Auto merge of #119286 - jyn514:linker-output, r=bjorn3

show linker output even if the linker succeeds

Show stderr and stderr by default, controlled by a new `linker_messages` lint.

fixes https://github.com/rust-lang/rust/issues/83436. fixes https://github.com/rust-lang/rust/issues/38206. cc https://rust-lang.zulipchat.com/#narrow/stream/233931-t-compiler.2Fmajor-changes/topic/uplift.20some.20-Zverbose.20calls.20and.20rename.20to.E2.80.A6.20compiler-team.23706/near/408986134

<!-- try-job: dist-x86_64-msvc -->
try-job: aarch64-apple

r? `@bjorn3`

3 files changed, 88 insertions, 14 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index df35b5e8426..9688a5d47f2 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -15,12 +15,14 @@ use rustc_ast::CRATE_NODE_ID;
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::temp_dir::MaybeTempDir;
-use rustc_errors::DiagCtxtHandle;
+use rustc_errors::{DiagCtxtHandle, LintDiagnostic};
 use rustc_fs_util::{fix_windows_verbatim_for_gcc, try_canonicalize};
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
+use rustc_macros::LintDiagnostic;
 use rustc_metadata::fs::{METADATA_FILENAME, copy_to_stdout, emit_wrapper_file};
 use rustc_metadata::{find_native_static_library, walk_native_lib_search_dirs};
 use rustc_middle::bug;
+use rustc_middle::lint::lint_level;
 use rustc_middle::middle::debugger_visualizer::DebuggerVisualizerFile;
 use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::middle::exported_symbols::SymbolExportKind;
@@ -29,6 +31,7 @@ use rustc_session::config::{
     OutputType, PrintKind, SplitDwarfKind, Strip,
 };
 use rustc_session::cstore::DllImport;
+use rustc_session::lint::builtin::LINKER_MESSAGES;
 use rustc_session::output::{check_file_is_writeable, invalid_output_for_target, out_filename};
 use rustc_session::search_paths::PathKind;
 use rustc_session::utils::NativeLibKind;
@@ -749,6 +752,14 @@ fn link_dwarf_object(sess: &Session, cg_results: &CodegenResults, executable_out
     }
 }
 
+#[derive(LintDiagnostic)]
+#[diag(codegen_ssa_linker_output)]
+/// Translating this is kind of useless. We don't pass translation flags to the linker, so we'd just
+/// end up with inconsistent languages within the same diagnostic.
+struct LinkerOutput {
+    inner: String,
+}
+
 /// Create a dynamic library or executable.
 ///
 /// This will invoke the system linker/cc to create the resulting file. This links to all upstream
@@ -981,6 +992,11 @@ fn link_natively(
 
     match prog {
         Ok(prog) => {
+            let is_msvc_link_exe = sess.target.is_like_msvc
+                && flavor == LinkerFlavor::Msvc(Lld::No)
+                // Match exactly "link.exe"
+                && linker_path.to_str() == Some("link.exe");
+
             if !prog.status.success() {
                 let mut output = prog.stderr.clone();
                 output.extend_from_slice(&prog.stdout);
@@ -997,16 +1013,9 @@ fn link_natively(
                 // is not a Microsoft LNK error then suggest a way to fix or
                 // install the Visual Studio build tools.
                 if let Some(code) = prog.status.code() {
-                    if sess.target.is_like_msvc
-                        && flavor == LinkerFlavor::Msvc(Lld::No)
-                        // Respect the command line override
-                        && sess.opts.cg.linker.is_none()
-                        // Match exactly "link.exe"
-                        && linker_path.to_str() == Some("link.exe")
-                        // All Microsoft `link.exe` linking error codes are
-                        // four digit numbers in the range 1000 to 9999 inclusive
-                        && (code < 1000 || code > 9999)
-                    {
+                    // All Microsoft `link.exe` linking ror codes are
+                    // four digit numbers in the range 1000 to 9999 inclusive
+                    if is_msvc_link_exe && (code < 1000 || code > 9999) {
                         let is_vs_installed = windows_registry::find_vs_version().is_ok();
                         let has_linker =
                             windows_registry::find_tool(&sess.target.arch, "link.exe").is_some();
@@ -1028,8 +1037,49 @@ fn link_natively(
 
