Renamed from defaultNull to Sentinel pointer value and updated the LangRef

Author: ranapratap55

llvm/docs/LangRef.rst

@@ -3062,13 +3062,14 @@ as follows:
     this set are considered to support most general arithmetic operations
     efficiently.
 ``z[n]:<value>``
-    This specifies the default null value for an address space. ``n`` denotes
-    the address space number, and if not specified, it is considered to be
-    for the unlisted address space. For unlisted address space, the default
-    null value is ``0``. ``value`` denotes the default null value for an
-    address space ``n``. To represent negatives values, prefix ``neg`` is
-    added to ``value``. for e.g., ``z0:neg1`` represents for ``0`` address
-    space ``-1`` is the default null value.
+    This specifies the sentinel pointer value for an address space. Sentinel
+    pointer value is the default non zero null value for a given address
+    space. ``n`` denotes the address space number, and if not specified, it
+    is considered to be for the unlisted address space. For unlisted address
+    space, the sentinel pointer value is ``0``. ``value`` denotes the sentinel
+    pointer value for an address space ``n``. To represent negatives values,
+    prefix ``neg`` is added to ``value``. for e.g., ``z0:neg1`` represents for
+    ``0`` address space ``-1`` is the sentinel pointer value.
 ``ni:<address space0>:<address space1>:<address space2>...``
     This specifies pointer types with the specified address spaces
     as :ref:`Non-Integral Pointer Type <nointptrtype>` s.  The ``0``

llvm/include/llvm/IR/DataLayout.h

@@ -165,7 +165,7 @@ class DataLayout {
   /// well-defined bitwise representation.
   SmallVector<unsigned, 8> NonIntegralAddressSpaces;
 
-  DenseMap<unsigned, int64_t> AddrSpaceToNonZeroValueMap;
+  DenseMap<unsigned, int64_t> AddrSpaceToSentinelValueMap;
 
   /// Attempts to set the alignment of the given type. Returns an error
   /// description on failure.
@@ -302,15 +302,15 @@ class DataLayout {
     return ManglingMode == MM_WinCOFFX86;
   }
 
-  int64_t getDefaultNullPointerValue(unsigned AddrSpace) {
-    auto It = AddrSpaceToNonZeroValueMap.find(AddrSpace);
-    if (It == AddrSpaceToNonZeroValueMap.end())
+  int64_t getSentinelPointerValue(unsigned AddrSpace) {
+    auto It = AddrSpaceToSentinelValueMap.find(AddrSpace);
+    if (It == AddrSpaceToSentinelValueMap.end())
       return 0;
     return It->second;
   }
 
-  void setDefaultNullPointerValue(unsigned AddrSpace, int64_t Value) {
-    AddrSpaceToNonZeroValueMap[AddrSpace] = Value;
+  void setSentinelPointerValue(unsigned AddrSpace, int64_t Value) {
+    AddrSpaceToSentinelValueMap[AddrSpace] = Value;
   }
 
   /// Returns true if symbols with leading question marks should not receive IR

llvm/lib/IR/DataLayout.cpp

@@ -216,7 +216,7 @@ void DataLayout::reset(StringRef Desc) {
   if (Error Err = setPointerAlignmentInBits(0, Align(8), Align(8), 64, 64))
     return report_fatal_error(std::move(Err));
 
-  setDefaultNullPointerValue(INT_MAX, 0);
+  setSentinelPointerValue(INT_MAX, 0);
 
   if (Error Err = parseSpecifier(Desc))
     return report_fatal_error(std::move(Err));
@@ -527,7 +527,7 @@ Error DataLayout::parseSpecifier(StringRef Desc) {
       if (Tok.empty()) {
         if (Error Err = getIntForAddrSpace(Rest, Value))
           return Err;
-        setDefaultNullPointerValue(INT_MAX, Value);
+        setSentinelPointerValue(INT_MAX, Value);
         break;
       } else {
         if (Error Err = getInt(Tok, AddrSpace))
@@ -543,7 +543,7 @@ Error DataLayout::parseSpecifier(StringRef Desc) {
         return Err;
       if (Error Err = getIntForAddrSpace(Tok, Value))
         return Err;
-      setDefaultNullPointerValue(AddrSpace, Value);
+      setSentinelPointerValue(AddrSpace, Value);
       break;
     }
     case 'G': { // Default address space for global variables.