[clang] [Driver] Honor /Fo when deriving the split-dwarf .dwo path (PR #199613)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Haohai Wen (HaohaiWen)

<details>
<summary>Changes</summary>

SplitDebugName checked -o and /o but not /Fo, so clang-cl /Fo<path> /c
fell through to the cwd-relative fallback and every .dwo landed in cwd
under <source-stem>.dwo regardless of the .obj location.

---
Full diff: https://github.com/llvm/llvm-project/pull/199613.diff


2 Files Affected:

- (modified) clang/lib/Driver/ToolChains/CommonArgs.cpp (+2-1) 
- (modified) clang/test/Driver/split-debug.c (+6) 


``````````diff
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 6a0dcfca62c60..f59b50f4f45ca 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -1882,7 +1882,8 @@ const char *tools::SplitDebugName(const JobAction &JA, const ArgList &Args,
   if (const Arg *A = Args.getLastArg(options::OPT_dumpdir)) {
     T = A->getValue();
   } else {
-    Arg *FinalOutput = Args.getLastArg(options::OPT_o, options::OPT__SLASH_o);
+    Arg *FinalOutput = Args.getLastArg(options::OPT_o, options::OPT__SLASH_o,
+                                       options::OPT__SLASH_Fo);
     if (FinalOutput && Args.hasArg(options::OPT_c)) {
       T = FinalOutput->getValue();
       llvm::sys::path::remove_filename(T);
diff --git a/clang/test/Driver/split-debug.c b/clang/test/Driver/split-debug.c
index 57f3989ed7b51..eaccc2784c50f 100644
--- a/clang/test/Driver/split-debug.c
+++ b/clang/test/Driver/split-debug.c
@@ -57,6 +57,12 @@
 // SINGLE_WITH_FILENAME: "-split-dwarf-file" "{{.*}}foo.o"
 // SINGLE_WITH_FILENAME-NOT: "-split-dwarf-output"
 
+/// /Fo drives the .dwo path so it lands next to the .obj.
+// RUN: %clang_cl -### -c --target=x86_64-unknown-windows-msvc -gdwarf -gsplit-dwarf /Foobj/out.obj -- %s 2>&1 | FileCheck %s --check-prefix=SPLIT_SLASH_FO
+// RUN: %clang_cl -### -c --target=x86_64-unknown-windows-msvc -gdwarf -gsplit-dwarf /Fo:obj/out.obj -- %s 2>&1 | FileCheck %s --check-prefix=SPLIT_SLASH_FO
+
+// SPLIT_SLASH_FO:      "-split-dwarf-file" "obj{{[/\\]}}out.dwo" "-split-dwarf-output" "obj{{[/\\]}}out.dwo"
+
 /// If linking is the final phase, the .dwo filename is derived from -o (if specified) or "a".
 // RUN: %clang -### --target=x86_64-unknown-linux-gnu -gsplit-dwarf -g %s -o obj/out 2>&1 | FileCheck %s --check-prefix=SPLIT_LINK
 // RUN: %clang_cl -### --target=x86_64-unknown-windows-msvc -gsplit-dwarf -g -o obj/out -- %s 2>&1 | FileCheck %s --check-prefix=SPLIT_LINK

``````````

</details>


https://github.com/llvm/llvm-project/pull/199613