search for: highpc

...nally I'd vote for -1, and make pre-v5 .debug_loc/.debug_ranges >sections be an extra-special case using -2. We can (I hope) standardize >on -1 for v6 onward, and document -1/-2 on the DWARF wiki as recommended >practice for prior versions. Would it make sense to use "LowPC > HighPC" in DWARF documentation as a sign for that case, instead of -1 or -2 ? Or more correct: To indicate that address range points into deleted code there should be used either zero length, either LowPC>HighPc range ? zero length address range is already defined in DWARF documentation. LowPC&...

...;s explicitly invalid" and -2 (max - 1) seems to be about the right thing. > > So it looks like following solution could fix both problems and be > relatively fast: > > "Resolve all relocations from debug sections into dead code to 1. Parse > debug sections and replace HighPc of an address range pointing to dead code > and specified as length to 1". > That second part seems pretty expensive compared to anything else the linker is doing with debug info. I'd try to avoid it if at all possible. > As the result all address ranges pointing into dead code...

...@ -61,6 +61,7 @@ + static char sccsid[] = "@(#)gmon.c 5.3 (Berkeley) 5/22/91"; + #endif /* not lint */ + ++#include <string.h> + #define DEBUG + #ifdef DEBUG + #include <stdio.h> +@@ -89,7 +90,7 @@ static int s_scale; + + extern int errno; + +-int ++void + monstartup(lowpc, highpc) + char *lowpc; + char *highpc; +@@ -341,6 +342,7 @@ overflow: + * profiling is what mcount checks to see if + * all the data structures are ready. + */ ++void + moncontrol(mode) + int mode; + {

So there have been several recent discussions about the issues around DWARF-agnostic linking and gc-sections, linkonce function definitions being dropped, etc - and just how much DWARF-awareness would be suitable in a linker to help with this situation. I'd like to discuss a narrower instance of this issue: Zero length gc'd/deduplicated functions. LLVM seems to at least produce zero

.... 4. split DWARF support. This solution does not work with split DWARF currently. But it could be useful for the split dwarf in two ways: a) The generation of skeleton file could be changed in such a way that address ranges pointing to garbage collected code would be replaced with lowpc=0, highpc=0. That would solve the problem of overlapping address ranges(D59553). b) The approach similar to dsymutil implementation could be used to generate monolithic debuginfo created from .dwo files. That suggestion is from - https://reviews.llvm.org/D74169#1888386. i.e., DWARFLinker could be t...

...j0KUKE70_57b4_rsj1TN0qB8NpBvVKtY63PsubKJQ$> >> . >> >> So it looks like following solution could fix both problems and be >> relatively fast: >> >> "Resolve all relocations from debug sections into dead code to 1. Parse >> debug sections and replace HighPc of an address range pointing to dead code >> and specified as length to 1". >> >> As the result all address ranges pointing into dead code would be marked >> as zero length. >> >> There still exist another problem: >> >> DWARF4: "A range lis...

...>> This solution does not work with split DWARF currently. But it could be useful for the split dwarf in two ways: >> a) The generation of skeleton file could be changed in such a way that address ranges pointing to garbage >> collected code would be replaced with lowpc=0, highpc=0. That would solve the problem of overlapping >> address ranges(D59553). >This wouldn't/couldn't completely address the issue - because some address ranges would be in the .dwo files >the linker can't see - and they'd still end up with the interesting address ranges....

...May/141599.html__;!!JmoZiZGBv3RvKRSx!r2Jqc2yEgxrb2QcQEocDHJBizj0KUKE70_57b4_rsj1TN0qB8NpBvVKtY63PsubKJQ$>. So it looks like following solution could fix both problems and be relatively fast: "Resolve all relocations from debug sections into dead code to 1. Parse debug sections and replace HighPc of an address range pointing to dead code and specified as length to 1". As the result all address ranges pointing into dead code would be marked as zero length. There still exist another problem: DWARF4: "A range list entry (but not a base address selection or end of list entry) whose...

...non-split) to signal certain addresses point to dead code with a > specific blessed value that linkers would need to implement - because with Split DWARF there's > no way to solve the non-CU addresses at the linker. I think the worthful solution for that signal value would be LowPC > HighPC. That does not require additional bits in DWARF. It would be natural to skip such address ranges since they explicitly marked as invalid. It could be implemented in a linker very easily. Probably, it would make sense to describe that usage in DWARF standard. As to the addresses which are not seen...

