Merge commit 'e3e07513da09' from apple/main into swift/next

Author: git apple-llvm automerger

lld/COFF/PDB.cpp

@@ -1648,9 +1648,13 @@ void PDBLinker::addSections(ArrayRef<OutputSection *> outputSections,
 }
 
 void PDBLinker::commit(codeview::GUID *guid) {
-  ExitOnError exitOnErr((config->pdbPath + ": ").str());
-  // Write to a file.
-  exitOnErr(builder.commit(config->pdbPath, guid));
+  // Print an error and continue if PDB writing fails. This is done mainly so
+  // the user can see the output of /time and /summary, which is very helpful
+  // when trying to figure out why a PDB file is too large.
+  if (Error e = builder.commit(config->pdbPath, guid)) {
+    checkError(std::move(e));
+    error("failed to write PDB file " + Twine(config->pdbPath));
+  }
 }
 
 static uint32_t getSecrelReloc() {

llvm/include/llvm/DebugInfo/MSF/MSFError.h

@@ -18,6 +18,7 @@ namespace msf {
 enum class msf_error_code {
   unspecified = 1,
   insufficient_buffer,
+  size_overflow,
   not_writable,
   no_stream,
   invalid_format,

llvm/lib/DebugInfo/MSF/MSFBuilder.cpp

@@ -15,6 +15,7 @@
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileOutputBuffer.h"
+#include "llvm/Support/FormatVariadic.h"
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
@@ -348,8 +349,9 @@ Expected<FileBufferByteStream> MSFBuilder::commit(StringRef Path,
     // block-based and as long as each stream is small enough, PDBs larger than
     // 4 GiB might work. Check if tools can handle these large PDBs, and if so
     // add support for writing them.
-    return make_error<MSFError>(msf_error_code::invalid_format,
-                                "Output larger than 4 GiB");
+    return make_error<MSFError>(
+        msf_error_code::size_overflow,
+        formatv("File size would have been {0,1:N}", FileSize));
   }
 
   auto OutFileOrError = FileOutputBuffer::create(Path, FileSize);

llvm/lib/DebugInfo/MSF/MSFError.cpp

@@ -27,6 +27,8 @@ class MSFErrorCategory : public std::error_category {
     case msf_error_code::insufficient_buffer:
       return "The buffer is not large enough to read the requested number of "
              "bytes.";
+    case msf_error_code::size_overflow:
+      return "Output data is larger than 4 GiB.";
     case msf_error_code::not_writable:
       return "The specified stream is not writable.";
     case msf_error_code::no_stream: