From 5544820ba75dc9c4beb0be868fdb337323834f79 Mon Sep 17 00:00:00 2001
From: Andrew Lenharth <andrew@lenharth.org>
Date: Wed, 21 Feb 2024 10:02:06 -0600
Subject: [PATCH] [FIRTOOL] More sane chisel interface directory handling
 (#6687)

Deal with a few more situations when outputting chisel interfaces.
---
 lib/Firtool/Firtool.cpp           | 9 ++++++---
 test/firtool/chisel-interface.fir | 4 ++++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/Firtool/Firtool.cpp b/lib/Firtool/Firtool.cpp
index 47e5781d281..22b964e9e53 100644
--- a/lib/Firtool/Firtool.cpp
+++ b/lib/Firtool/Firtool.cpp
@@ -80,11 +80,14 @@ LogicalResult firtool::populateCHIRRTLToLowFIRRTL(mlir::PassManager &pm,
   pm.nest<firrtl::CircuitOp>().addPass(firrtl::createInferResetsPass());
 
   if (opt.shouldExportChiselInterface()) {
-    if (opt.getChiselInterfaceOutputDirectory().empty()) {
+    StringRef outdir = opt.getChiselInterfaceOutputDirectory();
+    if (opt.isDefaultOutputFilename() && outdir.empty()) {
       pm.nest<firrtl::CircuitOp>().addPass(createExportChiselInterfacePass());
     } else {
-      pm.nest<firrtl::CircuitOp>().addPass(createExportSplitChiselInterfacePass(
-          opt.getChiselInterfaceOutputDirectory()));
+      if (outdir.empty())
+        outdir = opt.getOutputFilename();
+      pm.nest<firrtl::CircuitOp>().addPass(
+          createExportSplitChiselInterfacePass(outdir));
     }
   }
 
diff --git a/test/firtool/chisel-interface.fir b/test/firtool/chisel-interface.fir
index c8acf68291d..d8f183844b4 100644
--- a/test/firtool/chisel-interface.fir
+++ b/test/firtool/chisel-interface.fir
@@ -5,6 +5,10 @@
 ; RUN: firtool %s --disable-output --export-chisel-interface --chisel-interface-out-dir %t
 ; RUN: FileCheck %s -input-file=%t/Foo.scala
 
+; Test exporting a Chisel interface to the default directory.
+; RUN: firtool %s --split-verilog --export-chisel-interface -o %t
+; RUN: FileCheck %s -input-file=%t/Foo.scala
+
 ; CHECK-LABEL: // Generated by CIRCT
 ; CHECK-LABEL: package shelf.foo
 ; CHECK-LABEL: import chisel3._