MultiSource/Applications/spiff needs 1.2G virtual memory, crashes with ulimit 300

[edwintorok]

Bugzilla Link	6785
Version	unspecified
OS	Linux
CC	@lattner,@pwo

Extended Description

RunSafely sets a 300MB ulimit -v, and this causes MultiSource/Applications/spiff to crash on x86-64.

If I change the limit to 1200000, the test passes. This is not a regression if we look at the behavior: in LLVM 2.6 it has run out of memory too on all configurations, including native: Out of Memory exit 2

The difference is that now we crash when running out of memory, so I don't think this is a release blocker.

Something should be done for llvm 2.8, either make this test use less memory, or increase the limit in RunSafely.

[pwo]

This is a issue on llvm 2.7 freebsd/i386 too, the teste goes up to 580Mb RSS.

[edwintorok]

To fix the crash we could add an if in Allocator.cpp, here: MemSlab Slab = (MemSlab)Allocator.Allocate(Size, 0);

• if (Slab) {
• Slab->Size = Size;
• Slab->NextPtr = 0;
• }

And return early here: MemSlab *NewSlab = Allocator.Allocate(SlabSize);

• if (!NewSlab)
• return 0;

But then we hit this assert: assert(CurPtr <= End && "Unable to allocate memory!"); return Ptr; }

Even if I change that assert to return 0 (mem allocation failure is a real runtime condition, hence it shouldn't handled via asserts), I then crash in FoldingSetNode:

Thats because I made a mistake in my patch and inverted the condition (it returned 0 on success). I'll test to see if the correct patch makes this spiff crash go away.

[lattner]

Ok, well the jit is probably dying because it shares memory with that app. Feel free to hack the spiff code to reduce the problem size.

[edwintorok]

spiff itself:

$ cat Output/spiff.out-nat Out of Memory exit 2

Except for the JIT, in which case the JIT itself crashes.

[lattner]

Is spiff itself running out of memory, or some llvm tool when building it?

[edwintorok]

To fix the crash we could add an if in Allocator.cpp, here: MemSlab Slab = (MemSlab)Allocator.Allocate(Size, 0);

• if (Slab) {
• Slab->Size = Size;
• Slab->NextPtr = 0;
• }

And return early here: MemSlab *NewSlab = Allocator.Allocate(SlabSize);

• if (!NewSlab)
• return 0;

But then we hit this assert: assert(CurPtr <= End && "Unable to allocate memory!"); return Ptr; }

Even if I change that assert to return 0 (mem allocation failure is a real runtime condition, hence it shouldn't handled via asserts), I then crash in FoldingSetNode: 0 lli 0x0000000000a460ef 1 lli 0x0000000000a468fd 2 libpthread.so.0 0x0000003b3b00e990 3 lli 0x0000000000a264cb llvm::FoldingSetImpl::InsertNode(llvm::FoldingSetImpl::Node, void) + 43 4 lli 0x0000000000907067 llvm::ScalarEvolution::getUnknown(llvm::Value*) + 327 5 lli 0x00000000008809ef