[PATCH] D71374: Improve support of GNU mempcpy

[serge via Phabricator via cfe-commits]

serge-sans-paille updated this revision to Diff 233587.
serge-sans-paille added a comment.

@Jim obviously :-) Thanks for spotting that.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71374/new/

https://reviews.llvm.org/D71374

Files:
  clang/include/clang/Basic/Builtins.def
  clang/lib/AST/Decl.cpp
  clang/lib/CodeGen/CGBuiltin.cpp
  clang/lib/Sema/SemaChecking.cpp
  clang/test/Analysis/bstring.c


Index: clang/test/Analysis/bstring.c
===================================================================
--- clang/test/Analysis/bstring.c
+++ clang/test/Analysis/bstring.c
@@ -222,6 +222,9 @@
   char dst[1];
 
   mempcpy(dst, src, 4); // expected-warning{{Memory copy function overflows destination buffer}}
+#ifndef VARIANT
+// expected-warning@-2{{'mempcpy' will always overflow; destination buffer has size 1, but size argument is 4}}
+#endif
 }
 
 void mempcpy3 () {
@@ -243,6 +246,9 @@
   char dst[3];
 
   mempcpy(dst+2, src+2, 2); // expected-warning{{Memory copy function overflows destination buffer}}
+#ifndef VARIANT
+// expected-warning@-2{{'mempcpy' will always overflow; destination buffer has size 1, but size argument is 2}}
+#endif
 }
 
 void mempcpy6() {
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -340,7 +340,8 @@
   case Builtin::BI__builtin___strncat_chk:
   case Builtin::BI__builtin___strncpy_chk:
   case Builtin::BI__builtin___stpncpy_chk:
-  case Builtin::BI__builtin___memccpy_chk: {
+  case Builtin::BI__builtin___memccpy_chk:
+  case Builtin::BI__builtin___mempcpy_chk: {
     DiagID = diag::warn_builtin_chk_overflow;
     IsChkVariant = true;
     SizeIndex = TheCall->getNumArgs() - 2;
@@ -379,7 +380,9 @@
   case Builtin::BImemmove:
   case Builtin::BI__builtin_memmove:
   case Builtin::BImemset:
-  case Builtin::BI__builtin_memset: {
+  case Builtin::BI__builtin_memset:
+  case Builtin::BImempcpy:
+  case Builtin::BI__builtin_mempcpy: {
     DiagID = diag::warn_fortify_source_overflow;
     SizeIndex = TheCall->getNumArgs() - 1;
     ObjectIndex = 0;
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -2506,7 +2506,9 @@
     return RValue::get(nullptr);
   }
   case Builtin::BImemcpy:
-  case Builtin::BI__builtin_memcpy: {
+  case Builtin::BI__builtin_memcpy:
+  case Builtin::BImempcpy:
+  case Builtin::BI__builtin_mempcpy: {
     Address Dest = EmitPointerWithAlignment(E->getArg(0));
     Address Src = EmitPointerWithAlignment(E->getArg(1));
     Value *SizeVal = EmitScalarExpr(E->getArg(2));
@@ -2515,7 +2517,11 @@
     EmitNonNullArgCheck(RValue::get(Src.getPointer()), E->getArg(1)->getType(),
                         E->getArg(1)->getExprLoc(), FD, 1);
     Builder.CreateMemCpy(Dest, Src, SizeVal, false);
-    return RValue::get(Dest.getPointer());
+    if (BuiltinID == Builtin::BImempcpy ||
+        BuiltinID == Builtin::BI__builtin_mempcpy)
+      return RValue::get(Builder.CreateGEP(Dest.getPointer(), SizeVal));
+    else
+      return RValue::get(Dest.getPointer());
   }
 
   case Builtin::BI__builtin_char_memchr:
Index: clang/lib/AST/Decl.cpp
===================================================================
--- clang/lib/AST/Decl.cpp
+++ clang/lib/AST/Decl.cpp
@@ -3866,6 +3866,11 @@
   case Builtin::BImemcpy:
     return Builtin::BImemcpy;
 
+  case Builtin::BI__builtin_mempcpy:
+  case Builtin::BI__builtin___mempcpy_chk:
+  case Builtin::BImempcpy:
+    return Builtin::BImempcpy;
+
   case Builtin::BI__builtin_memmove:
   case Builtin::BI__builtin___memmove_chk:
   case Builtin::BImemmove:
@@ -3923,6 +3928,8 @@
         return Builtin::BImemset;
       else if (FnInfo->isStr("memcpy"))
         return Builtin::BImemcpy;
+      else if (FnInfo->isStr("mempcpy"))
+        return Builtin::BImempcpy;
       else if (FnInfo->isStr("memmove"))
         return Builtin::BImemmove;
       else if (FnInfo->isStr("memcmp"))
Index: clang/include/clang/Basic/Builtins.def
===================================================================
--- clang/include/clang/Basic/Builtins.def
+++ clang/include/clang/Basic/Builtins.def
@@ -984,6 +984,7 @@
 LIBBUILTIN(alloca, "v*z",         "f",     "stdlib.h", ALL_GNU_LANGUAGES)
 // POSIX string.h
 LIBBUILTIN(memccpy, "v*v*vC*iz",  "f",     "string.h", ALL_GNU_LANGUAGES)
+LIBBUILTIN(mempcpy, "v*v*vC*z",   "f",     "string.h", ALL_GNU_LANGUAGES)
 LIBBUILTIN(stpcpy, "c*c*cC*",     "f",     "string.h", ALL_GNU_LANGUAGES)
 LIBBUILTIN(stpncpy, "c*c*cC*z",   "f",     "string.h", ALL_GNU_LANGUAGES)
 LIBBUILTIN(strdup, "c*cC*",       "f",     "string.h", ALL_GNU_LANGUAGES)

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