Allow setting multiple debug types

[davide]

Do you plan to use this somewhere? Is there a way to test this behaviour?

[evgeny777]

Thanks for looking at it.
I'm using llvm libraries in a sample application and on some occasions would like to print debug output from more than one module, like this:

setCurrentDebugTypes({"dyld", "regalloc"});

Currently I can't do this because setCurrentDebugType() allows debugging only one module
Unfortunately I don't have a clue how to write unit test for this, but I think the change is straightforward.

[davide]

In D28109#630993, @evgeny777 wrote:

Thanks for looking at it.
I'm using llvm libraries in a sample application and on some occasions would like to print debug output from more than one module, like this:

setCurrentDebugTypes({"dyld", "regalloc"});

Currently I can't do this because setCurrentDebugType() allows debugging only one module
Unfortunately I don't have a clue how to write unit test for this, but I think the change is straightforward.

Maybe you can try writing a unit test, no?

[evgeny777]

Maybe you can try writing a unit test, no?

Do you have an idea how to do this? This is C++ library function not invoked anywhere inside llvm. I tried to find any test for *setCurrentDebugType(const char *)* (existing one), but looks like there is none either.

[davide]

In D28109#631017, @evgeny777 wrote:

Maybe you can try writing a unit test, no?

Do you have an idea how to do this? This is C++ library function not invoked anywhere inside llvm. I tried to find any test for *setCurrentDebugType(const char *)* (existing one), but looks like there is none either.

You can probably model it after any other unit test for the code living in Support/. If the original function is not tested, it's probably worth a test for that as well, if you don't mind/have bandwidth for. If you still can't find it, I'll provide a pointer.
Sorry for being a little pedantic here, but it's not uncommon for me to go around and remove code considered "dead" in the tree (because unused/untested) and 6 months later receive a mail from somebody with an out-of-tree backend/code complaining I broke their product. So, keeping in-tree tests is at least a way to differentiate between code that's obviously dead and code that's used by somewhere but doesn't live in-tree.

[evgeny777]

Added unit test. Thanks for a hint!

[davide]

LGTM. Thanks for your patience.

include/llvm/Support/Debug.h

 bool isCurrentDebugType(const char *Type);
 
 /// setCurrentDebugType - Set the current debug type, as if the -debug-only=X
 /// option were specified.  Note that DebugFlag also needs to be set to true for
 /// debug output to be produced.
 ///
 void setCurrentDebugType(const char *Type);
 
+/// setCurrentDebugTypes - Set the current debug type, as if the
+/// -debug-only=X,Y,Z option were specified. Note that DebugFlag
+/// also needs to be set to true for debug output to be produced.
+///
+void setCurrentDebugTypes(const char **Types, unsigned Count);
+
 /// DEBUG_WITH_TYPE macro - This macro should be used by passes to emit debug
 /// information.  In the '-debug' option is specified on the commandline, and if
 /// this is a debug build, then the code specified as the option to the macro
 /// will be executed.  Otherwise it will not be.  Example:
 ///
 /// DEBUG_WITH_TYPE("bitset", dbgs() << "Bitset contains: " << Bitset << "\n");
 ///
 /// This will emit the debug information if -debug is present, and -debug-only
 /// is not specified, or is specified as "bitset".
 #define DEBUG_WITH_TYPE(TYPE, X)                                        \
   do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)) { X; } \
   } while (false)
 
 #else
 #define isCurrentDebugType(X) (false)
 #define setCurrentDebugType(X)
+#define setCurrentDebugTypes(X, N)
 #define DEBUG_WITH_TYPE(TYPE, X) do { } while (false)
 #endif
 
 /// EnableDebugBuffering - This defaults to false.  If true, the debug
 /// stream will install signal handlers to dump any buffered debug
 /// output.  It allows clients to selectively allow the debug stream
 /// to install signal handlers if they are certain there will be no
 /// conflict.

lib/Support/Debug.cpp

bool isCurrentDebugType(const char *DebugType) {
   return false;
 }
 
 /// Set the current debug type, as if the -debug-only=X
 /// option were specified.  Note that DebugFlag also needs to be set to true for
 /// debug output to be produced.
 ///
 void setCurrentDebugType(const char *Type) {
-  CurrentDebugType->clear();
-  CurrentDebugType->push_back(Type);
+  setCurrentDebugTypes(&Type, 1);
 }
 
+void setCurrentDebugTypes(const char **Types, size_t Count) {
+  CurrentDebugType->clear();
+  for (size_t T = 0; T < Count; ++T)
+    CurrentDebugType->push_back(Types[T]);
+}
 } // namespace llvm
 
 // All Debug.h functionality is a no-op in NDEBUG mode.
 #ifndef NDEBUG
 
 // -debug - Command line option to enable the DEBUG statements in the passes.
 // This flag may only be enabled in debug builds.
 static cl::opt<bool, true>