<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jan 14, 2015 at 9:35 AM, Adrian Prantl <span dir="ltr"><<a href="mailto:aprantl@apple.com" target="_blank">aprantl@apple.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><br><div><div><div class="h5"><blockquote type="cite"><div>On Jan 14, 2015, at 9:21 AM, David Blaikie <<a href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@gmail.com</a>> wrote:</div><br><div><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jan 14, 2015 at 8:27 AM, Adrian Prantl <span dir="ltr"><<a href="mailto:aprantl@apple.com" target="_blank">aprantl@apple.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><br><div><div><div><blockquote type="cite"><div>On Jan 13, 2015, at 7:08 PM, David Blaikie <<a href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@gmail.com</a>> wrote:</div><br><div><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Jan 13, 2015 at 3:10 PM, Adrian Prantl <span dir="ltr"><<a href="mailto:aprantl@apple.com" target="_blank">aprantl@apple.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: adrian<br>
Date: Tue Jan 13 17:10:43 2015<br>
New Revision: 225846<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=225846&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=225846&view=rev</a><br>
Log:<br>
Debug Info: Turn DIExpression::getFrameRegister() into an isFrameRegister()<br>
function.<br>
<br>
NFC.<br>
<br>
Modified:<br>
llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp<br>
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp<br>
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h<br>
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp<br>
<br>
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp?rev=225846&r1=225845&r2=225846&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp?rev=225846&r1=225845&r2=225846&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp (original)<br>
+++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp Tue Jan 13 17:10:43 2015<br>
@@ -46,8 +46,9 @@ void DebugLocDwarfExpression::EmitUnsign<br>
BS.EmitULEB128(Value, Twine(Value));<br>
}<br>
<br>
-unsigned DebugLocDwarfExpression::getFrameRegister() {<br>
- llvm_unreachable("not available");<br>
+bool DebugLocDwarfExpression::isFrameRegister(unsigned MachineReg) {<br>
+ // This information is not available while emitting .debug_loc entries.<br></blockquote><div><br>Should it be? (should we keep track of it when building the DebugLocEntries in some way?)<br></div></div></div></div></div></blockquote><div><br></div></div></div><div>Generally yes, but it’s probably not a high priority. It would allow us to use the more idiomatic DW_OP_fbreg encoding. It would not actually save any space if the frame offset can be expressed as breg0-31.</div></div></div></blockquote><div><br>Ah, fair point. (one wonders about the utility of such an operation, then)<br></div></div></div></div></div></blockquote><div><br></div></div></div><div>Found it: (DW_AT_frame_base may be a complex expression)</div><div><br></div><div><span style="font-family:URWPalladioL;font-size:12pt;font-weight:700">DW_OP_fbreg</span></div><div><div title="Page 40"><div><div><p><span style="font-size:12.000000pt;font-family:'URWPalladioL'">The DW_OP_fbreg operation provides a signed LEB128 offset from the
address specified by the location description in the </span><span style="font-size:12.000000pt;font-family:'URWPalladioL';color:rgb(0.000000%,0.000000%,100.000000%)">DW_AT_frame_base
</span><span style="font-size:12.000000pt;font-family:'URWPalladioL'">attribute of the current function. (This is typically a “stack pointer” register
plus or minus some offset. On more sophisticated systems it might be a
location list that adjusts the offset according to changes in the stack pointer as
the PC changes.) </span></p></div></div></div></div></div></div></blockquote><div>Fun. So if/when we do that there would be some benefit to using fbreg, but not until then (except minor readability improvements in the dwarf dump, etc). Fair enough.<br><br>- David<br> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div><div><div title="Page 40"><div><div><span class="HOEnZb"><font color="#888888"><div>-- adrian</div>
</font></span></div>
</div>
</div></div><div><div class="h5"><blockquote type="cite"><div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div><span><font color="#888888"><div><br></div><div>-- adrian</div></font></span><div><div><br><blockquote type="cite"><div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
+ return false;<br>
}<br>
<br>
//===----------------------------------------------------------------------===//<br>
<br>
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp?rev=225846&r1=225845&r2=225846&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp?rev=225846&r1=225845&r2=225846&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp (original)<br>
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp Tue Jan 13 17:10:43 2015<br>
@@ -79,7 +79,7 @@ bool DwarfExpression::AddMachineRegIndir<br>
if (DwarfReg < 0)<br>
return false;<br>
<br>
- if (MachineReg == getFrameRegister()) {<br>
+ if (isFrameRegister(MachineReg)) {<br>
// If variable offset is based in frame register then use fbreg.<br>
EmitOp(dwarf::DW_OP_fbreg);<br>
EmitSigned(Offset);<br>
<br>
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h?rev=225846&r1=225845&r2=225846&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h?rev=225846&r1=225845&r2=225846&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h (original)<br>
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h Tue Jan 13 17:10:43 2015<br>
@@ -40,7 +40,7 @@ public:<br>
virtual void EmitSigned(int Value) = 0;<br>
virtual void EmitUnsigned(unsigned Value) = 0;<br>
<br>
- virtual unsigned getFrameRegister() = 0;<br>
+ virtual bool isFrameRegister(unsigned MachineReg) = 0;<br>
<br>
/// Emit a dwarf register operation.<br>
void AddReg(int DwarfReg, const char* Comment = nullptr);<br>
@@ -92,7 +92,7 @@ public:<br>
void EmitOp(uint8_t Op, const char *Comment) override;<br>
void EmitSigned(int Value) override;<br>
void EmitUnsigned(unsigned Value) override;<br>
- unsigned getFrameRegister() override;<br>
+ bool isFrameRegister(unsigned MachineReg) override;<br>
};<br>
<br>
}<br>
<br>
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=225846&r1=225845&r2=225846&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=225846&r1=225845&r2=225846&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp (original)<br>
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp Tue Jan 13 17:10:43 2015<br>
@@ -55,7 +55,7 @@ public:<br>
void EmitOp(uint8_t Op, const char* Comment = nullptr) override;<br>
void EmitSigned(int Value) override;<br>
void EmitUnsigned(unsigned Value) override;<br>
- unsigned getFrameRegister() override;<br>
+ bool isFrameRegister(unsigned MachineReg) override;<br>
};<br>
<br>
void DIEDwarfExpression::EmitOp(uint8_t Op, const char* Comment) {<br>
@@ -67,8 +67,8 @@ void DIEDwarfExpression::EmitSigned(int<br>
void DIEDwarfExpression::EmitUnsigned(unsigned Value) {<br>
DU.addUInt(DIE, dwarf::DW_FORM_udata, Value);<br>
}<br>
-unsigned DIEDwarfExpression::getFrameRegister() {<br>
- return getTRI()->getFrameRegister(*AP.MF);<br>
+bool DIEDwarfExpression::isFrameRegister(unsigned MachineReg) {<br>
+ return MachineReg == getTRI()->getFrameRegister(*AP.MF);<br>
}<br>
<br>
<br>
<br>
<br>
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</blockquote></div><br></div></div>
</div></blockquote></div></div></div><br></div></blockquote></div><br></div></div>
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