/src/wasm3/source/m3_env.c

Source
//
//  m3_env.c
//
//  Created by Steven Massey on 4/19/19.
//  Copyright © 2019 Steven Massey. All rights reserved.
//

#include <stdarg.h>
#include <limits.h>
#include <errno.h>
#include <float.h>
#include <ctype.h>

#include "m3_env.h"
#include "m3_compile.h"
#include "m3_exception.h"
#include "m3_info.h"


IM3Environment  m3_NewEnvironment  ()
{
    IM3Environment env = m3_AllocStruct (M3Environment);

    if (env)
    {
        _try
        {
            // create FuncTypes for all simple block return ValueTypes.
            // v128 is skipped: it parses as a slot but has no operations.
            for (u8 t = c_m3Type_none; t < c_m3Type_count; t++)
            {
                if (t == c_m3Type_v128)
                    continue;

                IM3FuncType ftype;
_               (AllocFuncType (& ftype, 1));

                ftype->numArgs = 0;
                ftype->numRets = (t == c_m3Type_none) ? 0 : 1;
                ftype->types [0] = t;

                Environment_AddFuncType (env, & ftype);

                env->retFuncTypes [t] = ftype;
            }
        }

        _catch:
        if (result)
        {
            m3_FreeEnvironment (env);
            env = NULL;
        }
    }

    return env;
}


void  Environment_Release  (IM3Environment i_environment)
{
    IM3FuncType ftype = i_environment->funcTypes;

    while (ftype)
    {
        IM3FuncType next = ftype->next;
        m3_Free (ftype);
        ftype = next;
    }

    m3log (runtime, "freeing %d pages from environment", CountCodePages (i_environment->pagesReleased));
    FreeCodePages (& i_environment->pagesReleased);
}


void  m3_FreeEnvironment  (IM3Environment i_environment)
{
    if (i_environment)
    {
        Environment_Release (i_environment);
        m3_Free (i_environment);
    }
}


void m3_SetCustomSectionHandler  (IM3Environment i_environment, M3SectionHandler i_handler)
{
    if (i_environment) i_environment->customSectionHandler = i_handler;
}


// returns the same io_funcType or replaces it with an equivalent that's already in the type linked list
M3Result  Environment_AddFuncType  (IM3Environment i_environment, IM3FuncType * io_funcType)
{
    IM3FuncType addType = * io_funcType;
    IM3FuncType newType = i_environment->funcTypes;

    while (newType)
    {
        if (AreFuncTypesEqual (newType, addType))
        {
            m3_Free (addType);
            break;
        }

        newType = newType->next;
    }

    if (newType == NULL)
    {
        // a type index has to fit in the heap type field of an m3type_t
        if (i_environment->numFuncTypes >= d_m3MaxSaneTypesCount)
        {
            m3_Free (addType);
            * io_funcType = NULL;
            return "too many distinct function types";
        }

        newType = addType;
        newType->canonicalIndex = i_environment->numFuncTypes++;
        newType->next = i_environment->funcTypes;
        i_environment->funcTypes = newType;
    }

    * io_funcType = newType;

    return m3Err_none;
}


IM3CodePage RemoveCodePageOfCapacity (M3CodePage ** io_list, u32 i_minimumLineCount)
{
    IM3CodePage prev = NULL;
    IM3CodePage page = * io_list;

    while (page)
    {
        if (NumFreeLines (page) >= i_minimumLineCount)
        {                                                           d_m3Assert (page->info.usageCount == 0);
            IM3CodePage next = page->info.next;
            if (prev)
                prev->info.next = next; // mid-list
            else
                * io_list = next;       // front of list

            break;
        }

        prev = page;
        page = page->info.next;
    }

    return page;
}


IM3CodePage  Environment_AcquireCodePage (IM3Environment i_environment, u32 i_minimumLineCount)
{
    return RemoveCodePageOfCapacity (& i_environment->pagesReleased, i_minimumLineCount);
}


void  Environment_ReleaseCodePages  (IM3Environment i_environment, IM3CodePage i_codePageList)
{
    IM3CodePage end = i_codePageList;

    while (end)
    {
        end->info.lineIndex = 0; // reset page
#if d_m3RecordBacktraces
        end->info.mapping->size = 0;
#endif // d_m3RecordBacktraces

        IM3CodePage next = end->info.next;
        if (not next)
            break;

        end = next;
    }

    if (end)
    {
        // push list to front
        end->info.next = i_environment->pagesReleased;
        i_environment->pagesReleased = i_codePageList;
    }
}


IM3Runtime  m3_NewRuntime  (IM3Environment i_environment, u32 i_stackSizeInBytes, void * i_userdata)
{
    IM3Runtime runtime = m3_AllocStruct (M3Runtime);

    if (runtime)
    {
        m3_ResetErrorInfo(runtime);

        runtime->environment = i_environment;
        runtime->userdata = i_userdata;

        runtime->originStack = m3_Malloc ("Wasm Stack", i_stackSizeInBytes + 4*sizeof (m3slot_t)); // TODO: more precise stack checks

        if (runtime->originStack)
        {
            runtime->stack = runtime->originStack;
            runtime->numStackSlots = i_stackSizeInBytes / sizeof (m3slot_t);         m3log (runtime, "new stack: %p, slots: %u", runtime->originStack, runtime->numStackSlots);
        }
        else m3_Free (runtime);
    }

    return runtime;
}

void *  m3_GetUserData  (IM3Runtime i_runtime)
{
    return i_runtime ? i_runtime->userdata : NULL;
}


void *  ForEachModule  (IM3Runtime i_runtime, ModuleVisitor i_visitor, void * i_info)
{
    void * r = NULL;

    IM3Module module = i_runtime->modules;

    while (module)
    {
        IM3Module next = module->next;
        r = i_visitor (module, i_info);
        if (r)
            break;

        module = next;
    }

    return r;
}


void *  _FreeModule  (IM3Module i_module, void * i_info)
{
    m3_FreeModule (i_module);
    return NULL;
}


void  Runtime_Release  (IM3Runtime i_runtime)
{
    ForEachModule (i_runtime, _FreeModule, NULL);                   d_m3Assert (i_runtime->numActiveCodePages == 0);

    Environment_ReleaseCodePages (i_runtime->environment, i_runtime->pagesOpen);
    Environment_ReleaseCodePages (i_runtime->environment, i_runtime->pagesFull);

    m3_Free (i_runtime->originStack);
}


void  m3_FreeRuntime  (IM3Runtime i_runtime)
{
    if (i_runtime)
    {
        m3_PrintProfilerInfo ();

        Runtime_Release (i_runtime);
        m3_Free (i_runtime);
    }
}

M3Result  EvaluateExpression  (IM3Module i_module, void * o_expressed, m3type_t i_type, bytes_t * io_bytes, cbytes_t i_end)
{
    M3Result result = m3Err_none;

    // OPTZ: use a simplified interpreter for expressions

    // create a temporary runtime context
#if defined(d_m3PreferStaticAlloc)
    static M3Runtime runtime;
#else
    M3Runtime runtime;
#endif
    M3_INIT (runtime);

    runtime.environment = i_module->runtime->environment;
    runtime.numStackSlots = i_module->runtime->numStackSlots;
    runtime.stack = i_module->runtime->stack;

    m3stack_t stack = (m3stack_t)runtime.stack;

    IM3Runtime savedRuntime = i_module->runtime;
    i_module->runtime = & runtime;

    IM3Compilation o = & runtime.compilation;
    o->runtime = & runtime;
    o->module =  i_module;
    o->wasm =    * io_bytes;
    o->wasmEnd = i_end;
    o->lastOpcodeStart = o->wasm;

    //  OPTZ: this code page could be erased after use.  maybe have 'empty' list in addition to full and open?
    o->page = AcquireCodePage (& runtime);  // AcquireUnusedCodePage (...)

