Adding MCOPY Instruction #2711

nagarev · 2024-09-05T14:01:20Z

Description

Besides memory copying being a basic operation, implementing it on the VM comes with overhead, as described in the EIP-5656

Currently memory copying can be achieved by the usage of CALL, MLOAD and MSTORE (among others opcodes) depending on the scenarios where the memory copy is being done.

The MCOPY instruction will be introduced at 0x5E.

Motivation and Context

Increase compatibility

How Has This Been Tested?

Types of changes

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)

Checklist:

My code follows the code style of this project.
My change requires a change to the documentation.
I have updated the documentation accordingly.
Tests for the changes have been added (for bug fixes / features)
Requires Activation Code (Hard Fork)

Other information:

N/A

rskj-core/src/main/java/org/ethereum/vm/program/Memory.java

fmacleal

Good job. Simple, straight to the point and with an amazing test. Well done!

rskj-core/src/test/java/co/rsk/vm/opcode/MCopyDslTest.java

rskj-core/src/test/resources/dsl/opcode/mcopy/mCopyTestCase1.txt

asoto-iov · 2024-09-23T13:55:53Z

rskj-core/src/main/java/org/ethereum/vm/VM.java

+            // gas cost = 3 * (length + 31) + memory expansion cost + very low
+            long length = stack.get(stack.size() - 3).longValue();
+            long newMemSize = memNeeded(stack.peek(), length);
+            long cost = 3 * (length + 31) + calcMemGas(oldMemSize, newMemSize, 0) + 3; // TODO -> Check copy size


In order to calculate the number of words we are missing to divide the total size by the dataword length being (length + 31) / 32 instead of only (length + 31) .
Also I think it is more readable if we store the different values separated adding a meaningful name to them

Nice! will continue with this in the next PR. 💪🏼

fmacleal

Nice job!
Really liked the organization from DSL tests and the tests itself, well done!

fmacleal · 2024-09-30T04:23:01Z

rskj-core/src/main/java/org/ethereum/vm/VM.java

+        DataWord length = program.stackPop();
+
+        if (isLogEnabled) {
+            hint = "dst: " + dst + " src: " + src + " length: " + length;


suggestion:

I noticed that you are not logging at the end, maybe would be good to log these parameters that you set.

Take a look at this comment @nagarev. :)

fmacleal

Well done @nagarev. These tests are pretty complete and shows a hard work in fulfil the scenarios of test from the EIP.

I just have a few comments to improve it even more the readability. But they are not blocking and doesn't prevent the approval.

You need to fix some tests though, it seems that it's broke for java-17 and java-21.

fmacleal · 2024-10-15T20:12:56Z

rskj-core/src/main/java/org/ethereum/vm/VM.java

+            // See "Gas Cost" section on EIP 5656
+            // gas cost = 3 * (length + 31) + memory expansion cost + very low


suggestion:

The part very low isn't clear as long as we read the EIP. I suggest you rephrase it. Maybe to gas fixed for very low mem usage. Or just put it plainly 3.

fmacleal · 2024-10-15T20:15:16Z

rskj-core/src/main/java/org/ethereum/vm/VM.java

+        DataWord length = program.stackPop();
+
+        if (isLogEnabled) {
+            hint = "dst: " + dst + " src: " + src + " length: " + length;


Take a look at this comment @nagarev. :)

fmacleal · 2024-10-15T20:24:58Z

rskj-core/src/test/java/co/rsk/vm/opcode/MCopyDslTest.java

suggestion:

You are using meaningful names for the variables and methods, I think you don't need the comments explaining that you are checking that a block has a single transaction, or that that the transaction has a receipt. Let the code speak for itself, you are already using principles of clean code with good names for variables and methods, the comments can age badly and wouldn't be missed. 🙂

