cmd/compile: add DWARF reg defs & fix 32-bit location list bug

Before DWARF location lists can be turned on, 3 bugs need
fixing.

This CL addresses two -- lack of register definitions for
various architectures, and bugs on 32-bit platforms.
The third bug comes later.

Passes
GO_GCFLAGS=-dwarflocationlists ./run.bash -no-rebuild
(-no-rebuild because the map dependence causes trouble)

Change-Id: I4223b48ade84763e4b048e4aeb81149f082c7bc7
Reviewed-on: https://go-review.googlesource.com/99255
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

2 files changed, 35 insertions, 10 deletions

diff --git a/src/cmd/internal/obj/ppc64/a.out.go b/src/cmd/internal/obj/ppc64/a.out.go
index 87577159d5..16a959d62a 100644
--- a/src/cmd/internal/obj/ppc64/a.out.go
+++ b/src/cmd/internal/obj/ppc64/a.out.go
@@ -255,6 +255,29 @@ const (
 	FREGEXT = REG_F26 /* first external register */
 )
 
+// OpenPOWER ABI for Linux Supplement Power Architecture 64-Bit ELF V2 ABI
+// https://openpowerfoundation.org/?resource_lib=64-bit-elf-v2-abi-specification-power-architecture
+var PPC64DWARFRegisters = map[int16]int16{}
+
+func init() {
+	// f assigns dwarfregister[from:to] = (base):(to-from+base)
+	f := func(from, to, base int16) {
+		for r := int16(from); r <= to; r++ {
+			PPC64DWARFRegisters[r] = r - from + base
+		}
+	}
+	f(REG_R0, REG_R31, 0)
+	f(REG_F0, REG_F31, 32)
+	f(REG_V0, REG_V31, 77)
+	f(REG_CR0, REG_CR7, 68)
+
+	f(REG_VS0, REG_VS31, 32)  // overlaps F0-F31
+	f(REG_VS32, REG_VS63, 77) // overlaps V0-V31
+	PPC64DWARFRegisters[REG_LR] = 65
+	PPC64DWARFRegisters[REG_CTR] = 66
+	PPC64DWARFRegisters[REG_XER] = 76
+}
+
 /*
  * GENERAL:
  *
diff --git a/src/cmd/internal/obj/ppc64/obj9.go b/src/cmd/internal/obj/ppc64/obj9.go
index c468ee93a4..4982a85fdb 100644
--- a/src/cmd/internal/obj/ppc64/obj9.go
+++ b/src/cmd/internal/obj/ppc64/obj9.go
@@ -1056,17 +1056,19 @@ func (c *ctxt9) stacksplit(p *obj.Prog, framesize int32) *obj.Prog {
 }
 
 var Linkppc64 = obj.LinkArch{
-	Arch:       sys.ArchPPC64,
-	Init:       buildop,
-	Preprocess: preprocess,
-	Assemble:   span9,
-	Progedit:   progedit,
+	Arch:           sys.ArchPPC64,
+	Init:           buildop,
+	Preprocess:     preprocess,
+	Assemble:       span9,
+	Progedit:       progedit,
+	DWARFRegisters: PPC64DWARFRegisters,
 }
 
 var Linkppc64le = obj.LinkArch{
-	Arch:       sys.ArchPPC64LE,
-	Init:       buildop,
-	Preprocess: preprocess,
-	Assemble:   span9,
-	Progedit:   progedit,
+	Arch:           sys.ArchPPC64LE,
+	Init:           buildop,
+	Preprocess:     preprocess,
+	Assemble:       span9,
+	Progedit:       progedit,
+	DWARFRegisters: PPC64DWARFRegisters,
 }