X86Disassembler: if verbose logging is going to nulls(), disable logging completely.

Otherwise we'll spend a ridiculous amount of time pretty printing debug output and then discarding it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140276 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/Target/X86/Disassembler/X86Disassembler.cpp b/lib/Target/X86/Disassembler/X86Disassembler.cpp
index 884e690efa..3aacb20e73 100644
--- a/lib/Target/X86/Disassembler/X86Disassembler.cpp
+++ b/lib/Target/X86/Disassembler/X86Disassembler.cpp
@@ -117,11 +117,15 @@ X86GenericDisassembler::getInstruction(MCInst &instr,
                                        raw_ostream &vStream,
                                        raw_ostream &cStream) const {
   InternalInstruction internalInstr;
+
+  dlog_t loggerFn = logger;
+  if (&vStream == &nulls())
+    loggerFn = 0; // Disable logging completely if it's going to nulls().
   
   int ret = decodeInstruction(&internalInstr,
                               regionReader,
                               (void*)&region,
-                              logger,
+                              loggerFn,
                               (void*)&vStream,
                               address,
                               fMode);