Initial skeleton of Subzero.

This includes just enough code to build the high-level ICE IR and dump it back out again.  There is a script szdiff.py that does a fuzzy diff of the input and output for verification.  See the comment in szdiff.py for a description of the fuzziness.

Building llvm2ice requires LLVM headers, libs, and tools (e.g. FileCheck) to be present.  These default to something like llvm_i686_linux_work/Release+Asserts/ based on the checked-out and built pnacl-llvm code; I'll try to figure out how to more automatically detect the build configuration.

"make check" runs the lit tests.

This CL has under 2000 lines of "interesting" Ice*.{h,cpp} code, plus 600 lines of llvm2ice.cpp driver code, and the rest is tests.

Here is the high-level mapping of source files to functionality:

IceDefs.h, IceTypes.h, IceTypes.cpp:
Commonly used types and utilities.

IceCfg.h, IceCfg.cpp:
Operations at the function level.

IceCfgNode.h, IceCfgNode.cpp:
Operations on basic blocks (nodes).

IceInst.h, IceInst.cpp:
Operations on instructions.

IceOperand.h, IceOperand.cpp:
Operations on operands, such as stack locations, physical registers, and constants.

BUG= none
R=jfb@chromium.org

Review URL: https://codereview.chromium.org/205613002

tests_lit/llvm2ice_tests/arith-opt.ll

diff --git a/tests_lit/llvm2ice_tests/arith-opt.ll b/tests_lit/llvm2ice_tests/arith-opt.ll
new file mode 100644
index 0000000..becbc9f
--- /dev/null
+++ b/tests_lit/llvm2ice_tests/arith-opt.ll
@@ -0,0 +1,110 @@
+; RUIN: %llvm2ice -verbose inst %s | FileCheck %s
+; RUIN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
+; RUN: %szdiff --llvm2ice=%llvm2ice %s | FileCheck --check-prefix=DUMP %s
+
+define i32 @Add(i32 %a, i32 %b) {
+; CHECK: define i32 @Add
+entry:
+  %add = add i32 %b, %a
+; CHECK: add
+  tail call void @Use(i32 %add)
+; CHECK: call Use
+  ret i32 %add
+}
+
+declare void @Use(i32)
+
+define i32 @And(i32 %a, i32 %b) {
+; CHECK: define i32 @And
+entry:
+  %and = and i32 %b, %a
+; CHECK: and
+  tail call void @Use(i32 %and)
+; CHECK: call Use
+  ret i32 %and
+}
+
+define i32 @Or(i32 %a, i32 %b) {
+; CHECK: define i32 @Or
+entry:
+  %or = or i32 %b, %a
+; CHECK: or
+  tail call void @Use(i32 %or)
+; CHECK: call Use
+  ret i32 %or
+}
+
+define i32 @Xor(i32 %a, i32 %b) {
+; CHECK: define i32 @Xor
+entry:
+  %xor = xor i32 %b, %a
+; CHECK: xor
+  tail call void @Use(i32 %xor)
+; CHECK: call Use
+  ret i32 %xor
+}
+
+define i32 @Sub(i32 %a, i32 %b) {
+; CHECK: define i32 @Sub
+entry:
+  %sub = sub i32 %a, %b
+; CHECK: sub
+  tail call void @Use(i32 %sub)
+; CHECK: call Use
+  ret i32 %sub
+}
+
+define i32 @Mul(i32 %a, i32 %b) {
+; CHECK: define i32 @Mul
+entry:
+  %mul = mul i32 %b, %a
+; CHECK: imul
+  tail call void @Use(i32 %mul)
+; CHECK: call Use
+  ret i32 %mul
+}
+
+define i32 @Sdiv(i32 %a, i32 %b) {
+; CHECK: define i32 @Sdiv
+entry:
+  %div = sdiv i32 %a, %b
+; CHECK: cdq
+; CHECK: idiv
+  tail call void @Use(i32 %div)
+; CHECK: call Use
+  ret i32 %div
+}
+
+define i32 @Srem(i32 %a, i32 %b) {
+; CHECK: define i32 @Srem
+entry:
+  %rem = srem i32 %a, %b
+; CHECK: cdq
+; CHECK: idiv
+  tail call void @Use(i32 %rem)
+; CHECK: call Use
+  ret i32 %rem
+}
+
+define i32 @Udiv(i32 %a, i32 %b) {
+; CHECK: define i32 @Udiv
+entry:
+  %div = udiv i32 %a, %b
+; CHECK: div
+  tail call void @Use(i32 %div)
+; CHECK: call Use
+  ret i32 %div
+}
+
+define i32 @Urem(i32 %a, i32 %b) {
+; CHECK: define i32 @Urem
+entry:
+  %rem = urem i32 %a, %b
+; CHECK: div
+  tail call void @Use(i32 %rem)
+; CHECK: call Use
+  ret i32 %rem
+}
+
+; ERRORS-NOT: ICE translation error
+; DUMP-NOT: SZ