[clang] [clang][CodeGen] Remove CWD fallback in compilation directory (PR #150130)

[Steven Wu via cfe-commits]

https://github.com/cachemeifyoucan updated https://github.com/llvm/llvm-project/pull/150130

>From 075ebf724c7ffd09723fa56fed9bbeca0d21e683 Mon Sep 17 00:00:00 2001
From: Steven Wu <stevenwu at apple.com>
Date: Tue, 22 Jul 2025 15:27:18 -0700
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20change?=
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Created using spr 1.3.6

[skip ci]
---
 clang/lib/Driver/ToolChains/Clang.cpp | 38 ++++++++++++++-------------
 clang/test/Driver/compilation-dir.c   |  4 +++
 2 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 1fc7002a3a186..4f35f1128dbdb 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -242,17 +242,19 @@ static bool ShouldEnableAutolink(const ArgList &Args, const ToolChain &TC,
 static const char *addDebugCompDirArg(const ArgList &Args,
                                       ArgStringList &CmdArgs,
                                       const llvm::vfs::FileSystem &VFS) {
+  std::string DebugCompDir;
   if (Arg *A = Args.getLastArg(options::OPT_ffile_compilation_dir_EQ,
-                               options::OPT_fdebug_compilation_dir_EQ)) {
-    if (A->getOption().matches(options::OPT_ffile_compilation_dir_EQ))
-      CmdArgs.push_back(Args.MakeArgString(Twine("-fdebug-compilation-dir=") +
-                                           A->getValue()));
+                               options::OPT_fdebug_compilation_dir_EQ))
+    DebugCompDir = A->getValue();
+
+  if (DebugCompDir.empty()) {
+    if (llvm::ErrorOr<std::string> CWD = VFS.getCurrentWorkingDirectory())
+      DebugCompDir = std::move(*CWD);
     else
-      A->render(Args, CmdArgs);
-  } else if (llvm::ErrorOr<std::string> CWD =
-                 VFS.getCurrentWorkingDirectory()) {
-    CmdArgs.push_back(Args.MakeArgString("-fdebug-compilation-dir=" + *CWD));
+      return nullptr;
   }
+  CmdArgs.push_back(
+      Args.MakeArgString("-fdebug-compilation-dir=" + DebugCompDir));
   StringRef Path(CmdArgs.back());
   return Path.substr(Path.find('=') + 1).data();
 }
@@ -541,17 +543,17 @@ static void addPGOAndCoverageFlags(const ToolChain &TC, Compilation &C,
     CmdArgs.push_back("-fcoverage-mcdc");
   }
 
+  StringRef CoverageCompDir;
   if (Arg *A = Args.getLastArg(options::OPT_ffile_compilation_dir_EQ,
-                               options::OPT_fcoverage_compilation_dir_EQ)) {
-    if (A->getOption().matches(options::OPT_ffile_compilation_dir_EQ))
-      CmdArgs.push_back(Args.MakeArgString(
-          Twine("-fcoverage-compilation-dir=") + A->getValue()));
-    else
-      A->render(Args, CmdArgs);
-  } else if (llvm::ErrorOr<std::string> CWD =
-                 D.getVFS().getCurrentWorkingDirectory()) {
-    CmdArgs.push_back(Args.MakeArgString("-fcoverage-compilation-dir=" + *CWD));
-  }
+                               options::OPT_fcoverage_compilation_dir_EQ))
+    CoverageCompDir = A->getValue();
+  if (CoverageCompDir.empty()) {
+    if (auto CWD = D.getVFS().getCurrentWorkingDirectory())
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine("-fcoverage-compilation-dir=") + *CWD));
+  } else
+    CmdArgs.push_back(Args.MakeArgString(Twine("-fcoverage-compilation-dir=") +
+                                         CoverageCompDir));
 
   if (Args.hasArg(options::OPT_fprofile_exclude_files_EQ)) {
     auto *Arg = Args.getLastArg(options::OPT_fprofile_exclude_files_EQ);
diff --git a/clang/test/Driver/compilation-dir.c b/clang/test/Driver/compilation-dir.c
index dbe801c9f5fcb..0e19efee3993f 100644
--- a/clang/test/Driver/compilation-dir.c
+++ b/clang/test/Driver/compilation-dir.c
@@ -8,3 +8,7 @@
 // RUN: %clang -### -integrated-as -ffile-compilation-dir=. -x assembler %s 2>&1 | FileCheck -check-prefixes=CHECK-DEBUG-COMPILATION-DIR %s
 // CHECK-DEBUG-COMPILATION-DIR: "-fdebug-compilation-dir=."
 // CHECK-DEBUG-COMPILATION-DIR-NOT: "-ffile-compilation-dir=."
+
+// RUN: cd %S
+// RUN: %clang -### -S %s 2>&1 | FileCheck -check-prefix=CHECK-CWD %s
+// CHECK-CWD: -fdebug-compilation-dir={{.*}}Driver