    if (o->page)
    {
        IM3FuncType ftype = runtime.environment->retFuncTypes[BaseTypeOf(i_type)];

        pc_t m3code = GetPagePC (o->page);
        result = CompileExpression (o, ftype);

        if (not result && o->maxStackSlots >= runtime.numStackSlots) {
            result = m3Err_trapStackOverflow;
        }

        if (not result)
        {
# if (d_m3EnableOpProfiling || d_m3EnableOpTracing)
            m3ret_t r = RunCode (m3code, stack, NULL, d_m3OpDefaultArgs, d_m3BaseCstr);
# else
            m3ret_t r = RunCode (m3code, stack, NULL, d_m3OpDefaultArgs);
# endif
            
            if (r == 0)
            {                                                                               m3log (runtime, "expression result: %s", SPrintValue (stack, i_type));
                if (SizeOfType (BaseTypeOf(i_type)) == sizeof (u32))
                {
                    * (u32 *) o_expressed = * ((u32 *) stack);
                }
                else
                {
                    * (u64 *) o_expressed = * ((u64 *) stack);
                }
            }
        }

        // TODO: EraseCodePage (...) see OPTZ above
        ReleaseCodePage (& runtime, o->page);
    }
    else result = m3Err_mallocFailedCodePage;

    runtime.originStack = NULL;        // prevent free(stack) in ReleaseRuntime
    Runtime_Release (& runtime);
    i_module->runtime = savedRuntime;

    * io_bytes = o->wasm;

    return result;
}


//---------------------------------------------------------------------------------------------------------------------------------
//  Linking a module's imports against the exports of the modules already loaded
//  into the same runtime, matched on the name a module was registered under.
//
//  This is best-effort: an import nothing satisfies is left alone rather than
//  rejected, because a host function may still be bound to it after the module
//  is loaded (m3_LinkRawFunction needs the runtime, so it cannot run earlier),
//  and because an unsatisfiable memory or global still has to be backed by
//  something for the module to be loadable at all.
//---------------------------------------------------------------------------------------------------------------------------------

// Whether an exporting memory or table satisfies what an import asks for. The
// exporter's *current* size is its minimum - one that has been grown satisfies
// a larger import than its declaration would - and it may be no less bounded.
static
bool  LimitsSatisfy  (u64 i_exportedSize, bool i_exportedHasMax, u64 i_exportedMax,
                      u64 i_importMin,    bool i_importHasMax,   u64 i_importMax)
{
    if (i_exportedSize < i_importMin)
        return false;

    if (i_importHasMax and (not i_exportedHasMax or i_exportedMax > i_importMax))
        return false;

    return true;
}


static
IM3Function  Module_FindExportedFunction  (IM3Module i_module, cstr_t i_name)
{
    for (u32 i = 0; i < i_module->numFunctions; ++i)
    {
        IM3Function f = & i_module->functions [i];

        if (f->export_name and strcmp (f->export_name, i_name) == 0)
        {
            // A module that re-exports an import names the placeholder here.
            // Resolve to the function that actually runs, or a host-side call
            // would run it against the importing module's memory.
            return Function_Implementation (f);
        }
    }

    return NULL;
}


static
IM3Memory  Module_FindExportedMemory  (IM3Module i_module, cstr_t i_name)
{
    for (u32 i = 0; i < i_module->numMemories; ++i)
    {
        IM3Memory memory = i_module->memories [i];

        if (memory->exportName and strcmp (memory->exportName, i_name) == 0)
            return memory;
    }

    return NULL;
}


static
IM3Table  Module_FindExportedTable  (IM3Module i_module, cstr_t i_name)
{
    for (u32 i = 0; i < i_module->numTables; ++i)
    {
        IM3Table table = i_module->tables [i];

        if (table->exportName and strcmp (table->exportName, i_name) == 0)
            return table;
    }

    return NULL;
}


static
IM3Global  Module_FindExportedGlobal  (IM3Module i_module, cstr_t i_name)
{
    for (u32 i = 0; i < i_module->numGlobals; ++i)
    {
        IM3Global g = & i_module->globals [i];

        if (g->name and strcmp (g->name, i_name) == 0)
            return g;
    }

    return NULL;
}


// Whether the module exports anything at all under this name. Export names are
// unique within a module, so a name one of the lookups above missed but this
// one finds is exported as something else - a kind the import cannot be
// satisfied by, rather than a name the module never exported.
static
bool  Module_HasExport  (IM3Module i_module, cstr_t i_name)
{
    for (u32 i = 0; i < i_module->numFunctions; ++i)
    {
        IM3Function f = & i_module->functions [i];

        if (f->export_name and strcmp (f->export_name, i_name) == 0)
            return true;
    }

    for (u32 i = 0; i < i_module->numMemories; ++i)
    {
        IM3Memory memory = i_module->memories [i];

        if (memory->exportName and strcmp (memory->exportName, i_name) == 0)
            return true;
    }

    for (u32 i = 0; i < i_module->numTables; ++i)
    {
        IM3Table table = i_module->tables [i];

        if (table->exportName and strcmp (table->exportName, i_name) == 0)
            return true;
    }

    for (u32 i = 0; i < i_module->numGlobals; ++i)
    {
        IM3Global g = & i_module->globals [i];

        if (g->name and strcmp (g->name, i_name) == 0)
            return true;
    }

#if d_m3HasExceptionHandling
    for (u32 i = 0; i < i_module->numTags; ++i)
    {
        IM3Tag tag = & i_module->tags [i];

        if (tag->name and strcmp (tag->name, i_name) == 0)
            return true;
    }
#endif

    return false;
}


// Points each of the module's imports at whatever already-loaded module exports
// it. Runs before anything is allocated or initialized: a memory import has to
// be resolved before InitMemory would give it pages of its own, and a global
// import before InitGlobals runs an initializer that reads it.
static
M3Result  LinkImports  (IM3Runtime io_runtime, IM3Module io_module)
{
    M3Result result = m3Err_none;

    for (u32 i = 0; i < io_module->numFunctions; ++i)
    {
        IM3Function f = & io_module->functions [i];

        if (f->wasm or not (f->import.moduleUtf8 and f->import.fieldUtf8))
            continue;

        IM3Module from = m3_FindModule (io_runtime, f->import.moduleUtf8);
        if (not from)
            continue;

        IM3Function exported = Module_FindExportedFunction (from, f->import.fieldUtf8);
        if (not exported)
        {
            // the import names a module that is loaded, so its exports settle the
            // question: a name it exports as something else is a type mismatch, and
            // one it does not export at all is an unknown import
            _throwif (m3Err_incompatibleImportType, Module_HasExport (from, f->import.fieldUtf8));
            _throw (m3Err_unknownImport);
        }

        // func types are canonical within an environment, so this is the
        // structural equivalence the spec asks for
        _throwif (m3Err_incompatibleImportType, exported->funcType != f->funcType);

        f->resolved = Function_Implementation (exported);
    }

    for (u32 i = 0; i < io_module->numMemories; ++i)
    {
        IM3Memory memory = io_module->memories [i];

        if (not memory->imported or memory->owner != io_module)
            continue;

        IM3Module from = m3_FindModule (io_runtime, memory->import.moduleUtf8);
        if (not from)
            continue;

        IM3Memory exported = Module_FindExportedMemory (from, memory->import.fieldUtf8);
        if (not exported)
        {
            _throwif (m3Err_incompatibleImportType, Module_HasExport (from, memory->import.fieldUtf8));
            _throw (m3Err_unknownImport);
        }

        // the address type is part of the memory type, so an i64 memory does
        // not satisfy an i32 import, or the other way round - and so is the page
        // size, which custom page sizes made a declared property of a memory
        _throwif (m3Err_incompatibleImportType, exported->isMemory64 != memory->isMemory64);
        _throwif (m3Err_incompatibleImportType, Memory_PageSize (exported) != Memory_PageSize (memory));

        _throwif (m3Err_incompatibleImportType,
                  not LimitsSatisfy (exported->numPages, exported->hasMax, exported->maxPages,
                                     memory->initPages,  memory->hasMax,   memory->maxPages));

