Commit Graph

6 Commits

Author SHA1 Message Date
Hans Wennborg ea89ff7c25 CodeView symbol dumper: use symbolic names for registers
https://reviews.llvm.org/D38469

llvm-svn: 314690
2017-10-02 17:44:47 +00:00
Reid Kleckner 8d8888ff42 [codeview] Change readobj symbol dumping format
Avoid duplicating DictScope with hand-written names everywhere.  Print
the S_-prefixed symbol kind for every record. This should make it easier
to search for certain kinds of records when debugging PDB linking.

llvm-svn: 307732
2017-07-11 23:41:41 +00:00
Reid Kleckner b5fced7324 [codeview] Check for a DIExpression offset for local variables
Fixes inalloca parameters, which previously all pointed to the same
offset. Extend the test to use llvm-readobj so that we can test the
offset in a readable way.

llvm-svn: 302578
2017-05-09 19:59:29 +00:00
Reid Kleckner 3a363fff7e Re-land "Use the frame index side table for byval and inalloca arguments"
This re-lands r302483. It was not the cause of PR32977.

llvm-svn: 302544
2017-05-09 16:02:20 +00:00
Reid Kleckner 9f29914d40 Revert "Use the frame index side table for byval and inalloca arguments"
This reverts r302483 and it's follow up fix.

llvm-svn: 302493
2017-05-09 01:14:39 +00:00
Reid Kleckner 45efcf0c96 Use the frame index side table for byval and inalloca arguments
Summary:
For inalloca functions, this is a very common code pattern:

  %argpack = type <{ i32, i32, i32 }>
  define void @f(%argpack* inalloca %args) {
  entry:
    %a = getelementptr inbounds %argpack, %argpack* %args, i32 0, i32 0
    %b = getelementptr inbounds %argpack, %argpack* %args, i32 0, i32 1
    %c = getelementptr inbounds %argpack, %argpack* %args, i32 0, i32 2
    tail call void @llvm.dbg.declare(metadata i32* %a, ... "a")
    tail call void @llvm.dbg.declare(metadata i32* %c, ... "b")
    tail call void @llvm.dbg.declare(metadata i32* %b, ... "c")

Even though these GEPs can be simplified to a constant offset from EBP
or RSP, we don't do that at -O0, and each GEP is computed into a
register. Registers used to compute argument addresses are typically
spilled and clobbered very quickly after the initial computation, so
live debug variable tracking loses information very quickly if we use
DBG_VALUE instructions.

This change moves processing of dbg.declare between argument lowering
and basic block isel, so that we can ask if an argument has a frame
index or not. If the argument lives in a register as is the case for
byval arguments on some targets, then we don't put it in the side table
and during ISel we emit DBG_VALUE instructions.

Reviewers: aprantl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32980

llvm-svn: 302483
2017-05-08 23:20:27 +00:00