VFS: Use anonymousMemoryMap for large 7z allocations (fixes #3013)

CHANGES

@@ -47,6 +47,7 @@ Misc:
  - Qt: Handle multiple save game files for disparate games separately (fixes mgba.io/i/2887)
  - Qt: Remove maligned double-click-to-fullscreen shortcut (closes mgba.io/i/2632)
  - Scripting: Add `callbacks:oneshot` for single-call callbacks
+ - VFS: Use anonymousMemoryMap for large 7z allocations (fixes mgba.io/i/3013)
 
 0.10.2: (2023-04-23)
 Emulation fixes:

src/util/vfs/vfs-lzma.c

@@ -7,7 +7,9 @@
 
 #ifdef USE_LZMA
 
+#include <mgba-util/memory.h>
 #include <mgba-util/string.h>
+#include <mgba-util/table.h>
 
 #include "third-party/lzma/7z.h"
 #include "third-party/lzma/7zAlloc.h"
@@ -26,15 +28,19 @@ struct VDirEntry7z {
 	char* utf8;
 };
 
+struct VDir7zAlloc {
+	ISzAlloc d;
+	struct Table allocs;
+};
+
 struct VDir7z {
 	struct VDir d;
 	struct VDirEntry7z dirent;
 
-	// What is all this garbage?
 	CFileInStream archiveStream;
 	CLookToRead2 lookStream;
 	CSzArEx db;
-	ISzAlloc allocImp;
+	struct VDir7zAlloc allocImp;
 	ISzAlloc allocTempImp;
 };
 
@@ -70,6 +76,43 @@ static bool _vd7zDeleteFile(struct VDir* vd, const char* path);
 static const char* _vde7zName(struct VDirEntry* vde);
 static enum VFSType _vde7zType(struct VDirEntry* vde);
 
+static void* _vd7zAlloc(ISzAllocPtr p, size_t size) {
+	struct VDir7zAlloc* alloc = (struct VDir7zAlloc*) p;
+	void* address;
+	if (size >= 0x10000) {
+		address = anonymousMemoryMap(size);
+	} else {
+		address = malloc(size);
+	}
+	if (address) {
+		TableInsert(&alloc->allocs, (uintptr_t) address >> 2, (void*) size);
+	}
+	return address;
+}
+
+static void _vd7zFree(ISzAllocPtr p, void* address) {
+	struct VDir7zAlloc* alloc = (struct VDir7zAlloc*) p;
+	size_t size = (size_t) TableLookup(&alloc->allocs, (uintptr_t) address >> 2);
+	if (size) {
+		if (size >= 0x10000) {
+			mappedMemoryFree(address, size);
+		} else {
+			free(address);
+		}
+		TableRemove(&alloc->allocs, (uintptr_t) address >> 2);
+	}
+}
+
+static void* _vd7zAllocTemp(ISzAllocPtr p, size_t size) {
+	UNUSED(p);
+	return malloc(size);
+}
+
+static void _vd7zFreeTemp(ISzAllocPtr p, void* address) {
+	UNUSED(p);
+	free(address);
+}
+
 struct VDir* VDirOpen7z(const char* path, int flags) {
 	if (flags & O_WRONLY || flags & O_CREAT) {
 		return 0;
@@ -83,11 +126,12 @@ struct VDir* VDirOpen7z(const char* path, int flags) {
 		return 0;
 	}
 
-	vd->allocImp.Alloc = SzAlloc;
+	vd->allocImp.d.Alloc = _vd7zAlloc;
-	vd->allocImp.Free = SzFree;
+	vd->allocImp.d.Free = _vd7zFree;
+	TableInit(&vd->allocImp.allocs, 0, NULL);
 
-	vd->allocTempImp.Alloc = SzAllocTemp;
+	vd->allocTempImp.Alloc = _vd7zAllocTemp;
-	vd->allocTempImp.Free = SzFreeTemp;
+	vd->allocTempImp.Free = _vd7zFreeTemp;
 
 	FileInStream_CreateVTable(&vd->archiveStream);
 	LookToRead2_CreateVTable(&vd->lookStream, False);
@@ -101,11 +145,12 @@ struct VDir* VDirOpen7z(const char* path, int flags) {
 	CrcGenerateTable();
 
 	SzArEx_Init(&vd->db);
-	SRes res = SzArEx_Open(&vd->db, &vd->lookStream.vt, &vd->allocImp, &vd->allocTempImp);
+	SRes res = SzArEx_Open(&vd->db, &vd->lookStream.vt, &vd->allocImp.d, &vd->allocTempImp);
 	if (res != SZ_OK) {
-		SzArEx_Free(&vd->db, &vd->allocImp);
+		SzArEx_Free(&vd->db, &vd->allocImp.d);
 		File_Close(&vd->archiveStream.file);
 		free(vd->lookStream.buf);
+		TableDeinit(&vd->allocImp.allocs);
 		free(vd);
 		return 0;
 	}
@@ -128,7 +173,7 @@ struct VDir* VDirOpen7z(const char* path, int flags) {
 
 bool _vf7zClose(struct VFile* vf) {
 	struct VFile7z* vf7z = (struct VFile7z*) vf;
-	IAlloc_Free(&vf7z->vd->allocImp, vf7z->outBuffer);
+	IAlloc_Free(&vf7z->vd->allocImp.d, vf7z->outBuffer);
 	free(vf7z);
 	return true;
 }
@@ -215,12 +260,13 @@ ssize_t _vf7zSize(struct VFile* vf) {
 
 bool _vd7zClose(struct VDir* vd) {
 	struct VDir7z* vd7z = (struct VDir7z*) vd;
-	SzArEx_Free(&vd7z->db, &vd7z->allocImp);
+	SzArEx_Free(&vd7z->db, &vd7z->allocImp.d);
 	File_Close(&vd7z->archiveStream.file);
 
 	free(vd7z->lookStream.buf);
 	free(vd7z->dirent.utf8);
 	vd7z->dirent.utf8 = 0;
+	TableDeinit(&vd7z->allocImp.allocs);
 
 	free(vd7z);
 	return true;
@@ -292,7 +338,7 @@ struct VFile* _vd7zOpenFile(struct VDir* vd, const char* path, int mode) {
 	SRes res = SzArEx_Extract(&vd7z->db, &vd7z->lookStream.vt, i, &blockIndex,
 		&vf->outBuffer, &outBufferSize,
 		&vf->bufferOffset, &vf->size,
-		&vd7z->allocImp, &vd7z->allocTempImp);
+		&vd7z->allocImp.d, &vd7z->allocTempImp);
 
 	if (res != SZ_OK) {
 		free(vf);