llvm dev - Apr 2017 - LLVMGetFirstFunction() / LLVMGetNextFunction( ) problem

Hi, I have a problem - looking for advice.

I have a source code file with two functions which are compiled into a .bc
file.
When the bitcode file is loaded, I can dump the module and see the two
functions:

...
; Materializable
; Function Attrs: noinline nounwind uwtable
define void @matmul(double*, double*, double*, i32, i32, i32) #0 {}

; Materializable
; Function Attrs: noinline nounwind uwtable
define i32 @main() #0 {}
...

However, when I use LLVMGetirstFunction() and LLVMGetNextFunction() to
iterate through the functions in the module, it only iterates through the
function "matmul".
It never finds main().

50      first_func = LLVMGetFirstFunction(module);
(gdb) next
151      last_func = LLVMGetLastFunction(module);
(gdb)
154      for (func = first_func; func != last_func; func
LLVMGetNextFunction(func)) {
(gdb)
155        func_name = LLVMGetValueName(func);
(gdb)
156        func_addr = LLVMGetFunctionAddress(engine, func_name);
(gdb) print func_name
$9 = 0x1efe180 "matmul"
(gdb) next
159        if (!func_addr) continue;
(gdb)
161        symbol_table_add(symbol_table, func_name, func_addr);
(gdb)
164        if ((size = mem_region_lookup(mem_region_anchor, func_addr))) {
symbol_table_add(symbol_table, "dummy_symbol", func_addr + size); }
(gdb)
154      for (func = first_func; func != last_func; func
LLVMGetNextFunction(func)) {
(gdb)
168      symbol_table_calc_symbol_sizes(symbol_table);

Any suggestions appreciated.

Toshi
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The intention of the API is that you iterate until LLVMGetNextFunction
returns NULL, not the last function. See their implementations:

LLVMValueRef LLVMGetLastFunction(LLVMModuleRef M) {
  Module *Mod = unwrap(M);
  Module::iterator I = Mod->end();
  if (I == Mod->begin())
    return nullptr;
  return wrap(&*--I);
}

LLVMValueRef LLVMGetNextFunction(LLVMValueRef Fn) {
  Function *Func = unwrap<Function>(Fn);
  Module::iterator I(Func);
  if (++I == Func->getParent()->end())
    return nullptr;
  return wrap(&*I);
}

On Fri, Apr 28, 2017 at 1:23 PM, Toshiyasu Morita via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi, I have a problem - looking for advice.
>
> I have a source code file with two functions which are compiled into a .bc
> file.
> When the bitcode file is loaded, I can dump the module and see the two
> functions:
>
> ...
> ; Materializable
> ; Function Attrs: noinline nounwind uwtable
> define void @matmul(double*, double*, double*, i32, i32, i32) #0 {}
>
> ; Materializable
> ; Function Attrs: noinline nounwind uwtable
> define i32 @main() #0 {}
> ...
>
> However, when I use LLVMGetirstFunction() and LLVMGetNextFunction() to
> iterate through the functions in the module, it only iterates through the
> function "matmul".
> It never finds main().
>
> 50      first_func = LLVMGetFirstFunction(module);
> (gdb) next
> 151      last_func = LLVMGetLastFunction(module);
> (gdb)
> 154      for (func = first_func; func != last_func; func >
LLVMGetNextFunction(func)) {
> (gdb)
> 155        func_name = LLVMGetValueName(func);
> (gdb)
> 156        func_addr = LLVMGetFunctionAddress(engine, func_name);
> (gdb) print func_name
> $9 = 0x1efe180 "matmul"
> (gdb) next
> 159        if (!func_addr) continue;
> (gdb)
> 161        symbol_table_add(symbol_table, func_name, func_addr);
> (gdb)
> 164        if ((size = mem_region_lookup(mem_region_anchor, func_addr)))
> { symbol_table_add(symbol_table, "dummy_symbol", func_addr +
size); }
> (gdb)
> 154      for (func = first_func; func != last_func; func >
LLVMGetNextFunction(func)) {
> (gdb)
> 168      symbol_table_calc_symbol_sizes(symbol_table);
>
> Any suggestions appreciated.
>
> Toshi
>
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
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That works - thanks for the explanation. Much appreciated.

Toshi

On Fri, Apr 28, 2017 at 1:39 PM, Reid Kleckner <rnk at google.com> wrote:
> The intention of the API is that you iterate until LLVMGetNextFunction
> returns NULL, not the last function. See their implementations:
>
> LLVMValueRef LLVMGetLastFunction(LLVMModuleRef M) {
>   Module *Mod = unwrap(M);
>   Module::iterator I = Mod->end();
>   if (I == Mod->begin())
>     return nullptr;
>   return wrap(&*--I);
> }
>
> LLVMValueRef LLVMGetNextFunction(LLVMValueRef Fn) {
>   Function *Func = unwrap<Function>(Fn);
>   Module::iterator I(Func);
>   if (++I == Func->getParent()->end())
>     return nullptr;
>   return wrap(&*I);
> }
>
> On Fri, Apr 28, 2017 at 1:23 PM, Toshiyasu Morita via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Hi, I have a problem - looking for advice.
>>
>> I have a source code file with two functions which are compiled into a
>> .bc file.
>> When the bitcode file is loaded, I can dump the module and see the two
>> functions:
>>
>> ...
>> ; Materializable
>> ; Function Attrs: noinline nounwind uwtable
>> define void @matmul(double*, double*, double*, i32, i32, i32) #0 {}
>>
>> ; Materializable
>> ; Function Attrs: noinline nounwind uwtable
>> define i32 @main() #0 {}
>> ...
>>
>> However, when I use LLVMGetirstFunction() and LLVMGetNextFunction() to
>> iterate through the functions in the module, it only iterates through
the
>> function "matmul".
>> It never finds main().
>>
>> 50      first_func = LLVMGetFirstFunction(module);
>> (gdb) next
>> 151      last_func = LLVMGetLastFunction(module);
>> (gdb)
>> 154      for (func = first_func; func != last_func; func >>
LLVMGetNextFunction(func)) {
>> (gdb)
>> 155        func_name = LLVMGetValueName(func);
>> (gdb)
>> 156        func_addr = LLVMGetFunctionAddress(engine, func_name);
>> (gdb) print func_name
>> $9 = 0x1efe180 "matmul"
>> (gdb) next
>> 159        if (!func_addr) continue;
>> (gdb)
>> 161        symbol_table_add(symbol_table, func_name, func_addr);
>> (gdb)
>> 164        if ((size = mem_region_lookup(mem_region_anchor,
func_addr)))
>> { symbol_table_add(symbol_table, "dummy_symbol", func_addr +
size); }
>> (gdb)
>> 154      for (func = first_func; func != last_func; func >>
LLVMGetNextFunction(func)) {
>> (gdb)
>> 168      symbol_table_calc_symbol_sizes(symbol_table);
>>
>> Any suggestions appreciated.
>>
>> Toshi
>>
>>
>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>>
>
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