<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Aug 31, 2015 at 9:05 AM, David Blaikie <span dir="ltr"><<a href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@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 dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote"><span class="">On Sun, Aug 30, 2015 at 6:43 PM, Frederic Riss via llvm-commits <span dir="ltr"><<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: friss<br>
Date: Sun Aug 30 20:43:14 2015<br>
New Revision: 246406<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=246406&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project?rev=246406&view=rev</a><br>
Log:<br>
[dsymutil] Fix handling of inlined_subprogram low_pcs<br>
<br>
The value of an inlined subprogram low_pc attribute should not<br>
get relocated, but it can happen that it matches the enclosing<br>
function's start address and thus gets the generic treatment.<br>
Special case it to avoid applying the PC offset twice.<br></blockquote></span><div><br>I'm a tad confused - do you store the low_pcs as offsets relative to the function<br></div></div></div></div></blockquote><div><br>(sorry, bouncy shuttle to work & accidentally sent before I finished that sentence...)<br><br>do you store the low_pcs as offsets relative to the function's low_pc? That's interesting - and perhaps something we should standardize/generalize to reduce relocations in all our DWARF output (but I don't think there's any standard for it yet in DWARF), but I'm not sure why that would require special casing the case where the two low_pcs are equal - wouldn't that just mean the low_pc of the inlined subroutine would be at zero offset from the subprogram's low_pc? (& still not relocated)</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div> </div><div><div class="h5"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Added:<br>
llvm/trunk/test/tools/dsymutil/ARM/dummy-debug-map-amr64.map<br>
llvm/trunk/test/tools/dsymutil/ARM/inlined-low_pc.c<br>
llvm/trunk/test/tools/dsymutil/Inputs/inlined-low_pc/<br>
llvm/trunk/test/tools/dsymutil/Inputs/inlined-low_pc/1.o<br>
Modified:<br>
llvm/trunk/test/tools/dsymutil/ARM/lit.local.cfg<br>
llvm/trunk/tools/dsymutil/DwarfLinker.cpp<br>
<br>
Added: llvm/trunk/test/tools/dsymutil/ARM/dummy-debug-map-amr64.map<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/dsymutil/ARM/dummy-debug-map-amr64.map?rev=246406&view=auto" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/dsymutil/ARM/dummy-debug-map-amr64.map?rev=246406&view=auto</a><br>
==============================================================================<br>
--- llvm/trunk/test/tools/dsymutil/ARM/dummy-debug-map-amr64.map (added)<br>
+++ llvm/trunk/test/tools/dsymutil/ARM/dummy-debug-map-amr64.map Sun Aug 30 20:43:14 2015<br>
@@ -0,0 +1,15 @@<br>
+# This is a dummy debug map used for some tests where the contents of the<br>
+# map are just an implementation detail. The tests wanting to use that file<br>
+# should put all there object files in an explicitely named sub-directory<br>
+# of Inputs, and they should be named 1.o, 2.o, ...<br>
+# As not finding an object file or symbols isn't a fatal error for dsymutil,<br>
+# you can extend this file with as much object files and symbols as needed.<br>
+<br>
+---<br>
+triple: 'arm64-apple-darwin'<br>
+objects:<br>
+ - filename: 1.o<br>
+ symbols:<br>
+ - { sym: _bar, objAddr: 0x0, binAddr: 0x10000, size: 0x10 }<br>
+...<br>
+<br>
<br>
Added: llvm/trunk/test/tools/dsymutil/ARM/inlined-low_pc.c<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/dsymutil/ARM/inlined-low_pc.c?rev=246406&view=auto" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/dsymutil/ARM/inlined-low_pc.c?rev=246406&view=auto</a><br>
==============================================================================<br>
--- llvm/trunk/test/tools/dsymutil/ARM/inlined-low_pc.c (added)<br>
+++ llvm/trunk/test/tools/dsymutil/ARM/inlined-low_pc.c Sun Aug 30 20:43:14 2015<br>
@@ -0,0 +1,15 @@<br>
+/* Compiled with: clang -arch=arm64 -O2 -g -c inlined_low_pc.c */<br>
+<br>
+static int foo(int i) { return 42 + i; }<br>
+int bar(int a) { return foo(a); }<br>
+<br>
+// RUN: llvm-dsymutil -f -y %p/dummy-debug-map-amr64.map -oso-prepend-path %p/../Inputs/inlined-low_pc -o - | llvm-dwarfdump - | FileCheck %s<br>
