[Mono-dev] [PATCH] MONO_IOMAP reporting option - string allocation locations

[Marek Habersack]

Hello everybody,

	Attached is an update to the original code I posted last week. The 
update adds support for reporting string allocation locations. It is 
useful with large code base where strings may be created in one location 
but used in many others. The code adds a new internal function which 
does the job of backtrace (3) but supports mono JIT. It's basically a 
lighter version of mono_jit_walk_stack which was too heavy for this 
purpose. The code needs to record stack location for each and every 
string allocated in the application and the runtime only to store it for 
later use when IOMAP kicks in. Doing that with mono_stack_walk rendered 
Mono many times slower and made debugging the application virtually 
impossible. The patch makes execution just slightly slower than usual. 
The reporting code uses simple heuristics to select the possible string 
allocation location - it attempts to ignore all methods from assemblies 
installed in GAC, from corlib and, should the two checks fail, from a 
list of assemblies and classes to ignore. This is done based on the 
premise that the Mono runtime and class libraries are case-sensitive and 
don't have the problem some applications might have (there's actually an 
instance where that assumption is incorrect - in System.Web we check for 
existence of web.config, Web.config and Web.Config - but it's intended 
:)). The results of the selection algorithm might not always be 
accurate, but they should be close enough to aid the developer to spot 
the location where string was allocated.
	Please review and let me know if I can commit.

marek
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