llvm-project/llvm/test/CodeGen/MIR
Reid Kleckner 9ea2c01264 [codeview] Emit S_FRAMEPROC and use S_DEFRANGE_FRAMEPOINTER_REL
Summary:
Before this change, LLVM would always describe locals on the stack as
being relative to some specific register, RSP, ESP, EBP, ESI, etc.
Variables in stack memory are pretty common, so there is a special
S_DEFRANGE_FRAMEPOINTER_REL symbol for them. This change uses it to
reduce the size of our debug info.

On top of the size savings, there are cases on 32-bit x86 where local
variables are addressed from ESP, but ESP changes across the function.
Unlike in DWARF, there is no FPO data to describe the stack adjustments
made to push arguments onto the stack and pop them off after the call,
which makes it hard for the debugger to find the local variables in
frames further up the stack.

To handle this, CodeView has a special VFRAME register, which
corresponds to the $T0 variable set by our FPO data in 32-bit.  Offsets
to local variables are instead relative to this value.

This is part of PR38857.

Reviewers: hans, zturner, javed.absar

Subscribers: aprantl, hiraditya, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D52217

llvm-svn: 343543
2018-10-01 21:59:45 +00:00
..
AArch64 Revert r343317 2018-09-28 17:01:50 +00:00
AMDGPU AMDGPU: Fix tests using old number for constant address space 2018-09-10 02:54:25 +00:00
ARM Followup on Proposal to move MIR physical register namespace to '$' sigil. 2018-01-31 22:04:26 +00:00
Generic [codeview] Emit S_FRAMEPROC and use S_DEFRANGE_FRAMEPOINTER_REL 2018-10-01 21:59:45 +00:00
Hexagon Followup on Proposal to move MIR physical register namespace to '$' sigil. 2018-01-31 22:04:26 +00:00
Mips Followup on Proposal to move MIR physical register namespace to '$' sigil. 2018-01-31 22:04:26 +00:00
NVPTX [MIR] Repurposing '$' sigil used by external symbols. Replacing with '&'. 2018-01-10 00:56:48 +00:00
PowerPC [if-converter] Handle BBs that terminate in ret during diamond conversion 2018-04-19 17:26:46 +00:00
WebAssembly [MIRParser][GlobalISel] Parsing vector pointer types (<M x pA>) 2018-05-08 02:02:50 +00:00
X86 [codeview] Emit S_FRAMEPROC and use S_DEFRANGE_FRAMEPOINTER_REL 2018-10-01 21:59:45 +00:00
README Add README describing the intention of test/CodeGen/MIR 2016-12-09 20:16:12 +00:00

README

This directory contains tests for the MIR file format parser and printer. It
was necessary to split the tests across different targets as no single target
covers all features available in machine IR.

Tests for codegen passes should NOT be here but in test/CodeGen/sometarget. As
a rule of thumb this directory should only contain tests using
'llc -run-pass none'.