*: remove "pure" and "const" attributes from throwing functions

The "pure" and "const" attributes are not so well-defined, and a
recent clang version implements an optimization which pushes the
definition's boundary beyond what I believed it was.  clang now
assumes that functions declared "pure" cannot throw exceptions, even
if they lack the "noexcept" specification.

When compiled with this new clang version, MPD will crash randomly if
an exception happens to get thrown by such as "pure" function
(https://github.com/MusicPlayerDaemon/MPD/issues/41).

This commit removes all such misplaced "pure" and "const" attributes,
closing #41.

27 files changed, 8 insertions, 61 deletions

diff --git a/NEWS b/NEWS
index c57c9dca3..349010e53 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,7 @@
 ver 0.20.7 (not yet released)
 * database
   - simple: fix false positive directory loop detection with NFS
+* fix random crashes when compiled with clang
 
 ver 0.20.6 (2017/03/10)
 * input
diff --git a/src/AudioParser.hxx b/src/AudioParser.hxx
index 6923dbad5..36c36740a 100644
--- a/src/AudioParser.hxx
+++ b/src/AudioParser.hxx
@@ -25,8 +25,6 @@
 #ifndef MPD_AUDIO_PARSER_HXX
 #define MPD_AUDIO_PARSER_HXX
 
-#include "Compiler.h"
-
 struct AudioFormat;
 
 /**
@@ -38,7 +36,6 @@ struct AudioFormat;
  * @param src the input string
  * @param mask if true, then "*" is allowed for any number of items
  */
-gcc_pure
 AudioFormat
 ParseAudioFormat(const char *src, bool mask);
 
diff --git a/src/Instance.hxx b/src/Instance.hxx
index babc0b3e6..7084b6089 100644
--- a/src/Instance.hxx
+++ b/src/Instance.hxx
@@ -117,7 +117,6 @@ struct Instance final
 	 * DatabaseError if this MPD configuration has no database (no
 	 * music_directory was configured).
 	 */
-	gcc_pure
 	const Database &GetDatabaseOrThrow() const;
 #endif
 
diff --git a/src/Main.cxx b/src/Main.cxx
index 0ea263a87..4924fbb2a 100644
--- a/src/Main.cxx
+++ b/src/Main.cxx
@@ -130,7 +130,6 @@ struct Config {
 	ReplayGainConfig replay_gain;
 };
 
-gcc_const
 static Config
 LoadConfig()
 {
diff --git a/src/Partition.hxx b/src/Partition.hxx
index b3c0bad72..873f40c92 100644
--- a/src/Partition.hxx
+++ b/src/Partition.hxx
@@ -200,7 +200,6 @@ struct Partition final : QueueListener, PlayerListener, MixerListener {
 	 */
 	const Database *GetDatabase() const;
 
-	gcc_pure
 	const Database &GetDatabaseOrThrow() const;
 
 	/**
diff --git a/src/Permission.cxx b/src/Permission.cxx
index 39b33bf1d..e955c4ca5 100644
--- a/src/Permission.cxx
+++ b/src/Permission.cxx
@@ -49,7 +49,6 @@ static std::map<std::string, unsigned> permission_passwords;
 
 static unsigned permission_default;
 
-gcc_pure
 static unsigned
 ParsePermission(const char *p)
 {
diff --git a/src/ReplayGainMode.hxx b/src/ReplayGainMode.hxx
index 37b76f16f..885151704 100644
--- a/src/ReplayGainMode.hxx
+++ b/src/ReplayGainMode.hxx
@@ -42,7 +42,6 @@ ToString(ReplayGainMode mode) noexcept;
  * Parse a string to a #ReplayGainMode.  Throws std::runtime_error on
  * error.
  */
-gcc_pure
 ReplayGainMode
 FromString(const char *s);
 
diff --git a/src/SongFilter.cxx b/src/SongFilter.cxx
index 96edfdea1..ed556ede0 100644
--- a/src/SongFilter.cxx
+++ b/src/SongFilter.cxx
@@ -57,7 +57,6 @@ locate_parse_type(const char *str) noexcept
 	return tag_name_parse_i(str);
 }
 