        // hand the slot over to the exporter's memory, and drop the placeholder
        m3_Free (memory->mallocated);
        m3_Free (memory->exportName);
        FreeImportInfo (& memory->import);
        m3_Free (memory);

        io_module->memories [i] = exported;
    }

    for (u32 i = 0; i < io_module->numTables; ++i)
    {
        IM3Table table = io_module->tables [i];

        if (not table->imported or table->owner != io_module)
            continue;

        IM3Module from = m3_FindModule (io_runtime, table->import.moduleUtf8);
        if (not from)
            continue;

        IM3Table exported = Module_FindExportedTable (from, table->import.fieldUtf8);
        if (not exported)
        {
            _throwif (m3Err_incompatibleImportType, Module_HasExport (from, table->import.fieldUtf8));
            _throw (m3Err_unknownImport);
        }

        _throwif (m3Err_incompatibleImportType, exported->type != table->type);

        // the index type is part of the table type, the same way it is for a memory
        _throwif (m3Err_incompatibleImportType, exported->isTable64 != table->isTable64);

        _throwif (m3Err_incompatibleImportType,
                  not LimitsSatisfy (exported->size,    exported->hasMax, exported->maxSize,
                                     table->initSize,   table->hasMax,    table->maxSize));

        // hand the slot over to the exporter's table, and drop the placeholder
        m3_Free (table->elements);
        m3_Free (table->exportName);
        FreeImportInfo (& table->import);
        m3_Free (table);

        io_module->tables [i] = exported;
    }

    for (u32 i = 0; i < io_module->numGlobals; ++i)
    {
        IM3Global g = & io_module->globals [i];

        if (not g->imported or not (g->import.moduleUtf8 and g->import.fieldUtf8))
            continue;

        IM3Module from = m3_FindModule (io_runtime, g->import.moduleUtf8);
        if (not from)
            continue;

        IM3Global exported = Module_FindExportedGlobal (from, g->import.fieldUtf8);
        if (not exported)
        {
            _throwif (m3Err_incompatibleImportType, Module_HasExport (from, g->import.fieldUtf8));
            _throw (m3Err_unknownImport);
        }

        _throwif (m3Err_incompatibleImportType, exported->type != g->type);
        _throwif (m3Err_incompatibleImportType, exported->isMutable != g->isMutable);

        g->resolved = exported->resolved ? exported->resolved : exported;
    }

    _catch: return result;
}


// Backs each of the module's memories with pages. LinkImports has already
// pointed any import it could satisfy at the exporting module's memory, and
// those are skipped here. An import nothing satisfied is still backed locally
// from its own declared limits, so that the module remains loadable.
M3Result  InitMemory  (IM3Runtime io_runtime, IM3Module i_module)
{
    M3Result result = m3Err_none;

    // Fixed from here on: the index space stops changing after parse, and
    // linking has already repointed any slot it was going to.
    i_module->memory0 = i_module->numMemories ? i_module->memories [0]
                                              : & i_module->emptyMemory;

    if (i_module->numMemories == 0)
    {
        // nothing addressable, but _mem still has to point somewhere
        i_module->emptyMemory.owner    = i_module;
        i_module->emptyMemory.pageSize = d_m3DefaultMemPageSize;

_       (ResizeMemory (io_runtime, & i_module->emptyMemory, 0));
    }

    for (u32 i = 0; i < i_module->numMemories; ++i)
    {
        IM3Memory memory = i_module->memories [i];

        // a slot that already points at another module's memory is that
        // module's to allocate
        if (memory->owner != i_module or memory->mallocated)
            continue;

        u32 pageSize = Memory_PageSize (memory);

        memory->pageSize = pageSize;

        // Without a declared maximum a memory may grow to the spec limit of
        // 2^|addrtype|/pagesize pages, which is the usual 65536 at the default
        // page size, 2^48 for a 64-bit memory, and a whole address space of
        // them when a page is a single byte. A declared maximum of zero is a
        // real limit, not the absence of one.
        //
        // 2^64/pagesize overflows a u64 only when a page is a single byte, and
        // a power-of-two page size divides the address space exactly, so the
        // 64-bit division below is 2^64/pagesize written so that it fits.
        if (not memory->hasMax)
            memory->maxPages = memory->isMemory64
                                 ? (pageSize > 1 ? (UINT64_MAX / pageSize) + 1 : UINT64_MAX)
                                 : (0x100000000ull / pageSize);

_       (ResizeMemory (io_runtime, memory, memory->initPages));
    }

    _catch: return result;
}


M3Result  ResizeMemory  (IM3Runtime io_runtime, IM3Memory memory, u64 i_numPages)
{
    M3Result result = m3Err_none;

    u64 numPagesToAlloc = i_numPages;

    if (numPagesToAlloc <= memory->maxPages)
    {
        // A 64-bit memory may ask for up to 2^48 pages, which overflows a u64
        // of bytes. Nothing that large can be backed, so refuse it up front
        // rather than multiplying into a wrapped size.
        _throwif ("linear memory limitation exceeded",
                  numPagesToAlloc > d_m3AddressLimit / memory->pageSize);

        u64 numPageBytes = numPagesToAlloc * memory->pageSize;

#if d_m3MaxLinearMemoryPages > 0
        // the limit is a memory size, counted in default-sized pages; comparing
        // it against a raw page count would make it 65536 times stricter for a
        // module whose pages are one byte
        _throwif("linear memory limitation exceeded",
                 numPageBytes > (u64) d_m3MaxLinearMemoryPages * d_m3DefaultMemPageSize);
#endif

        // Limit the amount of memory that gets actually allocated
        if (io_runtime->memoryLimit) {
            numPageBytes = M3_MIN (numPageBytes, (u64) io_runtime->memoryLimit);
        }

        _throwif("linear memory limitation exceeded", numPageBytes > (u64) SIZE_MAX - sizeof (M3MemoryHeader));

        size_t numBytes = (size_t) numPageBytes + sizeof (M3MemoryHeader);

        size_t numPreviousBytes = (size_t) memory->numPages * memory->pageSize;
        if (numPreviousBytes)
            numPreviousBytes += sizeof (M3MemoryHeader);

        void* newMem = m3_Realloc ("Wasm Linear Memory", memory->mallocated, numBytes, numPreviousBytes);
        _throwifnull(newMem);

        memory->mallocated = (M3MemoryHeader*)newMem;

# if d_m3LogRuntime
        M3MemoryHeader * oldMallocated = memory->mallocated;
# endif

        memory->numPages = numPagesToAlloc;

        memory->mallocated->length =  numPageBytes;
        memory->mallocated->runtime = io_runtime;
        memory->mallocated->memory  = memory;

        memory->mallocated->maxStack = (m3slot_t *) io_runtime->stack + io_runtime->numStackSlots;

        m3log (runtime, "resized old: %p; mem: %p; length: %zu; pages: %llu", oldMallocated, memory->mallocated, memory->mallocated->length, (unsigned long long) memory->numPages);
    }
    else result = m3Err_wasmMemoryOverflow;

    _catch: return result;
}


M3Result  InitGlobals  (IM3Module io_module)
{
    M3Result result = m3Err_none;

    if (io_module->numGlobals)
    {
        // placing the globals in their structs isn't good for cache locality, but i don't really know what the global
        // access patterns typically look like yet.

