[llvm-dev] Convert Function Pointer Call to Function Call at the IR Level

[Ahmad Nouralizadeh Khorrami via llvm-dev]

Hi,
I want to convert a function pointer call in the IR of MPlayer to a
function call. For example, I have the following line:
...
%10 = tail call i32 %7(%struct.demuxer* nonnull %0, i32 %1, i8* %2) #7,
!dbg !863222
...
I want to set the target which is stored in %7 to a real function called
"demux_lavf_control()" with the following definition:
...
define internal i32 @demux_lavf_control(%struct.demuxer.2657* nocapture
readonly, i32, i8* nocapture) #0 !dbg !963916 {
...
I wrote a function pass and found the mentioned function pointer call
(here, stored in "CallInstr") and set the call target as follows:
...
Module *theModule = F.getParent();
Function *targetFunc = theModule->getFunction("demux_lavf_control");
CalIInstr->setCalledFunction(targetFunc);
...
"F" is the function containing the call. But it leads to the following
error:
...
Call parameter type does not match function signature!
%struct.demuxer* %0
 %struct.demuxer.2657*  %10 = tail call i32
@demux_lavf_control(%struct.demuxer*
nonnull %0, i32 %1, i8* %2) #7, !dbg !863222
LLVM ERROR: Broken function found, compilation aborted!
...
The [names:types] of call operands before the change is:
...
[:%struct.demuxer*]
[:i32]
[:i8*]
[:i32 (%struct.demuxer*, i32, i8*)*]
...
And after the change is:
...
[:%struct.demuxer*]
[:i32]
[:i8*]
[demux_lavf_control:i32 (%struct.demuxer.2657*, i32, i8*)*]
...
How can I solve the problem?
Thanks in advance!
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