Add rudimentry debug info metadata emission (#4225)

This adds just the debug info metadata for Compilation Units (the top
level container of debug info) - but without anything in them, LLVM
won't emit them at all, so while this is testable at the IR level, it
isn't observable at the object level until more debug info is added.

A couple of starting points in this patch:
* A flag (`--debug-info`, seems to match the naming/style of other flags
in the carbon driver, though this is different from the naming
conventions of clang/gcc) that enables debug info when lowering. Open to
other names/approaches (on by default? historically debug info's been to
large/expensive to do this, so sticking with that precedent for now).
* Enabling that flag by default in the lowering tests - I do find the
churn on golden tests a bit rough, and adding more features to all the
tests means more churn, but it seems consistent with the approach so far
- keep an eye on this and perhaps revisit this if the churn gets too
annoying

---------

Co-authored-by: Carbon Infra Bot <[email protected]>
Co-authored-by: Jon Ross-Perkins <[email protected]>

toolchain/driver/driver.cpp

@@ -337,6 +337,14 @@ Excludes files with the given prefix from dumps.
 )""",
         },
         [&](auto& arg_b) { arg_b.Set(&exclude_dump_file_prefix); });
+    b.AddFlag(
+        {
+            .name = "debug-info",
+            .help = R"""(
+Emit DWARF debug information.
+)""",
+        },
+        [&](auto& arg_b) { arg_b.Set(&include_debug_info); });
   }
 
   Phase phase;
@@ -358,6 +366,7 @@ Excludes files with the given prefix from dumps.
   bool preorder_parse_tree = false;
   bool builtin_sem_ir = false;
   bool prelude_import = false;
+  bool include_debug_info = false;
 
   llvm::StringRef exclude_dump_file_prefix;
 };
@@ -523,6 +532,12 @@ auto Driver::ValidateCompileOptions(const CompileOptions& options) const
                       << options.phase << "'.\n";
         return false;
       }
+      if (options.include_debug_info) {
+        error_stream_
+            << "ERROR: Requested debug info but compile phase is limited to '"
+            << options.phase << "'.\n";
+        return false;
+      }
       [[fallthrough]];
     case Phase::Lower:
     case Phase::CodeGen:
@@ -676,8 +691,9 @@ class Driver::CompilationUnit {
       // TODO: Consider disabling instruction naming by default if we're not
       // producing textual LLVM IR.
       SemIR::InstNamer inst_namer(*tokens_, *parse_tree_, *sem_ir_);
-      module_ = Lower::LowerToLLVM(*llvm_context_, input_filename_, *sem_ir_,
-                                   &inst_namer, vlog_stream_);
+      module_ = Lower::LowerToLLVM(*llvm_context_, options_.include_debug_info,
+                                   input_filename_, *sem_ir_, &inst_namer,
+                                   vlog_stream_);
     });
     if (vlog_stream_) {
       CARBON_VLOG() << "*** llvm::Module ***\n";

toolchain/driver/testdata/fail_flags.carbon

@@ -0,0 +1,13 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// ARGS: compile --debug-info --phase=check %s
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/driver/testdata/fail_flags.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/driver/testdata/fail_flags.carbon
+// CHECK:STDERR: ERROR: Requested debug info but compile phase is limited to 'check'.
+//

toolchain/lower/file_context.cpp

@@ -21,11 +21,17 @@
 namespace Carbon::Lower {
 
 FileContext::FileContext(llvm::LLVMContext& llvm_context,
-                         llvm::StringRef module_name, const SemIR::File& sem_ir,
+                         bool include_debug_info, llvm::StringRef module_name,
+                         const SemIR::File& sem_ir,
                          const SemIR::InstNamer* inst_namer,
                          llvm::raw_ostream* vlog_stream)
     : llvm_context_(&llvm_context),
       llvm_module_(std::make_unique<llvm::Module>(module_name, llvm_context)),
+      di_builder_(*llvm_module_),
+      di_compile_unit_(
+          include_debug_info
+              ? BuildDICompileUnit(module_name, *llvm_module_, di_builder_)
+              : nullptr),
       sem_ir_(&sem_ir),
       inst_namer_(inst_namer),
       vlog_stream_(vlog_stream) {
@@ -80,6 +86,25 @@ auto FileContext::Run() -> std::unique_ptr<llvm::Module> {
   return std::move(llvm_module_);
 }
 
