From 9d24fb7ff318d7a88f0fa3e63eb0df4acafd9805 Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc@chromium.org>
Date: Fri, 16 Jun 2017 23:59:10 +0000
Subject: [WebAssembly] Use __stack_pointer global when writing wasm binary

This ensures that symbolic relocations are generated for stack
pointer manipulations.

These relocations are of type R_WEBASSEMBLY_GLOBAL_INDEX_LEB.
This change also adds support for reading relocations of this
type in WasmObjectFile.cpp.

Since its a globally imported symbol this does mean that
the get_global/set_global instruction won't be valid until
the objects are linked that global used in no longer an
imported global.

Differential Revision: https://reviews.llvm.org/D34172

llvm-svn: 305616
---
 llvm/test/MC/WebAssembly/func-address.ll |  5 ++---
 llvm/test/MC/WebAssembly/stack-ptr.ll    | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)
 create mode 100644 llvm/test/MC/WebAssembly/stack-ptr.ll

(limited to 'llvm/test/MC/WebAssembly')

diff --git a/llvm/test/MC/WebAssembly/func-address.ll b/llvm/test/MC/WebAssembly/func-address.ll
index c0a9d9a801f..15c09e0ebd8 100644
--- a/llvm/test/MC/WebAssembly/func-address.ll
+++ b/llvm/test/MC/WebAssembly/func-address.ll
@@ -25,11 +25,10 @@ entry:
 ; CHECK:   Section {
 ; CHECK:     Type: ELEM (0x9)
 ; CHECK:     Size: 7
-; CHECK:     Offset: 165
 ; CHECK:   }
 
 ; CHECK: Relocations [
-; CHECK:   Section (9) CODE {
+; CHECK:   Section (8) CODE {
 ; CHECK:     Relocation {
 ; CHECK:       Type: R_WEBASSEMBLY_FUNCTION_INDEX_LEB (0)
 ; CHECK:       Offset: 0x4
@@ -42,7 +41,7 @@ entry:
 ; CHECK:     }
 ; CHECK:     Relocation {
 ; CHECK:       Type: R_WEBASSEMBLY_TABLE_INDEX_SLEB (1)
-; CHECK:       Offset: 0x1A
+; CHECK:       Offset: 0x1E
 ; CHECK:       Index: 0x0
 ; CHECK:     }
 ; CHECK:   }
diff --git a/llvm/test/MC/WebAssembly/stack-ptr.ll b/llvm/test/MC/WebAssembly/stack-ptr.ll
new file mode 100644
index 00000000000..98d1311e154
--- /dev/null
+++ b/llvm/test/MC/WebAssembly/stack-ptr.ll
@@ -0,0 +1,21 @@
+; RUN: llc -mtriple wasm32-unknown-unknown-wasm -filetype=obj %s -o - | obj2yaml | FileCheck %s
+
+; Function that uses explict stack, and should generate a reference to
+; __stack_pointer, along with the corresponding reloction entry.
+define hidden void @foo() #0 {
+entry:
+  alloca i32, align 4
+  ret void
+}
+
+; CHECK:  - Type:            IMPORT
+; CHECK:     Imports:
+; CHECK:       - Module:          env
+; CHECK:         Field:           __stack_pointer
+; CHECK:         Kind:            GLOBAL
+; CHECK:         GlobalType:      I32
+; CHECK:         GlobalMutable:   false
+; CHECK:   - Type:            CODE
+; CHECK:     Relocations:
+; CHECK:       - Type:            R_WEBASSEMBLY_GLOBAL_INDEX_LEB
+; CHECK:         Index:           0
-- 
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