From dafb566710cd03b7fbb4b187a91f32be9452fd8c Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svoboda@apple.com>
Date: Tue, 11 Mar 2025 13:49:44 -0700
Subject: [Support] Return `LockFileManager` errors right away (#130627)

This patch removes some internal state out of `LockFileManager` by
moving the locking code from the constructor into new member function
`tryLock()` which returns the errors right away. This simplifies and
modernizes the interface.
---
 clang/lib/Frontend/CompilerInstance.cpp | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

(limited to 'clang/lib/Frontend/CompilerInstance.cpp')

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 6098e2e3..e9e9668 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -1483,29 +1483,28 @@ static bool compileModuleAndReadASTBehindLock(
   llvm::sys::fs::create_directories(Dir);
 
   while (true) {
-    llvm::LockFileManager Locked(ModuleFileName);
-    switch (Locked) {
-    case llvm::LockFileManager::LFS_Error:
+    llvm::LockFileManager Lock(ModuleFileName);
+    bool Owned;
+    if (llvm::Error Err = Lock.tryLock().moveInto(Owned)) {
       // ModuleCache takes care of correctness and locks are only necessary for
       // performance. Fallback to building the module in case of any lock
       // related errors.
       Diags.Report(ModuleNameLoc, diag::remark_module_lock_failure)
-          << Module->Name << Locked.getErrorMessage();
+          << Module->Name << toString(std::move(Err));
       // Clear out any potential leftover.
-      Locked.unsafeRemoveLockFile();
-      [[fallthrough]];
-    case llvm::LockFileManager::LFS_Owned:
+      Lock.unsafeRemoveLockFile();
+      return compileModuleAndReadASTImpl(ImportingInstance, ImportLoc,
+                                         ModuleNameLoc, Module, ModuleFileName);
+    }
+    if (Owned) {
       // We're responsible for building the module ourselves.
       return compileModuleAndReadASTImpl(ImportingInstance, ImportLoc,
                                          ModuleNameLoc, Module, ModuleFileName);
-
-    case llvm::LockFileManager::LFS_Shared:
-      break; // The interesting case.
     }
 
     // Someone else is responsible for building the module. Wait for them to
     // finish.
-    switch (Locked.waitForUnlock()) {
+    switch (Lock.waitForUnlock()) {
     case llvm::LockFileManager::Res_Success:
       break; // The interesting case.
     case llvm::LockFileManager::Res_OwnerDied:
@@ -1517,7 +1516,7 @@ static bool compileModuleAndReadASTBehindLock(
       Diags.Report(ModuleNameLoc, diag::remark_module_lock_timeout)
           << Module->Name;
       // Clear the lock file so that future invocations can make progress.
-      Locked.unsafeRemoveLockFile();
+      Lock.unsafeRemoveLockFile();
       continue;
     }
 
-- 
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