Fix emitting asm and object file output at the same time

src/librustc_llvm/lib.rs

@@ -2066,6 +2066,7 @@ extern {
                                    PM: PassManagerRef,
                                    M: ModuleRef,
                                    Output: *const c_char,
+                                   skip_codegen: bool,
                                    FileType: FileType) -> bool;
     pub fn LLVMRustPrintModule(PM: PassManagerRef,
                                M: ModuleRef,

src/librustc_trans/back/write.rs

@@ -56,11 +56,12 @@ pub fn write_output_file(
         pm: llvm::PassManagerRef,
         m: ModuleRef,
         output: &Path,
+        skip_codegen: bool,
         file_type: llvm::FileType) {
     unsafe {
         let output_c = path2cstr(output);
         let result = llvm::LLVMRustWriteOutputFile(
-                target, pm, m, output_c.as_ptr(), file_type);
+                target, pm, m, output_c.as_ptr(), skip_codegen, file_type);
         if !result {
             llvm_err(handler, format!("could not write output to {}", output.display()));
         }
@@ -543,15 +544,19 @@ unsafe fn optimize_and_codegen(cgcx: &CodegenContext,
         if config.emit_asm {
             let path = output_names.with_extension(&format!("{}.s", name_extra));
             with_codegen(tm, llmod, config.no_builtins, |cpm| {
-                write_output_file(cgcx.handler, tm, cpm, llmod, &path,
+                write_output_file(cgcx.handler, tm, cpm, llmod, &path, false,
                                   llvm::AssemblyFileType);
             });
         }
 
         if config.emit_obj {
+            // If we already emitted asm code, the codegen has already been done for this module,
+            // so don't do it again. See LLVMRustWriteOutputFile for details.
+            let skip_codegen = config.emit_asm;
             let path = output_names.with_extension(&format!("{}.o", name_extra));
             with_codegen(tm, llmod, config.no_builtins, |cpm| {
-                write_output_file(cgcx.handler, tm, cpm, llmod, &path, llvm::ObjectFileType);
+                write_output_file(cgcx.handler, tm, cpm, llmod, &path, skip_codegen,
+                                  llvm::ObjectFileType);
             });
         }
     });

src/rustllvm/PassWrapper.cpp

@@ -227,6 +227,7 @@ LLVMRustWriteOutputFile(LLVMTargetMachineRef Target,
                         LLVMPassManagerRef PMR,
                         LLVMModuleRef M,
                         const char *path,
+                        bool skipCodegen,
                         TargetMachine::CodeGenFileType FileType) {
   PassManager *PM = unwrap<PassManager>(PMR);
 
@@ -244,11 +245,21 @@ LLVMRustWriteOutputFile(LLVMTargetMachineRef Target,
     return false;
   }
 
+  // HACK: addPassesToEmitFile() also adds some codegen passes which are
+  // MachinePasses that may modify IR in a way that it becomes invalid (we've
+  // seen this with stack coloring). So the IR verifier would abort. Therefore,
+  // when we want to emit more than one filetype in a single run, we want to
+  // run the codegen passes and the verifier only for the first filetype.
+  // Telling LLVM to only start adding passes after it has seen a pass that
+  // doesn't exist allows us to achieve that.
+  char notAPass;
+  AnalysisID startBefore = skipCodegen ? (AnalysisID)&notAPass : nullptr;
+
 #if LLVM_VERSION_MINOR >= 7
-  unwrap(Target)->addPassesToEmitFile(*PM, OS, FileType, false);
+  unwrap(Target)->addPassesToEmitFile(*PM, OS, FileType, false, startBefore);
 #else
   formatted_raw_ostream FOS(OS);
-  unwrap(Target)->addPassesToEmitFile(*PM, FOS, FileType, false);
+  unwrap(Target)->addPassesToEmitFile(*PM, FOS, FileType, false, startBefore);
 #endif
   PM->run(*unwrap(M));
 

src/test/run-make/emit/Makefile

@@ -0,0 +1,7 @@
+-include ../tools.mk
+
+all:
+	$(RUSTC) -Copt-level=0 --emit=llvm-bc,llvm-ir,asm,obj,link test.rs
+	$(RUSTC) -Copt-level=1 --emit=llvm-bc,llvm-ir,asm,obj,link test.rs
+	$(RUSTC) -Copt-level=2 --emit=llvm-bc,llvm-ir,asm,obj,link test.rs
+	$(RUSTC) -Copt-level=3 --emit=llvm-bc,llvm-ir,asm,obj,link test.rs

src/test/run-make/emit/test.rs

@@ -0,0 +1,19 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Checks for issue #24876
+
+fn main() {
+    let mut v = 0;
+    for i in 0..0 {
+        v += i;
+    }
+    println!("{}", v)
+}