From a0f371a106f003bb6575bc8f19ab82121d8bc1c4 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Mon, 17 Apr 2017 17:51:36 +0000
Subject: Bitcode: Add a string table to the bitcode format.

Add a top-level STRTAB block containing a string table blob, and start storing
strings for module codes FUNCTION, GLOBALVAR, ALIAS, IFUNC and COMDAT in
the string table.

This change allows us to share names between globals and comdats as well
as between modules, and improves the efficiency of loading bitcode files by
no longer using a bit encoding for symbol names. Once we start writing the
irsymtab to the bitcode file we will also be able to share strings between
it and the module.

On my machine, link time for Chromium for Linux with ThinLTO decreases by
about 7% for no-op incremental builds or about 1% for full builds. Total
bitcode file size decreases by about 3%.

As discussed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2017-April/111732.html

Differential Revision: https://reviews.llvm.org/D31838

llvm-svn: 300464
---
 ...o-function-summary-callgraph-profile-summary.ll | 48 +++++++++++++++-------
 1 file changed, 33 insertions(+), 15 deletions(-)

(limited to 'llvm/test/Bitcode/thinlto-function-summary-callgraph-profile-summary.ll')

diff --git a/llvm/test/Bitcode/thinlto-function-summary-callgraph-profile-summary.ll b/llvm/test/Bitcode/thinlto-function-summary-callgraph-profile-summary.ll
index 3a5adea202e..982bb5cb7e5 100644
--- a/llvm/test/Bitcode/thinlto-function-summary-callgraph-profile-summary.ll
+++ b/llvm/test/Bitcode/thinlto-function-summary-callgraph-profile-summary.ll
@@ -6,27 +6,45 @@
 ; RUN: llvm-bcanalyzer -dump %t3.thinlto.bc | FileCheck %s --check-prefix=COMBINED
 
 
+; CHECK: <SOURCE_FILENAME
+; "hot_function"
+; CHECK-NEXT: <FUNCTION op0=0 op1=12
+; "hot1"
+; CHECK-NEXT: <FUNCTION op0=12 op1=4
+; "hot2"
+; CHECK-NEXT: <FUNCTION op0=16 op1=4
+; "hot3"
+; CHECK-NEXT: <FUNCTION op0=20 op1=4
+; "hot4"
+; CHECK-NEXT: <FUNCTION op0=24 op1=4
+; "cold"
+; CHECK-NEXT: <FUNCTION op0=28 op1=4
+; "none1"
+; CHECK-NEXT: <FUNCTION op0=32 op1=5
+; "none2"
+; CHECK-NEXT: <FUNCTION op0=37 op1=5
+; "none3"
+; CHECK-NEXT: <FUNCTION op0=42 op1=5
 ; CHECK-LABEL:       <GLOBALVAL_SUMMARY_BLOCK
 ; CHECK-NEXT:    <VERSION
-; See if the call to func is registered, using the expected callsite count
-; and profile count, with value id matching the subsequent value symbol table.
-; CHECK-NEXT:    <PERMODULE_PROFILE {{.*}} op4=[[HOT1:.*]] op5=3 op6=[[COLD:.*]] op7=1 op8=[[HOT2:.*]] op9=3 op10=[[HOT4:.*]] op11=3 op12=[[NONE1:.*]] op13=2 op14=[[HOT3:.*]] op15=3 op16=[[NONE2:.*]] op17=2 op18=[[NONE3:.*]] op19=2 op20=[[LEGACY:.*]] op21=3/>
+; CHECK-NEXT:    <VALUE_GUID op0=25 op1=123/>
+; op4=hot1 op6=cold op8=hot2 op10=hot4 op12=none1 op14=hot3 op16=none2 op18=none3 op20=123
+; CHECK-NEXT:    <PERMODULE_PROFILE {{.*}} op4=1 op5=3 op6=5 op7=1 op8=2 op9=3 op10=4 op11=3 op12=6 op13=2 op14=3 op15=3 op16=7 op17=2 op18=8 op19=2 op20=25 op21=3/>
 ; CHECK-NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
-; CHECK-LABEL:  <VALUE_SYMTAB
-; CHECK-NEXT:       <FNENTRY {{.*}} record string = 'hot_function
-; CHECK-DAG:        <ENTRY abbrevid=6 op0=[[NONE1]] {{.*}} record string = 'none1'
-; CHECK-DAG:        <ENTRY abbrevid=6 op0=[[COLD]] {{.*}} record string = 'cold'
-; CHECK-DAG:        <ENTRY abbrevid=6 op0=[[NONE2]] {{.*}} record string = 'none2'
-; CHECK-DAG:        <ENTRY abbrevid=6 op0=[[NONE3]] {{.*}} record string = 'none3'
-; CHECK-DAG:        <ENTRY abbrevid=6 op0=[[HOT1]] {{.*}} record string = 'hot1'
-; CHECK-DAG:        <ENTRY abbrevid=6 op0=[[HOT2]] {{.*}} record string = 'hot2'
-; CHECK-DAG:        <ENTRY abbrevid=6 op0=[[HOT3]] {{.*}} record string = 'hot3'
-; CHECK-DAG:        <ENTRY abbrevid=6 op0=[[HOT4]] {{.*}} record string = 'hot4'
-; CHECK-DAG:        <COMBINED_ENTRY abbrevid=11 op0=[[LEGACY]] op1=123/>
-; CHECK-LABEL:  </VALUE_SYMTAB>
+
+; CHECK: <STRTAB_BLOCK
+; CHECK-NEXT: blob data = 'hot_functionhot1hot2hot3hot4coldnone1none2none3'
 
 ; COMBINED:       <GLOBALVAL_SUMMARY_BLOCK
 ; COMBINED-NEXT:    <VERSION
+; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <VALUE_GUID
 ; COMBINED-NEXT:    <COMBINED abbrevid=
 ; COMBINED-NEXT:    <COMBINED abbrevid=
 ; COMBINED-NEXT:    <COMBINED abbrevid=
-- 
cgit v1.2.3