rewriter: add --enable-dav1d_get_picture-post-condition option, on …

…by default

We still want to be able to run the rewriter on `dav1d`
normally without post conditions while this is still a WIP.
Or on Arm, where IA2 still lacks support for post conditions.

tools/rewriter/GenCallAsm.cpp

@@ -1053,9 +1053,10 @@ std::string emit_asm_wrapper(AbiSignature &sig,
   // The name is `${target_name}_post_condition`,
   // and we only do this for `dav1d_get_picture`.
   std::optional<std::string> target_post_condition_name = std::nullopt;
-  if (target_name && *target_name == "dav1d_get_picture") {
+  if (enable_dav1d_get_picture_post_condition && target_name && *target_name == "dav1d_get_picture") {
     target_post_condition_name = *target_name + "_post_condition";
   }
+
   if (target_post_condition_name) {
     emit_post_condition_fn_call(aw, arch, *target_post_condition_name);
   }

tools/rewriter/GenCallAsm.h

@@ -20,6 +20,8 @@ enum class Arch {
     Aarch64, X86
 };
 
+extern bool enable_dav1d_get_picture_post_condition;
+
 // Generates a wrapper for a function named \p name with the signature \p sig.
 // The WrapperKind parameter \p kind determines the type of call which may
 // affect the order of operations and the layout of the wrapper stack frame.

tools/rewriter/SourceRewriter.cpp

@@ -98,10 +98,17 @@ static llvm::cl::opt<std::string>
                        llvm::cl::cat(SourceRewriterCategory),
                        llvm::cl::desc("<prefix for output files>"));
 
+static llvm::cl::opt<bool>
+    EnableDav1dGetPicturePostCondition("enable-dav1d_get_picture-post-condition",
+                                       llvm::cl::init(true),
+                                       llvm::cl::cat(SourceRewriterCategory),
+                                       llvm::cl::desc("enable calling the post condition function hardcoded for dav1d_get_picture"));
+
 static Arch Target;
 static std::string RootDirectory;
 static std::string OutputDirectory;
 static std::string OutputPrefix;
+bool enable_dav1d_get_picture_post_condition = true;
 
 // Map each translation unit's filename to its pkey.
 static std::map<Filename, Pkey> file_pkeys;
@@ -1098,6 +1105,7 @@ int main(int argc, const char **argv) {
   RootDirectory = RootDirectoryOption;
   OutputDirectory = OutputDirectoryOption;
   OutputPrefix = OutputPrefixOption;
+  enable_dav1d_get_picture_post_condition = EnableDav1dGetPicturePostCondition;
 
   RefactoringTool tool(options_parser.getCompilations(),
                        options_parser.getSourcePathList());