Track nested loop levels in CMake language with a stack of counters

It gets incremented while entering a loop block (e.g. foreach or while)
and gets decremented when leaving the block. Because scope borders for
example at function borders must be taken into account the counter is
put into a stack. With every new scope an empty counter is pushed on the
stack, when leaving the scope the original value is restored.

This will allow easy querying if the break command is properly nested
within a loop scope.

Signed-off-by: Gregor Jasny <gjasny@googlemail.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 61807b2..6eca0f0 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -171,6 +171,9 @@ void cmMakefile::Initialize()
   // Protect the directory-level policies.
   this->PushPolicyBarrier();
 
+  // push empty loop block
+  this->PushLoopBlockBarrier();
+
   // By default the check is not done.  It is enabled by
   // cmListFileCache in the top level if necessary.
   this->CheckCMP0000 = false;
@@ -3354,6 +3357,38 @@ void cmMakefile::PopFunctionBlockerBarrier(bool reportError)
 }
 
 //----------------------------------------------------------------------------
+void cmMakefile::PushLoopBlock()
+{
+  assert(!this->LoopBlockCounter.empty());
+  this->LoopBlockCounter.top()++;
+}
+
+void cmMakefile::PopLoopBlock()
+{
+  assert(!this->LoopBlockCounter.empty());
+  assert(this->LoopBlockCounter.top() > 0);
+  this->LoopBlockCounter.top()--;
+}
+
+void cmMakefile::PushLoopBlockBarrier()
+{
+  this->LoopBlockCounter.push(0);
+}
+
+void cmMakefile::PopLoopBlockBarrier()
+{
+  assert(!this->LoopBlockCounter.empty());
+  assert(this->LoopBlockCounter.top() == 0);
+  this->LoopBlockCounter.pop();
+}
+
+bool cmMakefile::IsLoopBlock() const
+{
+  assert(!this->LoopBlockCounter.empty());
+  return !this->LoopBlockCounter.empty() && this->LoopBlockCounter.top() > 0;
+}
+
+//----------------------------------------------------------------------------
 bool cmMakefile::ExpandArguments(
   std::vector<cmListFileArgument> const& inArgs,
   std::vector<std::string>& outArgs) const
@@ -4487,10 +4522,14 @@ void cmMakefile::PushScope()
   this->Internal->VarStack.push(cmDefinitions(parent));
   this->Internal->VarInitStack.push(init);
   this->Internal->VarUsageStack.push(usage);
+
+  this->PushLoopBlockBarrier();
 }
 
 void cmMakefile::PopScope()
 {
+  this->PopLoopBlockBarrier();
+
   cmDefinitions* current = &this->Internal->VarStack.top();
   std::set<std::string> init = this->Internal->VarInitStack.top();
   std::set<std::string> usage = this->Internal->VarUsageStack.top();