[Git][ghc/ghc][wip/romes/ghci-debugger-2] 5 commits: Do not deallocate stack for jump/switch table jumps
Rodrigo Mesquita (@alt-romes)
gitlab at gitlab.haskell.org
Fri Feb 28 10:34:03 UTC 2025
Rodrigo Mesquita pushed to branch wip/romes/ghci-debugger-2 at Glasgow Haskell Compiler / GHC
Commits:
a6a3ffa6 by Sven Tennie at 2025-02-27T23:34:47-05:00
Do not deallocate stack for jump/switch table jumps
Though the name is misleading, we consider them to be branching. For
branch instructions we do not deallocate (parts of) the stack, but keep
the stack pointer (sp) intact.
- - - - -
39e51ddb by Sven Tennie at 2025-02-27T23:34:47-05:00
Add reproducer for dealloc instructions in switch table jump expressions (#25733)
Measures taken to make the test stable:
- Use 'a' as variable prefix, because X86 32bit stumbled over the
variable name 'i386'
- Flush stdout to make test output deterministic
- Use type annotations to support 32bit archs
- - - - -
d427df93 by Sylvain Henry at 2025-02-27T23:35:30-05:00
Remove redundant location strings in expectJust and friends (#25743)
Now we can use HasDebugCallStack instead to avoid cluttering the code
with strings and to avoid maintaining those strings (e.g. renaming them
when functions are renamed...).
- - - - -
c74888eb by Rodrigo Mesquita at 2025-02-28T10:31:37+00:00
ghci: Don't set virtualCWD on every iteration
The calls to withVirtualCWD were introduced to fix #2973, but this bug
is no longer reproducible, even when `withVirtualCWD` is dropped.
This cleanup was originally motivated by the performance of :steplocal,
but the performance problem has now been fixed at its root in the next
commit.
Even then, `withVirtualCWD` seems to now be an unnecessary artifact, and
removing it simplifies the interpreter with no apparent drawbacks (testsuite is
also happy with this change)
- - - - -
e603f1c9 by Rodrigo Mesquita at 2025-02-28T10:33:51+00:00
ghci debugger: improve break/resume control flow
After interpreting bytecode (`evalStmt`), we may want to hand off
control to "GHCi.UI" in order to display an interactive break prompt:
1. When an /active/ breakpoint (one set with :break ...) is hit
2. At any breakpoint, when using :step from a breakpoint
3. At any breakpoint in the same function f, when :steplocal is called
from a breakpoint in f
4. At any breakpoint in the same module, when :stepmodule is used
Whether to pass control to the UI is now fully determined by
`handleRunStatus` which transforms an `EvalStatus_` into an
`ExecResult`. When `ExecBreak` is returned from `handleRunStatus` to
GHCi, it always means GHCi breaks.
`handleRunStatus` determines whether to loop and resume evaluation right away, or
when to return to GHCi (by returning `ExecBreak` or `ExecComplete`).
- (1) is queried using the `BreakpointStatus` message (the
`breakpointStatus` call)
- (2,3,4) are determined by the predicate `breakHere step span`, which
inspects the improved `SingleStep` type to determine whether we care
about this breakpoint even if it is not active.
This refactor solves two big performance problems with the previous control flow:
- We no longer call `withArgs/withProgram` repeatedly in the
break/resume loop, but rather just once "at the top".
- We now avoid computing the expensive `bindLocalsAtBreakpoint` for
breakpoints we'd never inspect.
In the interpreter_steplocal test added, calling `:steplocal` after breaking on `main = fib 25`
now takes 12 seconds rather than 49 seconds on my machine.
