From d8c119cc4fb1e717261a3f3a875ffeddf5528462 Mon Sep 17 00:00:00 2001
From: Daan Leijen <daan@microsoft.com>
Date: Sun, 9 Feb 2025 08:56:22 -0800
Subject: [PATCH] add mi_decl_maybe_unused; fix compilation with OPT_SIMD
 (issue #1009)

---
 ide/vs2022/mimalloc-lib.vcxproj          |  8 +++++++
 ide/vs2022/mimalloc-override-dll.vcxproj |  8 +++++++
 include/mimalloc/internal.h              | 27 ++++++++++++++++--------
 src/bitmap.c                             | 19 ++++++-----------
 4 files changed, 41 insertions(+), 21 deletions(-)

diff --git a/ide/vs2022/mimalloc-lib.vcxproj b/ide/vs2022/mimalloc-lib.vcxproj
index b0547769..035adf8d 100644
--- a/ide/vs2022/mimalloc-lib.vcxproj
+++ b/ide/vs2022/mimalloc-lib.vcxproj
@@ -178,6 +178,7 @@
       <CompileAs>CompileAsCpp</CompileAs>
       <SupportJustMyCode>false</SupportJustMyCode>
       <LanguageStandard>stdcpp20</LanguageStandard>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Lib>
       <AdditionalLibraryDirectories>
@@ -197,6 +198,7 @@
       <CompileAs>CompileAsCpp</CompileAs>
       <SupportJustMyCode>false</SupportJustMyCode>
       <LanguageStandard>stdcpp20</LanguageStandard>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <PostBuildEvent>
       <Command>
@@ -224,6 +226,7 @@
       <CompileAs>CompileAsCpp</CompileAs>
       <SupportJustMyCode>false</SupportJustMyCode>
       <LanguageStandard>stdcpp20</LanguageStandard>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <PostBuildEvent>
       <Command>
@@ -251,6 +254,7 @@
       <CompileAs>CompileAsCpp</CompileAs>
       <SupportJustMyCode>false</SupportJustMyCode>
       <LanguageStandard>stdcpp20</LanguageStandard>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <PostBuildEvent>
       <Command>
@@ -283,6 +287,7 @@
       <CompileAs>CompileAsCpp</CompileAs>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <LanguageStandard>stdcpp20</LanguageStandard>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
@@ -312,6 +317,7 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <EnableEnhancedInstructionSet>AdvancedVectorExtensions2</EnableEnhancedInstructionSet>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
@@ -348,6 +354,7 @@
       <LanguageStandard>stdcpp20</LanguageStandard>
       <EnableEnhancedInstructionSet>CPUExtensionRequirementsARMv81</EnableEnhancedInstructionSet>
       <ExceptionHandling>Sync</ExceptionHandling>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
@@ -384,6 +391,7 @@
       <LanguageStandard>stdcpp20</LanguageStandard>
       <EnableEnhancedInstructionSet>CPUExtensionRequirementsARMv81</EnableEnhancedInstructionSet>
       <ExceptionHandling>Sync</ExceptionHandling>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
diff --git a/ide/vs2022/mimalloc-override-dll.vcxproj b/ide/vs2022/mimalloc-override-dll.vcxproj
index be69716f..3c2ef98f 100644
--- a/ide/vs2022/mimalloc-override-dll.vcxproj
+++ b/ide/vs2022/mimalloc-override-dll.vcxproj
@@ -174,6 +174,7 @@
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <SupportJustMyCode>false</SupportJustMyCode>
       <CompileAs>CompileAsCpp</CompileAs>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <AdditionalDependencies>$(ProjectDir)\..\..\bin\mimalloc-redirect32.lib;%(AdditionalDependencies)</AdditionalDependencies>
@@ -204,6 +205,7 @@
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <SupportJustMyCode>false</SupportJustMyCode>
       <CompileAs>CompileAsCpp</CompileAs>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <AdditionalDependencies>$(ProjectDir)\..\..\bin\mimalloc-redirect.lib;%(AdditionalDependencies)</AdditionalDependencies>
@@ -234,6 +236,7 @@
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <SupportJustMyCode>false</SupportJustMyCode>
       <CompileAs>CompileAsCpp</CompileAs>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <AdditionalDependencies>$(ProjectDir)\..\..\bin\mimalloc-redirect-arm64.lib;%(AdditionalDependencies)</AdditionalDependencies>
@@ -264,6 +267,7 @@
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <SupportJustMyCode>false</SupportJustMyCode>
       <CompileAs>CompileAsCpp</CompileAs>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <AdditionalDependencies>$(ProjectDir)\..\..\bin\mimalloc-redirect-arm64ec.lib;%(AdditionalDependencies)</AdditionalDependencies>
@@ -298,6 +302,7 @@
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <CompileAs>CompileAsCpp</CompileAs>
       <BufferSecurityCheck>false</BufferSecurityCheck>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
@@ -332,6 +337,7 @@
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <CompileAs>CompileAsCpp</CompileAs>
       <BufferSecurityCheck>false</BufferSecurityCheck>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
@@ -367,6 +373,7 @@
       <CompileAs>CompileAsCpp</CompileAs>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <EnableEnhancedInstructionSet>CPUExtensionRequirementsARMv81</EnableEnhancedInstructionSet>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
@@ -402,6 +409,7 @@
       <CompileAs>CompileAsCpp</CompileAs>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <EnableEnhancedInstructionSet>CPUExtensionRequirementsARMv81</EnableEnhancedInstructionSet>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
diff --git a/include/mimalloc/internal.h b/include/mimalloc/internal.h
index 151c81a3..a76f7baf 100644
--- a/include/mimalloc/internal.h
+++ b/include/mimalloc/internal.h
@@ -18,11 +18,7 @@ terms of the MIT license. A copy of the license can be found in the file
 #include "track.h"
 #include "bits.h"
 
