[llvm-commits] [llvm] r122990 - /llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp
Bill Wendling
isanbard at gmail.com
Thu Jan 6 18:54:45 PST 2011
Author: void
Date: Thu Jan 6 20:54:45 2011
New Revision: 122990
URL: http://llvm.org/viewvc/llvm-project?rev=122990&view=rev
Log:
Early exit if we don't have invokes. The 'Unwinds' vector isn't modified unless
we have invokes, so there is no functionality change here.
Modified:
llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp
Modified: llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp?rev=122990&r1=122989&r2=122990&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp Thu Jan 6 20:54:45 2011
@@ -319,8 +319,12 @@
Unwinds.push_back(UI);
}
}
- // If we don't have any invokes or unwinds, there's nothing to do.
- if (Unwinds.empty() && Invokes.empty()) return false;
+
+ NumInvokes += Invokes.size();
+ NumUnwinds += Unwinds.size();
+
+ // If we don't have any invokes, there's nothing to do.
+ if (Invokes.empty()) return false;
// Find the eh.selector.*, eh.exception and alloca calls.
//
@@ -334,6 +338,7 @@
SmallVector<CallInst*,16> EH_Selectors;
SmallVector<CallInst*,16> EH_Exceptions;
SmallVector<Instruction*,16> JmpbufUpdatePoints;
+
// Note: Skip the entry block since there's nothing there that interests
// us. eh.selector and eh.exception shouldn't ever be there, and we
// want to disregard any allocas that are there.
@@ -353,236 +358,231 @@
}
}
}
+
// If we don't have any eh.selector calls, we can't determine the personality
// function. Without a personality function, we can't process exceptions.
if (!PersonalityFn) return false;
- NumInvokes += Invokes.size();
- NumUnwinds += Unwinds.size();
+ // We have invokes, so we need to add register/unregister calls to get this
+ // function onto the global unwind stack.
+ //
+ // First thing we need to do is scan the whole function for values that are
+ // live across unwind edges. Each value that is live across an unwind edge we
+ // spill into a stack location, guaranteeing that there is nothing live across
+ // the unwind edge. This process also splits all critical edges coming out of
+ // invoke's.
+ splitLiveRangesAcrossInvokes(Invokes);
+
+ BasicBlock *EntryBB = F.begin();
+ // Create an alloca for the incoming jump buffer ptr and the new jump buffer
+ // that needs to be restored on all exits from the function. This is an
+ // alloca because the value needs to be added to the global context list.
+ unsigned Align = 4; // FIXME: Should be a TLI check?
+ AllocaInst *FunctionContext =
+ new AllocaInst(FunctionContextTy, 0, Align,
+ "fcn_context", F.begin()->begin());
+
+ Value *Idxs[2];
+ const Type *Int32Ty = Type::getInt32Ty(F.getContext());
+ Value *Zero = ConstantInt::get(Int32Ty, 0);
+ // We need to also keep around a reference to the call_site field
+ Idxs[0] = Zero;
+ Idxs[1] = ConstantInt::get(Int32Ty, 1);
+ CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "call_site",
+ EntryBB->getTerminator());
+
+ // The exception selector comes back in context->data[1]
+ Idxs[1] = ConstantInt::get(Int32Ty, 2);
+ Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "fc_data",
+ EntryBB->getTerminator());
+ Idxs[1] = ConstantInt::get(Int32Ty, 1);
+ Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2,
+ "exc_selector_gep",
+ EntryBB->getTerminator());
+ // The exception value comes back in context->data[0]
+ Idxs[1] = Zero;
+ Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2,
+ "exception_gep",
+ EntryBB->getTerminator());
+
+ // The result of the eh.selector call will be replaced with a a reference to
+ // the selector value returned in the function context. We leave the selector
+ // itself so the EH analysis later can use it.
+ for (int i = 0, e = EH_Selectors.size(); i < e; ++i) {
+ CallInst *I = EH_Selectors[i];
+ Value *SelectorVal = new LoadInst(SelectorAddr, "select_val", true, I);
+ I->replaceAllUsesWith(SelectorVal);
+ }
- if (!Invokes.empty()) {
- // We have invokes, so we need to add register/unregister calls to get
- // this function onto the global unwind stack.
