[llvm] [DataLayout] Add byte specification (PR #106536)

[Matt Arsenault via llvm-commits]

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@@ -357,6 +357,36 @@ static Error parseAlignment(StringRef Str, Align &Alignment, StringRef Name,
   return Error::success();
 }
 
+Error DataLayout::parseByteSpec(StringRef Spec) {
+  // b:<size>
+  assert(Spec.front() == 'b');
+  StringRef Rest = Spec.drop_front();
+  if (!Rest.consume_front(":") || Rest.empty())
+    return createSpecFormatError("b:<size>");
+
+  if (Error Err = parseSize(Rest, ByteWidth))
+    return Err;
+
+  if (ByteWidth != 8 && ByteWidth != 16 && ByteWidth != 32)
+    return createStringError("unsupported byte width");
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arsenm wrote:

Missing tests for these error conditions 

https://github.com/llvm/llvm-project/pull/106536