-#if (MI_DEBUG>0)
-#define mi_trace_message(...)  _mi_trace_message(__VA_ARGS__)
-#else
-#define mi_trace_message(...)
-#endif
+#define mi_decl_cache_align     mi_decl_align(64)
 
 #if defined(_MSC_VER)
 #pragma warning(disable:4127)   // suppress constant conditional warning (due to MI_SECURE paths)
@@ -52,19 +48,32 @@ terms of the MIT license. A copy of the license can be found in the file
 #define mi_decl_hidden
 #endif
 
-#define mi_decl_cache_align     mi_decl_align(64)
+#if (defined(__GNUC__) && (__GNUC__ >= 7)) || defined(__clang__) // includes clang and icc
+#define mi_decl_maybe_unused    __attribute__((unused))
+#elif __cplusplus >= 201703L    // c++17
+#define mi_decl_maybe_unused    [[maybe_unused]]
+#else 
+#define mi_decl_maybe_unused
+#endif
+
+#if defined(__cplusplus)
+#define mi_decl_externc         extern "C"
+#else
+#define mi_decl_externc
+#endif
 
 
 #if defined(__EMSCRIPTEN__) && !defined(__wasi__)
 #define __wasi__
 #endif
 
-#if defined(__cplusplus)
-#define mi_decl_externc       extern "C"
+#if (MI_DEBUG>0)
+#define mi_trace_message(...)  _mi_trace_message(__VA_ARGS__)
 #else
-#define mi_decl_externc
+#define mi_trace_message(...)
 #endif
 
+
 // "libc.c"
 #include <stdarg.h>
 int           _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args);
diff --git a/src/bitmap.c b/src/bitmap.c
index f3030153..6214980b 100644
--- a/src/bitmap.c
+++ b/src/bitmap.c
@@ -184,26 +184,23 @@ static inline bool mi_bfield_atomic_try_clear_mask(_Atomic(mi_bfield_t)* b, mi_b
   return mi_bfield_atomic_try_clear_mask_of(b, mask, expect, all_clear);
 }
 