...dead code with a > > > specific blessed value that linkers would need to implement - because > with Split DWARF there's > > > no way to solve the non-CU addresses at the linker. > > > > I think the worthful solution for that signal value would be LowPC > > HighPC. > > That does not require additional bits in DWARF. > > It would be natural to skip such address ranges since they explicitly > marked as invalid. > > It could be implemented in a linker very easily. Probably, it would make > sense to describe that > > usage in DWARF...

...sed value that linkers would need to implement - because > >> with Split DWARF there's > >> > > no way to solve the non-CU addresses at the linker. > >> > > >> > I think the worthful solution for that signal value would be LowPC > > >> HighPC. > >> > That does not require additional bits in DWARF. > >> > It would be natural to skip such address ranges since they explicitly > >> marked as invalid. > >> > It could be implemented in a linker very easily. Probably, it would make > >> sen...

...t; > >> > > >> So it looks like following solution could fix both problems and be > > >> relatively fast: > > >> > > >> "Resolve all relocations from debug sections into dead code to 1. Parse > > >> debug sections and replace HighPc of an address range pointing to dead > > code > > >> and specified as length to 1". > > >> > > >> As the result all address ranges pointing into dead code would be > > marked > > >> as zero length. > > >> > > >&gt...

...ke following solution could fix both problems and be > > > > >> relatively fast: > > > > >> > > > > >> "Resolve all relocations from debug sections into dead code to 1. > > Parse > > > > >> debug sections and replace HighPc of an address range pointing to > > dead > > > > code > > > > >> and specified as length to 1". > > > > >> > > > > >> As the result all address ranges pointing into dead code would be > > > > marked > > &...

...al certain addresses point to dead code with a > > specific blessed value that linkers would need to implement - because with Split DWARF there's > > no way to solve the non-CU addresses at the linker. > > I think the worthful solution for that signal value would be LowPC > HighPC. > That does not require additional bits in DWARF. > It would be natural to skip such address ranges since they explicitly marked as invalid. > It could be implemented in a linker very easily. Probably, it would make sense to describe that > usage in DWARF standard. > > As to the...

...and be > >> > > > >> relatively fast: > >> > > > >> > >> > > > >> "Resolve all relocations from debug sections into dead code to 1. > >> > Parse > >> > > > >> debug sections and replace HighPc of an address range pointing to > >> > dead > >> > > > code > >> > > > >> and specified as length to 1". > >> > > > >> > >> > > > >> As the result all address ranges pointing into dead code wo...

...point to dead code with a > > > specific blessed value that linkers would need to implement - because with Split DWARF there's > > > no way to solve the non-CU addresses at the linker. > > > > I think the worthful solution for that signal value would be LowPC > HighPC. > > That does not require additional bits in DWARF. > > It would be natural to skip such address ranges since they explicitly marked as invalid. > > It could be implemented in a linker very easily. Probably, it would make sense to describe that > > usage in DWARF standard....

...point to dead code with a > > > specific blessed value that linkers would need to implement - because with Split DWARF there's > > > no way to solve the non-CU addresses at the linker. > > > > I think the worthful solution for that signal value would be LowPC > HighPC. > > That does not require additional bits in DWARF. > > It would be natural to skip such address ranges since they explicitly marked as invalid. > > It could be implemented in a linker very easily. Probably, it would make sense to describe that > > usage in DWARF standard....

...with a > > > > specific blessed value that linkers would need to implement - because with Split DWARF there's > > > > no way to solve the non-CU addresses at the linker. > > > > > > I think the worthful solution for that signal value would be LowPC > HighPC. > > > That does not require additional bits in DWARF. > > > It would be natural to skip such address ranges since they explicitly marked as invalid. > > > It could be implemented in a linker very easily. Probably, it would make sense to describe that > > > usage...

...; > > specific blessed value that linkers would need to implement - because with Split DWARF there's > > > > > no way to solve the non-CU addresses at the linker. > > > > > > > > I think the worthful solution for that signal value would be LowPC > HighPC. > > > > That does not require additional bits in DWARF. > > > > It would be natural to skip such address ranges since they explicitly marked as invalid. > > > > It could be implemented in a linker very easily. Probably, it would make sense to describe that >...

...cific blessed value that linkers would need to implement - because with Split DWARF there's > > > > > > no way to solve the non-CU addresses at the linker. > > > > > > > > > > I think the worthful solution for that signal value would be LowPC > HighPC. > > > > > That does not require additional bits in DWARF. > > > > > It would be natural to skip such address ranges since they explicitly marked as invalid. > > > > > It could be implemented in a linker very easily. Probably, it would make sense to desc...