[5.3] IRGen: Fix enumPayload value witness emission for huge types

lib/IRGen/GenType.cpp

@@ -687,15 +687,26 @@ llvm::Value *irgen::getFixedTypeEnumTagSinglePayload(
 
   llvm::Value *caseIndexFromValue = zero;
   if (fixedSize > Size(0)) {
-    // Read up to one pointer-sized 'chunk' of the payload.
-    // The size of the chunk does not have to be a power of 2.
-    auto *caseIndexType = llvm::IntegerType::get(Ctx,
-        fixedSize.getValueInBits());
-    auto *caseIndexAddr = Builder.CreateBitCast(valueAddr,
-        caseIndexType->getPointerTo());
-    caseIndexFromValue = Builder.CreateZExtOrTrunc(
-        Builder.CreateLoad(Address(caseIndexAddr, Alignment(1))),
-        IGM.Int32Ty);
+    // llvm only supports integer types upto a certain size (i.e selection dag
+    // will crash).
+    if (fixedSize.getValueInBits() <= llvm::IntegerType::MAX_INT_BITS / 4) {
+      // Read up to one pointer-sized 'chunk' of the payload.
+      // The size of the chunk does not have to be a power of 2.
+      auto *caseIndexType =
+          llvm::IntegerType::get(Ctx, fixedSize.getValueInBits());
+      auto *caseIndexAddr =
+          Builder.CreateBitCast(valueAddr, caseIndexType->getPointerTo());
+      caseIndexFromValue = Builder.CreateZExtOrTrunc(
+          Builder.CreateLoad(Address(caseIndexAddr, Alignment(1))),
+          IGM.Int32Ty);
+    } else {
+      auto *caseIndexType = llvm::IntegerType::get(Ctx, 32);
+      auto *caseIndexAddr =
+          Builder.CreateBitCast(valueAddr, caseIndexType->getPointerTo());
+      caseIndexFromValue = Builder.CreateZExtOrTrunc(
+          Builder.CreateLoad(Address(caseIndexAddr, Alignment(1))),
+          IGM.Int32Ty);
+    }
   }
 
   auto *result1 = Builder.CreateAdd(
@@ -867,11 +878,25 @@ void irgen::storeFixedTypeEnumTagSinglePayload(
   payloadIndex->addIncoming(payloadIndex0, payloadLT4BB);
 
   if (fixedSize > Size(0)) {
-    // Write the value to the payload as a zero extended integer.
-    auto *intType = Builder.getIntNTy(fixedSize.getValueInBits());
-    Builder.CreateStore(
-        Builder.CreateZExtOrTrunc(payloadIndex, intType),
-        Builder.CreateBitCast(valueAddr, intType->getPointerTo()));
+    if (fixedSize.getValueInBits() <= llvm::IntegerType::MAX_INT_BITS / 4) {
+      // Write the value to the payload as a zero extended integer.
+      auto *intType = Builder.getIntNTy(fixedSize.getValueInBits());
+      Builder.CreateStore(
+          Builder.CreateZExtOrTrunc(payloadIndex, intType),
+          Builder.CreateBitCast(valueAddr, intType->getPointerTo()));
+    } else {
+      // Write the value to the payload as a zero extended integer.
+      Size limit = IGM.getPointerSize();
+      auto *intType = Builder.getIntNTy(limit.getValueInBits());
+      Builder.CreateStore(
+          Builder.CreateZExtOrTrunc(payloadIndex, intType),
+          Builder.CreateBitCast(valueAddr, intType->getPointerTo()));
+      // Zero the remainder of the payload.
+      auto zeroAddr = Builder.CreateConstByteArrayGEP(valueAddr, limit);
+      auto zeroSize = Builder.CreateSub(
+          size, llvm::ConstantInt::get(size->getType(), limit.getValue()));
+      Builder.CreateMemSet(zeroAddr, Builder.getInt8(0), zeroSize);
+    }
   }
   // Write to the extra tag bytes, if any.
   emitSetTag(IGF, extraTagBitsAddr, extraTagIndex, numExtraTagBytes);

test/IRGen/Inputs/huge_c_type.h

@@ -0,0 +1,31 @@
+#include <stdint.h>
+
+typedef uint8_t bool;
+
+#define CREATE_ARRAY(T, N)                                                     \
+  struct {                                                                     \
+    T data[N];                                                                 \
+    uint64_t size;                                                             \
+  }
+
+typedef struct {
+    int32_t a;
+    double b[16];
+} Thing;
+
+typedef struct {
+  uint64_t a;
+  bool b;
+  CREATE_ARRAY(Thing, 16) c;
+  uint32_t d;
+  uint64_t e;
+  uint64_t f;
+  CREATE_ARRAY(uint32_t, 4) g;
+  CREATE_ARRAY(uint64_t, 4) h;
+  CREATE_ARRAY(uint64_t, 4) i;
+} Thing2;
+
+typedef struct {
+  int64_t a;
+  CREATE_ARRAY(Thing2, 512) c;
+} Thing3;

test/IRGen/huge_c_type.swift

@@ -0,0 +1,10 @@
+// RUN: %target-swift-frontend -import-objc-header %S/Inputs/huge_c_type.h %s -disable-llvm-optzns -emit-ir | %FileCheck %s
+// Make sure that this does not crash during LLVM's ISel. It does not like huge
+// llvm::IntegerTypes.
+// RUN: %target-swift-frontend -import-objc-header %S/Inputs/huge_c_type.h %s -c
+
+// CHECK-NOT:i9535616
+
+public func doIt(a: Thing3) {
+  print(a)
+}