[llvm] r344377 - Better support for POSIX paths in PDBs.

[Zachary Turner via llvm-commits]

Author: zturner
Date: Fri Oct 12 10:26:19 2018
New Revision: 344377

URL: http://llvm.org/viewvc/llvm-project?rev=344377&view=rev
Log:
Better support for POSIX paths in PDBs.

This a resubmission of a patch which was previously reverted
due to breaking several lld tests.  The issues causing those
failures have been fixed, so the patch is now resubmitted.

---Original Commit Message---

While it doesn't make a *ton* of sense for POSIX paths to be
in PDBs, it's possible to occur in real scenarios involving
cross compilation.

The tools need to be able to handle this, because certain types
of debugging scenarios are possible without a running process
and so don't necessarily require you to be on a Windows system.
These include post-mortem debugging and binary forensics (e.g.
using a debugger to disassemble functions and examine symbols
without running the process).

There's changes in clang, LLD, and lldb in this patch.  After
this the cross-platform disassembly and source-list tests pass
on Linux.

Furthermore, the behavior of LLD can now be summarized by a much
simpler rule than before: Unless you specify /pdbsourcepath and
/pdbaltpath, the PDB ends up with paths that are valid within
the context of the machine that the link is performed on.

Differential Revision: https://reviews.llvm.org/D53149

Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp?rev=344377&r1=344376&r2=344377&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp Fri Oct 12 10:26:19 2018
@@ -73,6 +73,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FormatVariadic.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/SMLoc.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
@@ -134,7 +135,9 @@ StringRef CodeViewDebug::getFullFilepath
 
   // If this is a Unix-style path, just use it as is. Don't try to canonicalize
   // it textually because one of the path components could be a symlink.
-  if (!Dir.empty() && Dir[0] == '/') {
+  if (Dir.startswith("/") || Filename.startswith("/")) {
+    if (llvm::sys::path::is_absolute(Filename, llvm::sys::path::Style::posix))
+      return Filename;
     Filepath = Dir;
     if (Dir.back() != '/')
       Filepath += '/';