- //
- // First thing we need to do is scan the whole function for values that are
- // live across unwind edges. Each value that is live across an unwind edge
- // we spill into a stack location, guaranteeing that there is nothing live
- // across the unwind edge. This process also splits all critical edges
- // coming out of invoke's.
- splitLiveRangesAcrossInvokes(Invokes);
-
- BasicBlock *EntryBB = F.begin();
- // Create an alloca for the incoming jump buffer ptr and the new jump buffer
- // that needs to be restored on all exits from the function. This is an
- // alloca because the value needs to be added to the global context list.
- unsigned Align = 4; // FIXME: Should be a TLI check?
- AllocaInst *FunctionContext =
- new AllocaInst(FunctionContextTy, 0, Align,
- "fcn_context", F.begin()->begin());
-
- Value *Idxs[2];
- const Type *Int32Ty = Type::getInt32Ty(F.getContext());
- Value *Zero = ConstantInt::get(Int32Ty, 0);
- // We need to also keep around a reference to the call_site field
- Idxs[0] = Zero;
- Idxs[1] = ConstantInt::get(Int32Ty, 1);
- CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
- "call_site",
- EntryBB->getTerminator());
-
- // The exception selector comes back in context->data[1]
- Idxs[1] = ConstantInt::get(Int32Ty, 2);
- Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
- "fc_data",
- EntryBB->getTerminator());
- Idxs[1] = ConstantInt::get(Int32Ty, 1);
- Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2,
- "exc_selector_gep",
- EntryBB->getTerminator());
- // The exception value comes back in context->data[0]
- Idxs[1] = Zero;
- Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2,
- "exception_gep",
- EntryBB->getTerminator());
-
- // The result of the eh.selector call will be replaced with a
- // a reference to the selector value returned in the function
- // context. We leave the selector itself so the EH analysis later
- // can use it.
- for (int i = 0, e = EH_Selectors.size(); i < e; ++i) {
- CallInst *I = EH_Selectors[i];
- Value *SelectorVal = new LoadInst(SelectorAddr, "select_val", true, I);
- I->replaceAllUsesWith(SelectorVal);
- }
- // eh.exception calls are replaced with references to the proper
- // location in the context. Unlike eh.selector, the eh.exception
- // calls are removed entirely.
- for (int i = 0, e = EH_Exceptions.size(); i < e; ++i) {
- CallInst *I = EH_Exceptions[i];
- // Possible for there to be duplicates, so check to make sure
- // the instruction hasn't already been removed.
- if (!I->getParent()) continue;
- Value *Val = new LoadInst(ExceptionAddr, "exception", true, I);
- const Type *Ty = Type::getInt8PtrTy(F.getContext());
- Val = CastInst::Create(Instruction::IntToPtr, Val, Ty, "", I);
+ // eh.exception calls are replaced with references to the proper location in
+ // the context. Unlike eh.selector, the eh.exception calls are removed
+ // entirely.
+ for (int i = 0, e = EH_Exceptions.size(); i < e; ++i) {
+ CallInst *I = EH_Exceptions[i];
+ // Possible for there to be duplicates, so check to make sure the
+ // instruction hasn't already been removed.
+ if (!I->getParent()) continue;
+ Value *Val = new LoadInst(ExceptionAddr, "exception", true, I);
+ const Type *Ty = Type::getInt8PtrTy(F.getContext());
+ Val = CastInst::Create(Instruction::IntToPtr, Val, Ty, "", I);
- I->replaceAllUsesWith(Val);
- I->eraseFromParent();
- }
+ I->replaceAllUsesWith(Val);
+ I->eraseFromParent();
+ }
- // The entry block changes to have the eh.sjlj.setjmp, with a conditional
- // branch to a dispatch block for non-zero returns. If we return normally,
- // we're not handling an exception and just register the function context
- // and continue.
-
- // Create the dispatch block. The dispatch block is basically a big switch
- // statement that goes to all of the invoke landing pads.
- BasicBlock *DispatchBlock =
- BasicBlock::Create(F.getContext(), "eh.sjlj.setjmp.catch", &F);
-
- // Add a call to dispatch_setup at the start of the dispatch block. This
- // is expanded to any target-specific setup that needs to be done.
