jyapayne/Nim
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

--exception:goto switch for deterministic exception handling (#12977)

Browse source 
This implements "deterministic" exception handling for Nim based on goto instead of setjmp. This means raising an exception is much cheaper than in C++'s table based implementations. Supports hard realtime systems. Default for --gc:arc and the C target because it's generally a good idea and arc is all about deterministic behavior.

Note: This implies that fatal runtime traps are not catchable anymore! This needs to be documented.
This commit is contained in:
Andreas Rumpf 2020-01-01 10:01:49 +01:00 • committed by GitHub
commit c3344862b0
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
23 changed files with 640 additions and 183 deletions
Download patch file Download diff file Expand all files Collapse all files

11
compiler/ast.nim
View file

@ -1763,7 +1763,7 @@ proc toObject*(typ: PType): PType =
proc isImportedException*(t: PType; conf: ConfigRef): bool =
assert t != nil
if optNoCppExceptions in conf.globalOptions:
if conf.exc != excCpp:
return false
let base = t.skipTypes({tyAlias, tyPtr, tyDistinct, tyGenericInst})
@ -1834,7 +1834,7 @@ template assignment*(t: PType): PSym = t.attachedOps[attachedAsgn]
template asink*(t: PType): PSym = t.attachedOps[attachedSink]
const magicsThatCanRaise = {
mNone, mSlurp, mStaticExec, mParseExprToAst, mParseStmtToAst}
mNone, mSlurp, mStaticExec, mParseExprToAst, mParseStmtToAst, mEcho}
proc canRaiseConservative*(fn: PNode): bool =
if fn.kind == nkSym and fn.sym.magic notin magicsThatCanRaise:
@ -1844,9 +1844,12 @@ proc canRaiseConservative*(fn: PNode): bool =
proc canRaise*(fn: PNode): bool =
if fn.kind == nkSym and (fn.sym.magic notin magicsThatCanRaise or
{sfImportc, sfInfixCall} * fn.sym.flags == {sfImportc}):
{sfImportc, sfInfixCall} * fn.sym.flags == {sfImportc} or
sfGeneratedOp in fn.sym.flags):
result = false
elif fn.kind == nkSym and fn.sym.magic == mEcho:
result = true
else:
result = fn.typ != nil and ((fn.typ.n[0].len < effectListLen) or
result = fn.typ != nil and fn.typ.n != nil and ((fn.typ.n[0].len < effectListLen) or
(fn.typ.n[0][exceptionEffects] != nil and
fn.typ.n[0][exceptionEffects].safeLen > 0))