InstrProf: Allow multiple functions with the same name

This updates the instrumentation based profiling format so that when
we have multiple functions with the same name (but different function
hashes) we keep all of them instead of rejecting the later ones.

There are a number of scenarios where this can come up where it's more
useful to keep multiple function profiles:

* Name collisions in unrelated libraries that are profiled together.
* Multiple "main" functions from multiple tools built against a common
  library.
* Combining profiles from different build configurations (ie, asserts
  and no-asserts)

The profile format now stores the number of counters between the hash
and the counts themselves, so that multiple sets of counts can be
stored. Since this is backwards incompatible, I've bumped the format
version and added some trivial logic to skip this when reading the old
format.

llvm-svn: 214585

3 files changed, 69 insertions, 2 deletions

diff --git a/llvm/test/tools/llvm-profdata/Inputs/compat.profdata.v1 b/llvm/test/tools/llvm-profdata/Inputs/compat.profdata.v1
new file mode 100644
index 00000000000..fd17459d091
--- /dev/null
+++ b/llvm/test/tools/llvm-profdata/Inputs/compat.profdata.v1
diff --git a/llvm/test/tools/llvm-profdata/compat.proftext b/llvm/test/tools/llvm-profdata/compat.proftext
new file mode 100644
index 00000000000..14da3374b5e
--- /dev/null
+++ b/llvm/test/tools/llvm-profdata/compat.proftext
@@ -0,0 +1,47 @@
+# Compatibility tests for older profile format versions. These ensure
+# that we don't break compatibility with an older profile version
+# without noticing it.
+
+# The input file at %S/Inputs/compat.profdata.v1 was generated with
+# llvm-profdata merge from r214548.
+
+# RUN: llvm-profdata show %S/Inputs/compat.profdata.v1 --function function_count_only --counts | FileCheck %s -check-prefix=FUNC_COUNT_ONLY
+function_count_only
+0
+1
+97531
+# FUNC_COUNT_ONLY:      Hash: 0x{{0+$}}
+# FUNC_COUNT_ONLY-NEXT: Counters: 1
+# FUNC_COUNT_ONLY-NEXT: Function count: 97531
+# FUNC_COUNT_ONLY-NEXT: Block counts: []
+
+# RUN: llvm-profdata show %S/Inputs/compat.profdata.v1 --function "name with spaces" --counts | FileCheck %s -check-prefix=SPACES
+name with spaces
+1024
+2
+0
+0
+# SPACES:      Hash: 0x{{0+}}400
+# SPACES-NEXT: Counters: 2
+# SPACES-NEXT: Function count: 0
+# SPACES-NEXT: Block counts: [0]
+
+# RUN: llvm-profdata show %S/Inputs/compat.profdata.v1 --function large_numbers --counts | FileCheck %s -check-prefix=LARGENUM
+large_numbers
+4611686018427387903
+6
+2305843009213693952
+1152921504606846976
+576460752303423488
+288230376151711744
+144115188075855872
+72057594037927936
+# LARGENUM:      Hash: 0x3fffffffffffffff
+# LARGENUM-NEXT: Counters: 6
+# LARGENUM-NEXT: Function count: 2305843009213693952
+# LARGENUM-NEXT: Block counts: [1152921504606846976, 576460752303423488, 288230376151711744, 144115188075855872, 72057594037927936]
+
+# RUN: llvm-profdata show %S/Inputs/compat.profdata.v1 | FileCheck %s -check-prefix=SUMMARY
+# SUMMARY: Total functions: 3
+# SUMMARY: Maximum function count: 2305843009213693952
+# SUMMARY: Maximum internal block count: 1152921504606846976
diff --git a/llvm/test/tools/llvm-profdata/hash-mismatch.proftext b/llvm/test/tools/llvm-profdata/hash-mismatch.proftext
index e4f1a4ca431..fe0d4fb4f6b 100644
--- a/llvm/test/tools/llvm-profdata/hash-mismatch.proftext
+++ b/llvm/test/tools/llvm-profdata/hash-mismatch.proftext
@@ -1,6 +1,18 @@
-# RUN: llvm-profdata merge %s -o %t.out 2>&1 | FileCheck %s
-# CHECK: hash-mismatch.proftext: foo: Function hash mismatch
+# If we see the same function name, but with different hashes, make
+# sure we keep both.
 
+# RUN: llvm-profdata merge %s -o %t 2>&1
+# RUN: llvm-profdata show %t -all-functions -counts > %t.out
+
+# The function ordering is non-deterministic, so we need to do our
+# checks in multiple runs.
+# RUN: FileCheck -check-prefix=FOO3 -check-prefix=BOTH %s -input-file %t.out
+# RUN: FileCheck -check-prefix=FOO4 -check-prefix=BOTH %s -input-file %t.out
+
+# FOO3: Hash: 0x{{0+}}3
+# FOO3-NEXT: Counters: 3
+# FOO3-NEXT: Function count: 1
+# FOO3-NEXT: Block counts: [2, 3]
 foo
 3
 3
@@ -8,6 +20,10 @@ foo
 2
 3
 
+# FOO4: Hash: 0x{{0+}}4
+# FOO4-NEXT: Counters: 4
+# FOO4-NEXT: Function count: 11
+# FOO4-NEXT: Block counts: [22, 33, 44]
 foo
 4
 4
@@ -15,3 +31,7 @@ foo
 22
 33
 44
+
+# BOTH: Total functions: 2
+# BOTH: Maximum function count: 11
+# BOTH: Maximum internal block count: 44