fmacleal · 2024-10-15T20:26:41Z

rskj-core/src/test/java/co/rsk/vm/opcode/MCopyDslTest.java

+        // There's one block (b01) containing only 1 transaction
+        Block block1 = world.getBlockByName("b01");
+        Assertions.assertNotNull(block1);
+        Assertions.assertEquals(1, block1.getTransactionsList().size());
+
+        // There's a transaction called txTestMCopy
+        Transaction txTestMCopy = world.getTransactionByName("txTestMCopy");
+        Assertions.assertNotNull(txTestMCopy);
+
+        // Transaction txTestMCopy has a transaction receipt
+        TransactionReceipt txTestMCopyReceipt = world.getTransactionReceiptByName("txTestMCopy");
+        Assertions.assertNotNull(txTestMCopyReceipt);
+
+        // Transaction txTestMCopy has been processed correctly
+        byte[] creationStatus = txTestMCopyReceipt.getStatus();
+        Assertions.assertNotNull(creationStatus);
+        Assertions.assertEquals(1, creationStatus.length);
+        Assertions.assertEquals(1, creationStatus[0]);


suggestion:

You could extract these assertions to a method, because they are repeating thoroughly in your class. Something like this one here could do the job.v Be aware that you might need to adapt this methid, since you might have transactionReceipt but with the length 0.

fmacleal · 2024-10-15T21:00:02Z

rskj-core/src/test/java/co/rsk/vm/opcode/MCopyDslTest.java

+    // https://github.com/ethereum/execution-spec-tests/blob/c0065176a79f89d93f4c326186fc257ec5b8d5f1/tests/cancun/eip5656_mcopy/test_mcopy.py)
+
+    @Test
+    void testMCOPY_overwriteCases_behaveAsExpected() throws FileNotFoundException, DslProcessorException {


praise:

Well done my friend, this test it's very complete and it should have been a bit tricky understand the python one and convert it to a proper DSL. 👏

github-actions · 2024-11-04T13:57:07Z

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

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rskj-core/src/main/java/org/ethereum/vm/program/Memory.java Fixed Show fixed Hide fixed

rskj-core/src/main/java/org/ethereum/vm/program/Memory.java Fixed Show fixed Hide fixed

rskj-core/src/main/java/org/ethereum/vm/program/Memory.java Fixed Show fixed Hide fixed

fmacleal previously approved these changes Sep 19, 2024

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rskj-core/src/test/java/co/rsk/vm/opcode/MCopyDslTest.java Outdated Show resolved Hide resolved

rskj-core/src/test/resources/dsl/opcode/mcopy/mCopyTestCase1.txt Outdated Show resolved Hide resolved

asoto-iov reviewed Sep 23, 2024

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nagarev dismissed fmacleal’s stale review via 1331067 September 26, 2024 13:17

nagarev force-pushed the add-mcopy branch 2 times, most recently from e640b71 to a47d5c9 Compare September 27, 2024 02:38

nagarev requested review from asoto-iov and fmacleal September 27, 2024 14:37

fmacleal previously approved these changes Sep 27, 2024

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fmacleal reviewed Sep 30, 2024

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Vovchyk dismissed fmacleal’s stale review via 37501a7 October 1, 2024 12:02

nagarev force-pushed the add-mcopy branch from 37501a7 to aa8e0e1 Compare October 2, 2024 22:12

fmacleal approved these changes Oct 15, 2024

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nagarev force-pushed the add-mcopy branch from 5af80de to 46e2934 Compare November 4, 2024 13:56

nagarev added 12 commits November 22, 2024 10:47

Adding basic structure

0fb8b76

Adding mcopy implementation

f0b9eea

Adding mcopy basic scenario dsl test

8b39075

Adding gas cost calculation WIP

b917b4c

Applying suggestions

6c71e3e

Updating contract code

e340f2b

Adding basic cases

14b572d

Adding overwrite cases

ac3b22d

Add solidity contracts

c8684cf

Adding new dsl test

ff50bce

Updating contracts

e4e7902

Adding new tests

1ba7a01

nagarev force-pushed the add-mcopy branch from 46e2934 to 1ba7a01 Compare November 22, 2024 13:48

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Adding MCOPY Instruction #2711

Adding MCOPY Instruction #2711

nagarev commented Sep 5, 2024

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		// See "Gas Cost" section on EIP 5656
		// gas cost = 3 * (length + 31) + memory expansion cost + very low

Adding MCOPY Instruction #2711

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Adding MCOPY Instruction #2711

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nagarev commented Sep 5, 2024

Description

Motivation and Context

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Types of changes

Checklist:

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