Hannes Siebenhandl pushed to branch wip/fendor/hpc-bc-support at Glasgow Haskell Compiler / GHC Commits: 2169ba58 by fendor at 2026-04-13T09:26:03+02:00 Make HPC work with bytecode interpreter Add support to generate .tix files from bytecode objects and the bytecode interpreter. Conceptually, we insert HPC ticks into the bytecode similar to how we insert breakpoints. HPC and breakpoints do not share the same tick array but we use a separate tick-array for hpc/breakpoint ticks during bytecode generation. We teach the bytecode interpreter to handle hpc ticks. The implementation is quite trivial, simply increment the counter in the global hpc_ticks array for the respective module. This hpc_ticks array is generated as part of the `CStub`, so we can rely on it existing. A tricky bit is "registering" a bytecode object for HPC instrumentation. In the compiled case, this is achieved via CStub and initializer/finalizers `.init` sections which are called when the executable is run. After the initializers have been invoked, which is before `hs_init_ghc`, we then call `startup_hpc` in `hs_init_ghc` iff any modules were "registered" for hpc instrumentation via `hs_hpc_module`. Since bytecode objects are loaded after starting up GHCi, this workflow doesn't work for supporting `hpc` and the `hpc` run-time is never started, even if a module is added for instrumentation. We fix this issue by employing the same technique as is for `SptEntry`s: * We introduce a new field to `CompiledByteCode`, called `ByteCodeHpcInfo` which contains enough information to call `hs_hpc_module`, allowing us to register the module for `hpc` instrumentation`. * After registering the module, we unconditionally call `startupHpc`, to make sure the .tix file is written. Calling `startupHpc` multiple times is safe. Calling `hs_hpc_module` multiple times for the same module is also safe. If we didn't register the hpc module in this way, evaluating a bytecode object instrumented with `-fhpc` without registering it in the `hpc` run-time will simply not generate any `.tix` files for this bytecode object. However, this shouldn't happen if everything is set up correctly. Closes #27036 - - - - - 51 changed files: - compiler/GHC/ByteCode/Asm.hs - compiler/GHC/ByteCode/Binary.hs - compiler/GHC/ByteCode/Instr.hs - compiler/GHC/ByteCode/Types.hs - compiler/GHC/Driver/Backend.hs - compiler/GHC/Driver/CodeOutput.hs - compiler/GHC/Driver/Main.hs - compiler/GHC/Driver/Session.hs - compiler/GHC/HsToCore.hs - compiler/GHC/HsToCore/Coverage.hs - compiler/GHC/HsToCore/Ticks.hs - compiler/GHC/Iface/Tidy.hs - compiler/GHC/Linker/Loader.hs - compiler/GHC/Runtime/Interpreter.hs - compiler/GHC/StgToByteCode.hs - compiler/GHC/Types/HpcInfo.hs - compiler/GHC/Unit/Module/ModGuts.hs - + libraries/ghci/GHCi/Coverage.hs - libraries/ghci/GHCi/Message.hs - libraries/ghci/GHCi/Run.hs - libraries/ghci/ghci.cabal.in - rts/Disassembler.c - rts/Hpc.c - rts/Interpreter.c - rts/include/rts/Bytecodes.h - testsuite/tests/hpc/Makefile - testsuite/tests/hpc/T17073.stdout → testsuite/tests/hpc/T17073a.stdout - + testsuite/tests/hpc/T17073b.stdout - testsuite/tests/hpc/T20568.stdout → testsuite/tests/hpc/T20568a.stdout - + testsuite/tests/hpc/T20568b.stdout - testsuite/tests/hpc/all.T - testsuite/tests/hpc/fork/Makefile - testsuite/tests/hpc/function/Makefile - testsuite/tests/hpc/function/test.T - + testsuite/tests/hpc/function/tough1.stderr - + testsuite/tests/hpc/function/tough1.stdout - testsuite/tests/hpc/function2/test.T - + testsuite/tests/hpc/function2/tough3.script - + testsuite/tests/hpc/ghc_ghci/BytecodeMain.hs - testsuite/tests/hpc/ghc_ghci/Makefile - + testsuite/tests/hpc/ghc_ghci/hpc_ghc_ghci_bytecode.stdout - testsuite/tests/hpc/ghc_ghci/test.T - testsuite/tests/hpc/hpcrun.pl - testsuite/tests/hpc/simple/Makefile - + testsuite/tests/hpc/simple/hpc002.hs - + testsuite/tests/hpc/simple/hpc002.stdout - + testsuite/tests/hpc/simple/hpc003.hs - + testsuite/tests/hpc/simple/hpc003.script - + testsuite/tests/hpc/simple/hpc003.stderr - + testsuite/tests/hpc/simple/hpc003.stdout - testsuite/tests/hpc/simple/test.T The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2169ba58505b46032346792404bb962d... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2169ba58505b46032346792404bb962d... You're receiving this email because of your account on gitlab.haskell.org.