<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Feb 2, 2015, at 10:39 AM, David Blaikie <<a href="mailto:dblaikie@gmail.com" class="">dblaikie@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><br class=""><div class="gmail_extra"><br class=""><div class="gmail_quote">On Mon, Feb 2, 2015 at 10:31 AM, Adrian Prantl <span dir="ltr" class=""><<a href="mailto:aprantl@apple.com" target="_blank" class="">aprantl@apple.com</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: adrian<br class="">
Date: Mon Feb 2 12:31:58 2015<br class="">
New Revision: 227827<br class="">
<br class="">
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=227827&view=rev" target="_blank" class="">http://llvm.org/viewvc/llvm-project?rev=227827&view=rev</a><br class="">
Log:<br class="">
Debug Info: Relax assertion in isUnsignedDIType() to allow floats to be<br class="">
described by integer constants. This is a bit ugly, but if the source<br class="">
language allows arbitrary type casting, the debug info must follow suit.<br class="">
<br class="">
For example:<br class="">
void foo() {<br class="">
float a;<br class="">
*(int *)&a = 0;<br class="">
}<br class="">
For the curious: SROA replaces the float alloca with an i32 alloca, which<br class="">
is then optimized away and described via dbg.value(i32 0, ...).<br class=""></blockquote><div class=""><br class=""></div><div class="">Not sure this is the right answer - even if the IR looks like that, it may be that we need to convert the constant back to the appropriate type before emitting the debug info?<br class=""></div></div></div></div></div></blockquote><div>Sounds reasonable, but if I understand the code in DwarfUnit correctly, there would not be any difference in the output:</div><div><br class=""></div><div><div> } else if (DVInsn->getOperand(0).isFPImm())</div><div> addConstantFPValue(*VariableDie, DVInsn->getOperand(0));</div><div class="">-></div><div class=""><div class="">/// addConstantFPValue - Add constant value entry in variable DIE.</div><div class="">void DwarfUnit::addConstantFPValue(DIE &Die, const ConstantFP *CFP) {</div><div class=""> // Pass this down to addConstantValue as an unsigned bag of bits.</div><div class=""> addConstantValue(Die, CFP->getValueAPF().bitcastToAPInt(), true);</div><div class="">}</div></div><div class="">-></div><div class="">void DwarfUnit::addConstantValue(DIE &Die, const APInt &Val, bool Unsigned) {</div><div class="">-></div><div class=""><div class="">void DwarfUnit::addConstantValue(DIE &Die, const APInt &Val, DIType Ty) {</div><div class=""> addConstantValue(Die, Val, isUnsignedDIType(DD, Ty));</div><div class="">}</div><div class=""><br class=""></div><div class="">-- adrian </div></div></div></div><div><br class=""></div><div><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class="gmail_extra"><div class="gmail_quote"><div class=""><br class="">- David</div><div class=""> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br class="">
Added:<br class="">
llvm/trunk/test/DebugInfo/X86/float_const.ll<br class="">
Modified:<br class="">
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp<br class="">
<br class="">
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp<br class="">
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=227827&r1=227826&r2=227827&view=diff" target="_blank" class="">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=227827&r1=227826&r2=227827&view=diff</a><br class="">
==============================================================================<br class="">
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp (original)<br class="">
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp Mon Feb 2 12:31:58 2015<br class="">
@@ -606,6 +606,7 @@ static bool isUnsignedDIType(DwarfDebug<br class="">
Encoding == dwarf::DW_ATE_unsigned_char ||<br class="">
Encoding == dwarf::DW_ATE_signed ||<br class="">
Encoding == dwarf::DW_ATE_signed_char ||<br class="">
+ Encoding == dwarf::DW_ATE_float ||<br class="">
Encoding == dwarf::DW_ATE_UTF || Encoding == dwarf::DW_ATE_boolean ||<br class="">
