[clang] [clang][Driver] Ensure intermediate bitcode files are written according to `/Fo` (PR #189977)

[via cfe-commits]

https://github.com/rthomas-activision updated https://github.com/llvm/llvm-project/pull/189977

>From 1e698a3919320b8e5594b02383bc6ff65e06f497 Mon Sep 17 00:00:00 2001
From: Romain Thomas <romain.thomas at activision.com>
Date: Wed, 1 Apr 2026 10:19:43 +0200
Subject: [PATCH 1/3] [clang][Driver] Ensure intermediate bitcode files are
 written according to `/Fo`

With the following compilation process:

```
$ mkdir -p src/ tmp/
$ cat << 'EOF' > src/main.c
int main() { return 0; }
EOF
$ clang-cl /c /Fo:tmp/ /clang:-fembed-bitcode src/main.c
```

the object file `main.obj` is generated in the `tmp/` directory
but the intermediate `main.bc` is placed in the current working directory.

Ensure that intermediate `.bc` files are written to the same
directory specified by `/Fo`.
---
 clang/lib/Driver/Driver.cpp    | 6 ++++++
 clang/test/Driver/cl-outputs.c | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 0686a89d42faf..7d11d61cb84da 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -6629,6 +6629,12 @@ const char *Driver::GetNamedOutputPath(Compilation &C, const JobAction &JA,
             ->getValue();
     NamedOutput =
         MakeCLOutputFilename(C.getArgs(), Val, BaseName, types::TY_Object);
+  } else if ((JA.getType() == types::TY_LLVM_BC ||
+              JA.getType() == types::TY_LLVM_IR) &&
+             IsCLMode() && C.getArgs().hasArg(options::OPT__SLASH_Fo)) {
+    StringRef Val = C.getArgs().getLastArg(options::OPT__SLASH_Fo)->getValue();
+    NamedOutput =
+        MakeCLOutputFilename(C.getArgs(), Val, BaseName, JA.getType());
   } else {
     const char *Suffix =
         types::getTypeTempSuffix(JA.getType(), IsCLMode() || IsDXCMode());
diff --git a/clang/test/Driver/cl-outputs.c b/clang/test/Driver/cl-outputs.c
index a8509e795c295..fc5fb49d2a514 100644
--- a/clang/test/Driver/cl-outputs.c
+++ b/clang/test/Driver/cl-outputs.c
@@ -310,3 +310,6 @@
 
 // RUN: %clang_cl -target x86_64-windows -fdebug-compilation-dir=. /Z7 /Fofoo/a.obj -### -- %s 2>&1 | FileCheck -check-prefix=RELATIVE_OBJPATH2 %s
 // RELATIVE_OBJPATH2: "-object-file-name=foo\\a.obj"
+
+// RUN: %clang_cl /c /Fodir/ /clang:-fembed-bitcode -### -- %s 2>&1 | FileCheck -check-prefix=FoNAMEBC %s
+// FoNAMEBC:  "-o" "dir/cl-outputs.bc"

>From 6943feeb8f7af540ab5fd2082372635e1ebf8eb9 Mon Sep 17 00:00:00 2001
From: Romain Thomas <romain.thomas at activision.com>
Date: Thu, 2 Apr 2026 18:38:46 +0200
Subject: [PATCH 2/3] updates tests to include `-emit-llvm`

---
 clang/test/Driver/cl-outputs.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/clang/test/Driver/cl-outputs.c b/clang/test/Driver/cl-outputs.c
index fc5fb49d2a514..e2ce16ee840e1 100644
--- a/clang/test/Driver/cl-outputs.c
+++ b/clang/test/Driver/cl-outputs.c
@@ -313,3 +313,9 @@
 
 // RUN: %clang_cl /c /Fodir/ /clang:-fembed-bitcode -### -- %s 2>&1 | FileCheck -check-prefix=FoNAMEBC %s
 // FoNAMEBC:  "-o" "dir/cl-outputs.bc"
+
+// RUN: %clang_cl /c /clang:-emit-llvm -### -- %s 2>&1 | FileCheck -check-prefix=FoNAMEBC2 %s
+// FoNAMEBC2:  "-o" "cl-outputs.bc"
+
+// RUN: %clang_cl /c /Fodir/ /clang:-emit-llvm -### -- %s 2>&1 | FileCheck -check-prefix=FoNAMEBC3 %s
+// FoNAMEBC3:  "-o" "dir/cl-outputs.bc"

