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authorRafael Espindola <rafael.espindola@gmail.com>2011-05-16 03:05:33 +0000
committerRafael Espindola <rafael.espindola@gmail.com>2011-05-16 03:05:33 +0000
commit0e00c6c561181be7e9cc75ad2fee9cd4cbbfca1e (patch)
treece64246a87e40887e6b6a022317abfec99e024d1 /lib
parentbaaa3201681d58434a54f9cedfd600c248dc10e9 (diff)
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Don't do tail calls in a function that call setjmp. The stack might be
corrupted when setjmp returns again. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131399 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r--lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp34
-rw-r--r--lib/Transforms/Scalar/TailRecursionElimination.cpp9
-rw-r--r--lib/VMCore/Function.cpp33
3 files changed, 39 insertions, 37 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index f510fb5..d1d28ce 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -208,38 +208,6 @@ void SelectionDAGISel::getAnalysisUsage(AnalysisUsage &AU) const {
MachineFunctionPass::getAnalysisUsage(AU);
}
-/// FunctionCallsSetJmp - Return true if the function has a call to setjmp or
-/// other function that gcc recognizes as "returning twice". This is used to
-/// limit code-gen optimizations on the machine function.
-///
-/// FIXME: Remove after <rdar://problem/8031714> is fixed.
-static bool FunctionCallsSetJmp(const Function *F) {
- const Module *M = F->getParent();
- static const char *ReturnsTwiceFns[] = {
- "_setjmp",
- "setjmp",
- "sigsetjmp",
- "setjmp_syscall",
- "savectx",
- "qsetjmp",
- "vfork",
- "getcontext"
- };
-
- for (unsigned I = 0; I < array_lengthof(ReturnsTwiceFns); ++I)
- if (const Function *Callee = M->getFunction(ReturnsTwiceFns[I])) {
- if (!Callee->use_empty())
- for (Value::const_use_iterator
- I = Callee->use_begin(), E = Callee->use_end();
- I != E; ++I)
- if (const CallInst *CI = dyn_cast<CallInst>(*I))
- if (CI->getParent()->getParent() == F)
- return true;
- }
-
- return false;
-}
-
/// SplitCriticalSideEffectEdges - Look for critical edges with a PHI value that
/// may trap on it. In this case we have to split the edge so that the path
/// through the predecessor block that doesn't go to the phi block doesn't
@@ -390,7 +358,7 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
}
// Determine if there is a call to setjmp in the machine function.
- MF->setCallsSetJmp(FunctionCallsSetJmp(&Fn));
+ MF->setCallsSetJmp(Fn.callsFunctionThatReturnsTwice());
// Replace forward-declared registers with the registers containing
// the desired value.
diff --git a/lib/Transforms/Scalar/TailRecursionElimination.cpp b/lib/Transforms/Scalar/TailRecursionElimination.cpp
index 539cc6f..e21eb9d 100644
--- a/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ b/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -59,6 +59,7 @@
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
+#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/InlineCost.h"
@@ -209,10 +210,10 @@ bool TailCallElim::runOnFunction(Function &F) {
}
}
- // Finally, if this function contains no non-escaping allocas, mark all calls
- // in the function as eligible for tail calls (there is no stack memory for
- // them to access).
- if (!FunctionContainsEscapingAllocas)
+ // Finally, if this function contains no non-escaping allocas, or calls
+ // setjmp, mark all calls in the function as eligible for tail calls
+ //(there is no stack memory for them to access).
+ if (!FunctionContainsEscapingAllocas && !F.callsFunctionThatReturnsTwice())
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
if (CallInst *CI = dyn_cast<CallInst>(I)) {
diff --git a/lib/VMCore/Function.cpp b/lib/VMCore/Function.cpp
index 013c458..ce2186f 100644
--- a/lib/VMCore/Function.cpp
+++ b/lib/VMCore/Function.cpp
@@ -24,6 +24,7 @@
#include "llvm/Support/Threading.h"
#include "SymbolTableListTraitsImpl.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
using namespace llvm;
@@ -406,4 +407,36 @@ bool Function::hasAddressTaken(const User* *PutOffender) const {
return false;
}
+/// callsFunctionThatReturnsTwice - Return true if the function has a call to
+/// setjmp or other function that gcc recognizes as "returning twice".
+///
+/// FIXME: Remove after <rdar://problem/8031714> is fixed.
+/// FIXME: Is the obove FIXME valid?
+bool Function::callsFunctionThatReturnsTwice() const {
+ const Module *M = this->getParent();
+ static const char *ReturnsTwiceFns[] = {
+ "_setjmp",
+ "setjmp",
+ "sigsetjmp",
+ "setjmp_syscall",
+ "savectx",
+ "qsetjmp",
+ "vfork",
+ "getcontext"
+ };
+
+ for (unsigned I = 0; I < array_lengthof(ReturnsTwiceFns); ++I)
+ if (const Function *Callee = M->getFunction(ReturnsTwiceFns[I])) {
+ if (!Callee->use_empty())
+ for (Value::const_use_iterator
+ I = Callee->use_begin(), E = Callee->use_end();
+ I != E; ++I)
+ if (const CallInst *CI = dyn_cast<CallInst>(*I))
+ if (CI->getParent()->getParent() == this)
+ return true;
+ }
+
+ return false;
+}
+
// vim: sw=2 ai