-/*
 // Tries to clear a bit atomically. Returns `true` if the bit transitioned from 1 to 0
 // and `false` otherwise leaving the bfield `b` as-is.
 // `all_clear` is set to true if the new bfield became zero (and false otherwise)
-static inline bool mi_bfield_atomic_try_clear(_Atomic(mi_bfield_t)* b, size_t idx, bool* all_clear) {
+mi_decl_maybe_unused static inline bool mi_bfield_atomic_try_clear(_Atomic(mi_bfield_t)* b, size_t idx, bool* all_clear) {
   mi_assert_internal(idx < MI_BFIELD_BITS);
   const mi_bfield_t mask = mi_bfield_one()<<idx;
   return mi_bfield_atomic_try_clear_mask(b, mask, all_clear);
 }
 
-
 // Tries to clear a byte atomically, and returns true if the byte atomically transitioned from 0xFF to 0
 // `all_clear` is set to true if the new bfield became zero (and false otherwise)
-static inline bool mi_bfield_atomic_try_clear8(_Atomic(mi_bfield_t)*b, size_t idx, bool* all_clear) {
+mi_decl_maybe_unused static inline bool mi_bfield_atomic_try_clear8(_Atomic(mi_bfield_t)*b, size_t idx, bool* all_clear) {
   mi_assert_internal(idx < MI_BFIELD_BITS);
   mi_assert_internal((idx%8)==0);
   const mi_bfield_t mask = ((mi_bfield_t)0xFF)<<idx;
   return mi_bfield_atomic_try_clear_mask(b, mask, all_clear);
 }
-*/
 
 // Try to clear a full field of bits atomically, and return true all bits transitioned from all 1's to 0's.
 // and false otherwise leaving the bit field as-is.
@@ -526,16 +523,16 @@ static inline bool mi_bchunk_try_clearN(mi_bchunk_t* chunk, size_t cidx, size_t
 // ------- mi_bchunk_try_find_and_clear ---------------------------------------
 
 #if MI_OPT_SIMD && defined(__AVX2__)
-static inline __m256i mi_mm256_zero(void) {
+mi_decl_maybe_unused static inline __m256i mi_mm256_zero(void) {
   return _mm256_setzero_si256();
 }
-static inline __m256i mi_mm256_ones(void) {
+mi_decl_maybe_unused static inline __m256i mi_mm256_ones(void) {
   return _mm256_set1_epi64x(~0);
 }
-static inline bool mi_mm256_is_ones(__m256i vec) {
+mi_decl_maybe_unused static inline bool mi_mm256_is_ones(__m256i vec) {
   return _mm256_testc_si256(vec, _mm256_cmpeq_epi32(vec, vec));
 }
-static inline bool mi_mm256_is_zero( __m256i vec) {
+mi_decl_maybe_unused static inline bool mi_mm256_is_zero( __m256i vec) {
   return _mm256_testz_si256(vec,vec);
 }
 #endif
@@ -643,8 +640,7 @@ static inline bool mi_bchunk_try_find_and_clear_1(mi_bchunk_t* chunk, size_t n,
   return mi_bchunk_try_find_and_clear(chunk, pidx);
 }
 
-#if !(MI_OPT_SIMD && defined(__AVX2__) && (MI_BCHUNK_BITS==512))
-static inline bool mi_bchunk_try_find_and_clear8_at(mi_bchunk_t* chunk, size_t chunk_idx, size_t* pidx) {
+mi_decl_maybe_unused static inline bool mi_bchunk_try_find_and_clear8_at(mi_bchunk_t* chunk, size_t chunk_idx, size_t* pidx) {
   const mi_bfield_t b = mi_atomic_load_relaxed(&chunk->bfields[chunk_idx]);
   // has_set8 has low bit in each byte set if the byte in x == 0xFF
   const mi_bfield_t has_set8 =
@@ -663,7 +659,6 @@ static inline bool mi_bchunk_try_find_and_clear8_at(mi_bchunk_t* chunk, size_t c
   }
   return false;
 }
-#endif
 
 // find least aligned byte in a chunk with all bits set, and try unset it atomically
 // set `*pidx` to its bit index (0 <= *pidx < MI_BCHUNK_BITS) on success.