>From e37dfff4fbd4a8a1884b8ad95eb9bf0d397a0ae3 Mon Sep 17 00:00:00 2001
From: Romain Thomas <romain.thomas at activision.com>
Date: Fri, 3 Apr 2026 15:39:36 +0200
Subject: [PATCH 3/3] add support for the `-o` option with the appropriated
 tests

---
 clang/lib/Driver/Driver.cpp    |  9 +++++++--
 clang/test/Driver/cl-outputs.c | 15 +++++++++++----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 7d11d61cb84da..f77c7fde8b0a7 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -6631,8 +6631,13 @@ const char *Driver::GetNamedOutputPath(Compilation &C, const JobAction &JA,
         MakeCLOutputFilename(C.getArgs(), Val, BaseName, types::TY_Object);
   } else if ((JA.getType() == types::TY_LLVM_BC ||
               JA.getType() == types::TY_LLVM_IR) &&
-             IsCLMode() && C.getArgs().hasArg(options::OPT__SLASH_Fo)) {
-    StringRef Val = C.getArgs().getLastArg(options::OPT__SLASH_Fo)->getValue();
+             IsCLMode() &&
+             C.getArgs().hasArg(options::OPT__SLASH_Fo,
+                                options::OPT__SLASH_o)) {
+    StringRef Val =
+        C.getArgs()
+            .getLastArg(options::OPT__SLASH_Fo, options::OPT__SLASH_o)
+            ->getValue();
     NamedOutput =
         MakeCLOutputFilename(C.getArgs(), Val, BaseName, JA.getType());
   } else {
diff --git a/clang/test/Driver/cl-outputs.c b/clang/test/Driver/cl-outputs.c
index e2ce16ee840e1..c59adc8acb3b6 100644
--- a/clang/test/Driver/cl-outputs.c
+++ b/clang/test/Driver/cl-outputs.c
@@ -313,9 +313,16 @@
 
 // RUN: %clang_cl /c /Fodir/ /clang:-fembed-bitcode -### -- %s 2>&1 | FileCheck -check-prefix=FoNAMEBC %s
 // FoNAMEBC:  "-o" "dir/cl-outputs.bc"
+// FoNAMEBC:  "-o" "dir/cl-outputs.obj"
 
-// RUN: %clang_cl /c /clang:-emit-llvm -### -- %s 2>&1 | FileCheck -check-prefix=FoNAMEBC2 %s
-// FoNAMEBC2:  "-o" "cl-outputs.bc"
+// RUN: %clang_cl /c /clang:-emit-llvm -### -- %s 2>&1 | FileCheck -check-prefix=EMITLLVM %s
+// EMITLLVM:  "-o" "cl-outputs.bc"
 
-// RUN: %clang_cl /c /Fodir/ /clang:-emit-llvm -### -- %s 2>&1 | FileCheck -check-prefix=FoNAMEBC3 %s
-// FoNAMEBC3:  "-o" "dir/cl-outputs.bc"
+// RUN: %clang_cl /c /Fodir/ /clang:-emit-llvm -### -- %s 2>&1 | FileCheck -check-prefix=EMITLLVM_Fo %s
+// EMITLLVM_Fo:  "-o" "dir/cl-outputs.bc"
+
+// RUN: %clang_cl /c /odir/ /clang:-emit-llvm -### -- %s 2>&1 | FileCheck -check-prefix=EMITLLVM_o %s
+// EMITLLVM_o:  "-o" "dir/cl-outputs.bc"
+
+// RUN: %clang_cl /c /omain.bc /clang:-emit-llvm -### -- %s 2>&1 | FileCheck -check-prefix=EMITLLVM_oNAME %s
+// EMITLLVM_oNAME:  "-o" "main.bc"