Workaround for Clang generating wrong debug info

Clang obviously takes PWD as a basis for source paths in debug
information (AT_comp_dir) if it is set. Since the build tools are not
executed in a shell that would set PWD to a sensible value, debug
information with Clang is broken if the build environment got a wrong
PWD to start with, for example by starting Qt Creator from a shell
(which sets PWD).

Workaround is to explicitly unset PWD for the build environment used for
the Clang tool chain.

Task-number: QTCREATORBUG-8825

Change-Id: Ia3e47693121edd61b0ea43bddbb1fcaaac9eb390
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

2 files changed, 11 insertions, 0 deletions

diff --git a/src/plugins/projectexplorer/gcctoolchain.cpp b/src/plugins/projectexplorer/gcctoolchain.cpp
index 31f4a47fe1..b06c91cd7a 100644
--- a/src/plugins/projectexplorer/gcctoolchain.cpp
+++ b/src/plugins/projectexplorer/gcctoolchain.cpp
@@ -1059,6 +1059,16 @@ QList<FileName> ClangToolChain::suggestedMkspecList() const
     return QList<FileName>(); // Note: Not supported by Qt yet, so default to the mkspec the Qt was build with
 }
 
+void ClangToolChain::addToEnvironment(Environment &env) const
+{
+    GccToolChain::addToEnvironment(env);
+    // Clang takes PWD as basis for debug info, if set.
+    // When running Qt Creator from a shell, PWD is initially set to an "arbitrary" value.
+    // Since the tools are not called through a shell, PWD is never changed to the actual cwd,
+    // so we better make sure PWD is empty to begin with
+    env.unset(QLatin1String("PWD"));
+}
+
 ToolChain::CompilerFlags ClangToolChain::defaultCompilerFlags() const
 {
     return CompilerFlags(GnuExtensions | StandardC99 | StandardCxx11);
diff --git a/src/plugins/projectexplorer/gcctoolchain.h b/src/plugins/projectexplorer/gcctoolchain.h
index 4027453b46..e445d74b7e 100644
--- a/src/plugins/projectexplorer/gcctoolchain.h
+++ b/src/plugins/projectexplorer/gcctoolchain.h
@@ -158,6 +158,7 @@ public:
     ToolChain *clone() const;
 
     QList<Utils::FileName> suggestedMkspecList() const;
+    void addToEnvironment(Utils::Environment &env) const;
 
 protected:
     virtual CompilerFlags defaultCompilerFlags() const;