From 99ad915e32744eb771e9a0968bf7d0d1f52a9a07 Mon Sep 17 00:00:00 2001
From: David Wood <david@davidtw.co>
Date: Sun, 8 Nov 2020 17:27:33 +0000
Subject: [PATCH] compiletest: add split dwarf compare mode

This commit adds a Split DWARF compare mode to compiletest so that
debuginfo tests are also tested using Split DWARF in split mode (and
manually in single mode).

Signed-off-by: David Wood <david@davidtw.co>
---
 compiler/rustc_codegen_ssa/src/back/link.rs | 7 +++++++
 src/bootstrap/test.rs                       | 7 ++++++-
 src/tools/compiletest/src/common.rs         | 6 ++++++
 src/tools/compiletest/src/header.rs         | 2 ++
 src/tools/compiletest/src/runtest.rs        | 6 ++++++
 5 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 123d1ae55fb97..ccd4d103ddb7f 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -1037,6 +1037,13 @@ fn preserve_objects_for_their_debuginfo(sess: &Session) -> bool {
         return false;
     }
 
+    // Single mode keeps debuginfo in the same object file, but in such a way that it it skipped
+    // by the linker - so it's expected that when codegen units are linked together that this
+    // debuginfo would be lost without keeping around the temps.
+    if sess.opts.debugging_opts.split_dwarf == config::SplitDwarfKind::Single {
+        return true;
+    }
+
     // If we're on OSX then the equivalent of split dwarf is turned on by
     // default. The final executable won't actually have any debug information
     // except it'll have pointers to elsewhere. Historically we've always run
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index 78b5de7897d1f..b99692e8ba5b8 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -897,7 +897,12 @@ default_test!(Incremental {
     suite: "incremental"
 });
 
-default_test!(Debuginfo { path: "src/test/debuginfo", mode: "debuginfo", suite: "debuginfo" });
+default_test_with_compare_mode!(Debuginfo {
+    path: "src/test/debuginfo",
+    mode: "debuginfo",
+    suite: "debuginfo",
+    compare_mode: "split-dwarf"
+});
 
 host_test!(UiFullDeps { path: "src/test/ui-fulldeps", mode: "ui", suite: "ui-fulldeps" });
 
diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index 55d25fa7c52c2..80fbb06b94691 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -127,6 +127,8 @@ pub enum CompareMode {
     Nll,
     Polonius,
     Chalk,
+    SplitDwarf,
+    SplitDwarfSingle,
 }
 
 impl CompareMode {
@@ -135,6 +137,8 @@ impl CompareMode {
             CompareMode::Nll => "nll",
             CompareMode::Polonius => "polonius",
             CompareMode::Chalk => "chalk",
+            CompareMode::SplitDwarf => "split-dwarf",
+            CompareMode::SplitDwarfSingle => "split-dwarf-single",
         }
     }
 
@@ -143,6 +147,8 @@ impl CompareMode {
             "nll" => CompareMode::Nll,
             "polonius" => CompareMode::Polonius,
             "chalk" => CompareMode::Chalk,
+            "split-dwarf" => CompareMode::SplitDwarf,
+            "split-dwarf-single" => CompareMode::SplitDwarfSingle,
             x => panic!("unknown --compare-mode option: {}", x),
         }
     }
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index 59f64e7df0f41..a1be0a19f6854 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -852,6 +852,8 @@ impl Config {
                 Some(CompareMode::Nll) => name == "compare-mode-nll",
                 Some(CompareMode::Polonius) => name == "compare-mode-polonius",
                 Some(CompareMode::Chalk) => name == "compare-mode-chalk",
+                Some(CompareMode::SplitDwarf) => name == "compare-mode-split-dwarf",
+                Some(CompareMode::SplitDwarfSingle) => name == "compare-mode-split-dwarf-single",
                 None => false,
             } ||
             (cfg!(debug_assertions) && name == "debug") ||
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 7af0d91271b0c..828c4e89f0b1f 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -2017,6 +2017,12 @@ impl<'test> TestCx<'test> {
             Some(CompareMode::Chalk) => {
                 rustc.args(&["-Zchalk"]);
             }
+            Some(CompareMode::SplitDwarf) => {
+                rustc.args(&["-Zsplit-dwarf=split"]);
+            }
+            Some(CompareMode::SplitDwarfSingle) => {
+                rustc.args(&["-Zsplit-dwarf=single"]);
+            }
             None => {}
         }