ftl
index 56188714b44fd..60e97910e197d 100644
--- a/compiler/rustc_codegen_ssa/messages.ftl
+++ b/compiler/rustc_codegen_ssa/messages.ftl
@@ -30,6 +30,8 @@ codegen_ssa_copy_path = could not copy {$from} to {$to}: {$error}
codegen_ssa_copy_path_buf = unable to copy {$source_file} to {$output_path}: {$error}
+codegen_ssa_cpu_required = target requires explicitly specifying a cpu with `-C target-cpu`
+
codegen_ssa_create_temp_dir = couldn't create a temp dir: {$error}
codegen_ssa_dlltool_fail_import_library =
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 77e1fed720dfb..9c31cde259f08 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -616,6 +616,11 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
return ongoing_codegen;
}
+ if tcx.sess.target.need_explicit_cpu && tcx.sess.opts.cg.target_cpu.is_none() {
+ // The target has no default cpu, but none is set explicitly
+ tcx.dcx().emit_fatal(errors::CpuRequired);
+ }
+
let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
// Run the monomorphization collector and partition the collected items into
diff --git a/compiler/rustc_codegen_ssa/src/errors.rs b/compiler/rustc_codegen_ssa/src/errors.rs
index c7213bbc801f9..7132219fb3dc6 100644
--- a/compiler/rustc_codegen_ssa/src/errors.rs
+++ b/compiler/rustc_codegen_ssa/src/errors.rs
@@ -491,6 +491,10 @@ pub(crate) struct CheckInstalledVisualStudio;
#[diag(codegen_ssa_insufficient_vs_code_product)]
pub(crate) struct InsufficientVSCodeProduct;
+#[derive(Diagnostic)]
+#[diag(codegen_ssa_cpu_required)]
+pub(crate) struct CpuRequired;
+
#[derive(Diagnostic)]
#[diag(codegen_ssa_processing_dymutil_failed)]
#[note]
diff --git a/compiler/rustc_target/src/spec/json.rs b/compiler/rustc_target/src/spec/json.rs
index 9cdc0801b1f00..015ea97f2acb0 100644
--- a/compiler/rustc_target/src/spec/json.rs
+++ b/compiler/rustc_target/src/spec/json.rs
@@ -546,6 +546,7 @@ impl Target {
key!(link_env_remove, list);
key!(asm_args, list);
key!(cpu);
+ key!(need_explicit_cpu, bool);
key!(features);
key!(dynamic_linking, bool);
key!(direct_access_external_data, Option<bool>);
@@ -720,6 +721,7 @@ impl ToJson for Target {
target_option_val!(link_env_remove);
target_option_val!(asm_args);
target_option_val!(cpu);
+ target_option_val!(need_explicit_cpu);
target_option_val!(features);
target_option_val!(dynamic_linking);
target_option_val!(direct_access_external_data);
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 02962d55a60ed..b017145daa396 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -2240,6 +2240,9 @@ pub struct TargetOptions {
/// Default CPU to pass to LLVM. Corresponds to `llc -mcpu=$cpu`. Defaults
/// to "generic".
pub cpu: StaticCow<str>,
+ /// Whether a cpu needs to be explicitly set.
+ /// Set to true if there is no default cpu. Defaults to false.
+ pub need_explicit_cpu: bool,
/// Default target features to pass to LLVM. These features overwrite
/// `-Ctarget-cpu` but can be overwritten with `-Ctarget-features`.
/// Corresponds to `llc -mattr=$features`.
@@ -2676,6 +2679,7 @@ impl Default for TargetOptions {
link_script: None,
asm_args: cvs![],
cpu: "generic".into(),
+ need_explicit_cpu: false,
features: "".into(),
direct_access_external_data: None,
dynamic_linking: false,
diff --git a/tests/run-make/target-specs/require-explicit-cpu.json b/tests/run-make/target-specs/require-explicit-cpu.json
new file mode 100644
index 0000000000000..5cbb9573b3f12
--- /dev/null
+++ b/tests/run-make/target-specs/require-explicit-cpu.json
@@ -0,0 +1,11 @@
+{
+ "data-layout": "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-i128:128-f64:32:64-f80:32-n8:16:32-S128",
+ "linker-flavor": "gcc",
+ "llvm-target": "i686-unknown-linux-gnu",
+ "target-endian": "little",
+ "target-pointer-width": "32",
+ "target-c-int-width": "32",
+ "arch": "x86",
+ "os": "linux",
+ "need-explicit-cpu": true
+}
diff --git a/tests/run-make/target-specs/rmake.rs b/tests/run-make/target-specs/rmake.rs
index 79c888ab3406a..f36a5784c8930 100644
--- a/tests/run-make/target-specs/rmake.rs
+++ b/tests/run-make/target-specs/rmake.rs
@@ -63,4 +63,17 @@ fn main() {
.crate_type("lib")
.run_fail()
.assert_stderr_contains("data-layout for target");
+ rustc()
+ .input("foo.rs")
+ .target("require-explicit-cpu")
+ .crate_type("lib")
+ .run_fail()
+ .assert_stderr_contains("target requires explicitly specifying a cpu");
+ rustc()
+ .input("foo.rs")
+ .target("require-explicit-cpu")
+ .crate_type("lib")
+ .arg("-Ctarget-cpu=generic")
+ .run();
+ rustc().target("require-explicit-cpu").arg("--print=target-cpus").run();
}