        //          io_module->globalMemory = m3Alloc (m3reg_t, io_module->numGlobals);

        //          if (io_module->globalMemory)
        {
            for (u32 i = 0; i < io_module->numGlobals; ++i)
            {
                M3Global * g = & io_module->globals [i];                        m3log (runtime, "initializing global: %d", i);

                if (g->initExpr)
                {
                    bytes_t start = g->initExpr;

                    result = EvaluateExpression (io_module, & g->i64Value, g->type, & start, g->initExpr + g->initExprSize);

                    if (not result)
                    {
                        // io_module->globalMemory [i] = initValue;
                    }
                    else break;
                }
                else
                {                                                               m3log (runtime, "importing global");

                }
            }
        }
        //          else result = ErrorModule (m3Err_mallocFailed, io_module, "could allocate globals for module: '%s", io_module->name);
    }

    return result;
}


M3Result  InitDataSegments  (IM3Module io_module)
{
    M3Result result = m3Err_none;

    for (u32 i = 0; i < io_module->numDataSegments; ++i)
    {
        M3DataSegment * segment = & io_module->dataSegments [i];

        // A passive segment stays available for memory.init until data.drop.
        // An active one is copied here and then counts as dropped.
        if (segment->isPassive)
            continue;

        _throwif ("data segment memory index out of range",
                  segment->memoryRegion >= io_module->numMemories);

        IM3Memory io_memory = io_module->memories [segment->memoryRegion];

        _throwif ("unallocated linear memory", !(io_memory->mallocated));

        // The offset expression has the memory's address type, and is
        // unsigned: an i32 offset of -1 is 4294967295, way out of bounds
        // rather than negative.
        u64 segmentOffset = 0;
        bytes_t start = segment->initExpr;

        if (io_memory->isMemory64)
        {
_           (EvaluateExpression (io_module, & segmentOffset, c_m3Type_i64, & start, segment->initExpr + segment->initExprSize));
        }
        else
        {
            u32 offset32;
_           (EvaluateExpression (io_module, & offset32, c_m3Type_i32, & start, segment->initExpr + segment->initExprSize));
            segmentOffset = offset32;
        }

        m3log (runtime, "loading data segment: %d; size: %d; offset: %llu", i, segment->size, (unsigned long long) segmentOffset);

        if (segmentOffset <= io_memory->mallocated->length &&
            (u64) segment->size <= io_memory->mallocated->length - segmentOffset)
        {
            u8 * dest = m3MemData (io_memory->mallocated) + segmentOffset;
            memcpy (dest, segment->data, segment->size);
        } else {
            _throw ("data segment out of bounds");
        }

        segment->dropped = true;
    }

    _catch: return result;
}


// Turns a segment's elements into references. Element expressions are constant
// expressions restricted to ref.null/ref.func, so they're read directly rather
// than run through the compiler.
static
M3Result  ResolveElements  (IM3Module io_module, M3ElementSegment * i_segment, void ** o_elements)
{
    M3Result result = m3Err_none;

    bytes_t pos = i_segment->elements;
    cbytes_t end = io_module->elementSectionEnd;

    for (u32 e = 0; e < i_segment->numElements; ++e)
    {
        u32 funcIndex;
        void * ref = NULL;

        if (i_segment->isExpr)
        {
            m3opcode_t opcode;
_           (Read_opcode (& opcode, & pos, end));

            if (opcode == c_waOp_refFunc)
            {
_               (ReadLEB_u32 (& funcIndex, & pos, end));
                _throwif ("function index out of range", funcIndex >= io_module->numFunctions);
                ref = Function_Implementation (& io_module->functions [funcIndex]);
            }
            else if (opcode == c_waOp_refNull)
            {
                i8 waType;
                u8 nullType;
_               (ReadLEB_i7 (& waType, & pos, end));
_               (NormalizeType (& nullType, waType));
                _throwif (m3Err_typeMismatch, nullType != i_segment->type);
            }
            else if (opcode == c_waOp_getGlobal)
            {
                // wasm 2.0 lets an element expression read an imported
                // immutable global, which is how one module seeds another's
                // table with a reference it exported.
                u32 globalIndex;
_               (ReadLEB_u32 (& globalIndex, & pos, end));
                _throwif (m3Err_globaIndexOutOfBounds, globalIndex >= io_module->numGlobals);

                IM3Global global = & io_module->globals [globalIndex];

                _throwif (m3Err_globaIndexOutOfBounds, not global->imported);
                _throwif (m3Err_wasmMalformed, global->isMutable);
                _throwif (m3Err_typeMismatch, BaseTypeOf (global->type) != BaseTypeOf (i_segment->type));

                // read the cell the import was linked to, not the placeholder
                if (global->resolved)
                    global = global->resolved;

                ref = global->refValue;
            }
            else _throw ("constant expression required");

_           (Read_opcode (& opcode, & pos, end));
            _throwif (m3Err_wasmMalformed, opcode != c_waOp_end);
        }
        else
        {
_           (ReadLEB_u32 (& funcIndex, & pos, end));
            _throwif ("function index out of range", funcIndex >= io_module->numFunctions);
            ref = Function_Implementation (& io_module->functions [funcIndex]);
        }

        o_elements [e] = ref;
    }

    _catch: return result;
}


M3Result  InitTableAndElements  (IM3Module io_module)
{
    M3Result result = m3Err_none;

    cbytes_t end = io_module->elementSectionEnd;
    M3Table * table;

    for (u32 i = 0; i < io_module->numTables; ++i)
    {
        table = io_module->tables [i];

        // a slot pointing at another module's table is that module's to fill
        if (table->owner != io_module)
            continue;

        if (table->size)
        {
            table->elements = m3_AllocArray (void *, table->size);
            _throwifnull (table->elements);

            if (table->initExpr)
            {
                void * value = NULL;
                bytes_t start = table->initExpr;
_               (EvaluateExpression (io_module, & value, BaseTypeOf(table->type),
                                     & start, table->initExpr + table->initExprSize));

                for (u32 e = 0; e < table->size; ++e)
                    table->elements [e] = value;
            }
        }
    }

    for (u32 i = 0; i < io_module->numElementSegments; ++i)
    {
        M3ElementSegment * segment = & io_module->elementSegments [i];

        // Declarative segments only make their functions referenceable, and
        // passive ones wait for table.init, so neither is written out here.
        if (segment->mode == c_m3Elem_declarative)
        {
            segment->dropped = true;
            continue;
        }

        if (segment->mode == c_m3Elem_passive)
        {
            if (segment->numElements)
            {
                segment->resolved = m3_AllocArray (void *, segment->numElements);
                _throwifnull (segment->resolved);
_               (ResolveElements (io_module, segment, segment->resolved));
            }
            continue;
        }

        table = io_module->tables [segment->tableIndex];

        // The offset expression has the table's index type, and is unsigned:
        // an i32 offset of -1 is 4294967295, out of bounds rather than negative.
        u64 offset = 0;
        bytes_t expr = segment->initExpr;

        if (table->isTable64)
        {
_           (EvaluateExpression (io_module, & offset, c_m3Type_i64, & expr, end));
        }
        else
        {
            u32 offset32;
_           (EvaluateExpression (io_module, & offset32, c_m3Type_i32, & expr, end));
            offset = offset32;
        }

        _throwif ("out of bounds table access",
                  offset > table->size or segment->numElements > table->size - offset);

_       (ResolveElements (io_module, segment, table->elements + offset));

        segment->dropped = true;
    }

    _catch: return result;
}

M3Result  m3_CompileModule  (IM3Module io_module)
{
    M3Result result = m3Err_none;

    for (u32 i = 0; i < io_module->numFunctions; ++i)
    {
        IM3Function f = & io_module->functions [i];
        if (f->wasm and not f->compiled)
        {
_           (CompileFunction (f));
        }
    }

    _catch: return result;
}

#if d_m3HasExceptionHandling

M3Exception *  NewException  (IM3Runtime io_runtime, IM3Tag i_tag, u32 i_numArgs)
{
    M3Exception * exception = (M3Exception *) m3_Malloc ("M3Exception", sizeof (M3Exception) + i_numArgs * sizeof (u64));

    if (exception)
    {
        exception->tag      = i_tag;
        exception->numArgs  = i_numArgs;
        exception->reified  = false;
        exception->prev     = NULL;
        exception->next     = io_runtime->exceptions;

        if (exception->next)
            exception->next->prev = exception;

        io_runtime->exceptions = exception;
    }

    return exception;
}


// Releases one exception ahead of the rest. The caller has to know nothing can
// still name it: no exnref was ever taken of it, and its payload has already
// been copied out.
void  FreeException  (IM3Runtime io_runtime, M3Exception * i_exception)
{
    if (i_exception->prev)
        i_exception->prev->next = i_exception->next;
    else
        io_runtime->exceptions = i_exception->next;

    if (i_exception->next)
        i_exception->next->prev = i_exception->prev;

    if (io_runtime->pendingException == i_exception)
        io_runtime->pendingException = NULL;

    m3_Free_Impl (i_exception);
}


// Releases every exception the runtime still holds. Only safe once the Wasm
// stack is empty, which is why the outermost RunCodeChecked() is the one that
// calls it.
void  FreeExceptions  (IM3Runtime io_runtime)
{
    M3Exception * exception = io_runtime->exceptions;

    io_runtime->exceptions = NULL;
    io_runtime->pendingException = NULL;

    while (exception)
    {
        M3Exception * next = exception->next;
        m3_Free_Impl (exception);
        exception = next;
    }
}

