Fix load_elf to support non-file istream paths and add regression tests

[mikeagun]

Fix load_elf istream fallback and add Assume regression tests

load_elf fix: The ELF loader overhaul (#1026) added section-bounds validation using file_size(path) in
load_elf(istream, path). This breaks callers that pass in-memory data via std::stringstream with a non-file path
like "memory" — file_size("memory") fails with ERROR_FILE_NOT_FOUND. Fix: when file_size(path) fails, fall back to
seekg(0, end) + tellg() on the input stream. The section-bounds check still runs; only the size source changes.

Assume regression tests: The assertion crash fix (#1012, aa31b0e) shipped without test coverage. Added 3 YAML test
cases for reg-vs-reg Assume with differing inferred types (ctx==number, packet!=number, stack<number) and 1 Catch2
test for the istream non-file-path path.

Closes #1049

Summary by CodeRabbit

• Bug Fixes

  • Improved ELF data-size determination and section bounds validation to support stream-based inputs when file-size is unavailable, preventing incorrect bounds checks.

• Tests

  • Added a regression test for loading ELF data from non-file streams.
  • Added regression tests covering assume operations that compare operands with differing inferred types.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 060b700d-8ef1-4a76-a26c-83a4ce16ac48

📥 Commits

Reviewing files that changed from the base of the PR and between 2d8bfc8 and 333029a.

📒 Files selected for processing (1)

• src/io/elf_reader.cpp

---

Walkthrough

Replace direct use of std::filesystem::file_size for istream-based ELF input with a new get_data_size helper that falls back to measuring the stream; use data_size for ELF section bounds validation. Add a regression test for reading an ELF from a non-file path stream and add assume-type-mismatch test cases in YAML.

Changes

Cohort / File(s)	Summary
ELF Reader Core src/io/elf_reader.cpp	Add static std::uintmax_t get_data_size(std::istream& input_stream, const std::string& path) that tries std::filesystem::file_size(path) then falls back to seek-to-end on input_stream; replace direct file_size usage with data_size for ELF loading and section bounds checks; throw MalformedElf if size cannot be determined.
ELF Loader Tests src/test/test_elf_loader.cpp	Add #include <sstream> and #include "io/elf_reader.hpp" and a new test TEST_CASE("read_elf succeeds with istream and non-file path", "[elf]") that loads ELF from an in-memory stream and asserts non-empty programs.
Assume Operation Test Data test-data/jump.yaml	Add regression cases covering assume comparisons with mismatched operand types (ctx vs number, packet vs number, stack vs number) including pre-state, code, expected post-state and diagnostic expectations.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• Use gsl::narrow in asm files #710 — Changes to istream-based ELF loading/read_elf signatures and callers; likely related to stream/path handling updates.

Suggested reviewers

• elazarg

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Out of Scope Changes check	❓ Inconclusive	Changes in elf_reader.cpp and test_elf_loader.cpp directly address #1049. The test-data/jump.yaml additions for Assume operations with mismatched types appear related to a separate assertion crash fix (#1012) but are included as regression tests per the PR summary.	Clarify whether the jump.yaml Assume regression test cases are necessary for this PR scope or should be split into a separate change addressing #1012.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main changes: fixing load_elf to support non-file istream paths and adding regression tests, matching the primary objectives in the PR.
Linked Issues check	✅ Passed	The PR implementation directly addresses all coding requirements from #1049: introduces get_data_size helper that falls back to stream seek/tell when file_size fails, replaces file_size usage with this helper for data size determination, preserves section-bounds validation, and adds corresponding regression tests.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[mikeagun]

@elazarg Hi Elazar, would you have time to review this soon?

[elazarg]

@elazarg Hi Elazar, would you have time to review this soon?

Hi, thanks for the PR! I plan to review it next week.

[elazarg]

Thanks for the commit! A small suggestion, and a note - this looks like two unrelated PRs. Please separate PRs in the future (no need to split this one now).

[elazarg]

@mikeagun note the DSO check failure - please amend-sign-off and force-push

[elazarg]

Thanks!