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[rocjitsu] Cover oversized register region copies #15121

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Merged
IanWood1 merged 1 commit into from
Nov 5, 2026
+28 −1
Merged

[rocjitsu] Cover oversized register region copies #15121

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3 changes: 2 additions & 1 deletion emulation/rocjitsu/lib/rocjitsu/src/rocjitsu/vm/amdgpu/compute_unit.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1339,7 +1339,8 @@ class RJ_API_TYPE_EXPORT ComputeUnitCore : public simdojo::CompositeComponent {
/// `UnimplementedInst::what()` when that legacy exception is translated.
/// Otherwise the pointed-to string is unchanged.
/// @returns Failure for an unimplemented instruction stub or a reported operand
/// failure. The wavefront retains the reason for caller-owned diagnostics.
/// or register-access failure. The wavefront retains the reason for caller-owned
/// diagnostics.
/// Each call clears the previous error; a failed call does not halt the wavefront.
/// Other host failures inside implemented instructions still raise exceptions.
util::Result execute_instruction(Instruction *inst, Wavefront &wf,
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3 changes: 3 additions & 0 deletions emulation/rocjitsu/lib/rocjitsu/src/rocjitsu/vm/amdgpu/register_access.h
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Expand Up @@ -806,6 +806,9 @@ class RegisterAccess {
});
}

/// @brief Return raw lane words for one register in the region.
/// @returns Failure for a partial-byte region, reporting InvalidRegisterAccess
/// through the wavefront's instruction-execution error channel.
FailureOr<std::span<const uint32_t>> lanes(uint32_t relative_reg = 0) const {
assert(relative_reg < reg_count_ && "relative VGPR outside read region");
if (byte_mask_ != rocjitsu::ExecutionPlugin::kFullByteMask)
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23 changes: 23 additions & 0 deletions emulation/rocjitsu/tests/register_access_test.cpp
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Expand Up @@ -1883,6 +1883,29 @@ TEST(RegisterAccessTest, PartialByteRawRegionOperationsRejectBeforeSideEffects)
expect_failure([&] { return region.copy_dwords_lane_major(bytes, 1); });
}

TEST(RegisterAccessTest, OversizedRawRegionCopyRejectsBeforeSideEffects) {
Fixture fx(ROCJITSU_CODE_ARCH_CDNA4, kSgprsPerWave, /*wavefront_slots=*/1, kVgprsPerWave,
/*wave_size=*/64);
ASSERT_NE(fx.wf, nullptr);
ASSERT_EQ(fx.wf->wf_size(), 64u);
for (uint32_t lane = 0; lane < fx.wf->wf_size(); ++lane)
fx.cu->write_vgpr(fx.vgpr_base(), lane, 0x12340000u + lane);
auto region = RegisterAccess(*fx.wf).read_vgpr_region(
fx.vgpr_base(), /*reg_count=*/1, /*lane_mask=*/~uint64_t{0}, ExecutionPlugin::kFullByteMask);
ASSERT_TRUE(region.valid());
std::array<uint32_t, 65> words;
words.fill(0xAABBCCDDu);
const auto original_words = words;

fx.wf->clear_instruction_execution_error();
ASSERT_EQ(fx.wf->instruction_execution_error(), InstructionExecutionError::None);
ASSERT_EQ(fx.wf->instruction_execution_error_detail(), nullptr);
EXPECT_TRUE(region.copy_to(words).failed());
EXPECT_EQ(fx.wf->instruction_execution_error(), InstructionExecutionError::InvalidRegisterAccess);
EXPECT_STREQ(fx.wf->instruction_execution_error_detail(), "destination exceeds read region");
EXPECT_EQ(words, original_words);
}

TEST(RegisterAccessTest, ScalarBackedPartialByteStoresRejectBeforeObservation) {
Fixture fx;
ASSERT_NE(fx.wf, nullptr);
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