- Value *SetupArg =
- CastInst::Create(Instruction::BitCast, FunctionContext,
- Type::getInt8PtrTy(F.getContext()), "",
+ // The entry block changes to have the eh.sjlj.setjmp, with a conditional
+ // branch to a dispatch block for non-zero returns. If we return normally,
+ // we're not handling an exception and just register the function context and
+ // continue.
+
+ // Create the dispatch block. The dispatch block is basically a big switch
+ // statement that goes to all of the invoke landing pads.
+ BasicBlock *DispatchBlock =
+ BasicBlock::Create(F.getContext(), "eh.sjlj.setjmp.catch", &F);
+
+ // Add a call to dispatch_setup at the start of the dispatch block. This is
+ // expanded to any target-specific setup that needs to be done.
+ Value *SetupArg =
+ CastInst::Create(Instruction::BitCast, FunctionContext,
+ Type::getInt8PtrTy(F.getContext()), "",
+ DispatchBlock);
+ CallInst::Create(DispatchSetupFn, SetupArg, "", DispatchBlock);
+
+ // Insert a load of the callsite in the dispatch block, and a switch on its
+ // value. By default, we go to a block that just does an unwind (which is the
+ // correct action for a standard call).
+ BasicBlock *UnwindBlock =
+ BasicBlock::Create(F.getContext(), "unwindbb", &F);
+ Unwinds.push_back(new UnwindInst(F.getContext(), UnwindBlock));
+
+ Value *DispatchLoad = new LoadInst(CallSite, "invoke.num", true,
+ DispatchBlock);
+ SwitchInst *DispatchSwitch =
+ SwitchInst::Create(DispatchLoad, UnwindBlock, Invokes.size(),
DispatchBlock);
- CallInst::Create(DispatchSetupFn, SetupArg, "", DispatchBlock);
-
- // Insert a load of the callsite in the dispatch block, and a switch on
- // its value. By default, we go to a block that just does an unwind
- // (which is the correct action for a standard call).
- BasicBlock *UnwindBlock =
- BasicBlock::Create(F.getContext(), "unwindbb", &F);
- Unwinds.push_back(new UnwindInst(F.getContext(), UnwindBlock));
-
- Value *DispatchLoad = new LoadInst(CallSite, "invoke.num", true,
- DispatchBlock);
- SwitchInst *DispatchSwitch =
- SwitchInst::Create(DispatchLoad, UnwindBlock, Invokes.size(),
- DispatchBlock);
- // Split the entry block to insert the conditional branch for the setjmp.
- BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(),
- "eh.sjlj.setjmp.cont");
-
- // Populate the Function Context
- // 1. LSDA address
- // 2. Personality function address
- // 3. jmpbuf (save SP, FP and call eh.sjlj.setjmp)
-
- // LSDA address
- Idxs[0] = Zero;
- Idxs[1] = ConstantInt::get(Int32Ty, 4);
- Value *LSDAFieldPtr =
- GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
- "lsda_gep",
- EntryBB->getTerminator());
- Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr",
- EntryBB->getTerminator());
- new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator());
-
- Idxs[1] = ConstantInt::get(Int32Ty, 3);
- Value *PersonalityFieldPtr =
- GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
- "lsda_gep",
+ // Split the entry block to insert the conditional branch for the setjmp.
+ BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(),
+ "eh.sjlj.setjmp.cont");
+
+ // Populate the Function Context
+ // 1. LSDA address
+ // 2. Personality function address
+ // 3. jmpbuf (save SP, FP and call eh.sjlj.setjmp)
+
+ // LSDA address
+ Idxs[0] = Zero;
+ Idxs[1] = ConstantInt::get(Int32Ty, 4);
+ Value *LSDAFieldPtr =
+ GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "lsda_gep",
+ EntryBB->getTerminator());
+ Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr",
+ EntryBB->getTerminator());
+ new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator());
+
+ Idxs[1] = ConstantInt::get(Int32Ty, 3);
+ Value *PersonalityFieldPtr =
+ GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "lsda_gep",
+ EntryBB->getTerminator());
+ new StoreInst(PersonalityFn, PersonalityFieldPtr, true,
+ EntryBB->getTerminator());
+
+ // Save the frame pointer.
+ Idxs[1] = ConstantInt::get(Int32Ty, 5);
+ Value *JBufPtr
+ = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "jbuf_gep",
EntryBB->getTerminator());
- new StoreInst(PersonalityFn, PersonalityFieldPtr, true,
- EntryBB->getTerminator());
-
- // Save the frame pointer.
