[IR] Remove size argument from lifetime intrinsics (#150248)

Now that #149310 has restricted lifetime intrinsics to only work on
allocas, we can also drop the explicit size argument. Instead, the size
is implied by the alloca.

This removes the ability to only mark a prefix of an alloca alive/dead.
We never used that capability, so we should remove the need to handle
that possibility everywhere (though many key places, including stack
coloring, did not actually respect this).

1 files changed, 16 insertions, 31 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index d9bd443..6e0c2c1 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -4319,10 +4319,7 @@ static void emitWriteback(CodeGenFunction &CGF,
 
   if (writeback.WritebackExpr) {
     CGF.EmitIgnoredExpr(writeback.WritebackExpr);
-
-    if (writeback.LifetimeSz)
-      CGF.EmitLifetimeEnd(writeback.LifetimeSz,
-                          writeback.Temporary.getBasePointer());
+    CGF.EmitLifetimeEnd(writeback.Temporary.getBasePointer());
     return;
   }
 
@@ -5282,7 +5279,7 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   // If the call returns a temporary with struct return, create a temporary
   // alloca to hold the result, unless one is given to us.
   Address SRetPtr = Address::invalid();
-  llvm::Value *UnusedReturnSizePtr = nullptr;
+  bool NeedSRetLifetimeEnd = false;
   if (RetAI.isIndirect() || RetAI.isInAlloca() || RetAI.isCoerceAndExpand()) {
     // For virtual function pointer thunks and musttail calls, we must always
     // forward an incoming SRet pointer to the callee, because a local alloca
@@ -5296,11 +5293,8 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
       SRetPtr = ReturnValue.getAddress();
     } else {
       SRetPtr = CreateMemTempWithoutCast(RetTy, "tmp");
-      if (HaveInsertPoint() && ReturnValue.isUnused()) {
-        llvm::TypeSize size =
-            CGM.getDataLayout().getTypeAllocSize(ConvertTypeForMem(RetTy));
-        UnusedReturnSizePtr = EmitLifetimeStart(size, SRetPtr.getBasePointer());
-      }
+      if (HaveInsertPoint() && ReturnValue.isUnused())
+        NeedSRetLifetimeEnd = EmitLifetimeStart(SRetPtr.getBasePointer());
     }
     if (IRFunctionArgs.hasSRetArg()) {
       // A mismatch between the allocated return value's AS and the target's
@@ -5484,15 +5478,10 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
         Val = Builder.CreateFreeze(Val);
       IRCallArgs[FirstIRArg] = Val;
 
-      // Emit lifetime markers for the temporary alloca.
-      llvm::TypeSize ByvalTempElementSize =
-          CGM.getDataLayout().getTypeAllocSize(AI.getElementType());
-      llvm::Value *LifetimeSize =
-          EmitLifetimeStart(ByvalTempElementSize, AI.getPointer());
-
-      // Add cleanup code to emit the end lifetime marker after the call.
-      if (LifetimeSize) // In case we disabled lifetime markers.
-        CallLifetimeEndAfterCall.emplace_back(AI, LifetimeSize);
+      // Emit lifetime markers for the temporary alloca and add cleanup code to
+      // emit the end lifetime marker after the call.
+      if (EmitLifetimeStart(AI.getPointer()))
+        CallLifetimeEndAfterCall.emplace_back(AI);
 
       // Generate the copy.
       I->copyInto(*this, AI);
@@ -5653,9 +5642,9 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
       auto unpaddedCoercionType = ArgInfo.getUnpaddedCoerceAndExpandType();
       auto *unpaddedStruct = dyn_cast<llvm::StructType>(unpaddedCoercionType);
 
-      llvm::Value *tempSize = nullptr;
       Address addr = Address::invalid();
       RawAddress AllocaAddr = RawAddress::invalid();
+      bool NeedLifetimeEnd = false;
       if (I->isAggregate()) {
         addr = I->hasLValue() ? I->getKnownLValue().getAddress()
                               : I->getKnownRValue().getAggregateAddress();
@@ -5665,7 +5654,6 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
         assert(RV.isScalar()); // complex should always just be direct
 
         llvm::Type *scalarType = RV.getScalarVal()->getType();
-        auto scalarSize = CGM.getDataLayout().getTypeAllocSize(scalarType);
         auto scalarAlign = CGM.getDataLayout().getPrefTypeAlign(scalarType);
 
         // Materialize to a temporary.
@@ -5674,7 +5662,7 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
                                     layout->getAlignment(), scalarAlign)),
                                 "tmp",
                                 /*ArraySize=*/nullptr, &AllocaAddr);
-        tempSize = EmitLifetimeStart(scalarSize, AllocaAddr.getPointer());
+        NeedLifetimeEnd = EmitLifetimeStart(AllocaAddr.getPointer());
 
         Builder.CreateStore(RV.getScalarVal(), addr);
       }
@@ -5699,10 +5687,8 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
       }
       assert(IRArgPos == FirstIRArg + NumIRArgs);
 
-      if (tempSize) {
-        EmitLifetimeEnd(tempSize, AllocaAddr.getPointer());
-      }
-
+      if (NeedLifetimeEnd)
+        EmitLifetimeEnd(AllocaAddr.getPointer());
       break;
     }
 
@@ -5871,9 +5857,8 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   // can't depend on being inside of an ExprWithCleanups, so we need to manually
   // pop this cleanup later on. Being eager about this is OK, since this
   // temporary is 'invisible' outside of the callee.
-  if (UnusedReturnSizePtr)
-    pushFullExprCleanup<CallLifetimeEnd>(NormalEHLifetimeMarker, SRetPtr,
-                                         UnusedReturnSizePtr);
+  if (NeedSRetLifetimeEnd)
+    pushFullExprCleanup<CallLifetimeEnd>(NormalEHLifetimeMarker, SRetPtr);
 
   llvm::BasicBlock *InvokeDest = CannotThrow ? nullptr : getInvokeDest();
 
@@ -6007,7 +5992,7 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   // insertion point; this allows the rest of IRGen to discard
   // unreachable code.
   if (CI->doesNotReturn()) {
-    if (UnusedReturnSizePtr)
+    if (NeedSRetLifetimeEnd)
       PopCleanupBlock();
 
     // Strip away the noreturn attribute to better diagnose unreachable UB.
@@ -6122,7 +6107,7 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
       case ABIArgInfo::InAlloca:
       case ABIArgInfo::Indirect: {
         RValue ret = convertTempToRValue(SRetPtr, RetTy, SourceLocation());
-        if (UnusedReturnSizePtr)
+        if (NeedSRetLifetimeEnd)
           PopCleanupBlock();
         return ret;
       }