From 2fe076f06f988de188f77589cbd690ac4db1be33 Mon Sep 17 00:00:00 2001
From: Dan Horák <dan@danny.cz>
Date: Wed, 3 Feb 2021 12:07:56 +0100
Subject: Fix parameter passing on ppc64le (mozb#1690152)

---
 mozilla-1690152.patch | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 mozilla-1690152.patch

(limited to 'mozilla-1690152.patch')

diff --git a/mozilla-1690152.patch b/mozilla-1690152.patch
new file mode 100644
index 0000000..fb672d3
--- /dev/null
+++ b/mozilla-1690152.patch
@@ -0,0 +1,97 @@
+
+# HG changeset patch
+# User Cameron Kaiser <spectre@floodgap.com>
+# Date 1612231460 0
+# Node ID 579a66fd796690fb752485215b2edaa6167ebf16
+# Parent  a00504e040bfd34d01c74d478beb9d308ec085be
+Bug 1690152 - on ppc64 properly skip parameter slots if we overflow GPRs while still having FPRs to burn. r=tcampbell
+
+Differential Revision: https://phabricator.services.mozilla.com/D103724
+
+diff --git a/xpcom/reflect/xptcall/md/unix/xptcinvoke_ppc64_linux.cpp b/xpcom/reflect/xptcall/md/unix/xptcinvoke_ppc64_linux.cpp
+--- a/xpcom/reflect/xptcall/md/unix/xptcinvoke_ppc64_linux.cpp
++++ b/xpcom/reflect/xptcall/md/unix/xptcinvoke_ppc64_linux.cpp
+@@ -86,27 +86,37 @@ extern "C" void invoke_copy_to_stack(uin
+             case nsXPTType::T_WCHAR:  value = s->val.wc;            break;
+             default:                  value = (uint64_t) s->val.p;  break;
+             }
+         }
+ 
+         if (!s->IsIndirect() && s->type == nsXPTType::T_DOUBLE) {
+             if (nr_fpr < FPR_COUNT) {
+                 fpregs[nr_fpr++] = s->val.d;
+-                nr_gpr++;
++                // Even if we have enough FPRs, still skip space in
++                // the parameter area if we ran out of placeholder GPRs.
++                if (nr_gpr < GPR_COUNT) {
++                    nr_gpr++;
++                } else {
++                    d++;
++                }
+             } else {
+                 *((double *)d) = s->val.d;
+                 d++;
+             }
+         }
+         else if (!s->IsIndirect() && s->type == nsXPTType::T_FLOAT) {
+             if (nr_fpr < FPR_COUNT) {
+                 // Single-precision floats are passed in FPRs too.
+                 fpregs[nr_fpr++] = s->val.f;
+-                nr_gpr++;
++                if (nr_gpr < GPR_COUNT) {
++                    nr_gpr++;
++                } else {
++                    d++;
++                }
+             } else {
+ #ifdef __LITTLE_ENDIAN__
+                 *((float *)d) = s->val.f;
+ #else
+                 // Big endian needs adjustment to point to the least
+                 // significant word.
+                 float* p = (float*)d;
+                 p++;
+diff --git a/xpcom/reflect/xptcall/md/unix/xptcstubs_ppc64_linux.cpp b/xpcom/reflect/xptcall/md/unix/xptcstubs_ppc64_linux.cpp
+--- a/xpcom/reflect/xptcall/md/unix/xptcstubs_ppc64_linux.cpp
++++ b/xpcom/reflect/xptcall/md/unix/xptcstubs_ppc64_linux.cpp
+@@ -98,27 +98,37 @@ PrepareAndDispatch(nsXPTCStubBase * self
+                 nr_gpr++;
+             else
+                 ap++;
+         }
+ 
+         if (!param.IsOut() && type == nsXPTType::T_DOUBLE) {
+             if (nr_fpr < FPR_COUNT) {
+                 dp->val.d = fpregs[nr_fpr++];
+-                nr_gpr++;
++                // Even if we have enough FPRs, still skip space in
++                // the parameter area if we ran out of placeholder GPRs.
++                if (nr_gpr < GPR_COUNT) {
++                    nr_gpr++;
++                } else {
++                    ap++;
++                }
+             } else {
+                 dp->val.d = *(double*)ap++;
+             }
+             continue;
+         }
+         if (!param.IsOut() && type == nsXPTType::T_FLOAT) {
+             if (nr_fpr < FPR_COUNT) {
+                 // Single-precision floats are passed in FPRs too.
+                 dp->val.f = (float)fpregs[nr_fpr++];
+-                nr_gpr++;
++                if (nr_gpr < GPR_COUNT) {
++                    nr_gpr++;
++                } else {
++                    ap++;
++                }
+             } else {
+ #ifdef __LITTLE_ENDIAN__
+                 dp->val.f = *(float*)ap++;
+ #else
+                 // Big endian needs adjustment to point to the least
+                 // significant word.
+                 float* p = (float*)ap;
+                 p++;
+
-- 
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