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-rw-r--r--lib/CodeGen/SjLjEHPrepare.cpp182
1 files changed, 181 insertions, 1 deletions
diff --git a/lib/CodeGen/SjLjEHPrepare.cpp b/lib/CodeGen/SjLjEHPrepare.cpp
index 2a7a7cdc3c..baa70b961b 100644
--- a/lib/CodeGen/SjLjEHPrepare.cpp
+++ b/lib/CodeGen/SjLjEHPrepare.cpp
@@ -22,16 +22,22 @@
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/CodeGen/Passes.h"
+#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/IRBuilder.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include <set>
using namespace llvm;
+static cl::opt<bool> DisableOldSjLjEH("disable-old-sjlj-eh", cl::Hidden,
+ cl::desc("Disable the old SjLj EH preparation pass"));
+
STATISTIC(NumInvokes, "Number of invokes replaced");
STATISTIC(NumUnwinds, "Number of unwinds replaced");
STATISTIC(NumSpilled, "Number of registers live across unwind edges");
@@ -67,6 +73,9 @@ namespace {
}
private:
+ bool setupEntryBlockAndCallSites(Function &F);
+ void setupFunctionContext(Function &F, ArrayRef<LandingPadInst*> LPads);
+
void insertCallSiteStore(Instruction *I, int Number, Value *CallSite);
void markInvokeCallSite(InvokeInst *II, int InvokeNo, Value *CallSite,
SwitchInst *CatchSwitch);
@@ -698,7 +707,178 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
return true;
}
+/// setupFunctionContext - Allocate the function context on the stack and fill
+/// it with all of the data that we know at this point.
+void SjLjEHPass::setupFunctionContext(Function &F,
+ ArrayRef<LandingPadInst*> LPads) {
+ 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 =
+ TLI->getTargetData()->getPrefTypeAlignment(FunctionContextTy);
+ AllocaInst *FuncCtx =
+ new AllocaInst(FunctionContextTy, 0, Align, "fn_context", EntryBB->begin());
+
+ // Fill in the function context structure.
+ Value *Idxs[2];
+ Type *Int32Ty = Type::getInt32Ty(F.getContext());
+ Value *Zero = ConstantInt::get(Int32Ty, 0);
+ Value *One = ConstantInt::get(Int32Ty, 1);
+
+ // Keep around a reference to the call_site field.
+ Idxs[0] = Zero;
+ Idxs[1] = One;
+ CallSite = GetElementPtrInst::Create(FuncCtx, Idxs, "call_site",
+ EntryBB->getTerminator());
+
+ // Reference the __data field.
+ Idxs[1] = ConstantInt::get(Int32Ty, 2);
+ Value *FCData = GetElementPtrInst::Create(FuncCtx, Idxs, "__data",
+ EntryBB->getTerminator());
+
+ // The exception value comes back in context->__data[0].
+ Idxs[1] = Zero;
+ Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs,
+ "exception_gep",
+ EntryBB->getTerminator());
+
+ // The exception selector comes back in context->__data[1].
+ Idxs[1] = One;
+ Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs,
+ "exn_selector_gep",
+ EntryBB->getTerminator());
+
+ for (unsigned I = 0, E = LPads.size(); I != E; ++I) {
+ LandingPadInst *LPI = LPads[I];
+ IRBuilder<> Builder(LPI->getParent()->getFirstInsertionPt());
+
+ Value *ExnVal = Builder.CreateLoad(ExceptionAddr, true, "exn_val");
+ ExnVal = Builder.CreateIntToPtr(ExnVal, Type::getInt8PtrTy(F.getContext()));
+ Value *SelVal = Builder.CreateLoad(SelectorAddr, true, "exn_selector_val");
+
+ Type *LPadType = LPI->getType();
+ Value *LPadVal = UndefValue::get(LPadType);
+ LPadVal = Builder.CreateInsertValue(LPadVal, ExnVal, 0, "lpad.val");
+ LPadVal = Builder.CreateInsertValue(LPadVal, SelVal, 1, "lpad.val");
+
+ LPI->replaceAllUsesWith(LPadVal);
+ }
+
+ // Personality function
+ Idxs[1] = ConstantInt::get(Int32Ty, 3);
+ if (!PersonalityFn)
+ PersonalityFn = LPads[0]->getPersonalityFn();
+ Value *PersonalityFieldPtr =
+ GetElementPtrInst::Create(FuncCtx, Idxs, "pers_fn_gep",
+ EntryBB->getTerminator());
+ new StoreInst(PersonalityFn, PersonalityFieldPtr, true,
+ EntryBB->getTerminator());
+
+ // LSDA address
+ Idxs[1] = ConstantInt::get(Int32Ty, 4);
+ Value *LSDAFieldPtr =
+ GetElementPtrInst::Create(FuncCtx, Idxs, "lsda_gep",
+ EntryBB->getTerminator());
+ Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr",
+ EntryBB->getTerminator());
+ new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator());
+
+ // Get a reference to the jump buffer.
+ Idxs[1] = ConstantInt::get(Int32Ty, 5);
+ Value *JBufPtr =
+ GetElementPtrInst::Create(FuncCtx, Idxs, "jbuf_gep",
+ EntryBB->getTerminator());
+ Idxs[1] = Zero;
+ Value *FramePtr =
+ GetElementPtrInst::Create(JBufPtr, Idxs, "jbuf_fp_gep",
+ EntryBB->getTerminator());
+
+ // Save the frame pointer.
+ 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, "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());
+
+ // Add a call to dispatch_setup after the setjmp call. This is expanded to any
+ // target-specific setup that needs to be done.
+ CallInst::Create(DispatchSetupFn, DispatchVal, "", EntryBB->getTerminator());
+}
+
+/// setupEntryBlockAndCallSites - Setup the entry block by creating and filling
+/// the function context and marking the call sites with the appropriate
+/// values. These values are used by the DWARF EH emitter.
+bool SjLjEHPass::setupEntryBlockAndCallSites(Function &F) {
+ SmallVector<InvokeInst*, 16> Invokes;
+ SmallVector<LandingPadInst*, 16> LPads;
+
+ // Look through the terminators of the basic blocks to find invokes.
+ for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+ if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
+ Invokes.push_back(II);
+ LPads.push_back(II->getUnwindDest()->getLandingPadInst());
+ }
+
+ if (Invokes.empty()) return false;
+
+ setupFunctionContext(F, LPads);
+
+ // 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) {
+ insertCallSiteStore(Invokes[I], I + 1, CallSite);
+
+ ConstantInt *CallSiteNum =
+ ConstantInt::get(Type::getInt32Ty(F.getContext()), I + 1);
+
+ // Record the call site value for the back end so it stays associated with
+ // the invoke.
+ CallInst::Create(CallSiteFn, CallSiteNum, "", Invokes[I]);
+ }
+
+ // 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)) {
+ if (!CI->doesNotThrow())
+ insertCallSiteStore(CI, -1, CallSite);
+ } else if (ResumeInst *RI = dyn_cast<ResumeInst>(I)) {
+ insertCallSiteStore(RI, -1, CallSite);
+ }
+ }
+
+ return true;
+}
+
bool SjLjEHPass::runOnFunction(Function &F) {
- bool Res = insertSjLjEHSupport(F);
+ bool Res = false;
+ if (!DisableOldSjLjEH)
+ Res = insertSjLjEHSupport(F);
+ else
+ Res = setupEntryBlockAndCallSites(F);
return Res;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-03 01:10:21 +0000