commit f0d3dcec97a1e335452071440a73081908da712f
author Rong Xu <xur@google.com> Mon Jul 08 21:03:12 2019 +0000
committer Rong Xu <xur@google.com> Mon Jul 08 21:03:12 2019 +0000
tree 8249eaa6e8dfe759615ad7a80a507f6c23dc20b4
parent c5630ac641396b37699364043bb8da297991e066

llvm-profdata] Handle the cases of overlapping input file and output file

Currently llvm-profdata does not expect the same file name for the input profile
and the output profile.
>llvm-profdata merge A.profraw B.profraw -o B.profraw
The above command runs successfully but the resulted B.profraw is not correct.
This patch fixes the issue by moving the initialization of writer after loading
the profile.

For the show command, the following will report a confusing error of
"Empty raw profile file":
>llvm-profdata show B.profraw -o B.profraw
It's harder to fix as we need to output something before loading the input profile.
I don't think that a fix for this is worth the effort. I just make the error explicit for
the show command.

Differential Revision: https://reviews.llvm.org/D64360

llvm-svn: 365386

llvm/tools/llvm-profdata/llvm-profdata.cpp

diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
index 10551fd..16d3ebe 100644
--- a/llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -317,11 +317,6 @@
       OutputFormat != PF_Text)
     exitWithError("Unknown format is specified.");
 
-  std::error_code EC;
-  raw_fd_ostream Output(OutputFilename.data(), EC, sys::fs::F_None);
-  if (EC)
-    exitWithErrorCode(EC, OutputFilename);
-
   std::mutex ErrorLock;
   SmallSet<instrprof_error, 4> WriterErrorCodes;
 
@@ -384,6 +379,11 @@
            WC->ErrWhence);
   }
 
+  std::error_code EC;
+  raw_fd_ostream Output(OutputFilename.data(), EC, sys::fs::F_None);
+  if (EC)
+    exitWithErrorCode(EC, OutputFilename);
+
   InstrProfWriter &Writer = Contexts[0]->Writer;
   if (OutputFormat == PF_Text) {
     if (Error E = Writer.writeText(Output))
@@ -433,12 +433,6 @@
                                StringRef OutputFilename,
                                ProfileFormat OutputFormat) {
   using namespace sampleprof;
-  auto WriterOrErr =
-      SampleProfileWriter::create(OutputFilename, FormatMap[OutputFormat]);
-  if (std::error_code EC = WriterOrErr.getError())
-    exitWithErrorCode(EC, OutputFilename);
-
-  auto Writer = std::move(WriterOrErr.get());
   StringMap<FunctionSamples> ProfileMap;
   SmallVector<std::unique_ptr<sampleprof::SampleProfileReader>, 5> Readers;
   LLVMContext Context;
@@ -473,6 +467,12 @@
       }
     }
   }
+  auto WriterOrErr =
+      SampleProfileWriter::create(OutputFilename, FormatMap[OutputFormat]);
+  if (std::error_code EC = WriterOrErr.getError())
+    exitWithErrorCode(EC, OutputFilename);
+
+  auto Writer = std::move(WriterOrErr.get());
   Writer->write(ProfileMap);
 }
 
@@ -1020,6 +1020,12 @@
   if (OutputFilename.empty())
     OutputFilename = "-";
 
+  if (!Filename.compare(OutputFilename)) {
+    errs() << sys::path::filename(argv[0])
+           << ": Input file name cannot be the same as the output file name!\n";
+    return 1;
+  }
+
   std::error_code EC;
   raw_fd_ostream OS(OutputFilename.data(), EC, sys::fs::F_Text);
   if (EC)