Rollup merge of #128970 - DianQK:lint-llvm-ir, r=nikic

Add `-Zlint-llvm-ir`

This flag is similar to `-Zverify-llvm-ir` and allows us to lint the generated IR.

r? compiler

Author: GuillaumeGomez

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -571,6 +571,7 @@ pub(crate) unsafe fn llvm_optimize(
             cgcx.opts.cg.linker_plugin_lto.enabled(),
             config.no_prepopulate_passes,
             config.verify_llvm_ir,
+            config.lint_llvm_ir,
             using_thin_buffers,
             config.merge_functions,
             unroll_loops,

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2225,6 +2225,7 @@ unsafe extern "C" {
         IsLinkerPluginLTO: bool,
         NoPrepopulatePasses: bool,
         VerifyIR: bool,
+        LintIR: bool,
         UseThinLTOBuffers: bool,
         MergeFunctions: bool,
         UnrollLoops: bool,

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -112,6 +112,7 @@ pub struct ModuleConfig {
     // Miscellaneous flags. These are mostly copied from command-line
     // options.
     pub verify_llvm_ir: bool,
+    pub lint_llvm_ir: bool,
     pub no_prepopulate_passes: bool,
     pub no_builtins: bool,
     pub time_module: bool,
@@ -237,6 +238,7 @@ impl ModuleConfig {
             bc_cmdline: sess.target.bitcode_llvm_cmdline.to_string(),
 
             verify_llvm_ir: sess.verify_llvm_ir(),
+            lint_llvm_ir: sess.opts.unstable_opts.lint_llvm_ir,
             no_prepopulate_passes: sess.opts.cg.no_prepopulate_passes,
             no_builtins: no_builtins || sess.target.no_builtins,
 

compiler/rustc_interface/src/tests.rs

@@ -795,6 +795,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(instrument_xray, Some(InstrumentXRay::default()));
     tracked!(link_directives, false);
     tracked!(link_only, true);
+    tracked!(lint_llvm_ir, true);
     tracked!(llvm_module_flag, vec![("bar".to_string(), 123, "max".to_string())]);
     tracked!(llvm_plugins, vec![String::from("plugin_name")]);
     tracked!(location_detail, LocationDetail { file: true, line: false, column: false });

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -713,7 +713,7 @@ extern "C" LLVMRustResult LLVMRustOptimize(
     LLVMModuleRef ModuleRef, LLVMTargetMachineRef TMRef,
     LLVMRustPassBuilderOptLevel OptLevelRust, LLVMRustOptStage OptStage,
     bool IsLinkerPluginLTO, bool NoPrepopulatePasses, bool VerifyIR,
-    bool UseThinLTOBuffers, bool MergeFunctions, bool UnrollLoops,
+    bool LintIR, bool UseThinLTOBuffers, bool MergeFunctions, bool UnrollLoops,
     bool SLPVectorize, bool LoopVectorize, bool DisableSimplifyLibCalls,
     bool EmitLifetimeMarkers, LLVMRustSanitizerOptions *SanitizerOptions,
     const char *PGOGenPath, const char *PGOUsePath, bool InstrumentCoverage,
@@ -842,6 +842,13 @@ extern "C" LLVMRustResult LLVMRustOptimize(
         });
   }
 
+  if (LintIR) {
+    PipelineStartEPCallbacks.push_back(
+        [](ModulePassManager &MPM, OptimizationLevel Level) {
+          MPM.addPass(createModuleToFunctionPassAdaptor(LintPass()));
+        });
+  }
+
   if (InstrumentGCOV) {
     PipelineStartEPCallbacks.push_back(
         [](ModulePassManager &MPM, OptimizationLevel Level) {

compiler/rustc_session/src/options.rs

@@ -1811,6 +1811,8 @@ options! {
         "link the `.rlink` file generated by `-Z no-link` (default: no)"),
     linker_features: LinkerFeaturesCli = (LinkerFeaturesCli::default(), parse_linker_features, [UNTRACKED],
         "a comma-separated list of linker features to enable (+) or disable (-): `lld`"),
+    lint_llvm_ir: bool = (false, parse_bool, [TRACKED],
+        "lint LLVM IR (default: no)"),
     lint_mir: bool = (false, parse_bool, [UNTRACKED],
         "lint MIR before and after each transformation"),
     llvm_module_flag: Vec<(String, u32, String)> = (Vec::new(), parse_llvm_module_flag, [TRACKED],

src/doc/unstable-book/src/compiler-flags/lint-llvm-ir.md

@@ -0,0 +1,7 @@
+# `lint-llvm-ir`
+
+---------------------
+
+This flag will add `LintPass` to the start of the pipeline.
+You can use it to check for common errors in the LLVM IR generated by `rustc`.
+You can add `-Cllvm-args=-lint-abort-on-error` to abort the process if errors were found.

tests/codegen/cast-target-abi.rs

@@ -1,7 +1,7 @@
 // ignore-tidy-linelength
 //@ revisions:aarch64 loongarch64 powerpc64 sparc64 x86_64
-// FIXME: Add `-Cllvm-args=--lint-abort-on-error` after LLVM 19
-//@ compile-flags: -O -C no-prepopulate-passes -C passes=lint
+//@ min-llvm-version: 19
+//@ compile-flags: -O -Cno-prepopulate-passes -Zlint-llvm-ir -Cllvm-args=-lint-abort-on-error
 
 //@[aarch64] compile-flags: --target aarch64-unknown-linux-gnu
 //@[aarch64] needs-llvm-components: arm

tests/codegen/cffi/ffi-out-of-bounds-loads.rs

@@ -1,5 +1,6 @@
 //@ revisions: linux apple
-//@ compile-flags: -C opt-level=0 -C no-prepopulate-passes -C passes=lint
+//@ min-llvm-version: 19
+//@ compile-flags: -Copt-level=0 -Cno-prepopulate-passes -Zlint-llvm-ir -Cllvm-args=-lint-abort-on-error
 
 //@[linux] compile-flags: --target x86_64-unknown-linux-gnu
 //@[linux] needs-llvm-components: x86