Keep track of stack usage, report line that used the most

This won't keep track of everything, but was useful in tracking down
some recursive variables in the android build that shouldn't have been
recursive (they were using 1MB+ of stack).

Change-Id: I5e6b70480cffbebb09dfd72276017559480da948

1 files changed, 14 insertions, 0 deletions

diff --git a/eval.h b/eval.h
index 97a2c23..2b62892 100644
--- a/eval.h
+++ b/eval.h
@@ -86,6 +86,15 @@ class Evaluator {
   string GetShellFlag();
   string GetShellAndFlag();
 
+  void CheckStack() {
+    void* addr = __builtin_frame_address(0);
+    if (__builtin_expect(addr < lowest_stack_ && addr >= stack_addr_, 0)) {
+      lowest_stack_ = addr;
+      lowest_loc_ = loc_;
+    }
+  }
+  void DumpStackStats() const;
+
  private:
   Var* EvalRHS(Symbol lhs,
                Value* rhs,
@@ -119,6 +128,11 @@ class Evaluator {
   Symbol posix_sym_;
   bool is_posix_;
 
+  void* stack_addr_;
+  size_t stack_size_;
+  void* lowest_stack_;
+  Loc lowest_loc_;
+
   static unordered_set<Symbol> used_undefined_vars_;
 
   Symbol kati_readonly_;