feat: add WASM host functions (Wasmi version) by mvadari · Pull Request #6075 · XRPLF/rippled

mvadari · 2025-11-24T21:20:11Z

High Level Overview of Change

This PR adds all the Wasmi integration code and the host functions specified in XLS-102. It also adds tests for all of this.

Note for reviewers: 100k lines of this PR are just WASM-compiled test fixtures, and another 5k lines are WASM test fixture source code. So while this PR is still quite large, it's not as large as it seems on the surface.

Context of Change

This PR depends on #5999 and replaces #5791

It is part of an effort to split up the Smart Escrow work into smaller, more managable-to-review PRs.

XLS-102: https://xls.xrpl.org/xls/XLS-0102-wasm-vm.html

Stack of PRs (from develop outwards):

Type of Change

Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
Refactor (non-breaking change that only restructures code)
Performance (increase or change in throughput and/or latency)
Tests (you added tests for code that already exists, or your new feature included in this PR)
Documentation update
Chore (no impact to binary, e.g. .gitignore, formatting, dropping support for older tooling)
Release

API Impact

N/A

Test Plan

Several tests are added to this PR.

…nctions

* Reject non-canonical binaries * Review fixes * Cleanup Number2 class * Use enum instead of 0

* add readme to src/xrpl/app/wasm * important block * respond to copilot

* Add functions with many parameters * Add 10k locals function * Module with 5k functions * fix typo Co-authored-by: Mayukha Vadari <mvadari@gmail.com> --------- Co-authored-by: Mayukha Vadari <mvadari@gmail.com>

* clean up some hf code * fix comments * fix ubsan * Revert "fix ubsan"

* Remove ability to re-use wasm module * Check that HFS object is always new * Fix clang format * Remove perf tests * temp build fix * Fix merge

…functions

vvysokikh1 · 2026-03-02T14:20:45Z

src/xrpld/app/wasm/detail/HostFuncWrapper.cpp

+
+    if (slice->size() == uint256::bytes)
+    {
+        if (auto ret = hf->isAmendmentEnabled(uint256::fromVoid(slice->data())); *ret == 1)


*ret without .has_value() is a dangerous code pattern. It could be UB potentially. While isAmendmentEnabled cannot return an error now, it's not guaranteed that this will not happen in the future. If the hf class is not set correctly (let's say you use base class for some reason), it will actually return an unexpected and instead of proper error handling we will have an UB

vvysokikh1 · 2026-03-02T14:27:02Z

src/xrpld/app/wasm/detail/HostFuncWrapper.cpp

+    auto const* runtime = reinterpret_cast<InstanceWrapper const*>(hf->getRT());
+    int index = 0;
+
+    if (params->data[1].of.i32 + params->data[3].of.i32 > maxWasmParamLength)


I probably raised this before, but can this overflow? These two params are provided by the user right?

vvysokikh1 · 2026-03-02T14:30:47Z

src/xrpld/app/wasm/detail/HostFuncImplFloat.cpp

+            return;
+
+        Number::setround(static_cast<Number::rounding_mode>(mode));
+        Number::setMantissaScale(MantissaRange::mantissa_scale::small);


While I don't see the issue here, I see the comments in original implementation:

/** Changes which mantissa scale is used for normalization. * * If you think you need to call this outside of unit tests, no you don't. */ static void setMantissaScale(MantissaRange::mantissa_scale scale);

Could you bring this up for discussion?

vvysokikh1 · 2026-03-02T14:48:34Z

src/xrpld/app/wasm/detail/HostFuncImplGetter.cpp

+        if (STI_ARRAY == field->getSType())
+        {
+            auto const* arr = static_cast<STArray const*>(field);
+            if (sfieldCode >= arr->size())


is there any chance sfieldCode can be negative? This will cause an issue

vvysokikh1 · 2026-03-02T14:51:55Z

src/xrpld/app/wasm/detail/HostFuncImplNFT.cpp

+// =========================================================
+
+Expected<Bytes, HostFunctionError>
+WasmHostFunctionsImpl::getNFT(AccountID const& account, uint256 const& nftId) const


this function name is a bit misleading, should it be getNFTUri or something like that?

