Check for $PWD in llvm::sys::current_path.

Some users (clang, libTooling) require this. After this patch we can remove
the calls to getenv("PWD") from clang.

llvm-svn: 188125

2 files changed, 22 insertions, 0 deletions

diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 4dcfa094a7b..f6a137e7a0b 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -298,6 +298,18 @@ UniqueID file_status::getUniqueID() const {
 }
 
 error_code current_path(SmallVectorImpl<char> &result) {
+  result.clear();
+
+  const char *pwd = ::getenv("PWD");
+  llvm::sys::fs::file_status PWDStatus, DotStatus;
+  if (pwd && llvm::sys::path::is_absolute(pwd) &&
+      !llvm::sys::fs::status(pwd, PWDStatus) &&
+      !llvm::sys::fs::status(".", DotStatus) &&
+      PWDStatus.getUniqueID() == DotStatus.getUniqueID()) {
+    result.append(pwd, pwd + strlen(pwd));
+    return error_code::success();
+  }
+
 #ifdef MAXPATHLEN
   result.reserve(MAXPATHLEN);
 #else
diff --git a/llvm/test/MC/ELF/comp-dir.s b/llvm/test/MC/ELF/comp-dir.s
index 59e3d7ded26..1b91f64a502 100644
--- a/llvm/test/MC/ELF/comp-dir.s
+++ b/llvm/test/MC/ELF/comp-dir.s
@@ -1,7 +1,17 @@
+// REQUIRES: shell
+// XFAIL: mingw
 // RUN: llvm-mc -triple=x86_64-linux-unknown -g -fdebug-compilation-dir=/test/comp/dir %s -filetype=obj -o %t.o
 // RUN: llvm-dwarfdump -debug-dump=info %t.o | FileCheck %s
 
 // CHECK: DW_AT_comp_dir [DW_FORM_string] ("{{([A-Za-z]:.*)?}}/test/comp/dir")
 
+// RUN: mkdir -p %t.foo
+// RUN: ln -sf %t.foo %t.bar
+// RUN: cd %t.foo
+// RUN: env PWD=%t.bar llvm-mc -triple=x86_64-linux-unknown -g %s -filetype=obj -o %t.o
+// RUN: llvm-dwarfdump -debug-dump=info %t.o | FileCheck --check-prefix=PWD %s
+// PWD: DW_AT_comp_dir [DW_FORM_string] ("{{.*}}.bar")
+
+
 f:
   nop