- Idxs[1] = ConstantInt::get(Int32Ty, 5);
- Value *JBufPtr
- = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
- "jbuf_gep",
- EntryBB->getTerminator());
- Idxs[1] = ConstantInt::get(Int32Ty, 0);
- Value *FramePtr =
- GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "jbuf_fp_gep",
- EntryBB->getTerminator());
-
- Value *Val = CallInst::Create(FrameAddrFn,
- ConstantInt::get(Int32Ty, 0),
- "fp",
- EntryBB->getTerminator());
- new StoreInst(Val, FramePtr, true, EntryBB->getTerminator());
-
- // Save the stack pointer.
- Idxs[1] = ConstantInt::get(Int32Ty, 2);
- Value *StackPtr =
- GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "jbuf_sp_gep",
+ Idxs[1] = ConstantInt::get(Int32Ty, 0);
+ Value *FramePtr =
+ GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "jbuf_fp_gep",
+ EntryBB->getTerminator());
+
+ Value *Val = CallInst::Create(FrameAddrFn,
+ ConstantInt::get(Int32Ty, 0),
+ "fp",
EntryBB->getTerminator());
+ new StoreInst(Val, FramePtr, true, EntryBB->getTerminator());
- Val = CallInst::Create(StackAddrFn, "sp", EntryBB->getTerminator());
- new StoreInst(Val, StackPtr, true, EntryBB->getTerminator());
-
- // Call the setjmp instrinsic. It fills in the rest of the jmpbuf.
- Value *SetjmpArg =
- CastInst::Create(Instruction::BitCast, JBufPtr,
- Type::getInt8PtrTy(F.getContext()), "",
- EntryBB->getTerminator());
- Value *DispatchVal = CallInst::Create(BuiltinSetjmpFn, SetjmpArg,
- "dispatch",
- EntryBB->getTerminator());
- // check the return value of the setjmp. non-zero goes to dispatcher.
- Value *IsNormal = new ICmpInst(EntryBB->getTerminator(),
- ICmpInst::ICMP_EQ, DispatchVal, Zero,
- "notunwind");
- // Nuke the uncond branch.
- EntryBB->getTerminator()->eraseFromParent();
-
- // Put in a new condbranch in its place.
- BranchInst::Create(ContBlock, DispatchBlock, IsNormal, EntryBB);
-
- // Register the function context and make sure it's known to not throw
- CallInst *Register =
- CallInst::Create(RegisterFn, FunctionContext, "",
- ContBlock->getTerminator());
- Register->setDoesNotThrow();
-
- // At this point, we are all set up, update the invoke instructions
- // to mark their call_site values, and fill in the dispatch switch
- // accordingly.
- for (unsigned i = 0, e = Invokes.size(); i != e; ++i)
- markInvokeCallSite(Invokes[i], i+1, CallSite, DispatchSwitch);
-
- // Mark call instructions that aren't nounwind as no-action
- // (call_site == -1). Skip the entry block, as prior to then, no function
- // context has been created for this function and any unexpected exceptions
- // thrown will go directly to the caller's context, which is what we want
- // anyway, so no need to do anything here.
- for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;) {
- for (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I)
- if (CallInst *CI = dyn_cast<CallInst>(I)) {
- // Ignore calls to the EH builtins (eh.selector, eh.exception)
- Constant *Callee = CI->getCalledFunction();
- if (Callee != SelectorFn && Callee != ExceptionFn
- && !CI->doesNotThrow())
- insertCallSiteStore(CI, -1, CallSite);
- }
- }
-
- // Replace all unwinds with a branch to the unwind handler.
- // ??? Should this ever happen with sjlj exceptions?
- for (unsigned i = 0, e = Unwinds.size(); i != e; ++i) {
- BranchInst::Create(UnwindBlock, Unwinds[i]);
- Unwinds[i]->eraseFromParent();
- }
+ // Save the stack pointer.
+ Idxs[1] = ConstantInt::get(Int32Ty, 2);
+ Value *StackPtr =
+ GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "jbuf_sp_gep",
+ EntryBB->getTerminator());
+
+ Val = CallInst::Create(StackAddrFn, "sp", EntryBB->getTerminator());
+ new StoreInst(Val, StackPtr, true, EntryBB->getTerminator());
+
+ // Call the setjmp instrinsic. It fills in the rest of the jmpbuf.