#endif // d_m3HasExceptionHandling


// Run compiled code on the runtime's stack, bounding native recursion for the
// duration of the call. The outermost invocation establishes the stack limit;
// nested ones (an imported function calling back into Wasm) inherit it.
static inline
M3Result  RunCodeChecked  (IM3Runtime i_runtime, IM3Function i_function)
{
    pc_t i_pc = i_function->compiled;

    // execution runs against the memory of the module the entry point belongs
    // to, not against some runtime-wide one
    M3MemoryHeader * _mem = Module_MemoryHeader (i_function->module);

    d_m3StackLimitEnter (i_runtime);
#if d_m3HasExceptionHandling
    // handler stacks don't nest across a call boundary: a host function calling
    // back into Wasm cannot be caught by a try_table its own caller entered
    u32 savedTryDepth = i_runtime->tryDepth;
    i_runtime->tryDepth = 0;
    i_runtime->exceptionNesting++;
#endif
# if (d_m3EnableOpProfiling || d_m3EnableOpTracing)
    M3Result result = (M3Result) RunCode (i_pc, (m3stack_t) i_runtime->stack, _mem, d_m3OpDefaultArgs, d_m3BaseCstr);
# else
    M3Result result = (M3Result) RunCode (i_pc, (m3stack_t) i_runtime->stack, _mem, d_m3OpDefaultArgs);
# endif
#if d_m3HasExceptionHandling
    i_runtime->tryDepth = savedTryDepth;

    // an exception that reached the bottom of the call stack found no handler
    if (M3_UNLIKELY (result == m3Err_pendingException))
        result = m3Err_trapUncaughtException;

    if (--i_runtime->exceptionNesting == 0)
        FreeExceptions (i_runtime);
#endif
    d_m3StackLimitLeave (i_runtime);

    return result;
}

M3Result  m3_RunStart  (IM3Module io_module)
{
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    // Execution disabled for fuzzing builds
    return m3Err_none;
#endif

    M3Result result = m3Err_none;
    i32 startFunctionTmp = -1;

    if (io_module and io_module->startFunction >= 0)
    {
        IM3Function function = & io_module->functions [io_module->startFunction];

        if (not function->compiled)
        {
_           (CompileFunction (function));
        }

        IM3FuncType ftype = function->funcType;
        if (ftype->numArgs != 0 || ftype->numRets != 0)
            _throw (m3Err_argumentCountMismatch);

        IM3Module module = function->module;
        IM3Runtime runtime = module->runtime;

        startFunctionTmp = io_module->startFunction;
        io_module->startFunction = -1;

        result = RunCodeChecked (runtime, function);

        if (result)
        {
            io_module->startFunction = startFunctionTmp;
            EXCEPTION_PRINT(result);
            goto _catch;
        }
    }

    _catch: return result;
}

// TODO: deal with main + side-modules loading efforcement
M3Result  m3_LoadModule  (IM3Runtime io_runtime, IM3Module io_module)
{
    M3Result result = m3Err_none;

    if (M3_UNLIKELY(io_module->runtime)) {
        return m3Err_moduleAlreadyLinked;
    }

    io_module->runtime = io_runtime;

    // linking first: a memory import has to be resolved before InitMemory would
    // give it pages of its own, and a global import before an initializer reads it
_   (LinkImports (io_runtime, io_module));

_   (InitMemory (io_runtime, io_module));
_   (InitGlobals (io_module));
    // Spec order: element segments are applied before data segments. It matters
    // when one of them traps - whatever ran before the trap stays done.
_   (InitTableAndElements (io_module));
_   (InitDataSegments (io_module));

    // Start func might use imported functions, which are not liked here yet,
    // so it will be called before a function call is attempted (in m3_FindFunction)

#ifdef DEBUG
    Module_GenerateNames(io_module);
#endif

    io_module->next = io_runtime->modules;
    io_runtime->modules = io_module;
    return result; // ok

_catch:
    // The runtime owns the module either way. Instantiation may already have
    // written this module's functions into a table another module owns, and the
    // spec keeps whatever it managed to do before the trap, so those entries
    // stay callable - retaining the module is what stops them dangling.
    //
    // It goes on the tail of the list rather than the head: it is not a module
    // anyone should find by name, only one whose functions may still be
    // reachable through someone else's table.
    io_module->next = NULL;

    IM3Module * tail = & io_runtime->modules;
    while (* tail)
        tail = & (* tail)->next;
    * tail = io_module;

    return result;
}

IM3Global  m3_FindGlobal  (IM3Module               io_module,
                           const char * const      i_globalName)
{
    // Search exports
    for (u32 i = 0; i < io_module->numGlobals; ++i)
    {
        IM3Global g = & io_module->globals [i];
        if (g->name and strcmp (g->name, i_globalName) == 0)
        {
            // a re-exported global is the one that was imported, so reads and
            // writes have to reach the cell that actually holds the value
            return g->resolved ? g->resolved : g;
        }
    }

    // Search imports
    for (u32 i = 0; i < io_module->numGlobals; ++i)
    {
        IM3Global g = & io_module->globals [i];

        if (g->import.moduleUtf8 and g->import.fieldUtf8)
        {
            if (strcmp (g->import.fieldUtf8, i_globalName) == 0)
            {
                return g->resolved ? g->resolved : g;
            }
        }
    }
    return NULL;
}

M3Result  m3_GetGlobal  (IM3Global                 i_global,
                         IM3TaggedValue            o_value)
{
    if (not i_global) return m3Err_globalLookupFailed;

    switch (i_global->type) {
    case c_m3Type_i32: o_value->value.i32 = i_global->i32Value; break;
    case c_m3Type_i64: o_value->value.i64 = i_global->i64Value; break;
# if d_m3HasFloat
    case c_m3Type_f32: o_value->value.f32 = i_global->f32Value; break;
    case c_m3Type_f64: o_value->value.f64 = i_global->f64Value; break;
# endif
    default: return m3Err_invalidTypeId;
    }

    o_value->type = (M3ValueType)(i_global->type);
    return m3Err_none;
}

M3Result  m3_SetGlobal  (IM3Global                 i_global,
                         const IM3TaggedValue      i_value)
{
    if (not i_global) return m3Err_globalLookupFailed;
    if (not i_global->isMutable) return m3Err_globalNotMutable;
    if (i_global->type != i_value->type) return m3Err_globalTypeMismatch;

    switch (i_value->type) {
    case c_m3Type_i32: i_global->i32Value = i_value->value.i32; break;
    case c_m3Type_i64: i_global->i64Value = i_value->value.i64; break;
# if d_m3HasFloat
    case c_m3Type_f32: i_global->f32Value = i_value->value.f32; break;
    case c_m3Type_f64: i_global->f64Value = i_value->value.f64; break;
# endif
    default: return m3Err_invalidTypeId;
    }

    return m3Err_none;
}

M3ValueType  m3_GetGlobalType  (IM3Global          i_global)
{
    return (i_global) ? (M3ValueType)(i_global->type) : c_m3Type_none;
}


void *  v_FindFunction  (IM3Module i_module, void * i_info)
{
    const char * const i_name = (const char *) i_info;

