Add a module Hash in the bitcode and the combined index, implementing a kind of "build-id"

This is intended to be used for ThinLTO incremental build.

Differential Revision: http://reviews.llvm.org/D18213

This is a recommit of r265095 after fixing the Windows issues.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 265111

1 files changed, 35 insertions, 0 deletions

diff --git a/llvm/test/Bitcode/module_hash.ll b/llvm/test/Bitcode/module_hash.ll
new file mode 100644
index 00000000000..fda6030a903
--- /dev/null
+++ b/llvm/test/Bitcode/module_hash.ll
@@ -0,0 +1,35 @@
+; Check per module hash.
+; RUN: llvm-as  -module-hash  %s -o - | llvm-bcanalyzer -dump | FileCheck %s --check-prefix=MOD1
+; MOD1: <HASH op0={{[0-9]*}} op1={{[0-9]*}} op2={{[0-9]*}} op3={{[0-9]*}} op4={{[0-9]*}} (match)/>
+; RUN: llvm-as  -module-hash  %p/Inputs/module_hash.ll -o - | llvm-bcanalyzer -dump | FileCheck %s --check-prefix=MOD2
+; MOD2: <HASH op0={{[0-9]*}} op1={{[0-9]*}} op2={{[0-9]*}} op3={{[0-9]*}} op4={{[0-9]*}} (match)/>
+
+; Check that the hash matches in the combined index.
+
+; First regenerate the modules with a summary
+; RUN: llvm-as  -module-hash -module-summary %s -o %t.m1.bc
+; RUN: llvm-as  -module-hash -module-summary %p/Inputs/module_hash.ll -o %t.m2.bc
+
+; Recover the hashes from the modules themselves.
+; RUN: llvm-bcanalyzer -dump %t.m1.bc | grep '<HASH'  > %t.hash
+; RUN: llvm-bcanalyzer -dump %t.m2.bc | grep '<HASH'  >> %t.hash
+
+; Generate the combined index and gather the hashes there.
+; RUN: llvm-lto --thinlto-action=thinlink -o - %t.m1.bc %t.m2.bc | llvm-bcanalyzer -dump  | grep '<HASH ' >> %t.hash
+
+; Validate the output now, the hahes in the individual modules and the combined index are in the same file.
+; RUN: cat %t.hash | FileCheck %s --check-prefix=COMBINED
+
+; First capture the value of the hash for the two modules.
+; COMBINED: <HASH op0=[[HASH1_1:[0-9]*]] op1=[[HASH1_2:[0-9]*]] op2=[[HASH1_3:[0-9]*]] op3=[[HASH1_4:[0-9]*]] op4=[[HASH1_5:[0-9]*]] (match)/>
+; COMBINED: <HASH op0=[[HASH2_1:[0-9]*]] op1=[[HASH2_2:[0-9]*]] op2=[[HASH2_3:[0-9]*]] op3=[[HASH2_4:[0-9]*]] op4=[[HASH2_5:[0-9]*]] (match)/>
+
+; Validate against the value extracted from the combined index
+; COMBINED-DAG: <HASH abbrevid={{[0-9]*}} op0=[[HASH1_1]] op1=[[HASH1_2]] op2=[[HASH1_3]] op3=[[HASH1_4]] op4=[[HASH1_5]]/>
+; COMBINED-DAG: <HASH abbrevid={{[0-9]*}} op0=[[HASH2_1]] op1=[[HASH2_2]] op2=[[HASH2_3]] op3=[[HASH2_4]] op4=[[HASH2_5]]/>
+
+
+; Need a function for the combined index to be populated.
+define void @foo() {
+    ret void
+}