+ Value *SetjmpArg =
+ CastInst::Create(Instruction::BitCast, JBufPtr,
+ Type::getInt8PtrTy(F.getContext()), "",
+ EntryBB->getTerminator());
+ Value *DispatchVal = CallInst::Create(BuiltinSetjmpFn, SetjmpArg,
+ "dispatch",
+ EntryBB->getTerminator());
+ // check the return value of the setjmp. non-zero goes to dispatcher.
+ Value *IsNormal = new ICmpInst(EntryBB->getTerminator(),
+ ICmpInst::ICMP_EQ, DispatchVal, Zero,
+ "notunwind");
+ // Nuke the uncond branch.
+ EntryBB->getTerminator()->eraseFromParent();
+
+ // Put in a new condbranch in its place.
+ BranchInst::Create(ContBlock, DispatchBlock, IsNormal, EntryBB);
+
+ // Register the function context and make sure it's known to not throw
+ CallInst *Register =
+ CallInst::Create(RegisterFn, FunctionContext, "",
+ ContBlock->getTerminator());
+ Register->setDoesNotThrow();
+
+ // At this point, we are all set up, update the invoke instructions to mark
+ // their call_site values, and fill in the dispatch switch accordingly.
+ for (unsigned i = 0, e = Invokes.size(); i != e; ++i)
+ markInvokeCallSite(Invokes[i], i+1, CallSite, DispatchSwitch);
+
+ // Mark call instructions that aren't nounwind as no-action (call_site ==
+ // -1). Skip the entry block, as prior to then, no function context has been
+ // created for this function and any unexpected exceptions thrown will go
+ // directly to the caller's context, which is what we want anyway, so no need
+ // to do anything here.
+ for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;) {
+ for (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I)
+ if (CallInst *CI = dyn_cast<CallInst>(I)) {
+ // Ignore calls to the EH builtins (eh.selector, eh.exception)
+ Constant *Callee = CI->getCalledFunction();
+ if (Callee != SelectorFn && Callee != ExceptionFn
+ && !CI->doesNotThrow())
+ insertCallSiteStore(CI, -1, CallSite);
+ }
+ }
- // Following any allocas not in the entry block, update the saved SP
- // in the jmpbuf to the new value.
- for (unsigned i = 0, e = JmpbufUpdatePoints.size(); i != e; ++i) {
- Instruction *AI = JmpbufUpdatePoints[i];
- Instruction *StackAddr = CallInst::Create(StackAddrFn, "sp");
- StackAddr->insertAfter(AI);
- Instruction *StoreStackAddr = new StoreInst(StackAddr, StackPtr, true);
- StoreStackAddr->insertAfter(StackAddr);
- }
+ // Replace all unwinds with a branch to the unwind handler.
+ // ??? Should this ever happen with sjlj exceptions?
+ for (unsigned i = 0, e = Unwinds.size(); i != e; ++i) {
+ BranchInst::Create(UnwindBlock, Unwinds[i]);
+ Unwinds[i]->eraseFromParent();
+ }
- // Finally, for any returns from this function, if this function contains an
- // invoke, add a call to unregister the function context.
- for (unsigned i = 0, e = Returns.size(); i != e; ++i)
- CallInst::Create(UnregisterFn, FunctionContext, "", Returns[i]);
+ // Following any allocas not in the entry block, update the saved SP in the
+ // jmpbuf to the new value.
+ for (unsigned i = 0, e = JmpbufUpdatePoints.size(); i != e; ++i) {
+ Instruction *AI = JmpbufUpdatePoints[i];
+ Instruction *StackAddr = CallInst::Create(StackAddrFn, "sp");
+ StackAddr->insertAfter(AI);
+ Instruction *StoreStackAddr = new StoreInst(StackAddr, StackPtr, true);
+ StoreStackAddr->insertAfter(StackAddr);
}
+ // Finally, for any returns from this function, if this function contains an
+ // invoke, add a call to unregister the function context.
+ for (unsigned i = 0, e = Returns.size(); i != e; ++i)
+ CallInst::Create(UnregisterFn, FunctionContext, "", Returns[i]);
+
return true;
}
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