`getPointerElementType()` is deprecated with LLVM 15.0.7

[aytey]

This is more of an FYI than an urgent fix, but I get a number of warnings when compiling your fork with LLVM 15.0.7:

/home/avj/clones/llvm2c/parser/createExpressions.cpp:127:45: warning: ‘llvm::Type* llvm::Type::getPointerElementType() const’ is deprecated: Deprecated without replacement, see https://llvm.org/docs/OpaquePointers.html for context and migration instructions [-Wdeprecated-declarations]
/home/avj/clones/llvm2c/parser/createExpressions.cpp:776:90: warning: ‘llvm::Type* llvm::Type::getPointerElementType() const’ is deprecated: Deprecated without replacement, see https://llvm.org/docs/OpaquePointers.html for context and migration instructions [-Wdeprecated-declarations]
/home/avj/clones/llvm2c/parser/memcpyToAssign.cpp:67:76: warning: ‘llvm::Type* llvm::Type::getPointerElementType() const’ is deprecated: Deprecated without replacement, see https://llvm.org/docs/OpaquePointers.html for context and migration instructions [-Wdeprecated-declarations]
/home/avj/clones/llvm2c/parser/parseMetadataTypes.cpp:285:68: warning: ‘llvm::Type* llvm::Type::getPointerElementType() const’ is deprecated: Deprecated without replacement, see https://llvm.org/docs/OpaquePointers.html for context and migration instructions [-Wdeprecated-declarations]
/home/avj/clones/llvm2c/parser/parseMetadataTypes.cpp:286:155: warning: ‘llvm::Type* llvm::Type::getPointerElementType() const’ is deprecated: Deprecated without replacement, see https://llvm.org/docs/OpaquePointers.html for context and migration instructions [-Wdeprecated-declarations]
/home/avj/clones/llvm2c/parser/parseMetadataTypes.cpp:288:155: warning: ‘llvm::Type* llvm::Type::getPointerElementType() const’ is deprecated: Deprecated without replacement, see https://llvm.org/docs/OpaquePointers.html for context and migration instructions [-Wdeprecated-declarations]
/home/avj/clones/llvm2c/parser/parseMetadataTypes.cpp:291:108: warning: ‘llvm::Type* llvm::Type::getPointerElementType() const’ is deprecated: Deprecated without replacement, see https://llvm.org/docs/OpaquePointers.html for context and migration instructions [-Wdeprecated-declarations]
/home/avj/clones/llvm2c/type/TypeHandler.cpp:69:112: warning: ‘llvm::Type* llvm::Type::getPointerElementType() const’ is deprecated: Deprecated without replacement, see https://llvm.org/docs/OpaquePointers.html for context and migration instructions [-Wdeprecated-declarations]
/home/avj/clones/llvm2c/type/TypeHandler.cpp:119:56: warning: ‘llvm::Type* llvm::Type::getPointerElementType() const’ is deprecated: Deprecated without replacement, see https://llvm.org/docs/OpaquePointers.html for context and migration instructions [-Wdeprecated-declarations]

Interestingly, for my inputs, this function is the cause of quite a lot of pain:

Program received signal SIGSEGV, Segmentation fault.
0x00005555555cc52d in llvm::Type::getNonOpaquePointerElementType (this=0x555555e8c000) at /usr/include/llvm/IR/Type.h:391
391         return ContainedTys[0];
(gdb) bt
#0  0x00005555555cc52d in llvm::Type::getNonOpaquePointerElementType (this=0x555555e8c000) at /usr/include/llvm/IR/Type.h:391
#1  llvm::Type::getPointerElementType (this=0x555555e8c000) at /usr/include/llvm/IR/Type.h:381
#2  TypeHandler::getType (this=this@entry=0x7fffffffd250, type=type@entry=0x555555e8c000) at /home/avj/clones/llvm2c/type/TypeHandler.cpp:69
#3  0x000055555558b3da in Program::getType (type=0x555555e8c000, this=0x7fffffffd250) at /home/avj/clones/llvm2c/core/Program.cpp:82
#4  Program::createNewUnnamedStruct (this=0x7fffffffd250, strct=strct@entry=0x555555e8ce50) at /home/avj/clones/llvm2c/core/Program.cpp:75
#5  0x00005555555cc4e1 in TypeHandler::getType (this=this@entry=0x7fffffffd250, type=<optimized out>) at /home/avj/clones/llvm2c/type/TypeHandler.cpp:130
#6  0x000055555558a135 in Program::getType (this=this@entry=0x7fffffffd250, type=<optimized out>) at /home/avj/clones/llvm2c/core/Program.cpp:82
#7  0x00005555555c50ab in parseStructItems (module=module@entry=0x555555e4ea80, program=...) at /home/avj/clones/llvm2c/parser/parseStructItems.cpp:17
#8  0x00005555555913ef in ProgramParser::parse (this=this@entry=0x7fffffffca38, file="/mnt/baranem/rust/target/debug/deps/rust-b15ed7701c2a689f.bc", bitcastUnions=false)
    at /home/avj/clones/llvm2c/parser/ProgramParser.cpp:140
#9  0x0000555555582f2a in main (argc=4, argv=0x7fffffffd6d8) at /usr/include/llvm/Support/CommandLine.h:1377

[vmihalko]

Parsing metadata and using the information to produce a more precise type was implemented and tried only with LLVM-14. If you don't need it, comment this: https://github.com/vmihalko/llvm2c/blob/vmihalko-devel/parser/ProgramParser.cpp#L158 pass out.

But also for LLVM-14, there might be programs that will crash, because after the LLVM optimizations, the program might change a lot. I wrote a little bit about some problems with parseMetadataTypes() in my master thesis: https://is.muni.cz/th/ps6x5/fi-pdflatex.pdf, chapter 3.3.2.