From 0d4f2ff9140fe08b89dcf473ace38ad3d709a1b1 Mon Sep 17 00:00:00 2001
From: Azat Khuzhin <a3at.mail@gmail.com>
Date: Wed, 18 May 2022 01:14:43 +0300
Subject: [PATCH] Relax aligned_alloc() restrictions

"Passing a size which is not an integral multiple of alignment" is too
strict, and lots of code relies on it, i.e.:

    (gdb) bt
    0  mi_aligned_alloc (alignment=8, size=44) at alloc-posix.c:88
    1  0x000000002dc55fdd in aligned_alloc (alignment=8, size=44) at alloc-override.c:251
    2  0x0000000017be85b6 in Memory::newImpl<std::align_val_t> (size=44, align=(unknown: 8)) at memory.h:47
    3  operator new (size=44, align=(unknown: 8)) at new_delete.cpp:60
    4  0x000000002ba66c5d in llvm::allocate_buffer(unsigned long, unsigned long) ()
    5  0x000000002898eba1 in llvm::MallocAllocator::Allocate(unsigned long, unsigned long) ()
    6  0x000000002b9e95ee in llvm::StringMapEntry<llvm::cl::Option*>* llvm::StringMapEntry<llvm::cl::Option*>::Create<llvm::MallocAllocator, llvm::cl::Option*>(llvm::StringRef, llvm::MallocAllocator&, llvm::cl::Option*&&) ()
    7  0x000000002b9e9428 in std::__1::pair<llvm::StringMapIterator<llvm::cl::Option*>, bool> llvm::StringMap<llvm::cl::Option*, llvm::MallocAllocator>::try_emplace<llvm::cl::Option*>(llvm::StringRef, llvm::cl::Option*&&) ()
    8  0x000000002b9e925f in llvm::StringMap<llvm::cl::Option*, llvm::MallocAllocator>::insert(std::__1::pair<llvm::StringRef, llvm::cl::Option*>) ()
    9  0x000000002b9dc689 in (anonymous namespace)::CommandLineParser::addOption(llvm::cl::Option*, llvm::cl::SubCommand*) ()
    10 0x000000002b9cf219 in (anonymous namespace)::CommandLineParser::addOption(llvm::cl::Option*, bool) ()
    11 0x000000002b9ce831 in llvm::cl::Option::addArgument() ()
---
 src/alloc-posix.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/alloc-posix.c b/src/alloc-posix.c
index 176e7ec3..43130c9a 100644
--- a/src/alloc-posix.c
+++ b/src/alloc-posix.c
@@ -83,7 +83,10 @@ mi_decl_nodiscard mi_decl_restrict void* mi_pvalloc(size_t size) mi_attr_noexcep
 }
 
 mi_decl_nodiscard mi_decl_restrict void* mi_aligned_alloc(size_t alignment, size_t size) mi_attr_noexcept {
-  if (mi_unlikely((size&(alignment-1)) != 0)) { // C11 requires alignment>0 && integral multiple, see <https://en.cppreference.com/w/c/memory/aligned_alloc>
+  // C11 requires alignment>0 && integral multiple, see <https://en.cppreference.com/w/c/memory/aligned_alloc>
+  // but "Passing a size which is not an integral multiple of alignment" it is too strict,
+  // and lots of code relies on this.
+  if (mi_unlikely(alignment==0 || !_mi_is_power_of_two(alignment))) {
     #if MI_DEBUG > 0
     _mi_error_message(EOVERFLOW, "(mi_)aligned_alloc requires the size to be an integral multiple of the alignment (size %zu, alignment %zu)\n", size, alignment);
     #endif