feat: PVM update 0.8.0

[TwEricShen]

Part of #1022

Summary

Aligns the PVM implementation with Gray Paper v0.8.0 Appendix A & B, including:

• Appendix A: basic block boundaries, gaschargedflag, A.9 ROB gas model, A.10 opcode cost tables, unlikely, branch/jump dual-target validation, deblob / 𝔳_inst first-run validation, IntegratedPVMType, etc.
• Appendix B: host call renumbering (grow_heap inserted at ID=1), per-function linear gas (Appendix H constants), invoke gas refund, machine 63-slot cap, bless / designate / query semantic updates.

The interpreter and recompiler share the same gas engine (GasCostForBlock / GasCostFromPC / blockGasAtPC). The recompiler bakes block gas at compile time (emitBlockGasCheck).

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Submodule: gas model test vectors

New submodule:

Field	Value
Path	pkg/test_data/new-gas-cost-model
Remote	https://github.com/koute/new-gas-cost-model.git
Purpose	GP A.9 gascostforblock vectors (aligned with koute / w3f/jamtestvectors PR #3)

Required for reviewers / CI (gas tests fail immediately if the vectors directory is missing):

git submodule update --init --recursive pkg/test_data/new-gas-cost-model
# or all submodules
git submodule update --init --recursive

Verify the submodule points at the expected commit:

git submodule status pkg/test_data/new-gas-cost-model

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Main changes (PVM)

Area	Files / modules	Description
A.9 Gas model	gas_sim.go, gas_opcode.go, gas_regs.go, gas_model.go	ROB pipeline simulation; gascostforblock = max(cycles−3, 1)
A.4 Block gas metering	invocation.go, block_info.go	Block-entry pre-charge, GasCharged flag, blockGasAtPC cache
A.10 + host gas	gas_const.go, host_call_*.go	Appendix H constants; MemGas linear billing
Recompiler	recompiler/gas.go, compiler.go	Per-instruction gas → block-level emitBlockGasCheck
Invoke / inner VM	host_call_refine.go, host_call_invoke_test.go	BlockBasedInvokeDecodedBlocks, suffix gas, gasChargedForIntegratedResume
Opcode / decode	instructions*.go, program_code.go	unlikely, branch dual-target, sjump, DeBlobProgramCode(blob, pc)
sbrk → grow_heap	host_call_general.go, recompiler emit	Opcode 101 semantics removed; heap growth via host call ID=1
Dual backend	execution_backend.go, interpreter/, recompiler/	PVM.WithExecutionBackend / SetExecutionBackend
Tooling	cmd/pvmtrace/deblob_program.go, scripts/scan_psi_a_program_blobs.py	Deblob API signature; scan Ψ_A program blobs from conformance traces

Implementation choice (not spelled out in GP)

Mid-block resume gas: when entry PC is mid-block and gaschargedflag=⊥, charge suffix GasCostFromPC(ι) (not the full containing block). Matches koute gas vectors and recompiler suffix compilation.

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Tests

Gas model (koute vectors) — expected all PASS

Data root: pkg/test_data/new-gas-cost-model/

Test function	What it checks	Vector prefix / dir	Count	Pass	Command
TestGasModelProgramVectors	End-to-end ROB / block gas scenarios	tests/programs/gas_*.json	23	23/23	go test ./PVM/ -run TestGasModelProgramVectors -count=1
TestGasModelInstVectors	Per-opcode block gas	tests/programs/inst_*.json	229	229/229	go test ./PVM/ -run TestGasModelInstVectors -count=1
TestGasModelRiscvVectors	Programs compiled from RISC-V	tests/programs/riscv_*.json	106	106/106	go test ./PVM/ -run TestGasModelRiscvVectors -count=1
TestGasModelMultistepVectors	ecalli / paging mid-block cases	tests/programs/multistep_*.json	4	4/4	go test ./PVM/ -run TestGasModelMultistepVectors -count=1
TestGasModelIntegrationVectors	Large programs + block gas tables	integration-tests/*.json	3	3/3	go test ./PVM/ -run TestGasModelIntegrationVectors -count=1
TestGasVectorHarnessSanity	JSON harness sanity (deblob, single-block consumed gas)	same gas_*.json	23	23/23	go test ./PVM/ -run TestGasVectorHarnessSanity -count=1

Total: 362 program vectors + 3 integration = 365 JSON files in the tree.

Run all gas-related tests:

go test ./PVM/ -count=1 -run 'TestGasModel|TestGasVectorHarnessSanity|TestBlockGasFromCycles|TestGasCost'

Each vector asserts GasCostForBlock(prog, pc) equals the JSON block-gas-costs entry.

