[llvm-mca] Default the output asm dialect used by the instruction printer to the input asm dialect.

The instruction printer used by llvm-mca to generate the performance report now
defaults the output assembly format to the format used for the input assembly
file.

On x86, the asm format can be either AT&T or Intel, depending on the
presence/absence of directive `.intel_syntax`.

Users can still specify a different assembly dialect with the command line flag
-output-asm-variant=<uint>.

llvm-svn: 330733

1 files changed, 16 insertions, 12 deletions

diff --git a/llvm/tools/llvm-mca/llvm-mca.cpp b/llvm/tools/llvm-mca/llvm-mca.cpp
index 9b9c70a8565..77fd70d459f 100644
--- a/llvm/tools/llvm-mca/llvm-mca.cpp
+++ b/llvm/tools/llvm-mca/llvm-mca.cpp
@@ -71,9 +71,10 @@ static cl::opt<std::string>
          cl::desc("Target a specific cpu type (-mcpu=help for details)"),
          cl::value_desc("cpu-name"), cl::init("generic"));
 
-static cl::opt<unsigned>
+static cl::opt<int>
     OutputAsmVariant("output-asm-variant",
-                     cl::desc("Syntax variant to use for output printing"));
+                     cl::desc("Syntax variant to use for output printing"),
+                     cl::init(-1));
 
 static cl::opt<unsigned> Iterations("iterations",
                                     cl::desc("Number of iterations to run"),
@@ -356,16 +357,6 @@ int main(int argc, char **argv) {
     return 1;
   }
 
-  std::unique_ptr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
-      Triple(TripleName), OutputAsmVariant, *MAI, *MCII, *MRI));
-  if (!IP) {
-    WithColor::error()
-        << "unable to create instruction printer for target triple '"
-        << TheTriple.normalize() << "' with assembly variant "
-        << OutputAsmVariant << ".\n";
-    return 1;
-  }
-
   std::unique_ptr<MCAsmParser> P(createMCAsmParser(SrcMgr, Ctx, Str, *MAI));
   MCAsmLexer &Lexer = P->getLexer();
   MCACommentConsumer CC(Regions);
@@ -386,6 +377,19 @@ int main(int argc, char **argv) {
     return 1;
   }
 
+  unsigned AssemblerDialect = P->getAssemblerDialect();
+  if (OutputAsmVariant >= 0)
+    AssemblerDialect = static_cast<unsigned>(OutputAsmVariant);
+  std::unique_ptr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
+      Triple(TripleName), AssemblerDialect, *MAI, *MCII, *MRI));
+  if (!IP) {
+    WithColor::error()
+        << "unable to create instruction printer for target triple '"
+        << TheTriple.normalize() << "' with assembly variant "
+        << AssemblerDialect << ".\n";
+    return 1;
+  }
+
   std::unique_ptr<llvm::ToolOutputFile> TOF = std::move(*OF);
 
   const MCSchedModel &SM = STI->getSchedModel();