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Fix some nasty callgraph dangling pointer problems in

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argpromotion and structretpromote.  Basically, when replacing
a function, they used the 'changeFunction' api which changes
the entry in the function map (and steals/reuses the callgraph
node).

This has some interesting effects: first, the problem is that it doesn't
update the "callee" edges in any callees of the function in the call graph.
Second, this covers for a major problem in all the CGSCC pass stuff, which 
is that it is completely broken when functions are deleted if they *don't*
reuse a CGN.  (there is a cute little fixme about this though :).

This patch changes the protocol that CGSCC passes must obey: now the CGSCC 
pass manager copies the SCC and preincrements its iterator to avoid passes
invalidating it.  This allows CGSCC passes to mutate the current SCC.  However
multiple passes may be run on that SCC, so if passes do this, they are now
required to *update* the SCC to be current when they return.

Other less interesting parts of this patch are that it makes passes update
the CG more directly, eliminates changeFunction, and requires clients of
replaceCallSite to specify the new callee CGN if they are changing it.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80527 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2009-08-31 00:19:58 +00:00
parent 52248ff682
commit 5095e3d1d1
11 changed files with 112 additions and 88 deletions
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4
lib/Transforms/IPO/FunctionAttrs.cpp
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@ -44,7 +44,7 @@ namespace {
FunctionAttrs() : CallGraphSCCPass(&ID) {}
// runOnSCC - Analyze the SCC, performing the transformation if possible.
bool runOnSCC(const std::vector<CallGraphNode *> &SCC);
bool runOnSCC(std::vector<CallGraphNode *> &SCC);
// AddReadAttrs - Deduce readonly/readnone attributes for the SCC.
bool AddReadAttrs(const std::vector<CallGraphNode *> &SCC);
@ -339,7 +339,7 @@ bool FunctionAttrs::AddNoAliasAttrs(const std::vector<CallGraphNode *> &SCC) {
return MadeChange;
}
bool FunctionAttrs::runOnSCC(const std::vector<CallGraphNode *> &SCC) {
bool FunctionAttrs::runOnSCC(std::vector<CallGraphNode *> &SCC) {
bool Changed = AddReadAttrs(SCC);
Changed |= AddNoCaptureAttrs(SCC);
Changed |= AddNoAliasAttrs(SCC);