                 sess.dcx().abort_if_errors();
             }
-            info!("linker stderr:\n{}", escape_string(&prog.stderr));
-            info!("linker stdout:\n{}", escape_string(&prog.stdout));
+
+            let stderr = escape_string(&prog.stderr);
+            let mut stdout = escape_string(&prog.stdout);
+            info!("linker stderr:\n{}", &stderr);
+            info!("linker stdout:\n{}", &stdout);
+
+            // Hide some progress messages from link.exe that we don't care about.
+            // See https://github.com/chromium/chromium/blob/bfa41e41145ffc85f041384280caf2949bb7bd72/build/toolchain/win/tool_wrapper.py#L144-L146
+            if is_msvc_link_exe {
+                if let Ok(str) = str::from_utf8(&prog.stdout) {
+                    let mut output = String::with_capacity(str.len());
+                    for line in stdout.lines() {
+                        if line.starts_with("   Creating library")
+                            || line.starts_with("Generating code")
+                            || line.starts_with("Finished generating code")
+                        {
+                            continue;
+                        }
+                        output += line;
+                        output += "\r\n"
+                    }
+                    stdout = escape_string(output.trim().as_bytes())
+                }
+            }
+
+            let (level, src) = codegen_results.crate_info.lint_levels.linker_messages;
+            let lint = |msg| {
+                lint_level(sess, LINKER_MESSAGES, level, src, None, |diag| {
+                    LinkerOutput { inner: msg }.decorate_lint(diag)
+                })
+            };
+
+            if !prog.stderr.is_empty() {
+                // We already print `warning:` at the start of the diagnostic. Remove it from the linker output if present.
+                let stderr = stderr
+                    .strip_prefix("warning: ")
+                    .unwrap_or(&stderr)
+                    .replace(": warning: ", ": ");
+                lint(format!("linker stderr: {stderr}"));
+            }
+            if !stdout.is_empty() {
+                lint(format!("linker stdout: {}", stdout))
+            }
         }
         Err(e) => {
             let linker_not_found = e.kind() == io::ErrorKind::NotFound;
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 6099dec2bb2..014bdeb46ad 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -44,7 +44,8 @@ use crate::mir::operand::OperandValue;
 use crate::mir::place::PlaceRef;
 use crate::traits::*;
 use crate::{
-    CachedModuleCodegen, CompiledModule, CrateInfo, ModuleCodegen, ModuleKind, errors, meth, mir,
+    CachedModuleCodegen, CodegenLintLevels, CompiledModule, CrateInfo, ModuleCodegen, ModuleKind,
+    errors, meth, mir,
 };
 
 pub(crate) fn bin_op_to_icmp_predicate(op: BinOp, signed: bool) -> IntPredicate {
@@ -924,6 +925,7 @@ impl CrateInfo {
             dependency_formats: Lrc::clone(tcx.dependency_formats(())),
             windows_subsystem,
             natvis_debugger_visualizers: Default::default(),
+            lint_levels: CodegenLintLevels::from_tcx(tcx),
         };
 
         info.native_libraries.reserve(n_crates);
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index 65c6067c740..40299ae2630 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -29,18 +29,23 @@ use rustc_ast as ast;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::unord::UnordMap;
+use rustc_hir::CRATE_HIR_ID;
 use rustc_hir::def_id::CrateNum;
 use rustc_macros::{Decodable, Encodable, HashStable};
 use rustc_middle::dep_graph::WorkProduct;
+use rustc_middle::lint::LintLevelSource;
 use rustc_middle::middle::debugger_visualizer::DebuggerVisualizerFile;
 use rustc_middle::middle::dependency_format::Dependencies;
 use rustc_middle::middle::exported_symbols::SymbolExportKind;
+use rustc_middle::ty::TyCtxt;
 use rustc_middle::util::Providers;
 use rustc_serialize::opaque::{FileEncoder, MemDecoder};
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use rustc_session::Session;
 use rustc_session::config::{CrateType, OutputFilenames, OutputType, RUST_CGU_EXT};
 use rustc_session::cstore::{self, CrateSource};
+use rustc_session::lint::Level;
+use rustc_session::lint::builtin::LINKER_MESSAGES;
 use rustc_session::utils::NativeLibKind;
 use rustc_span::Symbol;
 
@@ -200,6 +205,7 @@ pub struct CrateInfo {
     pub dependency_formats: Lrc<Dependencies>,
     pub windows_subsystem: Option<String>,
     pub natvis_debugger_visualizers: BTreeSet<DebuggerVisualizerFile>,
+    pub lint_levels: CodegenLintLevels,
 }
 
 #[derive(Encodable, Decodable)]
@@ -302,3 +308,19 @@ impl CodegenResults {
         Ok((codegen_results, outputs))
     }
 }
+
+/// A list of lint levels used in codegen.
+///
+/// When using `-Z link-only`, we don't have access to the tcx and must work
+/// solely from the `.rlink` file. `Lint`s are defined too early to be encodeable.
+/// Instead, encode exactly the information we need.
+#[derive(Copy, Clone, Debug, Encodable, Decodable)]
+pub struct CodegenLintLevels {
+    linker_messages: (Level, LintLevelSource),
+}
+
+impl CodegenLintLevels {
+    pub fn from_tcx(tcx: TyCtxt<'_>) -> Self {
+        Self { linker_messages: tcx.lint_level_at_node(LINKER_MESSAGES, CRATE_HIR_ID) }
+    }
+}