From 7fb9f58f85f1dc9c18c49bc1114d9d978fdbed33 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Mon, 1 Jan 2024 14:40:23 -0700
Subject: Compilation: rename before flush during whole cache mode

The linker needs to know the file system path of output in the flush
function because file paths inside the build artifacts reference each
other. Fixes a regression introduced in this branch.
---
 src/Compilation.zig | 122 +++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 83 insertions(+), 39 deletions(-)

(limited to 'src/Compilation.zig')

diff --git a/src/Compilation.zig b/src/Compilation.zig
index 250a94fe94..11b3328e0e 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -2216,39 +2216,6 @@ pub fn update(comp: *Compilation, main_progress_node: *std.Progress.Node) !void
     // -femit-llvm-bc, and -femit-asm, in the case of C objects.
     comp.emitOthers();
 
-    {
-        if (comp.bin_file) |lf| {
-            // This is needed before reading the error flags.
-            lf.flush(comp, main_progress_node) catch |err| switch (err) {
-                error.FlushFailure => {}, // error reported through link_error_flags
-                error.LLDReportedFailure => {}, // error reported via lockAndParseLldStderr
-                else => |e| return e,
-            };
-        }
-
-        if (comp.module) |zcu| {
-            try link.File.C.flushEmitH(zcu);
-
-            if (zcu.llvm_object) |llvm_object| {
-                if (build_options.only_c) unreachable;
-                const default_emit = switch (comp.cache_use) {
-                    .whole => |whole| .{
-                        .directory = whole.tmp_artifact_directory.?,
-                        .sub_path = "dummy",
-                    },
-                    .incremental => |incremental| .{
-                        .directory = incremental.artifact_directory,
-                        .sub_path = "dummy",
-                    },
-                };
-                try emitLlvmObject(comp, arena, default_emit, null, llvm_object, main_progress_node);
-            }
-        }
-    }
-
-    if (comp.totalErrorCount() != 0) return;
-    try maybeGenerateAutodocs(comp, main_progress_node);
-
     switch (comp.cache_use) {
         .whole => |whole| {
             const digest = man.final();
@@ -2261,15 +2228,32 @@ pub fn update(comp: *Compilation, main_progress_node: *std.Progress.Node) !void
                 whole.tmp_artifact_directory = null;
             } else unreachable;
 
-            if (comp.bin_file) |lf| {
-                lf.destroy();
-                comp.bin_file = null;
-            }
-
             const s = std.fs.path.sep_str;
             const tmp_dir_sub_path = "tmp" ++ s ++ Package.Manifest.hex64(tmp_dir_rand_int);
             const o_sub_path = "o" ++ s ++ digest;
 
+            // Work around windows `AccessDenied` if any files within this
+            // directory are open by closing and reopening the file handles.
+            const need_writable_dance = w: {
+                if (builtin.os.tag == .windows) {
+                    if (comp.bin_file) |lf| {
+                        // We cannot just call `makeExecutable` as it makes a false
+                        // assumption that we have a file handle open only when linking
+                        // an executable file. This used to be true when our linkers
+                        // were incapable of emitting relocatables and static archive.
+                        // Now that they are capable, we need to unconditionally close
+                        // the file handle and re-open it in the follow up call to
+                        // `makeWritable`.
+                        if (lf.file) |f| {
+                            f.close();
+                            lf.file = null;
+                            break :w true;
+                        }
+                    }
+                }
+                break :w false;
+            };
+
             renameTmpIntoCache(comp.local_cache_directory, tmp_dir_sub_path, o_sub_path) catch |err| {
                 return comp.setMiscFailure(
                     .rename_results,
@@ -2283,15 +2267,75 @@ pub fn update(comp: *Compilation, main_progress_node: *std.Progress.Node) !void
             };
             comp.wholeCacheModeSetBinFilePath(whole, &digest);
 
+            // The linker flush functions need to know the final output path
+            // for debug info purposes because executable debug info contains
+            // references object file paths.
+            if (comp.bin_file) |lf| {
+                lf.emit = .{
+                    .directory = comp.local_cache_directory,
+                    .sub_path = whole.bin_sub_path.?,
+                };
+
+                // Has to be after the `wholeCacheModeSetBinFilePath` above.
+                if (need_writable_dance) {
+                    try lf.makeWritable();
+                }
+            }
+
+            try flush(comp, arena, main_progress_node);
+            if (comp.totalErrorCount() != 0) return;
+
             // Failure here only means an unnecessary cache miss.
             man.writeManifest() catch |err| {
                 log.warn("failed to write cache manifest: {s}", .{@errorName(err)});
             };
 
+            if (comp.bin_file) |lf| {
+                lf.destroy();
+                comp.bin_file = null;
+            }
+
             assert(whole.lock == null);
             whole.lock = man.toOwnedLock();
         },
-        .incremental => {},
+        .incremental => {
+            try flush(comp, arena, main_progress_node);
+            if (comp.totalErrorCount() != 0) return;
+        },
+    }
+}
+
+fn flush(comp: *Compilation, arena: Allocator, prog_node: *std.Progress.Node) !void {
+    if (comp.bin_file) |lf| {
+        // This is needed before reading the error flags.
+        lf.flush(comp, prog_node) catch |err| switch (err) {
+            error.FlushFailure => {}, // error reported through link_error_flags
+            error.LLDReportedFailure => {}, // error reported via lockAndParseLldStderr
+            else => |e| return e,
+        };
+    }
+
+    if (comp.module) |zcu| {
+        try link.File.C.flushEmitH(zcu);
+
+        if (zcu.llvm_object) |llvm_object| {
+            if (build_options.only_c) unreachable;
+            const default_emit = switch (comp.cache_use) {
+                .whole => |whole| .{
+                    .directory = whole.tmp_artifact_directory.?,
+                    .sub_path = "dummy",
+                },
+                .incremental => |incremental| .{
+                    .directory = incremental.artifact_directory,
+                    .sub_path = "dummy",
+                },
+            };
+            try emitLlvmObject(comp, arena, default_emit, null, llvm_object, prog_node);
+        }
+    }
+
+    if (comp.totalErrorCount() == 0) {
+        try maybeGenerateAutodocs(comp, prog_node);
     }
 }
 
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