feat: Memory management refactoring and MSVC compilation fixes #162
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…r semantics ROOT CAUSE: The allocate() function was incorrectly constructing objects during memory allocation, violating C++ allocator requirements. MSVC's std::_Tree_node has a deleted default constructor, causing compilation failure. CHANGES: - container_allocator::allocate() now only allocates raw memory without constructing objects (removed mem::$new and ipc::construct calls) - container_allocator::deallocate() now only frees memory without destroying objects (removed mem::$delete and ipc::destroy_n calls) WHY THIS FIXES THE ISSUE: C++ allocator semantics require strict separation: * allocate() -> raw memory allocation only * construct() -> object construction with proper arguments * destroy() -> object destruction * deallocate() -> memory deallocation only Standard containers (like std::map) call construct() with proper arguments (key, value) to initialize nodes, not allocate(). Since std::_Tree_node in MSVC has no default constructor (= delete), attempting to construct it without arguments always fails. Fixes MSVC 2017 compilation error: error C2280: 'std::_Tree_node<...>::_Tree_node(void)': attempting to reference a deleted function
IMPROVEMENTS:
1. Add explicit zero-argument overload to avoid SFINAE ambiguity
2. Require at least one argument (A1) for parameterized overloads
3. Better separation between direct initialization and aggregate initialization
BENEFITS:
- Clearer intent: zero-argument construction is explicitly handled
- Avoids potential SFINAE ambiguity when empty parameter pack is used
- More maintainable: easier to understand which overload is selected
- Consistent with modern C++ best practices for variadic templates
TECHNICAL DETAILS:
- Zero-arg overload: Always uses T() for value initialization
- One-or-more-arg overload: Uses SFINAE to choose between:
* T(args...) for types with matching constructor
* T{args...} for aggregate types or types with initializer_list ctor
This is a code quality improvement and does not fix any compilation issues,
but provides better template overload resolution.
ROOT CAUSE: Array placement new (::new(buffer) T[N]) adds a hidden cookie (array size) before the array elements in some compiler implementations (particularly MSVC). The cookie is used for proper array destruction. However, the data_set buffer was sized only for sizeof(T[N]), not accounting for the cookie overhead. ISSUE: - Buffer allocated: sizeof(rand_buf[LoopCount]) - Actual space needed: sizeof(cookie) + sizeof(rand_buf[LoopCount]) - Result: Cookie and part of array written beyond buffer boundary - Consequence: Memory corruption, leading to invalid pointers in buffer objects SYMPTOM: In IPC.1v1 test, memcpy(buf, data, size) crashed because 'data' pointer (from buffer::data()) pointed to corrupted/invalid memory address. SOLUTION: Replace array placement new with individual element placement new: - Cast buffer to array pointer directly (no cookie needed) - Construct each element individually with placement new - Manually destroy each element in destructor This approach: - Eliminates cookie overhead - Provides precise control over object lifetime - Works consistently across all compilers Fixes crash in IPC.1v1 test case on MSVC.
…er names ISSUE: MSVC compiler reports warning C4138: '*/' found outside of comment for patterns like 'void */*p*/' where the pointer asterisk is immediately followed by a comment start. AFFECTED FILES: - include/libipc/mem/new.h (line 30) - src/libipc/platform/win/mutex.h (line 54) - src/libipc/platform/win/semaphore.h (line 53) CHANGES: Changed 'type */*param*/' to 'type * /*param*/' (added space before comment) Examples: - void */*p*/ → void * /*p*/ - char const */*name*/ → char const * /*name*/ This resolves the MSVC warning while maintaining code functionality and keeping the commented-out parameter names for documentation.
After rebasing onto master, test.h was moved to test/archive/. Updated include paths in test subdirectories: - test/imp/*.cpp: "test.h" -> "../archive/test.h" - test/mem/*.cpp: "test.h" -> "../archive/test.h" - test/concur/*.cpp: "test.h" -> "../archive/test.h" This ensures all test files can properly find the test header after the directory reorganization in master branch.
The acquire() function allocates id_info_t using mem::$new<id_info_t>(), so the release() function must use mem::$delete(ii) to deallocate it, not mem::free(ii). This ensures proper allocation/deallocation pairing. Issue: Memory allocated with mem::$new must be freed with mem::$delete to maintain consistent memory management semantics.
…ail.h Fixed two critical issues from the rebase: 1. Added LIBIPC_OS_FREEBSD macro definition in detect_plat.h to enable FreeBSD platform detection alongside other OS checks 2. Added missing #include "libipc/imp/detect_plat.h" in detail.h to properly include platform detection macros These fixes ensure FreeBSD compilation will work correctly with the unified platform detection system.
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Overview
This PR introduces a comprehensive memory management refactoring and fixes critical MSVC compilation issues, ensuring cross-platform compatibility.
Key Changes
🔧 Memory Management Refactoring (41 commits)
Core Memory System
mem::$newandmem::$deletewith proper pairing semanticsmemory_resourceandmonotonic_buffer_resourcefor flexible memory managementblock_poolfor fixed-size allocationscontainer_allocatorto follow C++ allocator requirements correctlylibipc/memory/→libipc/mem/for consistencyMemory Allocator Improvements
intrusive_stackfor lock-free data structures🐛 MSVC Compilation Fixes
Critical Fixes
container_allocator semantics (Commit 4338557): Fixed allocator to only allocate/deallocate memory, not construct/destroy objects
allocate()was incorrectly callingmem::$newwhich constructs objectsstd::_Tree_nodeon MSVC 2017uninitialized.h overload resolution (Commit 11973b9): Improved
construct()template overloadsArray placement new buffer overflow (Commit a83ba83): Fixed
data_setclass in testsC4138 warning (Commit 43b20b2): Fixed
*/*pattern in commented parametersvoid */*p*/→void * /*p*/to avoid warningshm_win.cpp memory pairing (Commit 636d84b): Fixed memory allocation/deallocation mismatch
acquire()usesmem::$new→release()must usemem::$delete, notmem::free🧪 Test Infrastructure Updates
test/imp/,test/mem/,test/concur/: Updated"test.h"→"../archive/test.h"🔧 Implementation Utilities
New Utilities (imp directory)
detect_plat.h: Unified platform detection with FreeBSD supportfmt: String formatting supportcodecvt: Character encoding conversionerror&log: Error handling and logging utilitiesresult: Result type for error handlingexpected: Expected type implementationnameof&scope_exit: Utility macrosCode Improvements
std::hashfmt🌐 Platform Support
LIBIPC_OS_FREEBSDmacroIPC_EXPORT→LIBIPC_EXPORT, platform-specific macros →LIBIPC_OS_*Testing
Platforms Tested
Test Cases
Migration Notes
Breaking Changes
mem::$new/$deletepairs instead ofmem::alloc/freewhere appropriatelibipc/memory/→libipc/mem/IPC_OS_*→LIBIPC_OS_*Upgrade Path
No API changes for library users. Internal refactoring only.
Related Issues
Checklist
Commits Summary
Total commits: 41
Key commit categories: