[clang] [CodeGen] Support arrays with initializers of 64-bit size (PR #92473)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Fangrui Song (MaskRay)

<details>
<summary>Changes</summary>

Based on @<!-- -->OfekShochat's https://reviews.llvm.org/D133648

init.c is the primary test for array initialization, but it uses a
32-bit triple, which would lead to an "array is too large" error. Add
the new test to array-init.c instead.

Fix #<!-- -->57353


---
Full diff: https://github.com/llvm/llvm-project/pull/92473.diff


3 Files Affected:

- (modified) clang/lib/CodeGen/CGExprConstant.cpp (+6-6) 
- (modified) clang/lib/Sema/SemaInit.cpp (+2-2) 
- (modified) clang/test/CodeGen/array-init.c (+7) 


``````````diff
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 94962091116af..ce57279a6eb65 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -393,7 +393,7 @@ bool ConstantAggregateBuilder::split(size_t Index, CharUnits Hint) {
 
 static llvm::Constant *
 EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
-                  llvm::Type *CommonElementType, unsigned ArrayBound,
+                  llvm::Type *CommonElementType, uint64_t ArrayBound,
                   SmallVectorImpl<llvm::Constant *> &Elements,
                   llvm::Constant *Filler);
 
@@ -949,11 +949,11 @@ tryEmitGlobalCompoundLiteral(ConstantEmitter &emitter,
 
 static llvm::Constant *
 EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
-                  llvm::Type *CommonElementType, unsigned ArrayBound,
+                  llvm::Type *CommonElementType, uint64_t ArrayBound,
                   SmallVectorImpl<llvm::Constant *> &Elements,
                   llvm::Constant *Filler) {
   // Figure out how long the initial prefix of non-zero elements is.
-  unsigned NonzeroLength = ArrayBound;
+  uint64_t NonzeroLength = ArrayBound;
   if (Elements.size() < NonzeroLength && Filler->isNullValue())
     NonzeroLength = Elements.size();
   if (NonzeroLength == Elements.size()) {
@@ -1252,12 +1252,12 @@ class ConstExprEmitter
   llvm::Constant *EmitArrayInitialization(const InitListExpr *ILE, QualType T) {
     auto *CAT = CGM.getContext().getAsConstantArrayType(ILE->getType());
     assert(CAT && "can't emit array init for non-constant-bound array");
-    unsigned NumInitElements = ILE->getNumInits();
-    unsigned NumElements = CAT->getZExtSize();
+    const uint64_t NumElements = CAT->getZExtSize();
 
     // Initialising an array requires us to automatically
     // initialise any elements that have not been initialised explicitly
-    unsigned NumInitableElts = std::min(NumInitElements, NumElements);
+    uint64_t NumInitableElts =
+        std::min<uint64_t>(ILE->getNumInits(), NumElements);
 
     QualType EltType = CAT->getElementType();
 
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 2177972f3af2c..353e911c5cc33 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -876,7 +876,7 @@ InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
 
   InitializedEntity ElementEntity = Entity;
   unsigned NumInits = ILE->getNumInits();
-  unsigned NumElements = NumInits;
+  uint64_t NumElements = NumInits;
   if (const ArrayType *AType = SemaRef.Context.getAsArrayType(ILE->getType())) {
     ElementType = AType->getElementType();
     if (const auto *CAType = dyn_cast<ConstantArrayType>(AType))
@@ -896,7 +896,7 @@ InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
     ElementType = ILE->getType();
 
   bool SkipEmptyInitChecks = false;
-  for (unsigned Init = 0; Init != NumElements; ++Init) {
+  for (uint64_t Init = 0; Init != NumElements; ++Init) {
     if (hadError)
       return;
 
diff --git a/clang/test/CodeGen/array-init.c b/clang/test/CodeGen/array-init.c
index 62e87edc29741..9075df68c7358 100644
--- a/clang/test/CodeGen/array-init.c
+++ b/clang/test/CodeGen/array-init.c
@@ -13,3 +13,10 @@ void testConstArrayInits(void)
   const int a2[5] = {0,0,0};
   const int a3[5] = {0};
 }
+
+/// https://github.com/llvm/llvm-project/issues/57353
+// CHECK: @big_char ={{.*}} global <{ i8, [4294967295 x i8] }> <{ i8 1, [4294967295 x i8] zeroinitializer }>
+char big_char[4294967296] = {1};
+
+// CHECK: @big_int ={{.*}} global <{ i32, [2147483647 x i32] }> <{ i32 1, [2147483647 x i32] zeroinitializer }>
+int big_int[0x200000000 >> 2] = {1};

``````````

</details>


https://github.com/llvm/llvm-project/pull/92473