[Type checker] Keep the type checker alive as long as the ASTContext is.

[DougGregor]

It is possible for the SIL optimizers, IRGen, etc. to request information
from the AST that only the type checker can provide, but the type checker
is typically torn down after the “type checking” phase. This can lead to
various crashes late in the compilation cycle.

Keep the type checker instance around as long as the ASTContext is alive
or until someone asks for it to be destroyed.

Fixes SR-285 / rdar://problem/23677338.

[DougGregor]

@swift-ci please test

[DougGregor]

@swift-ci please test source compatibility

[DougGregor]

@swift-ci please smoke test compiler performance

[swift-ci]

Build failed
Swift Test Linux Platform
Git Sha - 599e07e

[swift-ci]

Build comment file:

Summary for master smoketest

Unexpected test results, excluded stats for Kingfisher, ReactiveCocoa

Regressions found (see below)

• Debug
  • debug brief
  • debug detailed
• Release
  • release brief
  • release detailed

Debug

debug brief

Regressed (0)

name	old	new	delta	delta_pct

Improved (0)

name	old	new	delta	delta_pct

Unchanged (delta < 1.0% or delta < 100.0ms) (3)

name	old	new	delta	delta_pct
Frontend.NumInstructionsExecuted	182,643,279,658	182,728,161,393	84,881,735	0.05%
LLVM.NumLLVMBytesOutput	9,495,152	9,495,152	0	0.0%
time.swift-driver.wall	23.4s	23.4s	15.5ms	0.07%

debug detailed

Regressed (0)

name	old	new	delta	delta_pct

Improved (0)

name	old	new	delta	delta_pct

Unchanged (delta < 1.0% or delta < 100.0ms) (23)

name	old	new	delta	delta_pct
AST.NumImportedExternalDefinitions	4,559	4,559	0	0.0%
AST.NumLoadedModules	1,578	1,578	0	0.0%
AST.NumTotalClangImportedEntities	17,921	17,921	0	0.0%
AST.NumUsedConformances	1,352	1,352	0	0.0%
IRModule.NumIRBasicBlocks	32,527	32,527	0	0.0%
IRModule.NumIRFunctions	16,460	16,460	0	0.0%
IRModule.NumIRGlobals	14,145	14,145	0	0.0%
IRModule.NumIRInsts	443,820	443,820	0	0.0%
IRModule.NumIRValueSymbols	29,340	29,340	0	0.0%
LLVM.NumLLVMBytesOutput	9,495,152	9,495,152	0	0.0%
SILModule.NumSILGenFunctions	7,843	7,843	0	0.0%
SILModule.NumSILOptFunctions	10,695	10,695	0	0.0%
Sema.NumConformancesDeserialized	23,229	23,229	0	0.0%
Sema.NumConstraintScopes	70,308	70,308	0	0.0%
Sema.NumDeclsDeserialized	229,254	229,254	0	0.0%
Sema.NumDeclsValidated	16,641	16,641	0	0.0%
Sema.NumFunctionsTypechecked	6,090	6,090	0	0.0%
Sema.NumGenericSignatureBuilders	7,320	7,391	71	0.97%
Sema.NumLazyGenericEnvironments	52,371	52,371	0	0.0%
Sema.NumLazyGenericEnvironmentsLoaded	2,363	2,363	0	0.0%
Sema.NumLazyIterableDeclContexts	43,925	43,925	0	0.0%
Sema.NumTypesDeserialized	100,312	100,312	0	0.0%
Sema.NumTypesValidated	14,185	14,185	0	0.0%

Release

release brief

Regressed (0)

name	old	new	delta	delta_pct

Improved (0)

name	old	new	delta	delta_pct

Unchanged (delta < 1.0% or delta < 100.0ms) (3)

name	old	new	delta	delta_pct
Frontend.NumInstructionsExecuted	222,304,333,122	222,299,961,234	-4,371,888	-0.0%
LLVM.NumLLVMBytesOutput	10,617,520	10,617,512	-8	-0.0%
time.swift-driver.wall	41.2s	41.1s	-145.2ms	-0.35%

release detailed

Regressed (1)

name	old	new	delta	delta_pct
Sema.NumGenericSignatureBuilders	2,025	2,079	54	2.67% ⛔

Improved (0)

name	old	new	delta	delta_pct

Unchanged (delta < 1.0% or delta < 100.0ms) (22)

name	old	new	delta	delta_pct
AST.NumImportedExternalDefinitions	1,111	1,111	0	0.0%
AST.NumLoadedModules	105	105	0	0.0%
AST.NumTotalClangImportedEntities	4,574	4,574	0	0.0%
AST.NumUsedConformances	1,354	1,354	0	0.0%
IRModule.NumIRBasicBlocks	34,490	34,490	0	0.0%
IRModule.NumIRFunctions	15,010	15,010	0	0.0%
IRModule.NumIRGlobals	13,678	13,678	0	0.0%
IRModule.NumIRInsts	333,002	333,002	0	0.0%
IRModule.NumIRValueSymbols	27,634	27,634	0	0.0%
LLVM.NumLLVMBytesOutput	10,617,520	10,617,512	-8	-0.0%
SILModule.NumSILGenFunctions	6,076	6,076	0	0.0%
SILModule.NumSILOptFunctions	9,042	9,042	0	0.0%
Sema.NumConformancesDeserialized	15,090	15,090	0	0.0%
Sema.NumConstraintScopes	69,604	69,419	-185	-0.27%
Sema.NumDeclsDeserialized	45,610	45,610	0	0.0%
Sema.NumDeclsValidated	10,362	10,362	0	0.0%
Sema.NumFunctionsTypechecked	4,162	4,162	0	0.0%
Sema.NumLazyGenericEnvironments	10,068	10,068	0	0.0%
Sema.NumLazyGenericEnvironmentsLoaded	201	201	0	0.0%
Sema.NumLazyIterableDeclContexts	5,826	5,826	0	0.0%
Sema.NumTypesDeserialized	26,691	26,691	0	0.0%
Sema.NumTypesValidated	7,103	7,103	0	0.0%

---

[DougGregor]

@swift-ci please smoke test

[DougGregor]

@swift-ci please smoke test

[gottesmm]

+1!