Cheng Shao pushed to branch wip/ubsan at Glasgow Haskell Compiler / GHC Commits: 5cdcfaed by Ben Gamari at 2025-11-06T09:01:36-05:00 compiler: Exclude units with no exposed modules from unused package check Such packages cannot be "used" in the Haskell sense of the word yet are nevertheless necessary as they may provide, e.g., C object code or link flags. Fixes #24120. - - - - - 74b8397a by Brandon Chinn at 2025-11-06T09:02:19-05:00 Replace deprecated argparse.FileType - - - - - 36ddf988 by Ben Gamari at 2025-11-06T09:03:01-05:00 Bump unix submodule to 2.8.8.0 Closes #26474. - - - - - c32b3a29 by fendor at 2025-11-06T09:03:43-05:00 Fix assertion in `postStringLen` to account for \0 byte We fix the assertion to handle trailing \0 bytes in `postStringLen`. Before this change, the assertion looked like this: ASSERT(eb->begin + eb->size > eb->pos + len + 1); Let's assume some values to see why this is actually off by one: eb->begin = 0 eb->size = 1 eb->pos = 0 len = 1 then the assertion would trigger correctly: 0 + 1 > 0 + 1 + 1 => 1 > 2 => false as there is not enough space for the \0 byte (which is the trailing +1). However, if we change `eb->size = 2`, then we do have enough space for a string of length 1, but the assertion still fails: 0 + 2 > 0 + 1 + 1 => 2 > 2 => false Which causes the assertion to fail if there is exactly enough space for the string with a trailing \0 byte. Clearly, the assertion should be `>=`! If we switch around the operand, it should become more obvious that `<=` is the correct comparison: ASSERT(eb->pos + len + 1 <= eb->begin + eb->size); This is expresses more naturally that the current position plus the length of the string (and the null byte) must be smaller or equal to the overall size of the buffer. This change also is in line with the implementation in `hasRoomForEvent` and `hasRoomForVariableEvent`: ``` StgBool hasRoomForEvent(EventsBuf *eb, EventTypeNum eNum) { uint32_t size = ...; if (eb->pos + size > eb->begin + eb->size) ... ``` the check `eb->pos + size > eb->begin + eb->size` is identical to `eb->pos + size <= eb->begin + eb->size` plus a negation. - - - - - 3034a6f2 by Ben Gamari at 2025-11-06T09:04:24-05:00 Bump os-string submodule to 2.0.8 - - - - - 39567e85 by Cheng Shao at 2025-11-06T09:05:06-05:00 rts: use computed goto for instruction dispatch in the bytecode interpreter This patch uses computed goto for instruction dispatch in the bytecode interpreter. Previously instruction dispatch is done by a classic switch loop, so executing the next instruction requires two jumps: one to the start of the switch loop and another to the case block based on the instruction tag. By using computed goto, we can build a jump table consisted of code addresses indexed by the instruction tags themselves, so executing the next instruction requires only one jump, to the destination directly fetched from the jump table. Closes #12953. - - - - - 93fc7265 by sheaf at 2025-11-06T21:33:24-05:00 Correct hasFixedRuntimeRep in matchExpectedFunTys This commit fixes a bug in the representation-polymormorphism check in GHC.Tc.Utils.Unify.matchExpectedFunTys. The problem was that we put the coercion resulting from hasFixedRuntimeRep in the wrong place, leading to the Core Lint error reported in #26528. The change is that we have to be careful when using 'mkWpFun': it expects **both** the expected and actual argument types to have a syntactically fixed RuntimeRep, as explained in Note [WpFun-FRR-INVARIANT] in GHC.Tc.Types.Evidence. On the way, this patch improves some of the commentary relating to other usages of 'mkWpFun' in the compiler, in particular in the view pattern case of 'tc_pat'. No functional changes, but some stylistic changes to make the code more readable, and make it easier to understand how we are upholding the WpFun-FRR-INVARIANT. Fixes #26528 - - - - - c052c724 by Simon Peyton Jones at 2025-11-06T21:34:06-05:00 Fix a horrible shadowing bug in implicit parameters Fixes #26451. The change is in GHC.Tc.Solver.Monad.updInertDicts where we now do /not/ delete /Wanted/ implicit-parameeter constraints. This bug has been in GHC since 9.8! But it's quite hard to provoke; I contructed a tests in T26451, but it was hard to do so. - - - - - b253013e by Georgios Karachalias at 2025-11-07T17:21:57-05:00 Remove the `CoreBindings` constructor from `LinkablePart` Adjust HscRecompStatus to disallow unhydrated WholeCoreBindings from being passed as input to getLinkDeps (which would previously panic in this case). Fixes #26497 - - - - - ac7b737e by Sylvain Henry at 2025-11-07T17:22:51-05:00 Testsuite: pass ext-interp test way (#26552) Note that some tests are still marked as broken with the ext-interp way (see #26552 and #14335) - - - - - b10a1105 by Cheng Shao at 2025-11-08T13:11:06+01:00 hadrian: add support for building with UndefinedBehaviorSanitizer This patch adds a +ubsan flavour transformer to hadrian to build all stage1+ C/C++ code with UndefinedBehaviorSanitizer. This is particularly useful to catch potential undefined behavior in the RTS codebase. - - - - - 37 changed files: - compiler/GHC/Driver/Main.hs - compiler/GHC/Driver/Make.hs - compiler/GHC/Driver/Pipeline.hs - compiler/GHC/Linker/Deps.hs - compiler/GHC/Linker/Types.hs - compiler/GHC/Tc/Gen/Expr.hs - compiler/GHC/Tc/Gen/Pat.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Types/Evidence.hs - compiler/GHC/Tc/Utils/Instantiate.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Unit/Home/ModInfo.hs - compiler/GHC/Unit/Module/Status.hs - compiler/GHC/Unit/Module/WholeCoreBindings.hs - docs/users_guide/compare-flags.py - hadrian/doc/flavours.md - hadrian/src/Flavour.hs - libraries/base/tests/all.T - libraries/os-string - libraries/unix - rts/Interpreter.c - rts/eventlog/EventLog.c - rts/gen_event_types.py - rts/include/rts/Bytecodes.h - rts/rts.cabal - testsuite/driver/runtests.py - testsuite/driver/testlib.py - testsuite/tests/driver/T20696/all.T - + testsuite/tests/driver/T24120.hs - testsuite/tests/driver/all.T - testsuite/tests/driver/fat-iface/all.T - + testsuite/tests/rep-poly/T26528.hs - testsuite/tests/rep-poly/all.T - testsuite/tests/splice-imports/all.T - + testsuite/tests/typecheck/should_compile/T26451.hs - testsuite/tests/typecheck/should_compile/all.T The diff was not included because it is too large. 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