Fix memory pointer alignment in LowLevelCall.returnData()

[maradini77]

Summary

Fixes memory pointer alignment issue in LowLevelCall.returnData() function.

Problem

The free memory pointer at 0x40 was not aligned to 32-byte boundary, which violates Solidity ABI expectations and can cause incorrect subsequent allocations.

Solution

• Align free memory pointer to 32-byte boundary using bitwise operations

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Latest commit: bcfd6cb

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[coderabbitai]

Walkthrough

The LowLevelCall.sol contract has been modified to change how the free-memory pointer is updated following a returnData memory write operation. Instead of incrementing the pointer by the raw returndatasize, the pointer now advances to the next 32-byte aligned address after the returned data. This modification maintains the existing data copying mechanism while ensuring proper 32-byte memory alignment for the resulting bytes memory object. No public API changes were introduced.

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title Check	✅ Passed	The pull request title "Fix memory pointer alignment in LowLevelCall.returnData()" directly aligns with the changeset. The raw summary and PR description both confirm that the primary change is fixing memory pointer alignment in the LowLevelCall.returnData() function by ensuring the free-memory pointer is aligned to a 32-byte boundary. The title is concise, specific, and clearly identifies both the function being modified and the nature of the fix, making it easy for teammates scanning the history to understand the primary change.
Description Check	✅ Passed	The pull request description is clearly related to the changeset and provides meaningful context about the fix. It uses a structured format explaining the problem (unaligned free memory pointer violating Solidity ABI expectations), the specific function affected (LowLevelCall.returnData()), and the solution (aligning the pointer to 32-byte boundary using bitwise operations). The description is neither vague nor generic, and directly corresponds to the changes summarized in the raw summary.
Docstring Coverage	✅ Passed	No functions found in the changes. Docstring coverage check skipped.

✨ Finishing touches

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📥 Commits

Reviewing files that changed from the base of the PR and between 1cf1377 and bcfd6cb.

📒 Files selected for processing (1)

• contracts/utils/LowLevelCall.sol (1 hunks)

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🔇 Additional comments (1)

contracts/utils/LowLevelCall.sol (1)

108-108: LGTM! Alignment fix is mathematically correct.

The alignment logic properly rounds up returndatasize() to the next 32-byte boundary using and(add(returndatasize(), 0x1f), not(0x1f)), maintaining Solidity's memory management requirements and the "memory-safe" annotation. The function is used across multiple critical components (Address.sol, Create2.sol, draft-AccountERC7579.sol, ERC4626.sol).

No dedicated unit tests were found for returnData(). Consider adding test coverage for edge cases (non-aligned sizes like 1, 17, 31, 33 and aligned sizes like 32, 64, 96) to verify proper memory pointer alignment across all return data sizes.

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