(Ty.getTag() == dwarf::DW_TAG_unspecified_type &&<br class="">
Ty.getName() == "decltype(nullptr)")) &&<br class="">
<br class="">
Added: llvm/trunk/test/DebugInfo/X86/float_const.ll<br class="">
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/float_const.ll?rev=227827&view=auto" target="_blank" class="">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/float_const.ll?rev=227827&view=auto</a><br class="">
==============================================================================<br class="">
--- llvm/trunk/test/DebugInfo/X86/float_const.ll (added)<br class="">
+++ llvm/trunk/test/DebugInfo/X86/float_const.ll Mon Feb 2 12:31:58 2015<br class="">
@@ -0,0 +1,55 @@<br class="">
+; RUN: llc < %s -filetype=obj | llvm-dwarfdump -debug-dump=info - | FileCheck %s<br class="">
+; from (at -Os):<br class="">
+; void foo() {<br class="">
+; float a = 3.14;<br class="">
+; *(int *)&a = 0;<br class="">
+; }<br class="">
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"<br class="">
+target triple = "x86_64-apple-macosx10.10.0"<br class="">
+<br class="">
+; Function Attrs: nounwind optsize readnone uwtable<br class="">
+define void @foo() #0 {<br class="">
+entry:<br class="">
+ tail call void @llvm.dbg.declare(metadata float* undef, metadata !13, metadata !19), !dbg !20<br class="">
+ tail call void @llvm.dbg.value(metadata i32 1078523331, i64 0, metadata !13, metadata !19), !dbg !20<br class="">
+ tail call void @llvm.dbg.value(metadata i32 0, i64 0, metadata !13, metadata !19), !dbg !20<br class="">
+; CHECK: DW_AT_const_value [DW_FORM_sdata] (0)<br class="">
+; CHECK-NEXT: DW_AT_name {{.*}}"a"<br class="">
+ ret void, !dbg !21<br class="">
+}<br class="">
+<br class="">
+; Function Attrs: nounwind readnone<br class="">
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1<br class="">
+<br class="">
+; Function Attrs: nounwind readnone<br class="">
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1<br class="">
+<br class="">
+attributes #0 = { nounwind optsize readnone uwtable }<br class="">
+attributes #1 = { nounwind readnone }<br class="">
+<br class="">
+!<a href="http://llvm.dbg.cu/" target="_blank" class="">llvm.dbg.cu</a> = !{!0}<br class="">
+!llvm.module.flags = !{!15, !16, !17}<br class="">
+!llvm.ident = !{!18}<br class="">
+<br class="">
+!0 = !{!"0x11\0012\00clang version 3.7.0 (trunk 227686)\001\00\000\00\001", !1, !2, !3, !6, !2, !2} ; [ DW_TAG_compile_unit ] [foo.c] [DW_LANG_C99]<br class="">
+!1 = !{!"foo.c", !""}<br class="">
+!2 = !{}<br class="">
+!3 = !{!4}<br class="">
+!4 = !{!"0xf\00\000\0064\0064\000\000", null, null, !5} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from int]<br class="">
+!5 = !{!"0x24\00int\000\0032\0032\000\000\005", null, null} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]<br class="">
+!6 = !{!7}<br class="">
+!7 = !{!"0x2e\00foo\00foo\00\001\000\001\000\000\000\001\001", !8, !9, !10, null, void ()* @foo, null, null, !12} ; [ DW_TAG_subprogram ] [line 1] [def] [foo]<br class="">
+!8 = !{!"foo.c", !""}<br class="">
+!9 = !{!"0x29", !8} ; [ DW_TAG_file_type ]<br class="">
+!10 = !{!"0x15\00\000\000\000\000\000\000", null, null, null, !11, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]<br class="">
+!11 = !{null}<br class="">
+!12 = !{!13}<br class="">
+!13 = !{!"0x100\00a\002\000", !7, !9, !14} ; [ DW_TAG_auto_variable ] [a] [line 2]<br class="">
+!14 = !{!"0x24\00float\000\0032\0032\000\000\004", null, null} ; [ DW_TAG_base_type ] [float] [line 0, size 32, align 32, offset 0, enc DW_ATE_float]<br class="">
+!15 = !{i32 2, !"Dwarf Version", i32 2}<br class="">
+!16 = !{i32 2, !"Debug Info Version", i32 2}<br class="">
+!17 = !{i32 1, !"PIC Level", i32 2}<br class="">
+!18 = !{!"clang version 3.7.0 (trunk 227686)"}<br class="">
+!19 = !{!"0x102"} ; [ DW_TAG_expression ]<br class="">
+!20 = !MDLocation(line: 2, column: 9, scope: !7)<br class="">
+!21 = !MDLocation(line: 4, column: 1, scope: !7)<br class="">
<br class="">
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