asm mode: increase global vars size to a multiple of alignment

reported by @regehr
AliveToolkit · Dec 18, 2023 · 1c70b43 · 1c70b43
1 parent d7766a9
commit 1c70b43
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Showing 3 changed files with 20 additions and 0 deletions.
diff --git a/ir/value.cpp b/ir/value.cpp
@@ -81,6 +81,12 @@ StateValue NullPointerValue::toSMT(State &s) const {
 }
 
 
+void GlobalVariable::increaseSize(uint64_t newsize) {
+  assert(!arbitrary_size);
+  assert(newsize >= allocsize);
+  allocsize = newsize;
+}
+
 void GlobalVariable::print(ostream &os) const {
   os << getName() << " = " << (isconst ? "constant " : "global ");
   if (arbitrary_size)

diff --git a/ir/value.h b/ir/value.h
@@ -95,6 +95,7 @@ class GlobalVariable final : public Value {
   bool isArbitrarySize() const { return arbitrary_size; }
   unsigned getAlignment() const { return align; }
   bool isConst() const { return isconst; }
+  void increaseSize(uint64_t newsize);
   void print(std::ostream &os) const override;
   StateValue toSMT(State &s) const override;
 };

diff --git a/tools/transform.cpp b/tools/transform.cpp
@@ -1650,6 +1650,19 @@ void Transform::preprocess() {
       to_add.clear();
       to_remove.clear();
     }
+
+    // increase size of global variables to be a multiple of alignment
+    for (auto p : { &src, &tgt }) {
+      for (auto gv : p->getGlobalVars()) {
+        if (gv->isArbitrarySize())
+          continue;
+        auto align = gv->getAlignment();
+        auto sz = gv->size();
+        auto newsize = round_up(sz, align);
+        if (newsize != sz)
+          gv->increaseSize(newsize);
+      }
+    }
   }
 
   remove_unreachable_bbs(src);