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Gas model unit tests (non-vector)

Test function	What it checks	Command
TestBlockGasFromCycles	max(cycles−3, 1) formula	go test ./PVM/ -run TestBlockGasFromCycles -count=1
TestGasCostSingleTrapBlock	Trap block gas = 2	go test ./PVM/ -run TestGasCostSingleTrapBlock -count=1
TestGasCostMoveRegBlock	move_reg bypasses ROB	go test ./PVM/ -run TestGasCostMoveRegBlock -count=1
TestGasCostBranchToTrap	Branch → unlikely/trap costs	go test ./PVM/ -run TestGasCostBranchToTrap -count=1
TestInstructionCostEcalli / TestInstRegsEcalli	A.10 ecalli cost / reg analysis	`go test ./PVM/ -run 'TestInstructionCostEcalli

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Invocation / block gas behavior

Test function	What it checks	Command
TestBlockBasedInvokeDecodedBlocksChargesContainingBlock	Production path block charging	go test ./PVM/ -run TestBlockBasedInvokeDecodedBlocks -count=1
TestBlockBasedInvokeDecodedBlocksResumesAfterHostCall	Suffix gas after host call return	same
TestBlockBasedInvoke* / TestDebugSingleStepInvoke*	Legacy / trace paths	`go test ./PVM/ -run 'TestBlockBasedInvoke
TestBlockGasAtPCUsesCacheAtBlockEntry	Cache at block entry	go test ./PVM/ -run TestBlockGasAtPCUsesCacheAtBlockEntry -count=1
TestGasChargedForIntegratedResume / TestInvokeInnerTrapDeductsBlockGas	Inner invoke flag / gas	`go test ./PVM/ -run 'TestGasChargedForIntegratedResume

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Host-call gas / v0.8 semantics

Test function	What it checks	Command
TestAddGasAndUnitGasCost	MemGas / unit gas	go test ./PVM/ -run TestAddGasAndUnitGasCost -count=1
TestPagesGasCost	pages tiered gas	go test ./PVM/ -run TestPagesGasCost -count=1
TestLookupLinearGasOOG	Linear gas OOG	go test ./PVM/ -run TestLookupLinearGasOOG -count=1
TestQueryBlobLengthHUH / TestBlessManagerOnly	HUH boundaries	`go test ./PVM/ -run 'TestQueryBlobLengthHUH
TestFetchCost	fetch tiered gas	go test ./PVM/ -run TestFetchCost -count=1

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Recompiler (linux/amd64 + CGO)

Test function	What it checks	Command
TestCompileAllOpcodes	All opcodes compile	CGO_ENABLED=1 go test ./PVM/recompiler/ -run TestCompileAllOpcodes -count=1
TestExecuteInstructions	Compiled execution semantics	CGO_ENABLED=1 go test ./PVM/recompiler/ -run TestExecuteInstructions -count=1
TestBlockEntryOOGLeavesGasUnchanged	Block OOG leaves gas unchanged	CGO_ENABLED=1 go test ./PVM/recompiler/ -run TestBlockEntryOOG -count=1
TestBlockGasChargedAcrossHostCall	GasCharged flag across host call	CGO_ENABLED=1 go test ./PVM/recompiler/ -run TestBlockGasChargedAcrossHostCall -count=1
TestSuffixBlockGasMatchesGasCostFromPC	Suffix compile gas matches A.9	CGO_ENABLED=1 go test ./PVM/recompiler/ -run TestSuffixBlockGasMatchesGasCostFromPC -count=1
Makefile target	Recompiler tests in Docker	make run-recompiler-test

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Interpreter ↔ Recompiler consistency — currently FAIL (known)

Field	Details
Test function	TestInterpreterVsRecompilerProgramBlobs
What it checks	Same MetaCode program blob run through Ψ_M (Accumulate) on interpreter vs recompiler; requires matching Gas + ReasonOrBytes
Data	PVM/testdata/psi_a_consistency/blobs/*.bin (30 blobs)
How data was produced	scripts/scan_psi_a_program_blobs.py scans large keyvals (MetaCode preimages) from pkg/test_data/jam-conformance/fuzz-reports/0.7.2/traces/
Entry / gas	PC=5 (Ψ_A entry), gas=50_000_000
Platform	linux && amd64 && cgo
Command	make test-backend-consistency or CGO_ENABLED=1 go test -count=1 -timeout 30m -v ./PVM/ -run TestInterpreterVsRecompilerProgramBlobs
Current status	Failing; programs PANIC under 0.8.0 semantics (host call IDs shifted +1, grow_heap inserted, etc.) — not an interpreter/recompiler divergence
Note	Goal is backend consistency; meaningful only after refreshed 0.8 program blobs

Example blob scan:

python3 scripts/scan_psi_a_program_blobs.py \
  pkg/test_data/jam-conformance/fuzz-reports/0.7.2/traces \
  --limit-folders 30

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Suggested reviewer verification order

1. git submodule update --init --recursive pkg/test_data/new-gas-cost-model
2. Gas vectors: go test ./PVM/ -run 'TestGasModel|TestGasVectorHarnessSanity' -count=1
3. PVM unit tests: go test ./PVM/ -count=1 -skip TestInterpreterVsRecompilerProgramBlobs
4. CGO_ENABLED=1 go test ./PVM/recompiler/... -count=1 (linux/amd64)

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Related

• Gray Paper v0.7.2...v0.8.0 compare
• Gas vectors: koute/new-gas-cost-model / w3f/jamtestvectors PR #3