+auto FileContext::BuildDICompileUnit(llvm::StringRef module_name,
+                                     llvm::Module& llvm_module,
+                                     llvm::DIBuilder& di_builder)
+    -> llvm::DICompileUnit* {
+  llvm_module.addModuleFlag(llvm::Module::Max, "Dwarf Version", 5);
+  llvm_module.addModuleFlag(llvm::Module::Warning, "Debug Info Version",
+                            llvm::DEBUG_METADATA_VERSION);
+  // FIXME: Include directory path in the compile_unit_file.
+  llvm::DIFile* compile_unit_file = di_builder.createFile(module_name, "");
+  // FIXME: Introduce a new language code for Carbon. C works well for now since
+  // it's something debuggers will already know/have support for at least.
+  // Probably have to bump to C++ at some point for virtual functions,
+  // templates, etc.
+  return di_builder.createCompileUnit(llvm::dwarf::DW_LANG_C, compile_unit_file,
+                                      "carbon",
+                                      /*isOptimized=*/false, /*Flags=*/"",
+                                      /*RV=*/0);
+}
+
 auto FileContext::GetGlobal(SemIR::InstId inst_id) -> llvm::Value* {
   auto inst = sem_ir().insts().Get(inst_id);
 

toolchain/lower/file_context.h

@@ -6,6 +6,7 @@
 #define CARBON_TOOLCHAIN_LOWER_FILE_CONTEXT_H_
 
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "toolchain/sem_ir/file.h"
@@ -16,7 +17,7 @@ namespace Carbon::Lower {
 // Context and shared functionality for lowering handlers.
 class FileContext {
  public:
-  explicit FileContext(llvm::LLVMContext& llvm_context,
+  explicit FileContext(llvm::LLVMContext& llvm_context, bool include_debug_info,
                        llvm::StringRef module_name, const SemIR::File& sem_ir,
                        const SemIR::InstNamer* inst_namer,
                        llvm::raw_ostream* vlog_stream);
@@ -25,6 +26,11 @@ class FileContext {
   // the main execution loop.
   auto Run() -> std::unique_ptr<llvm::Module>;
 
+  // Create the DICompileUnit metadata for this compilation.
+  auto BuildDICompileUnit(llvm::StringRef module_name,
+                          llvm::Module& llvm_module,
+                          llvm::DIBuilder& di_builder) -> llvm::DICompileUnit*;
+
   // Gets a callable's function. Returns nullptr for a builtin.
   auto GetFunction(SemIR::FunctionId function_id) -> llvm::Function* {
     return functions_[function_id.index];
@@ -85,6 +91,12 @@ class FileContext {
   llvm::LLVMContext* llvm_context_;
   std::unique_ptr<llvm::Module> llvm_module_;
 
+  // State for building the LLVM IR debug info metadata.
+  llvm::DIBuilder di_builder_;
+
+  // The DICompileUnit, if any - null implies debug info is not being emitted.
+  llvm::DICompileUnit* di_compile_unit_;
+
   // The input SemIR.
   const SemIR::File* const sem_ir_;
 

toolchain/lower/handle.cpp

@@ -7,6 +7,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/Value.h"
 #include "llvm/Support/Casting.h"

toolchain/lower/lower.cpp

@@ -8,12 +8,13 @@
 
 namespace Carbon::Lower {
 
-auto LowerToLLVM(llvm::LLVMContext& llvm_context, llvm::StringRef module_name,
-                 const SemIR::File& sem_ir, const SemIR::InstNamer* inst_namer,
+auto LowerToLLVM(llvm::LLVMContext& llvm_context, bool include_debug_info,
+                 llvm::StringRef module_name, const SemIR::File& sem_ir,
+                 const SemIR::InstNamer* inst_namer,
                  llvm::raw_ostream* vlog_stream)
     -> std::unique_ptr<llvm::Module> {
-  FileContext context(llvm_context, module_name, sem_ir, inst_namer,
-                      vlog_stream);
+  FileContext context(llvm_context, include_debug_info, module_name, sem_ir,
+                      inst_namer, vlog_stream);
   return context.Run();
 }
 

toolchain/lower/lower.h

@@ -13,8 +13,9 @@
 namespace Carbon::Lower {
 
 // Lowers SemIR to LLVM IR.
-auto LowerToLLVM(llvm::LLVMContext& llvm_context, llvm::StringRef module_name,
-                 const SemIR::File& sem_ir, const SemIR::InstNamer* inst_namer,
+auto LowerToLLVM(llvm::LLVMContext& llvm_context, bool include_debug_info,
+                 llvm::StringRef module_name, const SemIR::File& sem_ir,
+                 const SemIR::InstNamer* inst_namer,
                  llvm::raw_ostream* vlog_stream)
     -> std::unique_ptr<llvm::Module>;
 