-gcc_pure
 static AllocatedString<>
 ImportString(const char *p, bool fold_case)
 {
diff --git a/src/client/Client.hxx b/src/client/Client.hxx
index 24461878e..c3a9a9cc0 100644
--- a/src/client/Client.hxx
+++ b/src/client/Client.hxx
@@ -191,7 +191,6 @@ public:
 	/**
 	 * Wrapper for Instance::GetDatabaseOrThrow().
 	 */
-	gcc_pure
 	const Database &GetDatabaseOrThrow() const;
 
 	gcc_pure
diff --git a/src/config/Block.cxx b/src/config/Block.cxx
index 2f26de368..723e5f6f0 100644
--- a/src/config/Block.cxx
+++ b/src/config/Block.cxx
@@ -129,7 +129,6 @@ ConfigBlock::GetBlockValue(const char *name, unsigned default_value) const
 	return bp->GetUnsignedValue();
 }
 
-gcc_pure
 bool
 ConfigBlock::GetBlockValue(const char *name, bool default_value) const
 {
diff --git a/src/config/Block.hxx b/src/config/Block.hxx
index 8003a31b0..edfa5a7d2 100644
--- a/src/config/Block.hxx
+++ b/src/config/Block.hxx
@@ -44,13 +44,10 @@ struct BlockParam {
 	BlockParam(const char *_name, const char *_value, int _line=-1)
 		:name(_name), value(_value), line(_line), used(false) {}
 
-	gcc_pure
 	int GetIntValue() const;
 
-	gcc_pure
 	unsigned GetUnsignedValue() const;
 
-	gcc_pure
 	bool GetBoolValue() const;
 };
 
@@ -116,13 +113,10 @@ struct ConfigBlock {
 	AllocatedPath GetPath(const char *name,
 			      const char *default_value=nullptr) const;
 
-	gcc_pure
 	int GetBlockValue(const char *name, int default_value) const;
 
-	gcc_pure
 	unsigned GetBlockValue(const char *name, unsigned default_value) const;
 
-	gcc_pure
 	bool GetBlockValue(const char *name, bool default_value) const;
 };
 
diff --git a/src/config/ConfigGlobal.hxx b/src/config/ConfigGlobal.hxx
index b6c86b3c1..89a4b7cad 100644
--- a/src/config/ConfigGlobal.hxx
+++ b/src/config/ConfigGlobal.hxx
@@ -61,18 +61,9 @@ config_get_block(enum ConfigBlockOption option) noexcept;
  * @param key the attribute name
  * @param value the expected attribute value
  */
-gcc_pure
 const ConfigBlock *
 config_find_block(ConfigBlockOption option, const char *key, const char *value);
 
-/* Note on gcc_pure: Some of the functions declared pure are not
-   really pure in strict sense.  They have side effect such that they
-   validate parameter's value and signal an error if it's invalid.
-   However, if the argument was already validated or we don't care
-   about the argument at all, this may be ignored so in the end, we
-   should be fine with calling those functions pure.  */
-
-gcc_pure
 const char *
 config_get_string(enum ConfigOption option,
 		  const char *default_value=nullptr) noexcept;
@@ -87,11 +78,9 @@ config_get_string(enum ConfigOption option,
 AllocatedPath
 config_get_path(enum ConfigOption option);
 
-gcc_pure
 unsigned
 config_get_unsigned(enum ConfigOption option, unsigned default_value);
 
-gcc_pure
 static inline std::chrono::steady_clock::duration
 config_get_unsigned(ConfigOption option,
 		    std::chrono::steady_clock::duration default_value)
@@ -101,11 +90,9 @@ config_get_unsigned(ConfigOption option,
 	return std::chrono::steady_clock::duration(u);
 }
 
-gcc_pure
 unsigned
 config_get_positive(enum ConfigOption option, unsigned default_value);
 
-gcc_pure
 static inline std::chrono::steady_clock::duration
 config_get_positive(ConfigOption option,
 		    std::chrono::steady_clock::duration default_value)
@@ -115,7 +102,6 @@ config_get_positive(ConfigOption option,
 	return std::chrono::steady_clock::duration(u);
 }
 
-gcc_pure
 bool config_get_bool(enum ConfigOption option, bool default_value);
 
 #endif
diff --git a/src/config/Param.hxx b/src/config/Param.hxx
index e0a4b9a19..50c514a19 100644
--- a/src/config/Param.hxx
+++ b/src/config/Param.hxx
@@ -71,7 +71,6 @@ struct ConfigParam {
 	 *
 	 * Throws #std::runtime_error on error.
 	 */
-	gcc_pure
 	AllocatedPath GetPath() const;
 };
 
diff --git a/src/db/DatabaseSong.hxx b/src/db/DatabaseSong.hxx
index bafc1df89..9b3e36589 100644
--- a/src/db/DatabaseSong.hxx
+++ b/src/db/DatabaseSong.hxx
@@ -31,7 +31,6 @@ class DetachedSong;
  * "Detach" the #Song object, i.e. convert it to a #DetachedSong
  * instance.
  */
-gcc_pure
 DetachedSong
 DatabaseDetachSong(const Storage &storage, const LightSong &song);
 