vvysokikh1 · 2026-03-02T14:59:49Z

src/xrpld/app/wasm/detail/HostFuncWrapper.cpp

+    int64_t const x = gas >= impFunc.gas ? gas - impFunc.gas : 0;
+
+    if (runtime->setGas(x) < 0)
+    {
+        wasm_trap_t* trap = reinterpret_cast<wasm_trap_t*>(
+            WasmEngine::instance().newTrap("can't set gas"));  // LCOV_EXCL_LINE
+        return Unexpected(trap);                               // LCOV_EXCL_LINE
+    }
+
+    if (gas < impFunc.gas)
+    {
+        wasm_trap_t* trap =
+            reinterpret_cast<wasm_trap_t*>(WasmEngine::instance().newTrap("hf out of gas"));
+        return Unexpected(trap);
+    }
+


In case there's not enough gas, we first set gas to 0, and only then we check if there's enough gas to run the function. Is this intentional? Should we first check if there's enough and only then deduct?

vvysokikh1 · 2026-03-02T15:04:31Z

src/xrpld/app/wasm/WasmVM.h

+static std::string_view const W_ENV = "env";
+static std::string_view const W_HOST_LIB = "host_lib";
+static std::string_view const W_MEM = "memory";
+static std::string_view const W_STORE = "store";
+static std::string_view const W_LOAD = "load";
+static std::string_view const W_SIZE = "size";
+static std::string_view const W_ALLOC = "allocate";
+static std::string_view const W_DEALLOC = "deallocate";
+static std::string_view const W_PROC_EXIT = "proc_exit";
+
+static std::string_view const ESCROW_FUNCTION_NAME = "finish";
+
+uint32_t const MAX_PAGES = 128;  // 8MB = 64KB*128
+


This creates separate copies per translation unit. Use inline constexpr

vvysokikh1 · 2026-03-02T15:05:03Z

src/xrpld/app/wasm/detail/WasmVM.cpp

+    // std::cout << "runEscrowWasm, mod size: " << wasmCode.size()
+    //           << ", gasLimit: " << gasLimit << ", funcName: " << funcName;


nit: needs cleanup

vvysokikh1 · 2026-03-02T15:07:45Z

src/xrpld/app/wasm/ParamsHelper.h

+        float f32;
+        double f64;


These params are not used if I understand correctly, do you plan to use them later?

vvysokikh1 · 2026-03-02T15:08:20Z

src/xrpld/app/wasm/detail/WasmiVM.cpp

+
+    // Create and instantiate the module.
+    if (wasmCode.empty())
+        throw std::runtime_error("empty nodule");


nit: typo here

mvadari and others added 30 commits September 10, 2025 14:40

add WAMR dependency

45ab15d

Add WAMR integration code

dbc9dd5

add host functions

8341864

add tests

bfc048e

CODEOWNERS

51a9f10

misc host function files

f03c3aa

limits

b1d70db

bring out IOUAmount.h

129aa4b

add temBAD_WASM

2de8488

update tests

a15d65f

add fixtures files

bf32dc2

rearrange files

1b6312a

test: improve codecov in HostFuncWrapper.cpp (#5730)

ba52d34

chore: remove unneeded float stuff (#5729)

ebd90c4

Merge branch 'develop' into ripple/wamr

c34d09a

Merge branch 'ripple/wamr' into ripple/wamr-host-functions

cfe57c1

Merge branch 'develop' into ripple/wamr

6781068

Merge remote-tracking branch 'upstream/ripple/wamr' into wamr-host-fu…

1c646db

…nctions

fix merge issues

edfed06

Latests HF perf test (#5789)

