[llvm] e7cdce4 - [BitcodeReader] Simplify CST_CODE_DATA constant parsing (NFC) (#190846)

[via llvm-commits]

Author: Alex MacLean
Date: 2026-04-19T12:45:39-07:00
New Revision: e7cdce484bd273b3d6a26d4edc54ae4c37cea3b0

URL: https://github.com/llvm/llvm-project/commit/e7cdce484bd273b3d6a26d4edc54ae4c37cea3b0
DIFF: https://github.com/llvm/llvm-project/commit/e7cdce484bd273b3d6a26d4edc54ae4c37cea3b0.diff

LOG: [BitcodeReader] Simplify CST_CODE_DATA constant parsing (NFC) (#190846)

Cleanup boilerplate in the CST_CODE_DATA case for bitcode parser. This
is generally an aesthetic improvement and can significantly reduce stack
usage on some compilers (such as MSVC) where each SmallVector previously
was allocated it's own individual space.

Added: 
    

Modified: 
    llvm/lib/Bitcode/Reader/BitcodeReader.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index e01cf501b8841..fa7a3b214e463 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -73,6 +73,7 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/ModRef.h"
+#include "llvm/Support/SwapByteOrder.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/Triple.h"
 #include <algorithm>
@@ -3449,86 +3450,23 @@ Error BitcodeReader::parseConstants() {
       if (Record.empty())
         return error("Invalid data record");
 
-      Type *EltTy;
-      if (auto *Array = dyn_cast<ArrayType>(CurTy))
-        EltTy = Array->getElementType();
-      else
-        EltTy = cast<VectorType>(CurTy)->getElementType();
-      if (EltTy->isIntegerTy(8)) {
-        SmallVector<uint8_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::get(Context, Elts);
-        else
-          V = ConstantDataArray::get(Context, Elts);
-      } else if (EltTy->isIntegerTy(16)) {
-        SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::get(Context, Elts);
-        else
-          V = ConstantDataArray::get(Context, Elts);
-      } else if (EltTy->isIntegerTy(32)) {
-        SmallVector<uint32_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::get(Context, Elts);
-        else
-          V = ConstantDataArray::get(Context, Elts);
-      } else if (EltTy->isIntegerTy(64)) {
-        SmallVector<uint64_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::get(Context, Elts);
-        else
-          V = ConstantDataArray::get(Context, Elts);
-      } else if (EltTy->isByteTy(8)) {
-        SmallVector<uint8_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::getByte(EltTy, Elts);
-        else
-          V = ConstantDataArray::getByte(EltTy, Elts);
-      } else if (EltTy->isByteTy(16)) {
-        SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::getByte(EltTy, Elts);
-        else
-          V = ConstantDataArray::getByte(EltTy, Elts);
-      } else if (EltTy->isByteTy(32)) {
-        SmallVector<uint32_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::getByte(EltTy, Elts);
-        else
-          V = ConstantDataArray::getByte(EltTy, Elts);
-      } else if (EltTy->isByteTy(64)) {
-        SmallVector<uint64_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::getByte(EltTy, Elts);
-        else
-          V = ConstantDataArray::getByte(EltTy, Elts);
-      } else if (EltTy->isHalfTy()) {
-        SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::getFP(EltTy, Elts);
-        else
-          V = ConstantDataArray::getFP(EltTy, Elts);
-      } else if (EltTy->isBFloatTy()) {
-        SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::getFP(EltTy, Elts);
-        else
-          V = ConstantDataArray::getFP(EltTy, Elts);
-      } else if (EltTy->isFloatTy()) {
-        SmallVector<uint32_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::getFP(EltTy, Elts);
-        else
-          V = ConstantDataArray::getFP(EltTy, Elts);
-      } else if (EltTy->isDoubleTy()) {
-        SmallVector<uint64_t, 16> Elts(Record.begin(), Record.end());
-        if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::getFP(EltTy, Elts);
-        else
-          V = ConstantDataArray::getFP(EltTy, Elts);
-      } else {
+      Type *EltTy = CurTy->getContainedType(0);
+      if (!ConstantDataSequential::isElementTypeCompatible(EltTy))
         return error("Invalid type for value");
+
+      const unsigned EltBytes = EltTy->getScalarSizeInBits() / 8;
+      SmallString<128> RawData;
+      RawData.reserve(Record.size() * EltBytes);
+      for (uint64_t Val : Record) {
+        const char *Src = reinterpret_cast<const char *>(&Val);
+        if constexpr (sys::IsBigEndianHost)
+          Src += sizeof(uint64_t) - EltBytes;
+        RawData.append(Src, Src + EltBytes);
       }
+
+      V = isa<VectorType>(CurTy)
+              ? ConstantDataVector::getRaw(RawData.str(), Record.size(), EltTy)
+              : ConstantDataArray::getRaw(RawData.str(), Record.size(), EltTy);
       break;
     }
     case bitc::CST_CODE_CE_UNOP: {  // CE_UNOP: [opcode, opval]