Mips16 is really a processor decoding mode (ala thumb 1) and in the same
program, mips16 and mips32 functions can exist and can call each other.
If a jal type instruction encounters an address with the lower bit set, then
the processor switches to mips16 mode (if it is not already in it). If the
lower bit is not set, then it switches to mips32 mode.
The linker knows which functions are mips16 and which are mips32.
When relocation is performed on code labels, this lower order bit is
set if the code label is a mips16 code label.
In general this works just fine, however when creating exception handling
tables and dwarf, there are cases where you don't want this lower order
bit added in.
This has been traditionally distinguished in gas assembly source by using a
different syntax for the label.
lab1: ; this will cause the lower order bit to be added
lab2=. ; this will not cause the lower order bit to be added
In some cases, it does not matter because in dwarf and debug tables
the difference of two labels is used and in that case the lower order
bits subtract each other out.
To fix this, I have added to mcstreamer the notion of a debuglabel.
The default is for label and debug label to be the same. So calling
EmitLabel and EmitDebugLabel produce the same result.
For various reasons, there is only one set of labels that needs to be
modified for the mips exceptions to work. These are the "$eh_func_beginXXX"
labels.
Mips overrides the debug label suffix from ":" to "=." .
This initial patch fixes exceptions. More changes most likely
will be needed to DwarfCFException to make all of this work
for actual debugging. These changes will be to emit debug labels in some
places where a simple label is emitted now.
Some historical discussion on this from gcc can be found at:
http://gcc.gnu.org/ml/gcc-patches/2008-08/msg00623.htmlhttp://gcc.gnu.org/ml/gcc-patches/2008-11/msg01273.html
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controls each of the abbreviation sets (only a single one at the
moment) and computes offsets separately as well for each set
of DIEs.
No real function change, ordering of abbreviations for the skeleton
CU changed but only because we're computing in a separate order. Fix
the testcase not to care.
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InitSections is called before the MCContext is initialized it could cause
duplicate temporary symbols to be emitted later (after context initialization
resets the temporary label counter).
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Some languages, e.g. Ada and Pascal, allow you to specify that the array bounds
are different from the default (1 in these cases). If we have a lower bound
that's non-default, then we emit the lower bound. We also calculate the correct
upper bound in those cases.
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The count attribute is more accurate with regards to the size of an array. It
also obviates the upper bound attribute in the subrange. We can also better
handle an unbound array by setting the count to -1 instead of the lower bound to
1 and upper bound to 0.
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This reapplies the fix for PR13303 now with more justification. Based on my
execution of the GDB 7.5 test suite this results in:
expected passes: 16101 -> 20890 (+30%)
unexpected failures: 4826 -> 637 (-77%)
There are 23 checks that used to pass and now fail. They are all in
gdb.reverse. Investigating a few looks like they were accidentally passing
due to extra breakpoints being set by this bug. They're generally due to the
difference in end location between gcc and clang, the test suite is trying to
set breakpoints on the closing '}' that clang doesn't associate with any
instructions.
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missed in the first pass because the script didn't yet handle include
guards.
Note that the script is now able to handle all of these headers without
manual edits. =]
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The count field is necessary because there isn't a difference between the 'lo'
and 'hi' attributes for a one-element array and a zero-element array. When the
count is '0', we know that this is a zero-element array. When it's >=1, then
it's a normal constant sized array. When it's -1, then the array is unbounded.
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Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
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part of the compile unit CU and start separating out information into
the various sections that will be pulled out later.
WIP.
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argument. Instead, use a pair of .local and .comm directives.
This avoids spurious differences between binaries built by the
integrated assembler vs. those built by the external assembler,
since the external assembler may impose alignment requirements
on .lcomm symbols where the integrated assembler does not.
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