diff --git a/src/fs/AllocatedPath.hxx b/src/fs/AllocatedPath.hxx
index 2ee55479e..513453ffd 100644
--- a/src/fs/AllocatedPath.hxx
+++ b/src/fs/AllocatedPath.hxx
@@ -159,7 +159,7 @@ public:
 	 * Convert a UTF-8 C string to an #AllocatedPath instance.
 	 * Throws a std::runtime_error on error.
 	 */
-	gcc_pure gcc_nonnull_all
+	gcc_nonnull_all
 	static AllocatedPath FromUTF8Throw(const char *path_utf8);
 
 	/**
diff --git a/src/fs/Charset.hxx b/src/fs/Charset.hxx
index 84cf64ec6..7f7097b95 100644
--- a/src/fs/Charset.hxx
+++ b/src/fs/Charset.hxx
@@ -49,7 +49,7 @@ DeinitFSCharset() noexcept;
  *
  * Throws std::runtime_error on error.
  */
-gcc_pure gcc_nonnull_all
+gcc_nonnull_all
 PathTraitsUTF8::string
 PathToUTF8(PathTraitsFS::const_pointer_type path_fs);
 
@@ -58,7 +58,7 @@ PathToUTF8(PathTraitsFS::const_pointer_type path_fs);
  *
  * Throws std::runtime_error on error.
  */
-gcc_pure gcc_nonnull_all
+gcc_nonnull_all
 PathTraitsFS::string
 PathFromUTF8(PathTraitsUTF8::const_pointer_type path_utf8);
 
diff --git a/src/fs/io/BufferedReader.hxx b/src/fs/io/BufferedReader.hxx
index 6495b71ef..0e1b4a5b7 100644
--- a/src/fs/io/BufferedReader.hxx
+++ b/src/fs/io/BufferedReader.hxx
@@ -65,7 +65,6 @@ public:
 	 * it).  Throws std::runtime_error if not enough data is
 	 * available.
 	 */
-	gcc_pure
 	void *ReadFull(size_t size);
 
 	void Consume(size_t n) {
diff --git a/src/fs/io/FileReader.hxx b/src/fs/io/FileReader.hxx
index 7ca981f7d..7dc122217 100644
--- a/src/fs/io/FileReader.hxx
+++ b/src/fs/io/FileReader.hxx
@@ -86,7 +86,6 @@ public:
 
 	void Close();
 
-	gcc_pure
 	FileInfo GetFileInfo() const;
 
 	gcc_pure
diff --git a/src/lib/icu/Collate.hxx b/src/lib/icu/Collate.hxx
index d6f999214..d6cfcb764 100644
--- a/src/lib/icu/Collate.hxx
+++ b/src/lib/icu/Collate.hxx
@@ -38,7 +38,7 @@ gcc_pure gcc_nonnull_all
 int
 IcuCollate(const char *a, const char *b) noexcept;
 
-gcc_pure gcc_nonnull_all
+gcc_nonnull_all
 AllocatedString<char>
 IcuCaseFold(const char *src);
 
diff --git a/src/lib/icu/Converter.hxx b/src/lib/icu/Converter.hxx
index 80eec20c0..7ce545cf6 100644
--- a/src/lib/icu/Converter.hxx
+++ b/src/lib/icu/Converter.hxx
@@ -81,7 +81,7 @@ public:
 	 *
 	 * Throws std::runtime_error on error.
 	 */
-	gcc_pure gcc_nonnull_all
+	gcc_nonnull_all
 	AllocatedString<char> ToUTF8(const char *s) const;
 
 	/**
@@ -89,7 +89,7 @@ public:
 	 *
 	 * Throws std::runtime_error on error.
 	 */
-	gcc_pure gcc_nonnull_all
+	gcc_nonnull_all
 	AllocatedString<char> FromUTF8(const char *s) const;
 };
 
diff --git a/src/output/Wrapper.hxx b/src/output/Wrapper.hxx
index 55ffc91f4..5eb3d599c 100644
--- a/src/output/Wrapper.hxx
+++ b/src/output/Wrapper.hxx
@@ -68,7 +68,6 @@ struct AudioOutputWrapper {
 		return t.Delay();
 	}
 
-	gcc_pure
 	static void SendTag(AudioOutput *ao, const Tag &tag) {
 		T &t = Cast(*ao);
 		t.SendTag(tag);
@@ -89,7 +88,6 @@ struct AudioOutputWrapper {
 		t.Cancel();
 	}
 
