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Add the IR attribute 'sspstrong'.

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SSPStrong applies a heuristic to insert stack protectors in these situations:

* A Protector is required for functions which contain an array, regardless of
  type or length.

* A Protector is required for functions which contain a structure/union which
  contains an array, regardless of type or length.  Note, there is no limit to
  the depth of nesting.

* A protector is required when the address of a local variable (i.e., stack
  based variable) is exposed. (E.g., such as through a local whose address is
  taken as part of the RHS of an assignment or a local whose address is taken as
  part of a function argument.)

This patch implements the SSPString attribute to be equivalent to
SSPRequired. This will change in a subsequent patch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173230 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling
2013-01-23 06:41:41 +00:00
parent 28d65722d6
commit 114baee1fa
14 changed files with 856 additions and 44 deletions
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45
lib/Transforms/IPO/Inliner.cpp
View File

@@ -72,6 +72,40 @@ void Inliner::getAnalysisUsage(AnalysisUsage &AU) const {
typedef DenseMap<ArrayType*, std::vector<AllocaInst*> >
InlinedArrayAllocasTy;
/// \brief If the inlined function had a higher stack protection level than the
/// calling function, then bump up the caller's stack protection level.
static void AdjustCallerSSPLevel(Function *Caller, Function *Callee) {
// If upgrading the SSP attribute, clear out the old SSP Attributes first.
// Having multiple SSP attributes doesn't actually hurt, but it adds useless
// clutter to the IR.
AttrBuilder B;
B.addAttribute(Attribute::StackProtect)
.addAttribute(Attribute::StackProtectStrong);
AttributeSet OldSSPAttr = AttributeSet::get(Caller->getContext(),
AttributeSet::FunctionIndex,
B);
AttributeSet CallerAttr = Caller->getAttributes(),
CalleeAttr = Callee->getAttributes();
if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
Attribute::StackProtectReq)) {
Caller->removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
Caller->addFnAttr(Attribute::StackProtectReq);
} else if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
Attribute::StackProtectStrong) &&
!CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
Attribute::StackProtectReq)) {
Caller->removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
Caller->addFnAttr(Attribute::StackProtectStrong);
} else if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
Attribute::StackProtect) &&
!CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
Attribute::StackProtectReq) &&
!CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
Attribute::StackProtectStrong))
Caller->addFnAttr(Attribute::StackProtect);
}
/// InlineCallIfPossible - If it is possible to inline the specified call site,
/// do so and update the CallGraph for this operation.
///
@@ -91,16 +125,7 @@ static bool InlineCallIfPossible(CallSite CS, InlineFunctionInfo &IFI,
if (!InlineFunction(CS, IFI, InsertLifetime))
return false;
// If the inlined function had a higher stack protection level than the
// calling function, then bump up the caller's stack protection level.
if (Callee->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
Attribute::StackProtectReq))
Caller->addFnAttr(Attribute::StackProtectReq);
else if (Callee->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
Attribute::StackProtect) &&
!Caller->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
Attribute::StackProtectReq))
Caller->addFnAttr(Attribute::StackProtect);
AdjustCallerSSPLevel(Caller, Callee);
// Look at all of the allocas that we inlined through this call site. If we
// have already inlined other allocas through other calls into this function,