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authorChris Lattner <sabre@nondot.org>2005-03-24 03:04:50 +0000
committerChris Lattner <sabre@nondot.org>2005-03-24 03:04:50 +0000
commit7d671b88e890434ef99edb628d5a5cbc5ff208c6 (patch)
tree2d9fbf4597fe419a9e70d8d83174928a4d1dd16e /lib/Analysis
parent62da315c859eb20e0ad38c034f71901ac6558d4d (diff)
teach ds-aa about mod/ref for external function calls.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20801 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis')
-rw-r--r--lib/Analysis/DataStructure/DataStructureAA.cpp26
1 files changed, 25 insertions, 1 deletions
diff --git a/lib/Analysis/DataStructure/DataStructureAA.cpp b/lib/Analysis/DataStructure/DataStructureAA.cpp
index 65bdc6e2f2c..6f1cb56d860 100644
--- a/lib/Analysis/DataStructure/DataStructureAA.cpp
+++ b/lib/Analysis/DataStructure/DataStructureAA.cpp
@@ -178,9 +178,33 @@ DSAA::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
AliasAnalysis::ModRefResult Result =AliasAnalysis::getModRefInfo(CS, P, Size);
Function *F = CS.getCalledFunction();
- if (!F || F->isExternal() || Result == NoModRef)
+ if (!F || Result == NoModRef)
return Result;
+ if (F->isExternal()) {
+ // If we are calling an external function, and if this global doesn't escape
+ // the portion of the program we have analyzed, we can draw conclusions
+ // based on whether the global escapes the program.
+ Function *Caller = CS.getInstruction()->getParent()->getParent();
+ DSGraph *G = &TD->getDSGraph(*Caller);
+ DSScalarMap::iterator NI = G->getScalarMap().find(P);
+ if (NI == G->getScalarMap().end()) {
+ // If it wasn't in the local function graph, check the global graph. This
+ // can occur for globals who are locally reference but hoisted out to the
+ // globals graph despite that.
+ G = G->getGlobalsGraph();
+ NI = G->getScalarMap().find(P);
+ if (NI == G->getScalarMap().end())
+ return Result;
+ }
+
+ // If we found a node and it's complete, it cannot be passed out to the
+ // called function.
+ if (NI->second.getNode()->isComplete())
+ return NoModRef;
+ return Result;
+ }
+
// Get the graphs for the callee and caller. Note that we want the BU graph
// for the callee because we don't want all caller's effects incorporated!
const Function *Caller = CS.getInstruction()->getParent()->getParent();