-	gcc_pure
 	static bool Pause(AudioOutput *ao) {
 		T &t = Cast(*ao);
 		return t.Pause();
diff --git a/src/output/plugins/ShoutOutputPlugin.cxx b/src/output/plugins/ShoutOutputPlugin.cxx
index 8e797d9bd..16607fd62 100644
--- a/src/output/plugins/ShoutOutputPlugin.cxx
+++ b/src/output/plugins/ShoutOutputPlugin.cxx
@@ -74,7 +74,6 @@ static int shout_init_count;
 
 static constexpr Domain shout_output_domain("shout_output");
 
-gcc_pure
 static const char *
 require_block_string(const ConfigBlock &block, const char *name)
 {
diff --git a/src/protocol/ArgParser.hxx b/src/protocol/ArgParser.hxx
index 135f9e74b..8a23f25a8 100644
--- a/src/protocol/ArgParser.hxx
+++ b/src/protocol/ArgParser.hxx
@@ -21,7 +21,6 @@
 #define MPD_PROTOCOL_ARGPARSER_HXX
 
 #include "check.h"
-#include "Compiler.h"
 
 #include <limits>
 
@@ -30,15 +29,12 @@
 class SongTime;
 class SignedSongTime;
 
-gcc_pure
 uint32_t
 ParseCommandArgU32(const char *s);
 
-gcc_pure
 int
 ParseCommandArgInt(const char *s, int min_value, int max_value);
 
-gcc_pure
 int
 ParseCommandArgInt(const char *s);
 
@@ -55,31 +51,24 @@ struct RangeArg {
 	}
 };
 
-gcc_pure
 RangeArg
 ParseCommandArgRange(const char *s);
 
-gcc_pure
 unsigned
 ParseCommandArgUnsigned(const char *s, unsigned max_value);
 
-gcc_pure
 unsigned
 ParseCommandArgUnsigned(const char *s);
 
-gcc_pure
 bool
 ParseCommandArgBool(const char *s);
 
-gcc_pure
 float
 ParseCommandArgFloat(const char *s);
 
-gcc_pure
 SongTime
 ParseCommandArgSongTime(const char *s);
 
-gcc_pure
 SignedSongTime
 ParseCommandArgSignedSongTime(const char *s);
 
diff --git a/src/sticker/SongSticker.hxx b/src/sticker/SongSticker.hxx
index f52175e97..ea78d4e47 100644
--- a/src/sticker/SongSticker.hxx
+++ b/src/sticker/SongSticker.hxx
@@ -21,7 +21,6 @@
 #define MPD_SONG_STICKER_HXX
 
 #include "Match.hxx"
-#include "Compiler.h"
 
 #include <string>
 
@@ -34,7 +33,6 @@ class Database;
  *
  * Throws #SqliteError on error.
  */
-gcc_pure
 std::string
 sticker_song_get_value(const LightSong &song, const char *name);
 
diff --git a/src/storage/plugins/LocalStorage.cxx b/src/storage/plugins/LocalStorage.cxx
index 389d52a26..816286b1b 100644
--- a/src/storage/plugins/LocalStorage.cxx
+++ b/src/storage/plugins/LocalStorage.cxx
@@ -71,7 +71,6 @@ private:
 	AllocatedPath MapFSOrThrow(const char *uri_utf8) const;
 };
 
-gcc_pure
 static StorageFileInfo
 Stat(Path path, bool follow)
 {
diff --git a/src/util/TimeParser.cxx b/src/util/TimeParser.cxx
index b99433a75..9ce915c7f 100644
--- a/src/util/TimeParser.cxx
+++ b/src/util/TimeParser.cxx
@@ -28,6 +28,7 @@
  */
 
 #include "TimeParser.hxx"
+#include "Compiler.h"
 
 #include <stdexcept>
 
diff --git a/src/util/TimeParser.hxx b/src/util/TimeParser.hxx
index 8b539b4a7..97aa0c016 100644
--- a/src/util/TimeParser.hxx
+++ b/src/util/TimeParser.hxx
@@ -30,8 +30,6 @@
 #ifndef TIME_PARSER_HXX
 #define TIME_PARSER_HXX
 
-#include "Compiler.h"
-
 #include <chrono>
 
 /**
@@ -39,7 +37,6 @@
  *
  * Throws std::runtime_error on error.
  */
-gcc_pure
 std::chrono::system_clock::time_point
 ParseTimePoint(const char *s, const char *format);