[Support] Make DataExtractor string functions error-aware

Summary:
This patch adds an optional Error argument to DataExtractor functions
for string extraction, and makes them behave like other DataExtractor
functions (set the error if extraction fails, don't do anything if the
error is already set).

I have merged the StringRef and C string versions of the functions to
reduce code duplication.

Reviewers: dblaikie, MaskRay

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77307

1 files changed, 7 insertions, 12 deletions

diff --git a/llvm/lib/Support/DataExtractor.cpp b/llvm/lib/Support/DataExtractor.cpp
index d6fd9a5..764c3fa 100644
--- a/llvm/lib/Support/DataExtractor.cpp
+++ b/llvm/lib/Support/DataExtractor.cpp
@@ -152,23 +152,18 @@ DataExtractor::getSigned(uint64_t *offset_ptr, uint32_t byte_size) const {
   llvm_unreachable("getSigned unhandled case!");
 }
 
-const char *DataExtractor::getCStr(uint64_t *offset_ptr) const {
-  uint64_t offset = *offset_ptr;
-  StringRef::size_type pos = Data.find('\0', offset);
-  if (pos != StringRef::npos) {
-    *offset_ptr = pos + 1;
-    return Data.data() + offset;
-  }
-  return nullptr;
-}
+StringRef DataExtractor::getCStrRef(uint64_t *OffsetPtr, Error *Err) const {
+  ErrorAsOutParameter ErrAsOut(Err);
+  if (isError(Err))
+    return StringRef();
 
-StringRef DataExtractor::getCStrRef(uint64_t *offset_ptr) const {
-  uint64_t Start = *offset_ptr;
+  uint64_t Start = *OffsetPtr;
   StringRef::size_type Pos = Data.find('\0', Start);
   if (Pos != StringRef::npos) {
-    *offset_ptr = Pos + 1;
+    *OffsetPtr = Pos + 1;
     return StringRef(Data.data() + Start, Pos - Start);
   }
+  unexpectedEndReached(Err, Start);
   return StringRef();
 }