[TLI] Add support for reallocarray

From the man page (e.g. https://man.archlinux.org/man/reallocarray.3.en):

SYNOPSIS

reallocarray():

    Since glibc 2.29:
        _DEFAULT_SOURCE
    glibc 2.28 and earlier:
        _GNU_SOURCE

STANDARDS

reallocarray()
    None.

HISTORY

reallocarray()
    glibc 2.26. OpenBSD 5.6, FreeBSD 11.0.

Author: serge-sans-paille

clang/include/clang/Basic/Builtins.td

@@ -3224,6 +3224,13 @@ def AllocA : GNULibBuiltin<"stdlib.h"> {
   let AddBuiltinPrefixedAlias = 1;
 }
 
+// Available in glibc by default since since 2.29 and in GNU mode before.
+def ReallocArray : GNULibBuiltin<"stdlib.h"> {
+  let Spellings = ["reallocarray"];
+  let Prototype = "void*(void*, size_t, size_t)";
+}
+
+
 // POSIX malloc.h
 
 def MemAlign : GNULibBuiltin<"malloc.h"> {

clang/test/Sema/builtins-gnu-mode.c

@@ -8,6 +8,7 @@ int stpncpy;
 int strdup;
 int strndup;
 int index;
+int reallocarray;
 int rindex;
 int bzero;
 int strcasecmp;

llvm/include/llvm/Analysis/TargetLibraryInfo.def

@@ -2077,6 +2077,11 @@ TLI_DEFINE_ENUM_INTERNAL(reallocf)
 TLI_DEFINE_STRING_INTERNAL("reallocf")
 TLI_DEFINE_SIG_INTERNAL(Ptr, Ptr, SizeT)
 
+/// void *reallocarray(void *ptr, size_t nmemb, size_t size);
+TLI_DEFINE_ENUM_INTERNAL(reallocarray)
+TLI_DEFINE_STRING_INTERNAL("reallocarray")
+TLI_DEFINE_SIG_INTERNAL(Ptr, Ptr, SizeT, SizeT)
+
 /// char *realpath(const char *file_name, char *resolved_name);
 TLI_DEFINE_ENUM_INTERNAL(realpath)
 TLI_DEFINE_STRING_INTERNAL("realpath")

llvm/lib/Analysis/TargetLibraryInfo.cpp

@@ -852,6 +852,7 @@ static void initializeLibCalls(TargetLibraryInfoImpl &TLI, const Triple &T,
     TLI.setUnavailable(LibFunc_memrchr);
     TLI.setUnavailable(LibFunc_ntohl);
     TLI.setUnavailable(LibFunc_ntohs);
+    TLI.setUnavailable(LibFunc_reallocarray);
     TLI.setUnavailable(LibFunc_reallocf);
     TLI.setUnavailable(LibFunc_roundeven);
     TLI.setUnavailable(LibFunc_roundevenf);

llvm/lib/Transforms/Utils/BuildLibCalls.cpp

@@ -577,6 +577,21 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setArgNoUndef(F, 1);
     break;
+  case LibFunc_reallocarray:
+    Changed |= setAllocFamily(F, "malloc");
+    Changed |= setAllocKind(F, AllocFnKind::Realloc);
+    Changed |= setAllocatedPointerParam(F, 0);
+    Changed |= setAllocSize(F, 1, std::nullopt);
+    Changed |= setAllocSize(F, 2, std::nullopt);
+    Changed |= setOnlyAccessesInaccessibleMemOrArgMem(F);
+    Changed |= setRetNoUndef(F);
+    Changed |= setDoesNotThrow(F);
+    Changed |= setRetDoesNotAlias(F);
+    Changed |= setWillReturn(F);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setArgNoUndef(F, 1);
+    Changed |= setArgNoUndef(F, 2);
+    break;
   case LibFunc_read:
     // May throw; "read" is a valid pthread cancellation point.
     Changed |= setRetAndArgsNoUndef(F);

llvm/test/tools/llvm-tli-checker/ps4-tli-check.yaml

@@ -54,10 +54,10 @@
 ## the exact count first; the two directives should add up to that.
 ## Yes, this means additions to TLI will fail this test, but the argument
 ## to -COUNT can't be an expression.
-# AVAIL: TLI knows 522 symbols, 289 available
+# AVAIL: TLI knows 523 symbols, 289 available
 # AVAIL-COUNT-289: {{^}} available
 # AVAIL-NOT:       {{^}} available
-# UNAVAIL-COUNT-233: not available
+# UNAVAIL-COUNT-234: not available
 # UNAVAIL-NOT:       not available
 
 ## This is a large file so it's worth telling lit to stop here.

llvm/unittests/Analysis/TargetLibraryInfoTest.cpp

@@ -318,6 +318,7 @@ TEST_F(TargetLibraryInfoTest, ValidProto) {
       "declare void @qsort(i8*, i64, i64, i32 (i8*, i8*)*)\n"
       "declare i64 @readlink(i8*, i8*, i64)\n"
       "declare i8* @realloc(i8*, i64)\n"
+      "declare i8* @reallocarray(i8*, i64, i64)\n"
       "declare i8* @reallocf(i8*, i64)\n"
       "declare double @remainder(double, double)\n"
       "declare float @remainderf(float, float)\n"