[libcamera-devel] [PATCH] ipa: raspberrypi: Fix crash under LTO

[Laurent Pinchart]

Hi Naush and Dave,

Thank you for the patch.

On Fri, Mar 10, 2023 at 09:51:26AM +0000, Naushir Patuck via libcamera-devel wrote:
> From: Dave Jones <dave.jones at canonical.com>
> 
> When compiled with LTO (the default on Ubuntu), the global static
> objects camHelpers and algorithms cause a crash in raspberrypi_ipa_proxy
> at runtime as they're not allocated by the time the registration
> routines execute.
> 
> This is a fairly crude fix which just converts the global static objects
> into local static objects inside an equivalently named function.
> 
> Signed-off-by: Dave Jones <dave.jones at canonical.com>
> Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> Tested-by: Naushir Patuck <naush at raspberrypi.com>
> ---
>  src/ipa/raspberrypi/cam_helper.cpp           | 16 +++++++++++++---
>  src/ipa/raspberrypi/controller/algorithm.cpp | 19 +++++++++++++++----
>  2 files changed, 28 insertions(+), 7 deletions(-)
> 
> diff --git a/src/ipa/raspberrypi/cam_helper.cpp b/src/ipa/raspberrypi/cam_helper.cpp
> index d90ac1deda47..efe453dc6135 100644
> --- a/src/ipa/raspberrypi/cam_helper.cpp
> +++ b/src/ipa/raspberrypi/cam_helper.cpp
> @@ -9,6 +9,7 @@
>  
>  #include <limits>
>  #include <map>
> +#include <memory>
>  #include <string.h>
>  
>  #include "libcamera/internal/v4l2_videodevice.h"
> @@ -25,7 +26,16 @@ namespace libcamera {
>  LOG_DECLARE_CATEGORY(IPARPI)
>  }
>  
> -static std::map<std::string, CamHelperCreateFunc> camHelpers;
> +namespace {
> +
> +std::map<std::string, CamHelperCreateFunc> &camHelpers()
> +{
> +	static std::unique_ptr<std::map<std::string, CamHelperCreateFunc>> obj =
> +		std::make_unique<std::map<std::string, CamHelperCreateFunc>>();
> +	return *obj;

I think you could simply write

	static std::map<std::string, CamHelperCreateFunc> helpers;
	return helpers;

> +}
> +
> +} /* namespace */
>  
>  CamHelper *CamHelper::create(std::string const &camName)
>  {
> @@ -33,7 +43,7 @@ CamHelper *CamHelper::create(std::string const &camName)
>  	 * CamHelpers get registered by static RegisterCamHelper
>  	 * initialisers.
>  	 */
> -	for (auto &p : camHelpers) {
> +	for (auto &p : camHelpers()) {
>  		if (camName.find(p.first) != std::string::npos)
>  			return p.second();
>  	}
> @@ -253,5 +263,5 @@ void CamHelper::populateMetadata([[maybe_unused]] const MdParser::RegisterMap &r
>  RegisterCamHelper::RegisterCamHelper(char const *camName,
>  				     CamHelperCreateFunc createFunc)
>  {
> -	camHelpers[std::string(camName)] = createFunc;
> +	camHelpers()[std::string(camName)] = createFunc;
>  }
> diff --git a/src/ipa/raspberrypi/controller/algorithm.cpp b/src/ipa/raspberrypi/controller/algorithm.cpp
> index 6d91ee292bd1..2650f98bee5b 100644
> --- a/src/ipa/raspberrypi/controller/algorithm.cpp
> +++ b/src/ipa/raspberrypi/controller/algorithm.cpp
> @@ -4,9 +4,10 @@
>   *
>   * algorithm.cpp - ISP control algorithms
>   */
> -

Unrelated and unneeded change.

>  #include "algorithm.h"
>  
> +#include <memory>
> +
>  using namespace RPiController;
>  
>  int Algorithm::read([[maybe_unused]] const libcamera::YamlObject &params)
> @@ -34,14 +35,24 @@ void Algorithm::process([[maybe_unused]] StatisticsPtr &stats,
>  
>  /* For registering algorithms with the system: */
>  
> -static std::map<std::string, AlgoCreateFunc> algorithms;
> +namespace {
> +
> +static std::map<std::string, AlgoCreateFunc> &algorithms()
> +{
> +	static std::unique_ptr<std::map<std::string, AlgoCreateFunc>> obj =
> +		std::make_unique<std::map<std::string, AlgoCreateFunc>>();
> +	return *obj;

Same here.

> +}
> +
> +} /* namespace */
> +
>  std::map<std::string, AlgoCreateFunc> const &RPiController::getAlgorithms()
>  {
> -	return algorithms;
> +	return algorithms();
>  }
>  
>  RegisterAlgorithm::RegisterAlgorithm(char const *name,
>  				     AlgoCreateFunc createFunc)
>  {
> -	algorithms[std::string(name)] = createFunc;
> +	algorithms()[std::string(name)] = createFunc;
>  }

-- 
Regards,

Laurent Pinchart