Disable LLVM verification by default

config.toml.example

@@ -356,6 +356,9 @@
 # Print backtrace on internal compiler errors during bootstrap
 #backtrace-on-ice = false
 
+# Whether to verify generated LLVM IR
+#verify-llvm-ir = false
+
 # =============================================================================
 # Options for specific targets
 #

src/bootstrap/bin/rustc.rs

@@ -283,6 +283,10 @@ fn main() {
         cmd.arg("--cfg").arg("parallel_queries");
     }
 
+    if env::var_os("RUSTC_VERIFY_LLVM_IR").is_some() {
+        cmd.arg("-Z").arg("verify-llvm-ir");
+    }
+
     let color = match env::var("RUSTC_COLOR") {
         Ok(s) => usize::from_str(&s).expect("RUSTC_COLOR should be an integer"),
         Err(_) => 0,

src/bootstrap/builder.rs

@@ -898,6 +898,10 @@ impl<'a> Builder<'a> {
             cargo.env("RUSTC_BACKTRACE_ON_ICE", "1");
         }
 
+        if self.config.rust_verify_llvm_ir {
+            cargo.env("RUSTC_VERIFY_LLVM_IR", "1");
+        }
+
         cargo.env("RUSTC_VERBOSE", format!("{}", self.verbosity));
 
         // in std, we want to avoid denying warnings for stage 0 as that makes cfg's painful.

src/bootstrap/config.rs

@@ -105,6 +105,7 @@ pub struct Config {
     pub rust_dist_src: bool,
     pub rust_codegen_backends: Vec<Interned<String>>,
     pub rust_codegen_backends_dir: String,
+    pub rust_verify_llvm_ir: bool,
 
     pub build: Interned<String>,
     pub hosts: Vec<Interned<String>>,
@@ -311,6 +312,7 @@ struct Rust {
     lld: Option<bool>,
     deny_warnings: Option<bool>,
     backtrace_on_ice: Option<bool>,
+    verify_llvm_ir: Option<bool>,
 }
 
 /// TOML representation of how each build target is configured.
@@ -542,6 +544,7 @@ impl Config {
             config.save_toolstates = rust.save_toolstates.clone().map(PathBuf::from);
             set(&mut config.deny_warnings, rust.deny_warnings.or(flags.warnings));
             set(&mut config.backtrace_on_ice, rust.backtrace_on_ice);
+            set(&mut config.rust_verify_llvm_ir, rust.verify_llvm_ir);
 
             if let Some(ref backends) = rust.codegen_backends {
                 config.rust_codegen_backends = backends.iter()

src/librustc/session/config.rs

@@ -1152,8 +1152,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "gather codegen statistics"),
     asm_comments: bool = (false, parse_bool, [TRACKED],
         "generate comments into the assembly (may change behavior)"),
-    no_verify: bool = (false, parse_bool, [TRACKED],
-        "skip LLVM verification"),
+    verify_llvm_ir: bool = (false, parse_bool, [TRACKED],
+        "verify LLVM IR"),
     borrowck_stats: bool = (false, parse_bool, [UNTRACKED],
         "gather borrowck statistics"),
     no_landing_pads: bool = (false, parse_bool, [TRACKED],
@@ -3097,7 +3097,7 @@ mod tests {
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
 
         opts = reference.clone();
-        opts.debugging_opts.no_verify = true;
+        opts.debugging_opts.verify_llvm_ir = true;
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
 
         opts = reference.clone();

src/librustc/session/mod.rs

@@ -513,8 +513,8 @@ impl Session {
     pub fn asm_comments(&self) -> bool {
         self.opts.debugging_opts.asm_comments
     }
-    pub fn no_verify(&self) -> bool {
-        self.opts.debugging_opts.no_verify
+    pub fn verify_llvm_ir(&self) -> bool {
+        self.opts.debugging_opts.verify_llvm_ir
     }
     pub fn borrowck_stats(&self) -> bool {
         self.opts.debugging_opts.borrowck_stats

src/librustc_codegen_llvm/back/lto.rs

@@ -461,9 +461,12 @@ fn run_pass_manager(cgcx: &CodegenContext,
     unsafe {
         let pm = llvm::LLVMCreatePassManager();
         llvm::LLVMRustAddAnalysisPasses(tm, pm, llmod);
-        let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr() as *const _);
-        assert!(!pass.is_null());
-        llvm::LLVMRustAddPass(pm, pass);
+
+        if config.verify_llvm_ir {
+            let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr() as *const _);
+            assert!(!pass.is_null());
+            llvm::LLVMRustAddPass(pm, pass);
+        }
 
         // When optimizing for LTO we don't actually pass in `-O0`, but we force
         // it to always happen at least with `-O1`.
@@ -494,9 +497,11 @@ fn run_pass_manager(cgcx: &CodegenContext,
             }
         });
 
-        let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr() as *const _);
-        assert!(!pass.is_null());
-        llvm::LLVMRustAddPass(pm, pass);
+        if config.verify_llvm_ir {
+            let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr() as *const _);
+            assert!(!pass.is_null());
+            llvm::LLVMRustAddPass(pm, pass);
+        }
 
         time_ext(cgcx.time_passes, None, "LTO passes", ||
              llvm::LLVMRunPassManager(pm, llmod));

src/librustc_codegen_llvm/back/write.rs

@@ -232,7 +232,7 @@ pub struct ModuleConfig {
     emit_obj: bool,
     // Miscellaneous flags.  These are mostly copied from command-line
     // options.
-    no_verify: bool,
+    pub verify_llvm_ir: bool,
     no_prepopulate_passes: bool,
     no_builtins: bool,
     time_passes: bool,
@@ -271,7 +271,7 @@ impl ModuleConfig {
             embed_bitcode_marker: false,
             no_integrated_as: false,
 
-            no_verify: false,
+            verify_llvm_ir: false,
             no_prepopulate_passes: false,
             no_builtins: false,
             time_passes: false,
@@ -283,7 +283,7 @@ impl ModuleConfig {
     }
 
     fn set_flags(&mut self, sess: &Session, no_builtins: bool) {
-        self.no_verify = sess.no_verify();
+        self.verify_llvm_ir = sess.verify_llvm_ir();
         self.no_prepopulate_passes = sess.opts.cg.no_prepopulate_passes;
         self.no_builtins = no_builtins || sess.target.target.options.no_builtins;
         self.time_passes = sess.time_passes();
@@ -542,7 +542,7 @@ unsafe fn optimize(cgcx: &CodegenContext,
             true
         };
 
-        if !config.no_verify { assert!(addpass("verify")); }
+        if config.verify_llvm_ir { assert!(addpass("verify")); }
         if !config.no_prepopulate_passes {
             llvm::LLVMRustAddAnalysisPasses(tm, fpm, llmod);
             llvm::LLVMRustAddAnalysisPasses(tm, mpm, llmod);