    // Prefer exported functions
    for (u32 i = 0; i < i_module->numFunctions; ++i)
    {
        IM3Function f = & i_module->functions [i];
        if (f->export_name and strcmp (f->export_name, i_name) == 0)
        {
            // A module that re-exports an import names the placeholder here.
            // Resolve to the function that actually runs, or a host-side call
            // would run it against the importing module's memory.
            return Function_Implementation (f);
        }
    }

    // Search internal functions
    for (u32 i = 0; i < i_module->numFunctions; ++i)
    {
        IM3Function f = & i_module->functions [i];

        bool isImported = f->import.moduleUtf8 or f->import.fieldUtf8;

        if (isImported)
            continue;

        for (int j = 0; j < f->numNames; j++)
        {
            if (f->names [j] and strcmp (f->names [j], i_name) == 0)
                return f;
        }
    }

    return NULL;
}


// Shared tail of the two lookups: a function is only usable once it has code.
static
M3Result  PrepareFoundFunction  (IM3Function * o_function, IM3Function i_function)
{
    M3Result result = m3Err_none;

    if (not i_function->compiled)
    {
_       (CompileFunction (i_function))
    }

    _catch:
    * o_function = result ? NULL : i_function;

    return result;
}


// Searches every module in the runtime, most recently loaded first. That is a
// guess once more than one module is loaded and two of them export the same
// name - m3_FindFunctionIn says which module is meant.
M3Result  m3_FindFunction  (IM3Function * o_function, IM3Runtime i_runtime, const char * const i_functionName)
{
                                                                d_m3Assert (o_function and i_runtime and i_functionName);
    IM3Function function = NULL;

    if (not i_runtime->modules) {
        * o_function = NULL;
        return "no modules loaded";
    }

    function = (IM3Function) ForEachModule (i_runtime, v_FindFunction, (void *) i_functionName);

    if (not function)
    {
        * o_function = NULL;
        return ErrorModule (m3Err_functionLookupFailed, i_runtime->modules, "'%s'", i_functionName);
    }

    return PrepareFoundFunction (o_function, function);
}


IM3Module  m3_FindModule  (IM3Runtime i_runtime, const char * const i_moduleName)
{
    if (not i_runtime or not i_moduleName)
        return NULL;

    // the list is newest-first, so a name registered twice names the newer one
    for (IM3Module m = i_runtime->modules; m; m = m->next)
    {
        if (m->name and strcmp (m->name, i_moduleName) == 0)
            return m;
    }

    return NULL;
}


// Searches one module's exports, which is what naming a module means.
M3Result  m3_FindFunctionIn  (IM3Function * o_function, IM3Module i_module, const char * const i_functionName)
{
                                                                d_m3Assert (o_function and i_functionName);
    if (not i_module)
    {
        * o_function = NULL;
        return m3Err_functionLookupFailed;      // ErrorModule would deref it
    }

    IM3Function function = (IM3Function) v_FindFunction (i_module, (void *) i_functionName);

    if (not function)
    {
        * o_function = NULL;
        return ErrorModule (m3Err_functionLookupFailed, i_module, "'%s'", i_functionName);
    }

    return PrepareFoundFunction (o_function, function);
}


M3Result  m3_GetTableFunction  (IM3Function * o_function, IM3Module i_module, uint32_t i_index)
{
_try {
    M3Table * table;
    IM3Function function;

    _throwif ("no table", i_module->numTables == 0);

    table = i_module->tables [0];
    _throwif ("function index out of range", i_index >= table->size);

    function = (IM3Function) table->elements [i_index];

    if (function)
    {
        if (not function->compiled)
        {
_           (CompileFunction (function))
        }
    }

    * o_function = function;
}   _catch:
    return result;
}


static
M3Result checkStartFunction(IM3Module i_module)
{
    M3Result result = m3Err_none;                               d_m3Assert(i_module);

    // Check if start function needs to be called
    if (i_module->startFunction >= 0)
    {
        result = m3_RunStart (i_module);
    }

    return result;
}

uint32_t  m3_GetArgCount  (IM3Function i_function)
{
    if (i_function) {
        IM3FuncType ft = i_function->funcType;
        if (ft) {
            return ft->numArgs;
        }
    }
    return 0;
}

uint32_t  m3_GetRetCount  (IM3Function i_function)
{
    if (i_function) {
        IM3FuncType ft = i_function->funcType;
        if (ft) {
            return ft->numRets;
        }
    }
    return 0;
}


M3ValueType  m3_GetArgType  (IM3Function i_function, uint32_t index)
{
    if (i_function) {
        IM3FuncType ft = i_function->funcType;
        if (ft and index < ft->numArgs) {
            return (M3ValueType) BaseTypeOf(d_FuncArgType(ft, index));
        }
    }
    return c_m3Type_none;
}

M3ValueType  m3_GetRetType  (IM3Function i_function, uint32_t index)
{
    if (i_function) {
        IM3FuncType ft = i_function->funcType;
        if (ft and index < ft->numRets) {
            return (M3ValueType) BaseTypeOf(d_FuncRetType (ft, index));
        }
    }
    return c_m3Type_none;
}


u8 *  GetStackPointerForArgs  (IM3Function i_function)
{
    u64 * stack = (u64 *) i_function->module->runtime->stack;
    IM3FuncType ftype = i_function->funcType;

    stack += ftype->numRets;

    return (u8 *) stack;
}


M3Result  m3_CallV  (IM3Function i_function, ...)
{
    va_list ap;
    va_start(ap, i_function);
    M3Result r = m3_CallVL(i_function, ap);
    va_end(ap);
    return r;
}

static
void  ReportNativeStackUsage  ()
{
#   if d_m3LogNativeStack
        int stackUsed =  m3StackGetMax();
        fprintf (stderr, "Native stack used: %d\n", stackUsed);
#   endif
}


M3Result  m3_CallVL  (IM3Function i_function, va_list i_args)
{
    IM3Runtime runtime = i_function->module->runtime;
    IM3FuncType ftype = i_function->funcType;
    M3Result result = m3Err_none;
    u8* s = NULL;

    if (!i_function->compiled) {
        return m3Err_missingCompiledCode;
    }

# if d_m3RecordBacktraces
    ClearBacktrace (runtime);
# endif

    m3StackCheckInit();

_   (checkStartFunction(i_function->module))

    s = GetStackPointerForArgs (i_function);

    for (u32 i = 0; i < ftype->numArgs; ++i)
    {
        switch (d_FuncArgType(ftype, i)) {
        case c_m3Type_i32:  *(i32*)(s) = va_arg(i_args, i32);  s += 8; break;
        case c_m3Type_i64:  *(i64*)(s) = va_arg(i_args, i64);  s += 8; break;
        case c_m3Type_funcref:
        case c_m3Type_externref:
        case c_m3Type_exnref:    *(uintptr_t*)(s) = va_arg(i_args, uintptr_t); s += 8; break;
# if d_m3HasFloat
        case c_m3Type_f32:  *(f32*)(s) = va_arg(i_args, f64);  s += 8; break; // f32 is passed as f64
        case c_m3Type_f64:  *(f64*)(s) = va_arg(i_args, f64);  s += 8; break;
# endif
        default: return "unknown argument type";
        }
    }

    result = RunCodeChecked (runtime, i_function);
    ReportNativeStackUsage ();

    runtime->lastCalled = result ? NULL : i_function;

    _catch: return result;
}

M3Result  m3_Call  (IM3Function i_function, uint32_t i_argc, const void * i_argptrs[])
{
    IM3Runtime runtime = i_function->module->runtime;
    IM3FuncType ftype = i_function->funcType;
    M3Result result = m3Err_none;
    u8* s = NULL;

    if (i_argc != ftype->numArgs) {
        return m3Err_argumentCountMismatch;
    }
    if (!i_function->compiled) {
        return m3Err_missingCompiledCode;
    }

# if d_m3RecordBacktraces
    ClearBacktrace (runtime);
# endif

    m3StackCheckInit();

