[PATCH] D12776: [MC] Don't crash on division by zero

[Davide Italiano via llvm-commits]

davide created this revision.
davide added reviewers: rafael, echristo, grosbach.
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Maybe there's a better  way to handle this case (in the Parser?), but at least we now don't crash with FPE on such cases. Also, FWIW, gas seems to handle this in the same exact way (+ emitting a warning)

Repository:
  rL LLVM

http://reviews.llvm.org/D12776

Files:
  lib/MC/MCExpr.cpp
  test/MC/ELF/div-by-zero.s

Index: test/MC/ELF/div-by-zero.s
===================================================================
--- test/MC/ELF/div-by-zero.s
+++ test/MC/ELF/div-by-zero.s
@@ -0,0 +1,4 @@
+// Check that llvm-mc doesn't crash on division by zero.
+// RUN: llvm-mc -triple x86_64-pc-linux-gnu %s -o - 2>&1 
+
+.int 1/0
Index: lib/MC/MCExpr.cpp
===================================================================
--- lib/MC/MCExpr.cpp
+++ lib/MC/MCExpr.cpp
@@ -734,6 +734,11 @@
     // width, and gas defines the result of comparisons differently from
     // Apple as.
     int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
+
+    // Handle division by zero.
+    if (ABE->getOpcode() == MCBinaryExpr::Div && RHS == 0)
+      return false;
+
     int64_t Result = 0;
     switch (ABE->getOpcode()) {
     case MCBinaryExpr::AShr: Result = LHS >> RHS; break;


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