[clang] Fix DIFile directory root on Windows

[keith]

Summary

On unix systems this logic would not separate the file and directory of
the DIFile unless they shared more components at the start than just the
root path character. The logic to do this was unix specific so it didn't
work on Windows. Now we check if the entire root_path is the same as
what you were going to set as the Dir and use the full filepath in that
case.

[keith]

Adding since you might be interested in this, I think the Swift logic is also derived from this so it might have the same difference.

[mstorsjo]

clang/lib/CodeGen/CGDebugInfo.cpp

436

This change is correct IMO.

clang/test/CodeGen/debug-prefix-map.c

24

I presume that this patch goes on top of D111457? It might be good to set that one as the parent revision of this one, so that the premerge test runs applies them on top of each other (right now, this one failed to apply).

Isn't this particular change present (directory being "" here) already after the previous patch?

[keith]

clang/test/CodeGen/debug-prefix-map.c

24

That is marked as the parent of this patch in phab, but maybe I need to do something else to get them to apply?

24

Isn't this particular change present (directory being "" here) already after the previous patch?

This does still require this change since otherwise directory still gets C:

[mstorsjo]

clang/test/CodeGen/debug-prefix-map.c

24

Hmm, it seems like the premerge testing managed to start running this before the parent was set (and I didn't notice it when I looked at the patches the last round). If you reupload the patch later when this already is set, I think it should work though - but no hurry with that right now.

24

Oh, ok.

[keith]

clang/test/CodeGen/debug-prefix-map.c

24

Ah that's on my order of operations then, I submitted this, and then started the pre-warm, and haven't updated it since. Good to know, thanks. I will make sure CI passes here before landing anything regardless.

[keith]

Add more test path changes

[keith]

Update tests with new syntax and FileCheck variables

[keith]

Remove variables from test expectations

This didn't work out because of the double vs single slash of the expansions

[keith]

Replace \w with .

[keith]

Ping, all green here, I just had to mess with the test regex a bit

[compnerd]

clang/test/CodeGen/debug-prefix-map.c

7

I think that this illustrates my point on the base differential.

[keith]

Update subsitutions with dashes

clang/lib/CodeGen/CGDebugInfo.cpp

CGDebugInfo::createFile(StringRef FileName,
                         Optional<StringRef> Source) {
   StringRef Dir;
   StringRef File;
   std::string RemappedFile = remapDIPath(FileName);
   std::string CurDir = remapDIPath(getCurrentDirname());
   SmallString<128> DirBuf;
   SmallString<128> FileBuf;
   if (llvm::sys::path::is_absolute(RemappedFile)) {
-    // Strip the common prefix (if it is more than just "/") from current
-    // directory and FileName for a more space-efficient encoding.
+    // Strip the common prefix (if it is more than just "/" or "C:\") from
+    // current directory and FileName for a more space-efficient encoding.
     auto FileIt = llvm::sys::path::begin(RemappedFile);
     auto FileE = llvm::sys::path::end(RemappedFile);
     auto CurDirIt = llvm::sys::path::begin(CurDir);
     auto CurDirE = llvm::sys::path::end(CurDir);
     for (; CurDirIt != CurDirE && *CurDirIt == *FileIt; ++CurDirIt, ++FileIt)
       llvm::sys::path::append(DirBuf, *CurDirIt);
-    if (std::distance(llvm::sys::path::begin(CurDir), CurDirIt) == 1) {
-      // Don't strip the common prefix if it is only the root "/"
+    if (llvm::sys::path::root_path(DirBuf) == DirBuf) {
+      // Don't strip the common prefix if it is only the root ("/" or "C:\")
       // since that would make LLVM diagnostic locations confusing.
       Dir = {};
       File = RemappedFile;
     } else {
       for (; FileIt != FileE; ++FileIt)
         llvm::sys::path::append(FileBuf, *FileIt);
       Dir = DirBuf;
       File = FileBuf;

clang/test/CodeGen/debug-prefix-map.c

-// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=/UNLIKELY_PATH/empty %s -emit-llvm -o - | FileCheck %s -check-prefix CHECK-NO-MAIN-FILE-NAME
-// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=/UNLIKELY_PATH=empty %s -emit-llvm -o - | FileCheck %s -check-prefix CHECK-EVIL
-// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=/UNLIKELY_PATH/empty %s -emit-llvm -o - -main-file-name debug-prefix-map.c | FileCheck %s
-// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=/UNLIKELY_PATH/empty %s -emit-llvm -o - -fdebug-compilation-dir %p | FileCheck %s -check-prefix CHECK-COMPILATION-DIR
-// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=/UNLIKELY_PATH/empty %s -emit-llvm -o - -isysroot %p -debugger-tuning=lldb | FileCheck %s -check-prefix CHECK-SYSROOT
-// RUN: %clang -g -fdebug-prefix-map=%p=/UNLIKELY_PATH/empty -S -c %s -emit-llvm -o - | FileCheck %s
-// RUN: %clang -g -ffile-prefix-map=%p=/UNLIKELY_PATH/empty -S -c %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=%{fs-src-root}UNLIKELY_PATH%{fs-sep}empty %s -emit-llvm -o - | FileCheck %s -check-prefix CHECK-NO-MAIN-FILE-NAME
+// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=%{fs-src-root}UNLIKELY_PATH=empty %s -emit-llvm -o - | FileCheck %s -check-prefix CHECK-EVIL
+// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=%{fs-src-root}UNLIKELY_PATH%{fs-sep}empty %s -emit-llvm -o - -main-file-name debug-prefix-map.c | FileCheck %s
+// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=%{fs-src-root}UNLIKELY_PATH%{fs-sep}empty %s -emit-llvm -o - -fdebug-compilation-dir %p | FileCheck %s -check-prefix CHECK-COMPILATION-DIR
+// RUN: %clang_cc1 -debug-info-kind=standalone -fdebug-prefix-map=%p=%{fs-src-root}UNLIKELY_PATH%{fs-sep}empty %s -emit-llvm -o - -isysroot %p -debugger-tuning=lldb | FileCheck %s -check-prefix CHECK-SYSROOT
+// RUN: %clang -g -fdebug-prefix-map=%p=%{fs-src-root}UNLIKELY_PATH%{fs-sep}empty -S -c %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang -g -ffile-prefix-map=%p=%{fs-src-root}UNLIKELY_PATH%{fs-sep}empty -S -c %s -emit-llvm -o - | FileCheck %s
 