_   (checkStartFunction(i_function->module))

    s = GetStackPointerForArgs (i_function);

    for (u32 i = 0; i < ftype->numArgs; ++i)
    {
        switch (d_FuncArgType(ftype, i)) {
        case c_m3Type_i32:  *(i32*)(s) = *(i32*)i_argptrs[i];  s += 8; break;
        case c_m3Type_i64:  *(i64*)(s) = *(i64*)i_argptrs[i];  s += 8; break;
        case c_m3Type_funcref:
        case c_m3Type_externref:
        case c_m3Type_exnref:    *(uintptr_t*)(s) = *(uintptr_t*)i_argptrs[i]; s += 8; break;
# if d_m3HasFloat
        case c_m3Type_f32:  *(f32*)(s) = *(f32*)i_argptrs[i];  s += 8; break;
        case c_m3Type_f64:  *(f64*)(s) = *(f64*)i_argptrs[i];  s += 8; break;
# endif
        default: return "unknown argument type";
        }
    }

    result = RunCodeChecked (runtime, i_function);

    ReportNativeStackUsage ();

    runtime->lastCalled = result ? NULL : i_function;

    _catch: return result;
}

// Argument parsing for m3_CallArgv. Strict on purpose: the whole string has to
// be consumed, so "12abc" is rejected rather than read as 12, and an empty or
// unparsable argument is an error rather than the zero that strtoul with a
// NULL end pointer used to hand back. See wasm3/wasm3#367.
static
M3Result  ParseArgInteger  (ccstr_t i_arg, u32 i_numBits, u64 * o_value)
{
    if (not i_arg or not * i_arg)
        return "empty argument";

    // strtoull would skip leading space, but trailing space is rejected below;
    // accepting one and not the other would just be confusing
    if (isspace ((unsigned char) * i_arg))
        return "argument is not a number";

    char * end = NULL;
    u64 value;

    errno = 0;

    // an argument may be spelled signed or unsigned: -1 and 4294967295 name the
    // same i32
    if (* i_arg == '-')
    {
        i64 signedValue = strtoll (i_arg, & end, 10);

        if (i_numBits == 32 and (signedValue < INT32_MIN or signedValue > INT32_MAX))
            return "argument out of range";

        value = (u64) signedValue;
    }
    else
    {
        value = strtoull (i_arg, & end, 10);

        if (i_numBits == 32 and value > UINT32_MAX)
            return "argument out of range";
    }

    if (errno == ERANGE)
        return "argument out of range";

    if (end == i_arg or * end)
        return "argument is not a number";

    * o_value = value;

    return m3Err_none;
}


#if d_m3HasFloat
static
M3Result  ParseArgFloat  (ccstr_t i_arg, f64 * o_value)
{
    if (not i_arg or not * i_arg)
        return "empty argument";

    if (isspace ((unsigned char) * i_arg))
        return "argument is not a number";

    char * end = NULL;

    errno = 0;

    f64 value = strtod (i_arg, & end);

    if (end == i_arg or * end)
        return "argument is not a number";

    // strtod reports underflow through ERANGE as well, and a denormal result is
    // perfectly usable, so only an overflow to infinity is out of range
    if (errno == ERANGE and (value > DBL_MAX or value < -DBL_MAX))
        return "argument out of range";

    * o_value = value;

    return m3Err_none;
}
#endif


// A reference argument is either the null reference or a host handle written as
// an integer.
static
M3Result  ParseArgReference  (ccstr_t i_arg, u64 * o_value)
{
    if (i_arg and strcmp (i_arg, "null") == 0)
    {
        * o_value = 0;
        return m3Err_none;
    }

    return ParseArgInteger (i_arg, 64, o_value);
}


M3Result  m3_CallArgv  (IM3Function i_function, uint32_t i_argc, const char * i_argv[])
{
    IM3FuncType ftype = i_function->funcType;
    IM3Runtime runtime = i_function->module->runtime;
    M3Result result = m3Err_none;
    u8* s = NULL;

    if (i_argc != ftype->numArgs) {
        return m3Err_argumentCountMismatch;
    }
    if (!i_function->compiled) {
        return m3Err_missingCompiledCode;
    }

# if d_m3RecordBacktraces
    ClearBacktrace (runtime);
# endif

    m3StackCheckInit();

_   (checkStartFunction(i_function->module))

    s = GetStackPointerForArgs (i_function);

    for (u32 i = 0; i < ftype->numArgs; ++i)
    {
        u64 value = 0;
# if d_m3HasFloat
        f64 fvalue = 0;
# endif
        switch (d_FuncArgType(ftype, i)) {
        case c_m3Type_i32:  _ (ParseArgInteger   (i_argv[i], 32, & value)) *(i32*)(s) = (i32) value; s += 8; break;
        case c_m3Type_i64:  _ (ParseArgInteger   (i_argv[i], 64, & value)) *(i64*)(s) = (i64) value; s += 8; break;
        case c_m3Type_funcref:
        case c_m3Type_externref:
        case c_m3Type_exnref:
                            _ (ParseArgReference (i_argv[i], & value)) *(uintptr_t*)(s) = (uintptr_t) value; s += 8; break;
# if d_m3HasFloat
                                                                    // strtof would be less portable
        case c_m3Type_f32:  _ (ParseArgFloat     (i_argv[i], & fvalue)) *(f32*)(s) = (f32) fvalue; s += 8; break;
        case c_m3Type_f64:  _ (ParseArgFloat     (i_argv[i], & fvalue)) *(f64*)(s) = fvalue; s += 8; break;
# endif
        default: _throw ("unknown argument type");
        }
    }

    result = RunCodeChecked (runtime, i_function);

    ReportNativeStackUsage ();

    runtime->lastCalled = result ? NULL : i_function;

    _catch: return result;
}


//u8 * AlignStackPointerTo64Bits (const u8 * i_stack)
//{
//    uintptr_t ptr = (uintptr_t) i_stack;
//    return (u8 *) ((ptr + 7) & ~7);
//}


M3Result  m3_GetResults  (IM3Function i_function, uint32_t i_retc, const void * o_retptrs[])
{
    IM3FuncType ftype = i_function->funcType;
    IM3Runtime runtime = i_function->module->runtime;

    if (i_retc != ftype->numRets) {
        return m3Err_argumentCountMismatch;
    }
    if (i_function != runtime->lastCalled) {
        return "function not called";
    }

    u8* s = (u8*) runtime->stack;

    for (u32 i = 0; i < ftype->numRets; ++i)
    {
        switch (d_FuncRetType(ftype, i)) {
        case c_m3Type_i32:  *(i32*)o_retptrs[i] = *(i32*)(s); s += 8; break;
        case c_m3Type_i64:  *(i64*)o_retptrs[i] = *(i64*)(s); s += 8; break;
        case c_m3Type_funcref:
        case c_m3Type_externref:
        case c_m3Type_exnref:    *(uintptr_t*)o_retptrs[i] = *(uintptr_t*)(s); s += 8; break;
# if d_m3HasFloat
        case c_m3Type_f32:  *(f32*)o_retptrs[i] = *(f32*)(s); s += 8; break;
        case c_m3Type_f64:  *(f64*)o_retptrs[i] = *(f64*)(s); s += 8; break;
# endif
        default: return "unknown return type";
        }
    }
    return m3Err_none;
}

M3Result  m3_GetResultsV  (IM3Function i_function, ...)
{
    va_list ap;
    va_start(ap, i_function);
    M3Result r = m3_GetResultsVL(i_function, ap);
    va_end(ap);
    return r;
}