6be8f21

Merge branch 'develop' into ripple/wamr

c3dc33c

Merge branch 'ripple/wamr' into ripple/wamr-host-functions

9f58751

Switch to own wamr fork (#5808)

d24cd50

Merge branch 'develop' into ripple/wamr

50d6072

Merge branch 'ripple/wamr' into ripple/wamr-host-functions

b69b4a0

Merge branch 'develop' into ripple/wamr

cb702cc

Merge branch 'ripple/wamr' into ripple/wamr-host-functions

eaba76f

switch from wasm32-unknown-unknown to wasm32v1-none (#5814)

57fc1df

Merge branch 'develop' into ripple/wamr

299fbe0

Merge branch 'ripple/wamr' into ripple/wamr-host-functions

8dea76b

oleks-rip and others added 21 commits January 27, 2026 13:05

Fix for Big-Endian machines (#6245)

f1f2e26

Merge branch 'ripple/wasmi' into ripple/wasmi-host-functions

977caea

Reject non-canonical binaries (#6277)

c1c1b4e

* Reject non-canonical binaries * Review fixes * Cleanup Number2 class * Use enum instead of 0

Merge branch 'ripple/wasmi' into wasmi-host-functions

4eb34f3

fix clang-format

803a344

Merge branch 'ripple/wasmi' into wasmi-host-functions

8f97ec3

Merge branch 'ripple/wasmi' into wasmi-host-functions

0418ffb

use buffers for uint32 WASM params (#6291)

7c8279e

Fix negation of int64_t (#6296)

ba03a8a

Merge branch 'ripple/wasmi' into wasmi-host-functions

de55a5e

add readme to src/xrpld/app/wasm (#6340)

65f9cf8

* add readme to src/xrpl/app/wasm * important block * respond to copilot

Merge branch 'ripple/wasmi' into wasmi-host-functions

c1381f8

fix cspell issues in tests (#6348)

7767366

Add tests for wasm functions with many parameters (#6343)

6728ab5

* Add functions with many parameters * Add 10k locals function * Module with 5k functions * fix typo Co-authored-by: Mayukha Vadari <mvadari@gmail.com> --------- Co-authored-by: Mayukha Vadari <mvadari@gmail.com>

clean up some hf code (#6354)

f73d8a6

* clean up some hf code * fix comments * fix ubsan * Revert "fix ubsan"

Merge branch 'ripple/wasmi' into ripple/wasmi-host-functions

495dda7

fix pre-commit

fd524c4

fix build issues

1b4a564

UT for wasm parameters (#6413)

0392846

Test invalid opcodes (#6392)

1d9ec84

Disable reusing wasm module (#6364)

953b9a3

* Remove ability to re-use wasm module * Check that HFS object is always new * Fix clang format * Remove perf tests * temp build fix * Fix merge

mvadari mentioned this pull request Feb 27, 2026

Modularise the wasm module #6441

Open

13 tasks

mvadari and others added 2 commits February 27, 2026 16:28

Merge branch 'ripple/wasmi' into ripple/wasmi-host-functions

dc413ae

Merge remote-tracking branch 'upstream/ripple/wasmi' into wasmi-host-…

125df7a

…functions

This was referenced Feb 27, 2026

feat: add WASMI dependency #5999

Open

feat: SmartEscrow fee voting changes #5810

Open

XLS-100: Smart Escrows #6329

Open

mark SmartEscrow as Supported::yes #5811

Open

vvysokikh1 reviewed Mar 2, 2026

View reviewed changes

rename variable

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feat: add WASM host functions (Wasmi version)#6075

feat: add WASM host functions (Wasmi version)#6075
mvadari wants to merge 127 commits intoripple/wasmifrom
ripple/wasmi-host-functions

mvadari commented Nov 24, 2025 •

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		// std::cout << "runEscrowWasm, mod size: " << wasmCode.size()
		// << ", gasLimit: " << gasLimit << ", funcName: " << funcName;

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High Level Overview of Change

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mvadari commented Nov 24, 2025 •

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