move FlattenVariants out of AsmMatcherEmitter into a shared
CodeGenInstruction::FlattenAsmStringVariants method. Use it
to simplify the code in AsmWriterInst, which now no longer
needs to worry about variants.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117886 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/CodeGenInstruction.cpp b/utils/TableGen/CodeGenInstruction.cpp
index 6e71502..f7b45e24 100644
--- a/utils/TableGen/CodeGenInstruction.cpp
+++ b/utils/TableGen/CodeGenInstruction.cpp
@@ -321,3 +321,52 @@
return MVT::Other;
}
+
+/// FlattenAsmStringVariants - Flatten the specified AsmString to only
+/// include text from the specified variant, returning the new string.
+std::string CodeGenInstruction::
+FlattenAsmStringVariants(StringRef Cur, unsigned Variant) {
+ std::string Res = "";
+
+ for (;;) {
+ // Find the start of the next variant string.
+ size_t VariantsStart = 0;
+ for (size_t e = Cur.size(); VariantsStart != e; ++VariantsStart)
+ if (Cur[VariantsStart] == '{' &&
+ (VariantsStart == 0 || (Cur[VariantsStart-1] != '$' &&
+ Cur[VariantsStart-1] != '\\')))
+ break;
+
+ // Add the prefix to the result.
+ Res += Cur.slice(0, VariantsStart);
+ if (VariantsStart == Cur.size())
+ break;
+
+ ++VariantsStart; // Skip the '{'.
+
+ // Scan to the end of the variants string.
+ size_t VariantsEnd = VariantsStart;
+ unsigned NestedBraces = 1;
+ for (size_t e = Cur.size(); VariantsEnd != e; ++VariantsEnd) {
+ if (Cur[VariantsEnd] == '}' && Cur[VariantsEnd-1] != '\\') {
+ if (--NestedBraces == 0)
+ break;
+ } else if (Cur[VariantsEnd] == '{')
+ ++NestedBraces;
+ }
+
+ // Select the Nth variant (or empty).
+ StringRef Selection = Cur.slice(VariantsStart, VariantsEnd);
+ for (unsigned i = 0; i != Variant; ++i)
+ Selection = Selection.split('|').second;
+ Res += Selection.split('|').first;
+
+ assert(VariantsEnd != Cur.size() &&
+ "Unterminated variants in assembly string!");
+ Cur = Cur.substr(VariantsEnd + 1);
+ }
+
+ return Res;
+}
+
+