M3Result  m3_GetResultsVL  (IM3Function i_function, va_list o_rets)
{
    IM3Runtime runtime = i_function->module->runtime;
    IM3FuncType ftype = i_function->funcType;

    if (i_function != runtime->lastCalled) {
        return "function not called";
    }

    u8* s = (u8*) runtime->stack;
    for (u32 i = 0; i < ftype->numRets; ++i)
    {
        switch (d_FuncRetType(ftype, i)) {
        case c_m3Type_i32:  *va_arg(o_rets, i32*) = *(i32*)(s);  s += 8; break;
        case c_m3Type_i64:  *va_arg(o_rets, i64*) = *(i64*)(s);  s += 8; break;
        case c_m3Type_funcref:
        case c_m3Type_externref:
        case c_m3Type_exnref:    *va_arg(o_rets, uintptr_t*) = *(uintptr_t*)(s); s += 8; break;
# if d_m3HasFloat
        case c_m3Type_f32:  *va_arg(o_rets, f32*) = *(f32*)(s);  s += 8; break;
        case c_m3Type_f64:  *va_arg(o_rets, f64*) = *(f64*)(s);  s += 8; break;
# endif
        default: return "unknown argument type";
        }
    }
    return m3Err_none;
}

void  ReleaseCodePageNoTrack (IM3Runtime i_runtime, IM3CodePage i_codePage)
{
    if (i_codePage)
    {
        IM3CodePage * list;

        bool pageFull = (NumFreeLines (i_codePage) < d_m3CodePageFreeLinesThreshold);
        if (pageFull)
            list = & i_runtime->pagesFull;
        else
            list = & i_runtime->pagesOpen;

        PushCodePage (list, i_codePage);                        m3log (emit, "release page: %d to queue: '%s'", i_codePage->info.sequence, pageFull ? "full" : "open")
    }
}


IM3CodePage  AcquireCodePageWithCapacity  (IM3Runtime i_runtime, u32 i_minLineCount)
{
    IM3CodePage page = RemoveCodePageOfCapacity (& i_runtime->pagesOpen, i_minLineCount);

    if (not page)
    {
        page = Environment_AcquireCodePage (i_runtime->environment, i_minLineCount);

        if (not page)
            page = NewCodePage (i_runtime, i_minLineCount);

        if (page)
            i_runtime->numCodePages++;
    }

    if (page)
    {                                                            m3log (emit, "acquire page: %d", page->info.sequence);
        i_runtime->numActiveCodePages++;
    }

    return page;
}


IM3CodePage  AcquireCodePage  (IM3Runtime i_runtime)
{
    return AcquireCodePageWithCapacity (i_runtime, d_m3CodePageFreeLinesThreshold);
}


void  ReleaseCodePage  (IM3Runtime i_runtime, IM3CodePage i_codePage)
{
    if (i_codePage)
    {
        ReleaseCodePageNoTrack (i_runtime, i_codePage);
        i_runtime->numActiveCodePages--;

#       if defined (DEBUG)
            u32 numOpen = CountCodePages (i_runtime->pagesOpen);
            u32 numFull = CountCodePages (i_runtime->pagesFull);

            m3log (runtime, "runtime: %p; open-pages: %d; full-pages: %d; active: %d; total: %d", i_runtime, numOpen, numFull, i_runtime->numActiveCodePages, i_runtime->numCodePages);

            d_m3Assert (numOpen + numFull + i_runtime->numActiveCodePages == i_runtime->numCodePages);

#           if d_m3LogCodePages
                dump_code_page (i_codePage, /* startPC: */ NULL);
#           endif
#       endif
    }
}


#if d_m3VerboseErrorMessages
M3Result  m3Error  (M3Result i_result, IM3Runtime i_runtime, IM3Module i_module, IM3Function i_function,
                    const char * const i_file, u32 i_lineNum, const char * const i_errorMessage, ...)
{
    if (i_runtime)
    {
        i_runtime->error = (M3ErrorInfo){ .result = i_result, .runtime = i_runtime, .module = i_module,
                                          .function = i_function, .file = i_file, .line = i_lineNum };
        i_runtime->error.message = i_runtime->error_message;

        va_list args;
        va_start (args, i_errorMessage);
        vsnprintf (i_runtime->error_message, sizeof(i_runtime->error_message), i_errorMessage, args);
        va_end (args);
    }

    return i_result;
}
#endif


void  m3_GetErrorInfo  (IM3Runtime i_runtime, M3ErrorInfo* o_info)
{
    if (i_runtime)
    {
        *o_info = i_runtime->error;
        m3_ResetErrorInfo (i_runtime);
    }
}


void m3_ResetErrorInfo (IM3Runtime i_runtime)
{
    if (i_runtime)
    {
        M3_INIT(i_runtime->error);
        i_runtime->error.message = "";
    }
}

uint8_t *  m3_GetMemory  (IM3Module i_module, size_t * o_memorySizeInBytes, uint32_t i_memoryIndex)
{
    uint8_t * memory = NULL;
    size_t size = 0;

    if (i_module and i_memoryIndex < i_module->numMemories)
    {
        IM3Memory mem = i_module->memories [i_memoryIndex];

        if (mem->mallocated)
        {
            size = mem->mallocated->length;

            if (size)
                memory = m3MemData (mem->mallocated);
        }
    }

    if (o_memorySizeInBytes)
        * o_memorySizeInBytes = size;

    return memory;
}


size_t  m3_GetMemorySize  (IM3Module i_module, uint32_t i_memoryIndex)
{
    if (not i_module or i_memoryIndex >= i_module->numMemories)
        return 0;

    IM3Memory mem = i_module->memories [i_memoryIndex];

    return mem->mallocated ? mem->mallocated->length : 0;
}


size_t  m3_GetMemorySizeAt  (const void * i_memory)
{
    if (not i_memory)
        return 0;

    // the header sits immediately before the data it describes
    const M3MemoryHeader * header = ((const M3MemoryHeader *) i_memory) - 1;

    return header->length;
}


M3Result  m3_FindExportedMemory  (IM3Module i_module, cstr_t i_name, u32 * o_memoryIndex)
{
    if (not i_module or not i_name or not o_memoryIndex)
        return m3Err_unknownMemory;

    for (u32 i = 0; i < i_module->numMemories; ++i)
    {
        IM3Memory memory = i_module->memories [i];

        if (memory->exportName and strcmp (memory->exportName, i_name) == 0)
        {
            * o_memoryIndex = i;
            return m3Err_none;
        }
    }

    return m3Err_unknownMemory;
}


bool  Module_HasLinkedHostImport  (IM3Module i_module, cstr_t i_importModule)
{
    for (u32 i = 0; i < i_module->numFunctions; ++i)
    {
        IM3Function f = & i_module->functions [i];

        // hostMemory is set when a host function is bound to the import, so it
        // is also the mark of one - see CompileRawFunction
        if (not f->hostMemory or f->wasm or f->resolved)
            continue;

        if (f->import.moduleUtf8 and strcmp (f->import.moduleUtf8, i_importModule) == 0)
            return true;
    }

    return false;
}


M3Result  m3_BindImportMemory  (IM3Module io_module, cstr_t i_importModule, u32 i_memoryIndex)
{
    if (not io_module or not i_importModule)
        return m3Err_moduleNotLinked;

    if (i_memoryIndex >= io_module->numMemories)
        return m3Err_unknownMemory;

    // the memory itself, not the index: linking may have pointed this slot at
    // another module's memory, and growing one reallocates behind it
    IM3Memory memory = io_module->memories [i_memoryIndex];

    const bool wildcardModule = (strcmp (i_importModule, "*") == 0);

    for (u32 i = 0; i < io_module->numFunctions; ++i)
    {
        IM3Function f = & io_module->functions [i];

        // only an import that a host function was bound to has a memory to
        // pin: one with a body of its own reads memory through the interpreter,
        // and one resolved to another module's export runs that module's code
        if (not f->hostMemory or f->wasm or f->resolved)
            continue;

        if (wildcardModule or (f->import.moduleUtf8 and strcmp (f->import.moduleUtf8, i_importModule) == 0))
            f->hostMemory = memory;
    }

    return m3Err_none;
}


M3BacktraceInfo *  m3_GetBacktrace  (IM3Runtime i_runtime)
{
# if d_m3RecordBacktraces
    return & i_runtime->backtrace;
# else
    return NULL;
# endif
}


Coverage Report

Created: 2026-09-01 06:51