```
interpreter_steplocal(ghci) ghc/alloc 6,124,821,176 540,181,392 -91.2% GOOD
```
Fixes #25779
-------------------------
Metric Decrease:
interpreter_steplocal
-------------------------
- - - - -
102 changed files:
- compiler/GHC.hs
- compiler/GHC/Cmm/LayoutStack.hs
- compiler/GHC/Cmm/Liveness.hs
- compiler/GHC/Cmm/MachOp.hs
- compiler/GHC/Cmm/ProcPoint.hs
- compiler/GHC/CmmToAsm/AArch64/Instr.hs
- compiler/GHC/CmmToAsm/BlockLayout.hs
- compiler/GHC/CmmToAsm/CFG.hs
- compiler/GHC/CmmToAsm/PPC/Instr.hs
- compiler/GHC/CmmToAsm/Reg/Graph/SpillCost.hs
- compiler/GHC/CmmToAsm/Reg/Linear/JoinToTargets.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToLlvm/CodeGen.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Coercion/Opt.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Make.hs
- compiler/GHC/Core/Opt/CprAnal.hs
- compiler/GHC/Core/Opt/FloatIn.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/Simplify/Iteration.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Opt/StaticArgs.hs
- compiler/GHC/Core/Opt/WorkWrap/Utils.hs
- compiler/GHC/Core/SimpleOpt.hs
- compiler/GHC/Core/TyCo/Subst.hs
- compiler/GHC/Core/TyCon/Env.hs
- compiler/GHC/CoreToStg/Prep.hs
- compiler/GHC/Data/FastString/Env.hs
- compiler/GHC/Data/Graph/Directed.hs
- compiler/GHC/Data/Graph/Directed/Reachability.hs
- compiler/GHC/Data/Maybe.hs
- compiler/GHC/Driver/Backpack.hs
- compiler/GHC/Driver/Env.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Make.hs
- compiler/GHC/Driver/Pipeline.hs
- compiler/GHC/Driver/Pipeline/Execute.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Hs/Utils.hs
- compiler/GHC/HsToCore.hs
- compiler/GHC/HsToCore/Expr.hs
- compiler/GHC/HsToCore/Foreign/JavaScript.hs
- compiler/GHC/HsToCore/Match.hs
- compiler/GHC/HsToCore/Match/Constructor.hs
- compiler/GHC/HsToCore/Pmc/Desugar.hs
- compiler/GHC/HsToCore/Pmc/Solver.hs
- compiler/GHC/HsToCore/Quote.hs
- compiler/GHC/Iface/Decl.hs
- compiler/GHC/Iface/Ext/Ast.hs
- compiler/GHC/Iface/Syntax.hs
- compiler/GHC/Iface/Tidy.hs
- compiler/GHC/IfaceToCore.hs
- compiler/GHC/JS/Make.hs
- compiler/GHC/JS/Ppr.hs
- compiler/GHC/Linker/Deps.hs
- compiler/GHC/Parser/Header.hs
- compiler/GHC/Rename/Bind.hs
- compiler/GHC/Rename/HsType.hs
- compiler/GHC/Rename/Names.hs
- compiler/GHC/Runtime/Eval.hs
- compiler/GHC/Runtime/Eval/Types.hs
- compiler/GHC/Runtime/Interpreter.hs
- compiler/GHC/Stg/EnforceEpt.hs
- compiler/GHC/Stg/EnforceEpt/Rewrite.hs
- compiler/GHC/Stg/EnforceEpt/Types.hs
- compiler/GHC/Stg/Unarise.hs
- compiler/GHC/StgToByteCode.hs
- compiler/GHC/StgToCmm/Expr.hs
- compiler/GHC/StgToCmm/Foreign.hs
- compiler/GHC/StgToCmm/Lit.hs
- compiler/GHC/StgToJS/Literal.hs
- compiler/GHC/Tc/Deriv/Generate.hs
- compiler/GHC/Tc/Deriv/Generics.hs
- compiler/GHC/Tc/Errors.hs
- compiler/GHC/Tc/Errors/Ppr.hs
- compiler/GHC/Tc/Gen/Export.hs
- compiler/GHC/Tc/Gen/Expr.hs
- compiler/GHC/Tc/Gen/Match.hs
- compiler/GHC/Tc/Gen/Pat.hs
- compiler/GHC/Tc/Instance/Class.hs
- compiler/GHC/Tc/Instance/Family.hs
- compiler/GHC/Tc/TyCl.hs
- compiler/GHC/Tc/Utils/TcType.hs
- compiler/GHC/Tc/Zonk/Type.hs
- compiler/GHC/Types/Demand.hs
- compiler/GHC/Types/Name/Env.hs
- compiler/GHC/Types/Var/Env.hs
- compiler/GHC/Unit/Env.hs
- compiler/GHC/Unit/Home/Graph.hs
- compiler/GHC/Unit/Home/PackageTable.hs
- compiler/GHC/Unit/Module/Graph.hs
- compiler/GHC/Unit/Module/ModSummary.hs
- compiler/GHC/Unit/State.hs
- compiler/GHC/Utils/Misc.hs
- ghc/GHCi/UI.hs
- ghc/GHCi/UI/Monad.hs
- + testsuite/tests/cmm/should_run/JumpTableNoStackDealloc.hs
- + testsuite/tests/cmm/should_run/JumpTableNoStackDealloc.stdout
- + testsuite/tests/cmm/should_run/JumpTableNoStackDeallocGen.hs
- + testsuite/tests/cmm/should_run/JumpTableNoStackDealloc_cmm.cmm
- testsuite/tests/cmm/should_run/all.T
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/99c35f9153be108da5fdc6d01700a811bdd3b44b...e603f1c9abe3a8a6a3ac2bbeb8eb28ca54587ba4
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/99c35f9153be108da5fdc6d01700a811bdd3b44b...e603f1c9abe3a8a6a3ac2bbeb8eb28ca54587ba4
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