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No, I don't care about those functions that aren't called.<br>
<br>
Okay, I walked through the EmitCall family of functions of
CodeGenFunction, but didn't notice much. I guess that I'll have to
trace them through more carefully to see when it is done.<br>
<br>
My thought is to copy the debug info metadata emission logic used
during generating the function prolog to function declarations. Do
you think if it works?<br>
<br>
Thanks,<br>
<br>
<div class="moz-cite-prefix">On 11/12/2013 07:49 AM, David Blaikie
wrote:<br>
</div>
<blockquote
cite="mid:CAENS6Etb7AeyzpkFf09QMoDpFwcv+PuT3fBU0-LxgOhSjghcoQ@mail.gmail.com"
type="cite">
<div dir="ltr">Do you care about generating debug info for
declarations of functions that aren't even called? If so, then
the approach you're taking will be insufficient (since we won't
even emit an IR declaration for such a function)<br>
<br>
If not, then you might want to take a look at where the IR for
the call is constructed (I don't know where this is, but you
seem to be gaining some proficiency tracing through Clang/LLVM
internals that will serve you well here) and then see how the
target of the call is built and passed in to that.</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Mon, Nov 11, 2013 at 3:44 PM, Lewis
Burns <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:lewisurn@gmail.com" target="_blank">lewisurn@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> I ran Clang in a
debugger and traced how debug info metadata was emitted.
It's a part of code generation of functions.<br>
<br>
I have a question about when the declaration of an extern
function is emitted. For example, I have very simple code:<br>
<br>
<font face="Courier New, Courier, monospace">extern int
convert(unsigned u);<br>
<br>
void foo() {<br>
int x = convert(0);<br>
}<br>
</font><br>
The corresponding LLVM code is:<br>
<br>
<font face="Courier New, Courier, monospace">...<br>
; Function Attrs: nounwind uwtable<br>
define void @foo() #0 {<br>
entry:<br>
%x = alloca i32, align 4<br>
call void @llvm.dbg.declare(metadata !{i32* %x},
metadata !8), !dbg !10<br>
%call = call i32 @convert(i32 0), !dbg !10<br>
store i32 %call, i32* %x, align 4, !dbg !10<br>
ret void, !dbg !11<br>
}<br>
...<br>
declare i32 @convert(i32) #2 // when this line is
emitted<br>
</font><br>
My question is where the "<font face="Courier New,
Courier, monospace">declare i32 @convert(i32) #2"</font>
line is emitted. I tried many breakpoints in EmitXXX
family of functions in CodeGenModule and noticed that this
piece of code<br>
<br>
<font face="Courier New, Courier, monospace"> // Ignore
declarations, they will be emitted on their first use.<br>
if (const FunctionDecl *FD =
dyn_cast<FunctionDecl>(Global)) {<br>
// Forward declarations are emitted lazily on first
use.<br>
if (!FD->doesThisDeclarationHaveABody()) {<br>
if
(!FD->doesDeclarationForceExternallyVisibleDefinition())<br>
return;<br>
</font><br>
causes the postpone of emission of the convert function
declaration, but I couldn't figure out where and when the
declaration is emitted. I set a breakpoint in the
CodeGenModule::EmitDeferred() function, but nothing was
done in that function.<br>
<br>
Any help is really appreciated.
<div class="im"><br>
<br>
<div>On 11/09/2013 04:14 PM, David Blaikie wrote:<br>
</div>
</div>
<div>
<div class="h5">
<blockquote type="cite">
<p dir="ltr">For those following this thread a
critical detail would be that you want debug info
metadata.</p>
<p dir="ltr">There's no simple flag for this as we
don't attach the function debug info metadata to
every declaration, just to definitions (there's no
filtering step)</p>
<p dir="ltr">But why do you want this anyway? If
you're performing optimizations/transformations
based on debug info metadata, that's not really
the desired approach. Debug info is not meant to
affect code generation.</p>
<div class="gmail_quote">On Nov 9, 2013 7:59 AM,
"Lewis Burns" <<a moz-do-not-send="true"
href="mailto:lewisurn@gmail.com" target="_blank">lewisurn@gmail.com</a>>
wrote:<br type="attribution">
<blockquote class="gmail_quote" style="margin:0 0
0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> Hi,<br>
<br>
I haven't worked on Clang before and have a
simple question (supposedly) for those who are
familiar with metadata and LLVM bitcode
generation. Assume that I have a function
which is declared as extern as the following:<br>
<br>
<font face="Courier New, Courier, monospace">extern
int convert(unsigned u);</font><br>
<br>
I want to have Clang generate metadata nodes
for it by adding a metadata node of subprogram
into the list of subprograms defined in the
current compilation unit. The subprogram
metadata node and its associated nodes should
have the info of the type signature. For
example, I get the following set of metadata
nodes for function<br>
<font face="Courier New, Courier, monospace"><br>
int convert(unsigned u) {return 0;}<br>
<br>
!3 = metadata !{metadata !4, metadata !10,
metadata !33}<br>
!4 = metadata !{i32 786478, metadata !1,
metadata !5, metadata !"convert", metadata
!"convert", metadata !"", i32 23, metadata
!6, i1 false, i1 true, i32 0, i32 0, null,
i32 256, i1 false, i32 (i32)* @convert,
null, null, metadata !2, i32 23} ; [
DW_TAG_subprogram ] [line 23] [def]
[convert]<br>
!7 = metadata !{metadata !8, metadata !9}<br>
!8 = metadata !{i32 786468, null, null,
metadata !"int", i32 0, i64 32, i64 32, i64
0, i32 0, i32 5} ; [ DW_TAG_base_type ]
[int] [line 0, size 32, align 32, offset 0,
enc DW_ATE_signed]<br>
!9 = metadata !{i32 786468, null, null,
metadata !"unsigned int", i32 0, i64 32, i64
32, i64 0, i32 0, i32 7} ; [
DW_TAG_base_type ] [unsigned int] [line 0,
size 32, align 32, offset 0, enc
DW_ATE_unsigned]<br>
</font><br>
which allows me to extract the source-level
type signature for the function by using LLVM
debug info APIs. I'd like to get the
source-level type signature of the extern
declared function, but Clang does not produce
metadata for it.<br>
<br>
By looking at the Clang AST for the extern
declared function<br>
<br>
<font face="Courier New, Courier, monospace">|-FunctionDecl
0x70598c0 <line:23:1, col:30> convert
'int (unsigned int)' extern<br>
| |-ParmVarDecl 0x7059800 <col:20,
col:29> u 'unsigned int'<br>
</font><br>
I know that Clang has the information I need,
and I just need to turn off or remove the
filter that ignores functions whose bodies are
not available during metadata node or/and code
generation. Are there simple switches that do
this? If not, can anyone please explain how to
do it by pointing me to the right code
snippets?<br>
<br>
Thanks very much,<br>
<br>
<pre cols="72">--
Lewis</pre>
</div>
<br>
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</blockquote>
</div>
</blockquote>
<br>
</div>
</div>
<span class="HOEnZb"><font color="#888888">
<pre cols="72">--
Lewis</pre>
</font></span></div>
</blockquote>
</div>
<br>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Lewis</pre>
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