MC: Improve expression parsing and implement evaluation of absolute expressions
(missed files).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74450 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-mc/AsmExpr.cpp b/tools/llvm-mc/AsmExpr.cpp
new file mode 100644
index 0000000..7e4baf8
--- /dev/null
+++ b/tools/llvm-mc/AsmExpr.cpp
@@ -0,0 +1,92 @@
+//===- AsmExpr.cpp - Assembly file expressions ----------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AsmExpr.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCValue.h"
+using namespace llvm;
+
+AsmExpr::~AsmExpr() {
+}
+
+bool AsmExpr::EvaluateAsAbsolute(MCContext &Ctx, int64_t &Res) const {
+ switch (getKind()) {
+ default:
+ assert(0 && "Invalid assembly expression kind!");
+
+ case Constant:
+ Res = cast<AsmConstantExpr>(this)->getValue();
+ return true;
+
+ case SymbolRef: {
+ MCSymbol *Sym = cast<AsmSymbolRefExpr>(this)->getSymbol();
+ const MCValue *Value = Ctx.GetSymbolValue(Sym);
+
+ // FIXME: Return more information about the failure.
+ if (!Value || !Value->isConstant())
+ return false;
+
+ Res = Value->getConstant();
+ return true;
+ }
+
+ case Unary: {
+ const AsmUnaryExpr *AUE = cast<AsmUnaryExpr>(this);
+ int64_t Value;
+
+ if (!AUE->getSubExpr()->EvaluateAsAbsolute(Ctx, Value))
+ return false;
+
+ switch (AUE->getOpcode()) {
+ case AsmUnaryExpr::LNot: Res = !Value; break;
+ case AsmUnaryExpr::Minus: Res = -Value; break;
+ case AsmUnaryExpr::Not: Res = ~Value; break;
+ case AsmUnaryExpr::Plus: Res = +Value; break;
+ }
+
+ return true;
+ }
+
+ case Binary: {
+ const AsmBinaryExpr *ABE = cast<AsmBinaryExpr>(this);
+ int64_t LHS, RHS;
+
+ if (!ABE->getLHS()->EvaluateAsAbsolute(Ctx, LHS) ||
+ !ABE->getRHS()->EvaluateAsAbsolute(Ctx, RHS))
+ return false;
+
+ // FIXME: We need target hooks for the evaluation. It may be limited in
+ // width, and gas defines the result of comparisons differently from Apple
+ // as (the result is sign extended).
+ switch (ABE->getOpcode()) {
+ case AsmBinaryExpr::Add: Res = LHS + RHS; break;
+ case AsmBinaryExpr::And: Res = LHS & RHS; break;
+ case AsmBinaryExpr::Div: Res = LHS / RHS; break;
+ case AsmBinaryExpr::EQ: Res = LHS == RHS; break;
+ case AsmBinaryExpr::GT: Res = LHS > RHS; break;
+ case AsmBinaryExpr::GTE: Res = LHS >= RHS; break;
+ case AsmBinaryExpr::LAnd: Res = LHS && RHS; break;
+ case AsmBinaryExpr::LOr: Res = LHS || RHS; break;
+ case AsmBinaryExpr::LT: Res = LHS < RHS; break;
+ case AsmBinaryExpr::LTE: Res = LHS <= RHS; break;
+ case AsmBinaryExpr::Mod: Res = LHS % RHS; break;
+ case AsmBinaryExpr::Mul: Res = LHS * RHS; break;
+ case AsmBinaryExpr::NE: Res = LHS != RHS; break;
+ case AsmBinaryExpr::Or: Res = LHS | RHS; break;
+ case AsmBinaryExpr::Shl: Res = LHS << RHS; break;
+ case AsmBinaryExpr::Shr: Res = LHS >> RHS; break;
+ case AsmBinaryExpr::Sub: Res = LHS - RHS; break;
+ case AsmBinaryExpr::Xor: Res = LHS ^ RHS; break;
+ }
+
+ return true;
+ }
+ }
+}
+