Alias analysis chaining doesn't work

[asl]

Bugzilla Link	1518
Resolution	WONTFIX
Resolved on	Feb 22, 2010 12:42
Version	trunk
OS	Linux

Extended Description

Consider attached source file. This is our custom alias analysis helper for
llvm-qemu. It's easy to check, that it can be ImmutablePass, not ModulePass.

But this approach doesn't work (simple change ModulePass to ImmutablePass
everywhere plus runModule() -> initializePass()).

Also (maybe unrealted) - the name of BasicAA is reported wrong at -time-passes,
the name of its superclass is reported instead (NoAA)

[asl]

Ah, doesn't work = pass is initialized, but alias() method never called.

[asl]

QEMUAlisAnalysis.cpp

[llvmbot]

It works...

(gdb) r -qemu-aa -disable-output /tmp/a.bc -debug-pass=Structure -aa-eval
Starting program: /Volumes/src/llvm/Debug/bin/opt -qemu-aa -disable-output /tmp/a.bc -debug-
pass=Structure -aa-eval
Pass Arguments: -qemu-aa -aa-eval -domtree -verify
Target Data Layout
Basic Alias Analysis (default AA impl)
ModulePass Manager
QEMU Alias Analysis
FunctionPass Manager
Exhaustive Alias Analysis Precision Evaluator
-- Exhaustive Alias Analysis Precision Evaluator
Dominator Tree Construction
Module Verifier
-- Module Verifier
-- Dominator Tree Construction
-- QEMU Alias Analysis
===== Alias Analysis Evaluator Report =====
6 Total Alias Queries Performed
3 no alias responses (50.0%)
2 may alias responses (33.3%)
1 must alias responses (16.6%)
Alias Analysis Evaluator Pointer Alias Summary: 50%/33%/16%
Alias Analysis Mod/Ref Evaluator Summary: no mod/ref!

[llvmbot]

:)

[llvmbot]

There can be only one immutable alias analysis as it acts as default analysis. QEMUAliasAnalysis uses
basic aa as the default analysis so QEMUAliasAnalysis itself can not be an immutable alias analysis.

[llvmbot]

Updated docs.

[llvmbot]

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20070618/050656.html