From 097e26f4908b3099f112c3fdc5e043234f9adc53 Mon Sep 17 00:00:00 2001
From: Ben Boeckel <ben.boeckel@kitware.com>
Date: Wed, 14 Jan 2015 13:11:44 -0500
Subject: [PATCH] ninja: use the minimum of all command line length limits
 (#14892)

When choosing whether to use a response file, consider several possible
command line length limits for the current operating system, and choose
the smallest.
---
 Source/cmNinjaNormalTargetGenerator.cxx | 29 +++++++++++++++++++------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/Source/cmNinjaNormalTargetGenerator.cxx b/Source/cmNinjaNormalTargetGenerator.cxx
index a05719d8d..5595557c1 100644
--- a/Source/cmNinjaNormalTargetGenerator.cxx
+++ b/Source/cmNinjaNormalTargetGenerator.cxx
@@ -22,6 +22,7 @@
 
 #include <assert.h>
 #include <algorithm>
+#include <limits>
 
 #ifndef _WIN32
 #include <unistd.h>
@@ -371,15 +372,29 @@ cmNinjaNormalTargetGenerator
 
 static int calculateCommandLineLengthLimit(int linkRuleLength)
 {
+  static int const limits[] = {
 #ifdef _WIN32
-  return 8000 - linkRuleLength;
-#elif defined(__linux) || defined(__APPLE__) || defined(__HAIKU__)
-  // for instance ARG_MAX is 2096152 on Ubuntu or 262144 on Mac
-  return ((int)sysconf(_SC_ARG_MAX)) - linkRuleLength - 1000;
-#else
-  (void)linkRuleLength;
-  return -1;
+    8000,
 #endif
+#if defined(__APPLE__) || defined(__HAIKU__) || defined(__linux)
+    // for instance ARG_MAX is 2096152 on Ubuntu or 262144 on Mac
+    ((int)sysconf(_SC_ARG_MAX)) - 1000,
+#endif
+#if defined(__linux)
+    // #define MAX_ARG_STRLEN (PAGE_SIZE * 32) in Linux's binfmts.h
+    ((int)sysconf(_SC_PAGESIZE) * 32) - 1000,
+#endif
+    std::numeric_limits<int>::max()
+  };
+
+  size_t const arrSz = cmArraySize(limits);
+  int const sz = *std::min_element(limits, limits + arrSz);
+  if (sz == std::numeric_limits<int>::max())
+    {
+    return -1;
+    }
+
+  return sz - linkRuleLength;
 }