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| author | Guinevere Larsen <blarsen@redhat.com> | 2023-11-01 17:25:32 +0100 |
|---|---|---|
| committer | Guinevere Larsen <blarsen@redhat.com> | 2024-01-02 10:21:37 +0100 |
| commit | 528b729be1a293a21f44149351f3eba5b4e2d870 (patch) | |
| tree | 3959ec9a424c769dfeffe89440fc4c6165df3916 /gdb/doc | |
| parent | b22ee0e49ba2bac8a5295f0426c62e9bd2b311a1 (diff) | |
| download | gdb-528b729be1a293a21f44149351f3eba5b4e2d870.zip gdb-528b729be1a293a21f44149351f3eba5b4e2d870.tar.gz gdb-528b729be1a293a21f44149351f3eba5b4e2d870.tar.bz2 | |
gdb/dwarf2: Add support for DW_LNS_set_epilogue_begin in line-table
This commit adds a mechanism for GDB to detect the linetable opcode
DW_LNS_set_epilogue_begin. This opcode is set by compilers to indicate
that a certain instruction marks the point where the frame is destroyed.
While the standard allows for multiple points marked with epilogue_begin
in the same function, for performance reasons, the function that
searches for the epilogue address will only find the last address that
sets this flag for a given block.
This commit also changes amd64_stack_frame_destroyed_p_1 to attempt to
use the epilogue begin directly, and only if an epilogue can't be found
will it attempt heuristics based on the current instruction.
Finally, this commit also changes the dwarf assembler to be able to emit
epilogue-begin instructions, to make it easier to test this patch
Approved-By: Tom Tromey <tom@tromey.com>
Diffstat (limited to 'gdb/doc')
| -rw-r--r-- | gdb/doc/gdb.texinfo | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 42a9123..4ada257 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -20453,25 +20453,27 @@ objfile: /home/gnu/build/a.out ((struct objfile *) 0x6120000e0d40) compunit_symtab: simple.cpp ((struct compunit_symtab *) 0x6210000ff450) symtab: /home/gnu/src/simple.cpp ((struct symtab *) 0x6210000ff4d0) linetable: ((struct linetable *) 0x62100012b760): -INDEX LINE ADDRESS IS-STMT PROLOGUE-END +INDEX LINE ADDRESS IS-STMT PROLOGUE-END EPILOGUE-BEGIN 0 3 0x0000000000401110 Y -1 4 0x0000000000401114 Y Y +1 4 0x0000000000401114 Y Y Y 2 9 0x0000000000401120 Y 3 10 0x0000000000401124 Y Y -4 10 0x0000000000401129 +4 10 0x0000000000401129 Y Y 5 15 0x0000000000401130 Y 6 16 0x0000000000401134 Y Y 7 16 0x0000000000401139 -8 21 0x0000000000401140 Y +8 21 0x0000000000401140 Y Y 9 22 0x000000000040114f Y Y -10 22 0x0000000000401154 +10 22 0x0000000000401154 Y 11 END 0x000000000040115a Y @end smallexample @noindent The @samp{IS-STMT} column indicates if the address is a recommended breakpoint location to represent a line or a statement. The @samp{PROLOGUE-END} column indicates that a given address is an adequate place to set a breakpoint at the -first instruction following a function prologue. +first instruction following a function prologue. The @samp{EPILOGUE-BEGIN} +column indicates that a given address marks the point where a block's frame is +destroyed, making local variables hard or impossible to find. @kindex set always-read-ctf [on|off] @kindex show always-read-ctf |