[llvm] Implement support for -defsym assembler option

Summary:
Changes to llvm-mc to move common logic to separate function.

Related clang patch: https://reviews.llvm.org/D26213

Reviewers: rafael, t.p.northover, colinl, echristo, rengolin

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D26214

llvm-svn: 288396

1 files changed, 16 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index 7932fe441e3..77fe015eefe 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -260,6 +260,22 @@ MCSymbol *MCContext::lookupSymbol(const Twine &Name) const {
   return Symbols.lookup(NameRef);
 }
 
+int MCContext::setSymbolValue(MCStreamer &Streamer, std::string &I) {
+    auto Pair = StringRef(I).split('=');
+    if (Pair.second.empty()) {
+      errs() << "error: defsym must be of the form: sym=value: " << I << "\n";
+      return 1;
+    }
+    int64_t Value;
+    if (Pair.second.getAsInteger(0, Value)) {
+      errs() << "error: Value is not an integer: " << Pair.second << "\n";
+      return 1;
+    }
+    auto Symbol = getOrCreateSymbol(Pair.first);
+    Streamer.EmitAssignment(Symbol, MCConstantExpr::create(Value, *this));
+    return 0;
+}
+
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