[PATCH] D99393: [OCaml] Fix a possible crash in llvm_struct_name

[Josh Berdine via Phabricator via llvm-commits]

jberdine updated this revision to Diff 333517.
jberdine added a comment.

fix bug spotted in CR, formatting


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99393/new/

https://reviews.llvm.org/D99393

Files:
  llvm/bindings/ocaml/llvm/llvm_ocaml.c


Index: llvm/bindings/ocaml/llvm/llvm_ocaml.c
===================================================================
--- llvm/bindings/ocaml/llvm/llvm_ocaml.c
+++ llvm/bindings/ocaml/llvm/llvm_ocaml.c
@@ -56,6 +56,18 @@
   CAMLreturn(String);
 }
 
+CAMLprim value cstr_to_string_option(const char *CStr, mlsize_t Len) {
+  CAMLparam0();
+  CAMLlocal2(Option, String);
+  if (!CStr)
+    CAMLreturn(Val_int(0));
+  String = caml_alloc_string(Len);
+  memcpy((char *)String_val(String), CStr, Len);
+  Option = caml_alloc_small(1, 0);
+  Store_field(Option, 0, (value)String);
+  CAMLreturn(Option);
+}
+
 void llvm_raise(value Prototype, char *Message) {
   CAMLparam1(Prototype);
   caml_raise_with_arg(Prototype, llvm_string_of_message(Message));
@@ -529,17 +541,13 @@
 }
 
 /* lltype -> string option */
-CAMLprim value llvm_struct_name(LLVMTypeRef Ty)
-{
-  CAMLparam0();
-  CAMLlocal1(result);
-  const char *C = LLVMGetStructName(Ty);
-  if (C) {
-    result = caml_alloc_small(1, 0);
-    Store_field(result, 0, caml_copy_string(C));
-    CAMLreturn(result);
-  }
-  CAMLreturn(Val_int(0));
+CAMLprim value llvm_struct_name(LLVMTypeRef Ty) {
+  const char *CStr = LLVMGetStructName(Ty);
+  size_t Len;
+  if (!CStr)
+    return Val_int(0);
+  Len = strlen(CStr);
+  return cstr_to_string_option(CStr, Len);
 }
 
 /* lltype -> lltype array */
@@ -877,19 +885,9 @@
 
 /* llvalue -> string option */
 CAMLprim value llvm_get_mdstring(LLVMValueRef V) {
-  CAMLparam0();
-  CAMLlocal2(Option, Str);
-  const char *S;
-  unsigned Len;
-
-  if ((S = LLVMGetMDString(V, &Len))) {
-    Str = caml_alloc_string(Len);
-    memcpy((char *)String_val(Str), S, Len);
-    Option = alloc(1,0);
-    Store_field(Option, 0, Str);
-    CAMLreturn(Option);
-  }
-  CAMLreturn(Val_int(0));
+  size_t Len;
+  const char *CStr = LLVMGetMDString(V, &Len);
+  return cstr_to_string_option(CStr, Len);
 }
 
 CAMLprim value llvm_get_mdnode_operands(LLVMValueRef V) {
@@ -1045,22 +1043,12 @@
 
 /* llvalue -> string option */
 CAMLprim value llvm_string_of_const(LLVMValueRef Const) {
-  const char *S;
   size_t Len;
-  CAMLparam0();
-  CAMLlocal2(Option, Str);
-
-  if(LLVMIsAConstantDataSequential(Const) && LLVMIsConstantString(Const)) {
-    S = LLVMGetAsString(Const, &Len);
-    Str = caml_alloc_string(Len);
-    memcpy((char *)String_val(Str), S, Len);
-
-    Option = alloc(1, 0);
-    Field(Option, 0) = Str;
-    CAMLreturn(Option);
-  } else {
-    CAMLreturn(Val_int(0));
-  }
+  const char *CStr;
+  if (!LLVMIsAConstantDataSequential(Const) || !LLVMIsConstantString(Const))
+    return Val_int(0);
+  CStr = LLVMGetAsString(Const, &Len);
+  return cstr_to_string_option(CStr, Len);
 }
 
 /* llvalue -> int -> llvalue */


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