 #include "Inputs/stdio.h"
 
 int main(int argc, char **argv) {
   (void)argc;
   (void)argv;
   return 0;
 }
 
 void test_rewrite_includes(void) {
   __builtin_va_list argp;
   vprintf("string", argp);
 }
 
-// CHECK-NO-MAIN-FILE-NAME: !DIFile(filename: "/UNLIKELY_PATH/empty{{/|\\\\}}<stdin>"
-// CHECK-NO-MAIN-FILE-NAME: !DIFile(filename: "/UNLIKELY_PATH/empty{{/|\\\\}}{{.*}}",
-// On POSIX systems "Dir" should actually be empty, but on Windows we
-// can't recognize "/UNLIKELY_PATH" as being an absolute path.
-// CHECK-NO-MAIN-FILE-NAME-SAME:    directory: "{{()|(.*:.*)}}")
-// CHECK-NO-MAIN-FILE-NAME: !DIFile(filename: "/UNLIKELY_PATH/empty{{/|\\\\}}Inputs/stdio.h",
-// CHECK-NO-MAIN-FILE-NAME-SAME:    directory: "{{()|(.*:.*)}}")
+// CHECK-NO-MAIN-FILE-NAME: !DIFile(filename: "{{/|.:\\\\}}UNLIKELY_PATH{{/|\\\\}}empty{{/|\\\\}}<stdin>",
+// CHECK-NO-MAIN-FILE-NAME: !DIFile(filename: "{{/|.:\\\\}}UNLIKELY_PATH{{/|\\\\}}empty{{/|\\\\}}{{.*}}",
+// CHECK-NO-MAIN-FILE-NAME-SAME:    directory: "")
+// CHECK-NO-MAIN-FILE-NAME: !DIFile(filename: "{{/|.:\\\\}}UNLIKELY_PATH{{/|\\\\}}empty{{/|\\\\}}Inputs{{/|\\\\}}stdio.h",
+// CHECK-NO-MAIN-FILE-NAME-SAME:    directory: "")
 // CHECK-NO-MAIN-FILE-NAME-NOT: !DIFile(filename:
 
-// CHECK-EVIL: !DIFile(filename: "/UNLIKELY_PATH=empty{{/|\\\\}}{{.*}}"
-// CHECK-EVIL: !DIFile(filename: "/UNLIKELY_PATH=empty{{/|\\\\}}{{.*}}Inputs/stdio.h",
-// CHECK-EVIL-SAME:    directory: "{{()|(.*:.*)}}")
+// CHECK-EVIL: !DIFile(filename: "{{/|.:\\\\}}UNLIKELY_PATH=empty{{/|\\\\}}{{.*}}"
+// CHECK-EVIL: !DIFile(filename: "{{/|.:\\\\}}UNLIKELY_PATH=empty{{/|\\\\}}{{.*}}Inputs{{/|\\\\}}stdio.h",
+// CHECK-EVIL-SAME:    directory: "")
 // CHECK-EVIL-NOT: !DIFile(filename:
 
-// CHECK: !DIFile(filename: "/UNLIKELY_PATH/empty{{/|\\\\}}{{.*}}"
-// CHECK: !DIFile(filename: "/UNLIKELY_PATH/empty{{/|\\\\}}{{.*}}Inputs/stdio.h",
-// CHECK-SAME:    directory: "{{()|(.*:.*)}}")
+// CHECK: !DIFile(filename: "{{/|.:\\\\}}UNLIKELY_PATH{{/|\\\\}}empty{{/|\\\\}}{{.*}}",
+// CHECK: !DIFile(filename: "{{/|.:\\\\}}UNLIKELY_PATH{{/|\\\\}}empty{{/|\\\\}}{{.*}}Inputs{{/|\\\\}}stdio.h",
+// CHECK-SAME:    directory: ""
 // CHECK-NOT: !DIFile(filename:
 
-// CHECK-COMPILATION-DIR: !DIFile(filename: "{{.*}}", directory: "/UNLIKELY_PATH/empty")
-// CHECK-COMPILATION-DIR: !DIFile(filename: "{{.*}}Inputs/stdio.h", directory: "/UNLIKELY_PATH/empty")
+// CHECK-COMPILATION-DIR: !DIFile(filename: "{{.*}}", directory: "{{/|.:\\\\}}UNLIKELY_PATH{{/|\\\\}}empty")
+// CHECK-COMPILATION-DIR: !DIFile(filename: "{{.*}}Inputs{{/|\\\\}}stdio.h", directory: "{{/|.:\\\\}}UNLIKELY_PATH{{/|\\\\}}empty")
 // CHECK-COMPILATION-DIR-NOT: !DIFile(filename:
-// CHECK-SYSROOT: !DICompileUnit({{.*}}sysroot: "/UNLIKELY_PATH/empty"
+// CHECK-SYSROOT: !DICompileUnit({{.*}}sysroot: "{{/|.:\\\\}}UNLIKELY_PATH{{/|\\\\}}empty"