toolchain/lower/testdata/alias/local.carbon

@@ -24,3 +24,11 @@ fn F() -> i32 {
 // CHECK:STDOUT:   %.loc14 = load i32, ptr %a.var, align 4
 // CHECK:STDOUT:   ret i32 %.loc14
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "local.carbon", directory: "")

toolchain/lower/testdata/array/array_in_place.carbon

@@ -28,3 +28,11 @@ fn G() {
 // CHECK:STDOUT:   call void @F(ptr %.loc14_42.5.array.index)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "array_in_place.carbon", directory: "")

toolchain/lower/testdata/array/assign_return_value.carbon

@@ -47,3 +47,11 @@ fn Run() {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "assign_return_value.carbon", directory: "")

toolchain/lower/testdata/array/base.carbon

@@ -68,3 +68,11 @@ fn Run() {
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 3, 2, 1, 0 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "base.carbon", directory: "")

toolchain/lower/testdata/array/function_param.carbon

@@ -43,3 +43,11 @@ fn G() -> i32 {
 // CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) #0
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "function_param.carbon", directory: "")

toolchain/lower/testdata/basics/empty.carbon

@@ -10,3 +10,11 @@
 
 // CHECK:STDOUT: ; ModuleID = 'empty.carbon'
 // CHECK:STDOUT: source_filename = "empty.carbon"
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "empty.carbon", directory: "")

toolchain/lower/testdata/basics/false_true.carbon

@@ -28,3 +28,11 @@ fn T() -> bool {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i1 true
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "false_true.carbon", directory: "")

toolchain/lower/testdata/basics/int_types.carbon

@@ -35,3 +35,11 @@ fn F_u65536(a: u65536) -> u65536 { return a; }
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i65536 %a
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "int_types.carbon", directory: "")

toolchain/lower/testdata/basics/numeric_literals.carbon

@@ -59,3 +59,11 @@ fn F() {
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 1, 0 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "numeric_literals.carbon", directory: "")

toolchain/lower/testdata/basics/type_values.carbon

@@ -42,3 +42,11 @@ fn F64() -> type {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret %type zeroinitializer
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "type_values.carbon", directory: "")

toolchain/lower/testdata/basics/zero.carbon

@@ -19,3 +19,11 @@ fn Main() -> i32 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i32 0
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "zero.carbon", directory: "")

toolchain/lower/testdata/builtins/float.carbon

@@ -109,3 +109,11 @@ fn TestGreaterEq(a: f64, b: f64) -> bool { return GreaterEq(a, b); }
 // CHECK:STDOUT:   %float.greater_eq = fcmp oge double %a, %b
 // CHECK:STDOUT:   ret i1 %float.greater_eq
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "float.carbon", directory: "")

toolchain/lower/testdata/builtins/int.carbon

@@ -172,3 +172,11 @@ fn TestGreaterEq(a: i32, b: i32) -> bool { return GreaterEq(a, b); }
 // CHECK:STDOUT:   %int.greater_eq = icmp sge i32 %a, %b
 // CHECK:STDOUT:   ret i1 %int.greater_eq
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "int.carbon", directory: "")

toolchain/lower/testdata/builtins/method_vs_nonmethod.carbon

@@ -28,3 +28,11 @@ fn TestAddMethod(a: i32, b: i32) -> i32 { return a.(AddMethod)(b); }
 // CHECK:STDOUT:   %int.sadd = add i32 %a, %b
 // CHECK:STDOUT:   ret i32 %int.sadd
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "method_vs_nonmethod.carbon", directory: "")

toolchain/lower/testdata/builtins/overloaded_operator.carbon

@@ -30,3 +30,11 @@ fn AddThreeIntegers(a: i32, b: i32, c: i32) -> i32 {
 // CHECK:STDOUT:   %int.sadd.loc18_16 = add i32 %.loc18_12.4, %c
 // CHECK:STDOUT:   ret i32 %int.sadd.loc18_16
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "overloaded_operator.carbon", directory: "")

toolchain/lower/testdata/builtins/print.carbon

@@ -24,3 +24,11 @@ fn Main() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: declare i32 @printf(ptr, ...)
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "print.carbon", directory: "")

toolchain/lower/testdata/builtins/types.carbon

@@ -31,3 +31,11 @@ fn F() {
 // CHECK:STDOUT:   store i1 false, ptr %b.var, align 1
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "types.carbon", directory: "")