[PATCH] D112297: [LTO] Fix assertion failed when flushing bitcode incrementally for LTO output.

[Mingjie Xu via Phabricator via llvm-commits]

Enna1 updated this revision to Diff 396741.
Enna1 added a comment.

Update Patch.

> Why not SupportsSeeking = !EC && IsRegularFile; for non-Windows as well?

Use `SupportsSeeking = !EC && IsRegularFile;` for both Windows and non-Windows.

> ld.lld has very little to do with this LTO regression. It'd be good to use llvm-lto2 or llvm-lto to test this, not ld.lld

Cause https://reviews.llvm.org/D86905 the special file opening operation is only used in lld/ELF, so for now we can only test this bug in ld.lld.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D112297/new/

https://reviews.llvm.org/D112297

Files:
  lld/test/ELF/lto/emit-llvm_assertion_failture.ll
  llvm/include/llvm/Support/raw_ostream.h
  llvm/lib/Support/raw_ostream.cpp


Index: llvm/lib/Support/raw_ostream.cpp
===================================================================
--- llvm/lib/Support/raw_ostream.cpp
+++ llvm/lib/Support/raw_ostream.cpp
@@ -643,14 +643,10 @@
 
   // Get the starting position.
   off_t loc = ::lseek(FD, 0, SEEK_CUR);
-#ifdef _WIN32
-  // MSVCRT's _lseek(SEEK_CUR) doesn't return -1 for pipes.
   sys::fs::file_status Status;
   std::error_code EC = status(FD, Status);
-  SupportsSeeking = !EC && Status.type() == sys::fs::file_type::regular_file;
-#else
-  SupportsSeeking = loc != (off_t)-1;
-#endif
+  IsRegularFile = Status.type() == sys::fs::file_type::regular_file;
+  SupportsSeeking = !EC && IsRegularFile;
   if (!SupportsSeeking)
     pos = 0;
   else
Index: llvm/include/llvm/Support/raw_ostream.h
===================================================================
--- llvm/include/llvm/Support/raw_ostream.h
+++ llvm/include/llvm/Support/raw_ostream.h
@@ -444,6 +444,7 @@
   int FD;
   bool ShouldClose;
   bool SupportsSeeking = false;
+  bool IsRegularFile = false;
   mutable Optional<bool> HasColors;
 
 #ifdef _WIN32
@@ -514,6 +515,8 @@
 
   bool supportsSeeking() const { return SupportsSeeking; }
 
+  bool isRegularFile() const { return IsRegularFile; }
+
   /// Flushes the stream and repositions the underlying file descriptor position
   /// to the offset specified from the beginning of the file.
   uint64_t seek(uint64_t off);
Index: lld/test/ELF/lto/emit-llvm_assertion_failture.ll
===================================================================
--- /dev/null
+++ lld/test/ELF/lto/emit-llvm_assertion_failture.ll
@@ -0,0 +1,15 @@
+; Make sure that if --plugin-opt=emit-llvm is enabled and the output
+; is /dev/null, it should not cause a assertion failure in bitcode writer.
+
+; REQUIRES: x86
+
+; RUN: opt -module-hash -module-summary %s -o %t.o
+; RUN: ld.lld --plugin-opt=emit-llvm -mllvm -bitcode-flush-threshold=0 -o /dev/null %t.o
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @main() {
+  ret void
+}
+


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D112297.396741.patch
Type: text/x-patch
Size: 2116 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20211231/18c7ce1d/attachment.bin>