Move get[S|U]LEB128Size() to LEB128.h.

This commit moves getSLEB128Size() and getULEB128Size() from
MCAsmInfo to LEB128.h and removes some copy-and-paste code.

Besides, this commit also adds some unit tests for the LEB128
functions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201937 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 25 insertions, 0 deletions

diff --git a/include/llvm/Support/LEB128.h b/include/llvm/Support/LEB128.h
index 3d7379250a..6eb34eec8a 100644
--- a/include/llvm/Support/LEB128.h
+++ b/include/llvm/Support/LEB128.h
@@ -90,6 +90,31 @@ inline uint64_t decodeULEB128(const uint8_t *p, unsigned *n = 0) {
   return Value;
 }
 
+/// Utility function to get the size of the ULEB128-encoded value.
+inline unsigned getULEB128Size(uint64_t Value) {
+  unsigned Size = 0;
+  do {
+    Value >>= 7;
+    Size += sizeof(int8_t);
+  } while (Value);
+  return Size;
+}
+
+/// Utility function to get the size of the SLEB128-encoded value.
+inline unsigned getSLEB128Size(int64_t Value) {
+  unsigned Size = 0;
+  int Sign = Value >> (8 * sizeof(Value) - 1);
+  bool IsMore;
+
+  do {
+    unsigned Byte = Value & 0x7f;
+    Value >>= 7;
+    IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
+    Size += sizeof(int8_t);
+  } while (IsMore);
+  return Size;
+}
+
 }  // namespace llvm
 
 #endif  // LLVM_SYSTEM_LEB128_H