[llvm][Support] Take in CurrentDirectory as a parameter in ExpandResponseFiles

Summary:
This is a follow-up to D70769 and D70222, which allows propagation of
current directory down to ExpandResponseFiles for handling of relative paths.

Previously clients had to mutate FS to achieve that, which is not thread-safe
and can even be thread-hostile in the case of real file system.

Reviewers: sammccall

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D70857

1 files changed, 46 insertions, 28 deletions

diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index daeab6fade5..1f424075d47 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -24,6 +24,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Config/config.h"
@@ -42,6 +43,7 @@
 #include "llvm/Support/raw_ostream.h"
 #include <cstdlib>
 #include <map>
+#include <string>
 using namespace llvm;
 using namespace cl;
 
@@ -1045,14 +1047,12 @@ static bool hasUTF8ByteOrderMark(ArrayRef<char> S) {
   return (S.size() >= 3 && S[0] == '\xef' && S[1] == '\xbb' && S[2] == '\xbf');
 }
 
-static llvm::Error ExpandResponseFile(StringRef FName, StringSaver &Saver,
-                               TokenizerCallback Tokenizer,
-                               SmallVectorImpl<const char *> &NewArgv,
-                               bool MarkEOLs, bool RelativeNames,
-                               llvm::vfs::FileSystem &FS) {
-  llvm::ErrorOr<std::string> CurrDirOrErr = FS.getCurrentWorkingDirectory();
-  if (!CurrDirOrErr)
-    return llvm::errorCodeToError(CurrDirOrErr.getError());
+// FName must be an absolute path.
+static llvm::Error ExpandResponseFile(
+    StringRef FName, StringSaver &Saver, TokenizerCallback Tokenizer,
+    SmallVectorImpl<const char *> &NewArgv, bool MarkEOLs, bool RelativeNames,
+    llvm::vfs::FileSystem &FS) {
+  assert(sys::path::is_absolute(FName));
   llvm::ErrorOr<std::unique_ptr<MemoryBuffer>> MemBufOrErr =
       FS.getBufferForFile(FName);
   if (!MemBufOrErr)
@@ -1078,28 +1078,28 @@ static llvm::Error ExpandResponseFile(StringRef FName, StringSaver &Saver,
   // Tokenize the contents into NewArgv.
   Tokenizer(Str, Saver, NewArgv, MarkEOLs);
 
+  if (!RelativeNames)
+    return Error::success();
+  llvm::StringRef BasePath = llvm::sys::path::parent_path(FName);
   // If names of nested response files should be resolved relative to including
   // file, replace the included response file names with their full paths
   // obtained by required resolution.
-  if (RelativeNames)
-    for (unsigned I = 0; I < NewArgv.size(); ++I)
-      if (NewArgv[I]) {
-        StringRef Arg = NewArgv[I];
-        if (Arg.front() == '@') {
-          StringRef FileName = Arg.drop_front();
-          if (llvm::sys::path::is_relative(FileName)) {
-            SmallString<128> ResponseFile;
-            ResponseFile.append(1, '@');
-            if (llvm::sys::path::is_relative(FName)) {
-              ResponseFile.append(CurrDirOrErr.get());
-            }
-            llvm::sys::path::append(
-                ResponseFile, llvm::sys::path::parent_path(FName), FileName);
-            NewArgv[I] = Saver.save(ResponseFile.c_str()).data();
-          }
-        }
-      }
+  for (auto &Arg : NewArgv) {
+    // Skip non-rsp file arguments.
+    if (!Arg || Arg[0] != '@')
+      continue;
+
+    StringRef FileName(Arg + 1);
+    // Skip if non-relative.
+    if (!llvm::sys::path::is_relative(FileName))
+      continue;
 
+    SmallString<128> ResponseFile;
+    ResponseFile.push_back('@');
+    ResponseFile.append(BasePath);
+    llvm::sys::path::append(ResponseFile, FileName);
+    Arg = Saver.save(ResponseFile.c_str()).data();
+  }
   return Error::success();
 }
 
@@ -1107,10 +1107,11 @@ static llvm::Error ExpandResponseFile(StringRef FName, StringSaver &Saver,
 /// StringSaver and tokenization strategy.
 bool cl::ExpandResponseFiles(StringSaver &Saver, TokenizerCallback Tokenizer,
                              SmallVectorImpl<const char *> &Argv, bool MarkEOLs,
-                             bool RelativeNames, llvm::vfs::FileSystem &FS) {
+                             bool RelativeNames, llvm::vfs::FileSystem &FS,
+                             llvm::Optional<llvm::StringRef> CurrentDir) {
   bool AllExpanded = true;
   struct ResponseFileRecord {
-    const char *File;
+    std::string File;
     size_t End;
   };
 
@@ -1144,6 +1145,17 @@ bool cl::ExpandResponseFiles(StringSaver &Saver, TokenizerCallback Tokenizer,
     }
 
     const char *FName = Arg + 1;
+    // Note that CurrentDir is only used for top-level rsp files, the rest will
+    // always have an absolute path deduced from the containing file.
+    SmallString<128> CurrDir;
+    if (llvm::sys::path::is_relative(FName)) {
+      if (!CurrentDir)
+        llvm::sys::fs::current_path(CurrDir);
+      else
+        CurrDir = *CurrentDir;
+      llvm::sys::path::append(CurrDir, FName);
+      FName = CurrDir.c_str();
+    }
     auto IsEquivalent = [FName, &FS](const ResponseFileRecord &RFile) {
       llvm::ErrorOr<llvm::vfs::Status> LHS = FS.status(FName);
       if (!LHS) {
@@ -1206,6 +1218,12 @@ bool cl::ExpandResponseFiles(StringSaver &Saver, TokenizerCallback Tokenizer,
 
 bool cl::readConfigFile(StringRef CfgFile, StringSaver &Saver,
                         SmallVectorImpl<const char *> &Argv) {
+  SmallString<128> AbsPath;
+  if (sys::path::is_relative(CfgFile)) {
+    llvm::sys::fs::current_path(AbsPath);
+    llvm::sys::path::append(AbsPath, CfgFile);
+    CfgFile = AbsPath.str();
+  }
   if (llvm::Error Err =
           ExpandResponseFile(CfgFile, Saver, cl::tokenizeConfigFile, Argv,
                              /*MarkEOLs*/ false, /*RelativeNames*/ true,