From af7de05853f9ced4703b7dc470f7eb475f1ede9c Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Tue, 14 Apr 2020 08:15:30 -0400
Subject: Makefiles: Do not use '\#' escape sequence with Windows-style make
 tools

Since commit fbf7a92975 (Makefile: Handle '#' in COMPILE_OPTIONS,
2014-08-12, v3.1.0-rc1~174^2) we escape `#` as `\#` in `flags.make`
variable assignments so that they are not treated as a comment.
Windows-style make tools like NMake do not interpret backslashes
in that way.  Other means will be needed to handle `#` in contexts
where it is even possible.  The test suite is not covering this
for NMake anyway, and actually has a workaround in `Tests/TryCompile`
for the old behavior, which we can now update.
---
 Source/cmGlobalBorlandMakefileGenerator.h |  1 +
 Source/cmGlobalUnixMakefileGenerator3.cxx |  6 ++++++
 Source/cmGlobalUnixMakefileGenerator3.h   |  3 +++
 Source/cmMakefileTargetGenerator.cxx      | 14 ++++++++++----
 Tests/TryCompile/CMakeLists.txt           |  2 +-
 5 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/Source/cmGlobalBorlandMakefileGenerator.h b/Source/cmGlobalBorlandMakefileGenerator.h
index 9af0eac..3c97955 100644
--- a/Source/cmGlobalBorlandMakefileGenerator.h
+++ b/Source/cmGlobalBorlandMakefileGenerator.h
@@ -46,6 +46,7 @@ public:
 
   bool AllowNotParallel() const override { return false; }
   bool AllowDeleteOnError() const override { return false; }
+  bool CanEscapeOctothorpe() const override { return true; }
 
 protected:
   std::vector<GeneratedMakeCommand> GenerateBuildCommand(
diff --git a/Source/cmGlobalUnixMakefileGenerator3.cxx b/Source/cmGlobalUnixMakefileGenerator3.cxx
index 582877f..3ace290 100644
--- a/Source/cmGlobalUnixMakefileGenerator3.cxx
+++ b/Source/cmGlobalUnixMakefileGenerator3.cxx
@@ -117,6 +117,12 @@ void cmGlobalUnixMakefileGenerator3::ComputeTargetObjectDirectory(
   gt->ObjectDirectory = dir;
 }
 
+bool cmGlobalUnixMakefileGenerator3::CanEscapeOctothorpe() const
+{
+  // Make tools that use UNIX-style '/' paths also support '\' escaping.
+  return this->ForceUnixPaths;
+}
+
 void cmGlobalUnixMakefileGenerator3::Configure()
 {
   // Initialize CMAKE_EDIT_COMMAND cache entry.
diff --git a/Source/cmGlobalUnixMakefileGenerator3.h b/Source/cmGlobalUnixMakefileGenerator3.h
index 19b2b85..44a0fd6 100644
--- a/Source/cmGlobalUnixMakefileGenerator3.h
+++ b/Source/cmGlobalUnixMakefileGenerator3.h
@@ -157,6 +157,9 @@ public:
   /** Does the make tool tolerate .DELETE_ON_ERROR? */
   virtual bool AllowDeleteOnError() const { return true; }
 
+  /** Does the make tool interpret '\#' as '#'?  */
+  virtual bool CanEscapeOctothorpe() const;
+
   bool IsIPOSupported() const override { return true; }
 
   void ComputeTargetObjectDirectory(cmGeneratorTarget* gt) const override;
diff --git a/Source/cmMakefileTargetGenerator.cxx b/Source/cmMakefileTargetGenerator.cxx
index 5bb4c57..dc3a2a1 100644
--- a/Source/cmMakefileTargetGenerator.cxx
+++ b/Source/cmMakefileTargetGenerator.cxx
@@ -341,12 +341,16 @@ void cmMakefileTargetGenerator::WriteTargetLanguageFlags()
                           << "\n";
   }
 
+  bool const escapeOctothorpe = this->GlobalGenerator->CanEscapeOctothorpe();
+
   for (std::string const& language : languages) {
     std::string defines = this->GetDefines(language, this->GetConfigName());
     std::string includes = this->GetIncludes(language, this->GetConfigName());
-    // Escape comment characters so they do not terminate assignment.
-    cmSystemTools::ReplaceString(defines, "#", "\\#");
-    cmSystemTools::ReplaceString(includes, "#", "\\#");
+    if (escapeOctothorpe) {
+      // Escape comment characters so they do not terminate assignment.
+      cmSystemTools::ReplaceString(defines, "#", "\\#");
+      cmSystemTools::ReplaceString(includes, "#", "\\#");
+    }
     *this->FlagFileStream << language << "_DEFINES = " << defines << "\n\n";
     *this->FlagFileStream << language << "_INCLUDES = " << includes << "\n\n";
 
@@ -357,7 +361,9 @@ void cmMakefileTargetGenerator::WriteTargetLanguageFlags()
     for (const std::string& arch : architectures) {
       std::string flags =
         this->GetFlags(language, this->GetConfigName(), arch);
-      cmSystemTools::ReplaceString(flags, "#", "\\#");
+      if (escapeOctothorpe) {
+        cmSystemTools::ReplaceString(flags, "#", "\\#");
+      }
       *this->FlagFileStream << language << "_FLAGS" << arch << " = " << flags
                             << "\n\n";
     }
diff --git a/Tests/TryCompile/CMakeLists.txt b/Tests/TryCompile/CMakeLists.txt
index 9ec9b70..df921d8 100644
--- a/Tests/TryCompile/CMakeLists.txt
+++ b/Tests/TryCompile/CMakeLists.txt
@@ -187,7 +187,7 @@ try_compile(SHOULD_FAIL_DUE_TO_BAD_SOURCE
 if(SHOULD_FAIL_DUE_TO_BAD_SOURCE AND NOT CMAKE_GENERATOR MATCHES "Watcom WMake|NMake Makefiles")
   string(REPLACE "\n" "\n  " output "  ${output}")
   message(SEND_ERROR "try_compile with bad#source.c did not fail:\n${output}")
-elseif(NOT output MATCHES [[(bad#source\.c|bad\\)]])
+elseif(NOT output MATCHES [[(bad#source\.c|bad\.c|bad')]])
   string(REPLACE "\n" "\n  " output "  ${output}")
   message(SEND_ERROR "try_compile with bad#source.c failed without mentioning bad source:\n${output}")
 else()
-- 
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