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Fix alignas() on non-packed architectures (#839).

Unbreak the build with Clang on architectures where JACK uses non-packed
data structures, like arm64 or powerpc. The alignment errors are exposed
there because:
 * The non-packed data structures require 8 byte alignment.
 * alignas() is not allowed to weaken alignment requirements to 4 bytes.
 * Clang enforces this according to standard, GCC ignores it.

Use an additional alignas() specifier to let the compiler choose between
minimum alignment (packed) and "natural" alignment (non-packed). This is
both standard c++11 and compatible with older GCC, which does not
propagate alignment requirements of packed substructures properly.
tags/v1.9.21
Florian Walpen Filipe Coelho <falktx@falktx.com> 2 years ago
parent
commit
21b293dbc3
4 changed files with 5 additions and 5 deletions
  1. +1
    -1
      common/JackAtomicArrayState.h
  2. +1
    -1
      common/JackAtomicState.h
  3. +1
    -1
      common/JackConnectionManager.h
  4. +2
    -2
      common/JackEngineControl.h

+ 1
- 1
common/JackAtomicArrayState.h View File

@@ -122,7 +122,7 @@ class JackAtomicArrayState
// fState[2] ==> request

T fState[3];
alignas(UInt32) volatile AtomicArrayCounter fCounter;
alignas(UInt32) alignas(AtomicArrayCounter) volatile AtomicArrayCounter fCounter;

UInt32 WriteNextStateStartAux(int state, bool* result)
{


+ 1
- 1
common/JackAtomicState.h View File

@@ -94,7 +94,7 @@ class JackAtomicState
protected:

T fState[2];
alignas(UInt32) volatile AtomicCounter fCounter;
alignas(UInt32) alignas(AtomicCounter) volatile AtomicCounter fCounter;
SInt32 fCallWriteCounter;

UInt32 WriteNextStateStartAux()


+ 1
- 1
common/JackConnectionManager.h View File

@@ -417,7 +417,7 @@ class SERVER_EXPORT JackConnectionManager
JackFixedArray1<PORT_NUM_FOR_CLIENT> fInputPort[CLIENT_NUM]; /*! Table of input port per refnum : to find a refnum for a given port */
JackFixedArray<PORT_NUM_FOR_CLIENT> fOutputPort[CLIENT_NUM]; /*! Table of output port per refnum : to find a refnum for a given port */
JackFixedMatrix<CLIENT_NUM> fConnectionRef; /*! Table of port connections by (refnum , refnum) */
alignas(UInt32) JackActivationCount fInputCounter[CLIENT_NUM]; /*! Activation counter per refnum */
alignas(UInt32) alignas(JackActivationCount) JackActivationCount fInputCounter[CLIENT_NUM]; /*! Activation counter per refnum */
JackLoopFeedback<CONNECTION_NUM_FOR_PORT> fLoopFeedback; /*! Loop feedback connections */

bool IsLoopPathAux(int ref1, int ref2) const;


+ 2
- 2
common/JackEngineControl.h View File

@@ -64,7 +64,7 @@ struct SERVER_EXPORT JackEngineControl : public JackShmMem
int fClientPriority;
int fMaxClientPriority;
char fServerName[JACK_SERVER_NAME_SIZE+1];
alignas(UInt32) JackTransportEngine fTransport;
alignas(UInt32) alignas(JackTransportEngine) JackTransportEngine fTransport;
jack_timer_type_t fClockSource;
int fDriverNum;
bool fVerbose;
@@ -86,7 +86,7 @@ struct SERVER_EXPORT JackEngineControl : public JackShmMem
UInt64 fConstraint;

// Timer
alignas(UInt32) JackFrameTimer fFrameTimer;
alignas(UInt32) alignas(JackFrameTimer) JackFrameTimer fFrameTimer;

#ifdef JACK_MONITOR
JackEngineProfiling fProfiler;


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