+<br>
+// CHECK: DW_TAG_subprogram<br>
+// CHECK: DW_AT_low_pc{{.*}}0x0000000000010000<br>
+// CHECK: DW_AT_name{{.*}}"bar"<br>
+// CHECK-NOT: NULL<br>
+// CHECK: DW_TAG_inlined_subroutine<br>
+// CHECK-NEXT: DW_AT_abstract_origin{{.*}}"foo"<br>
+// CHECK-NEXT: DW_AT_low_pc{{.*}}0x0000000000010000<br>
+<br>
<br>
Modified: llvm/trunk/test/tools/dsymutil/ARM/lit.local.cfg<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/dsymutil/ARM/lit.local.cfg?rev=246406&r1=246405&r2=246406&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/dsymutil/ARM/lit.local.cfg?rev=246406&r1=246405&r2=246406&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/test/tools/dsymutil/ARM/lit.local.cfg (original)<br>
+++ llvm/trunk/test/tools/dsymutil/ARM/lit.local.cfg Sun Aug 30 20:43:14 2015<br>
@@ -2,3 +2,6 @@ if not 'ARM' in config.root.targets:<br>
config.unsupported = True<br>
if not 'AArch64' in config.root.targets:<br>
config.unsupported = True<br>
+<br>
+config.suffixes = ['.test', '.cpp', '.c']<br>
+<br>
<br>
Added: llvm/trunk/test/tools/dsymutil/Inputs/inlined-low_pc/1.o<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/dsymutil/Inputs/inlined-low_pc/1.o?rev=246406&view=auto" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/dsymutil/Inputs/inlined-low_pc/1.o?rev=246406&view=auto</a><br>
==============================================================================<br>
Binary files llvm/trunk/test/tools/dsymutil/Inputs/inlined-low_pc/1.o (added) and llvm/trunk/test/tools/dsymutil/Inputs/inlined-low_pc/1.o Sun Aug 30 20:43:14 2015 differ<br>
<br>
Modified: llvm/trunk/tools/dsymutil/DwarfLinker.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/dsymutil/DwarfLinker.cpp?rev=246406&r1=246405&r2=246406&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/dsymutil/DwarfLinker.cpp?rev=246406&r1=246405&r2=246406&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/tools/dsymutil/DwarfLinker.cpp (original)<br>
+++ llvm/trunk/tools/dsymutil/DwarfLinker.cpp Sun Aug 30 20:43:14 2015<br>
@@ -1206,6 +1206,7 @@ private:<br>
const char *Name, *MangledName; ///< Names.<br>
uint32_t NameOffset, MangledNameOffset; ///< Offsets in the string pool.<br>
<br>
+ uint64_t OrigLowPc; ///< Value of AT_low_pc in the input DIE<br>
uint64_t OrigHighPc; ///< Value of AT_high_pc in the input DIE<br>
int64_t PCOffset; ///< Offset to apply to PC addresses inside a function.<br>
<br>
@@ -1214,8 +1215,8 @@ private:<br>
<br>
AttributesInfo()<br>
: Name(nullptr), MangledName(nullptr), NameOffset(0),<br>
- MangledNameOffset(0), OrigHighPc(0), PCOffset(0), HasLowPc(false),<br>
- IsDeclaration(false) {}<br>
+ MangledNameOffset(0), OrigLowPc(UINT64_MAX), OrigHighPc(0),<br>
+ PCOffset(0), HasLowPc(false), IsDeclaration(false) {}<br>
};<br>
<br>
/// \brief Helper for cloneDIE.<br>
@@ -2274,7 +2275,12 @@ unsigned DwarfLinker::cloneAddressAttrib<br>
if (AttrSpec.Attr == dwarf::DW_AT_low_pc) {<br>
if (Die.getTag() == dwarf::DW_TAG_inlined_subroutine ||<br>
Die.getTag() == dwarf::DW_TAG_lexical_block)<br>
- Addr += Info.PCOffset;<br>
+ // The low_pc of a block or inline subroutine might get<br>
+ // relocated because it happens to match the low_pc of the<br>
+ // enclosing subprogram. To prevent issues with that, always use<br>
+ // the low_pc from the input DIE if relocations have been applied.<br>
+ Addr = (Info.OrigLowPc != UINT64_MAX ? Info.OrigLowPc : Addr) +<br>
+ Info.PCOffset;<br>
else if (Die.getTag() == dwarf::DW_TAG_compile_unit) {<br>
Addr = Unit.getLowPc();<br>
if (Addr == UINT64_MAX)<br>
@@ -2522,6 +2528,11 @@ DIE *DwarfLinker::cloneDIE(const DWARFDe<br>
// high_pc value is done in cloneAddressAttribute().<br>
AttrInfo.OrigHighPc =<br>
InputDIE.getAttributeValueAsAddress(&U, dwarf::DW_AT_high_pc, 0);<br>
+ // Also store the low_pc. It might get relocated in an<br>
+ // inline_subprogram that happens at the beginning of its<br>
+ // inlining function.<br>
+ AttrInfo.OrigLowPc =<br>
+ InputDIE.getAttributeValueAsAddress(&U, dwarf::DW_AT_low_pc, UINT64_MAX);<br>
}<br>
<br>
// Reset the Offset to 0 as we will be working on the local copy of<br>
<br>
<br>
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</blockquote></div></div></div><br></div></div>
</blockquote></div><br></div></div>